Tagged: EarthSky Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 4:20 pm on January 31, 2023 Permalink | Reply
    Tags: "Lucy spacecraft to visit an asteroid this year", A new target added to its mission: the tiny asteroid (152830) 1999 VD57, , , , , , EarthSky, , Lucy’s original plan was to visit the main-belt asteroid (52246) Donaldjohanson in 2025 followed by a tour of nine Trojan asteroids starting in 2033., , The new target will be a good test for the spacecraft’s inventive tracking system.   

    From “EarthSky” And The National Aeronautics and Space Administration : “Lucy spacecraft to visit an asteroid this year” 

    1

    From “EarthSky”

    And

    The National Aeronautics and Space Administration

    1.31.23
    Kelly Kizer Whitt

    NASA’s Lucy spacecraft is in the midst of three Earth flybys that ultimately will fling it to the main asteroid belt and Jupiter’s Trojan asteroids. In October 2022, a year after the spacecraft’s launch, Lucy made its first flyby of Earth. On January 24, 2023, Lucy’s team added a new target to its mission: the tiny asteroid (152830) 1999 VD57. With a small maneuver, Lucy will be able to get a close look at this asteroid by late 2023, two years ahead of its originally planned rendezvous with a main-belt asteroid.

    On November 1, 2023, Lucy will swing past the still-unnamed (152830) 1999 VD57. To get there, engineers will begin a series of small maneuvers in May 2023. As a bonus, the detour allows scientists to conduct an engineering test of the spacecraft’s asteroid-tracking navigation system.

    Finding the new target

    Lucy’s original plan was to visit the main-belt asteroid (52246) Donaldjohanson in 2025, followed by a tour of nine Trojan asteroids starting in 2033. But the team found a small, conveniently located asteroid that Lucy could visit between its first and second gravity assists from Earth. Raphael Marschall of the Nice Observatory in France identified asteroid 1999 VD57, which is just 0.4 miles (700 m) in size. Marschall said:

    “There are millions of asteroids in the main asteroid belt. I selected 500,000 asteroids with well-defined orbits to see if Lucy might be traveling close enough to get a good look at any of them, even from a distance. This asteroid really stood out. Lucy’s trajectory as originally designed will take it within 40,000 miles of the asteroid, at least three times closer than the next closest asteroid.”

    With a slight change of plans and direction, the team now can bring Lucy even closer to the asteroid. From the original distance of 40,000 miles, Lucy will now buzz by at 280 miles (450 km) distant.

    A tracking-system test for the Lucy spacecraft

    The new target will be a good test for the spacecraft’s inventive tracking system. Engineers created the new system to solve a long-standing problem for flyby missions. Previously, it’s been difficult to determine just how far a spacecraft is from an asteroid. In addition, that makes it hard to know exactly where to point the cameras. Hal Levison, Lucy principal investigator from the Southwest Research Institute, said:

    “In the past, most flyby missions have accounted for this uncertainty by taking a lot of images of the region where the asteroid might be, meaning low efficiency and lots of images of blank space. Lucy will be the first flyby mission to employ this innovative and complex system to automatically track the asteroid during the encounter. This novel system will allow the team to take many more images of the target.”

    The advantages of 1999 VD57

    The little asteroid 1999 VD57 will be a great proving ground for the new procedure. The angle at which Lucy will approach the asteroid relative to the sun will be similar to the Trojan asteroid encounters. Therefore, the scientists will get to practice under similar conditions years before the main event.

    3
    When the Lucy spacecraft reaches the inner edge of the main asteroid belt in fall 2023, it will fly by the small, still-unnamed asteroid (152830) 1999 VD57. This artist’s concept shows an overhead view of Lucy’s path through the inner solar system around November 1, 2023. Image via NASA’s Goddard Space Flight Center.

    See the full article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra,
    Spitzer and associated programs, and now the NASA/ESA/CSA James Webb Space Telescope. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
  • richardmitnick 12:27 am on January 28, 2023 Permalink | Reply
    Tags: "What is the Milky Way? It’s our home galaxy", , , , , EarthSky,   

    From “EarthSky” : “What is the Milky Way? It’s our home galaxy” 

    1

    From “EarthSky”

    1.27.23
    Andy Briggs

    1
    Amr Abdulwahab captured this image of the Milky Way on July 8, 2022, from Sahara el Beyda, the White Desert Protected Area, a national park in Egypt.

    Do you think of the Milky Way as a starry band across a dark night sky? Or do you think of it as a great spiral galaxy in space? Both are correct. Both refer to our home galaxy, our local island in the vast ocean of the universe, composed of hundreds of billions of stars, one of which is our sun.

    Long ago, it was possible for everybody in the world to see a dark, star-strewn sky when they looked heavenward at night. In those ancient times, humans looked to the starry sky and saw a ghostly band of light arcing from horizon to horizon. This graceful arc of light moved across the sky with the seasons. The most casual sky-watchers could notice that darkness obscured parts of the band, which we now know to be vast clouds of dust.

    Myths of the Milky Way

    Myths and legends grew up in different cultures around this mysterious apparition in the heavens. Each culture explained this band of light in the sky according to its own beliefs. To the ancient Armenians, it was straw strewn across the sky by the god Vahagn. In eastern Asia, it was the Silvery River of Heaven. The Finns and Estonians saw it as the Pathway of the Birds.

    Meanwhile, because ancient Greek and Roman legends and myths came to dominate western culture, it was their interpretations that were passed down to a majority of languages. Both the Greeks and the Romans saw the starry band as a river of milk. The Greek myth said it was milk from the breast of the goddess Hera, divine wife of Zeus. The Romans saw the river of light as milk from their goddess Ops.

    Thus it was bequeathed the name by which, today, we know that ghostly arc stretching across the sky: the “Milky Way”.

    2
    William Mathe captured this image on August 15, 2020, at the top of Rocky Mountain National Park in Colorado.

    Observing the river of stars

    When you are standing under a completely dark, starry sky, away from light pollution, the Milky Way appears like a cloud across the cosmos. But that cloud betrays no clue as to what it actually is. Until the invention of the telescope, no human could have known the nature of the Milky Way.

    Just point even a small telescope anywhere along its length and you will be rewarded with a beautiful sight. What appears as a cloud to the unaided eye resolves into countless stars. Their distance and close relative proximity to each other do not permit us to pick them out individually with just our eyes.

    It’s the same way a raincloud looks solid in the sky but actually consists of countless water droplets. The stars of the Milky Way merge together into a single band of light. But through a telescope, we see the Milky Way for what it truly is: a spiral arm of our galaxy.

    What is the Milky Way?

    Thus we arrive at the second answer to the question of what the Milky Way is. To astronomers, it is the name given to the entire galaxy we live in, not just the part of it we see in the sky. If this seems confusing, we must acknowledge the need for our galaxy to have a name.

    Many other galaxies are designated by catalog numbers rather than names, for example the New General Catalogue [NGC+++]. First published in 1888, it merely assigns a sequential number to each. More recent catalog numbers contain information of far more use to astronomers, for example, the galaxy’s location on the sky and during which survey it was discovered. Moreover, a galaxy may appear in more than one catalog and thus possess more than one designation. For example, the galaxy NGC 2470 is also known as 2MFGC 6271.

    Other galaxies, particularly those brighter and closer, received names from astronomers of the 17th and 18th centuries. The names reflected their appearance: the Pinwheel, the Sombrero, the Sunflower, the Cartwheel, the cigar and so forth. These names came long before any systematic sky surveys with numerical labeling systems.

    In time, the galaxies with descriptive labels received catalog numbers as well. Yet, our own galaxy does not appear in any index of galaxies. So, it needed a name for astronomers to refer to it by. Thus we call it the “Milky Way” instead of the galaxy or our galaxy. That name refers to both that river of light across the sky, which is part of our galaxy, and the galaxy as a whole. When not using the name, astronomers refer to it with a capital G (the Galaxy), and all other galaxies with a lowercase g.

    Where is the sun in our galaxy?

    Our solar system lies about 2/3 of the way out from the galactic center. We’re 26,000 light-years from the center, or 153,000 trillion miles (246,000 trillion km).

    When we look toward the edge of the galaxy, we see the Orion-Cygnus Arm (or the Orion spur). The solar system is just on the inner edge of this spiral arm.

    Or we can look toward the center of the galaxy, in the direction of Sagittarius. Vast clouds of dark gas hide the galactic center from us. Only in recent decades have astronomers pierced that dusty fog with infrared telescopes. A study of around 100 stars at the galactic center revealed that those giant clouds of dark dust were hiding a monster: a black hole. This black hole – known as Sagittarius A* – has a mass four million times that of our sun.

    1
    In this artist’s concept of the Milky Way, you can see the sun’s location below the central bar, at the inward side of the Orion Arm (called by its slightly dated name, the Orion Spur). The Orion Arm lies between the Sagittarius Arm and the Perseus Arm. Credit: R. Hurt/ NASA-JPL Caltech.

    The stats on our galaxy

    Our Milky Way galaxy is one of billions in the universe. We do not know exactly how many galaxies exist: a modern estimate vastly increases previous counts to as many as 2 trillion.

    The Milky Way is approximately 100,000 light-years across, or 600,000 trillion miles (950,000 trillion km). We do not know its exact age, but we assume it came into being in the very early universe along with most other galaxies: within perhaps a billion years after the Big Bang. Estimates of how many stars live within the Milky Way vary quite considerably, but it seems to be somewhere between 100 billion and double that figure.

    Why is there so much variance? Simply because it is so difficult to count the number of stars in the galaxy from our vantage point here on Earth. Imagine being in a banquet room full of people and trying to count everyone without being able to move around the room. From where you are standing, all you can do is make an estimate because people close to you block the view of those farther away. Neither can you see what size and shape the room is. The mass of people hides the edges of the room. It’s exactly the same from our position in the galaxy.

    3
    The Milky Way as seen in different wavelengths of light. The most familiar view is optical (or visible) light, which is the 3rd image from the bottom. In optical light, gas clouds darken our view of much of the galaxy. But look in the same direction in infrared light, and you can see through the clouds (4th, 5th and 6th image from the bottom). Read more about these images. Image via NASA.

    Seeing the city of stars

    It is this inability to see the structure of the Milky Way from our location inside it that meant for most of human history we did not even recognize that we live inside a galaxy in the first place. Indeed, we did not even realize what a galaxy is: a vast city of stars, separated from others by even vaster distances.

    [I highly recommend a video, from “NatGeo” Inside the Milky Way available here [ https://www.youtube.com/watch?v=hXFQ0xGfOJU ]

    Without telescopes, we couldn’t see most of the other galaxies in the sky. The unaided eye can only see three of them: from the Northern Hemisphere we can see the Andromeda galaxy. Also known as Messier 31, the Andromeda galaxy lies some two million light-years from us.

    In fact, it’s the farthest object we can see with our eyes alone, under dark skies. The skies in the Southern Hemisphere also have the Small and Large Magellanic Clouds, two amorphous dwarf galaxies orbiting our own.

    They are far larger and brighter in the sky than Messier 31 simply because they are much closer to us.

    4
    The Large and Small Magellanic Clouds over Paranal in Chile. These are satellite galaxies of the Milky Way that you can only see from the Southern Hemisphere. Image via the European Southern Observatory.

    Other galaxies in the universe

    Until the 1910s, astronomers had not observationally confirmed the existence of other galaxies. Astronomers long believed that those fuzzy patches of light they saw through their telescopes were nebulae, vast clouds of gas and dust in our own galaxy.

    But the concept of other galaxies was born earlier, in the early and mid-18th century. Swedish philosopher and scientist Emanuel Swedenborg and English astronomer Thomas Wright apparently conceived the idea independently of each other. Building upon the work of Wright, German philosopher Immanuel Kant referred to galaxies as island universes. The first observational evidence came in 1912 by American astronomer Vesto Slipher, who found that the spectra of the “nebulae” he measured were redshifted and thus much further away than astronomers previously thought.

    Edwin Hubble and distant galaxies

    And then came Edwin Hubble. Through years of painstaking work at the Mount Wilson Observatory in California, he confirmed in the 1920s that we do not live in a unique location. Our galaxy is just one of perhaps trillions.

    Hubble came to this realization by studying a type of star known as a Cepheid variable, which pulsates with a regular periodicity. The intrinsic brightness of a Cepheid variable is directly related to its pulsation period: by measuring how long it takes for the star to brighten, fade and brighten again you can calculate how bright it is, that is to say, how much light it emits. Consequently, by observing how bright it appears from the Earth, you can calculate its distance.

    It’s like seeing distant car headlights at night and estimating how far away the car is from how bright its lights appear. You can judge the distance of the car because you know all car headlights have about the same brightness.

    Cepheid variables in Andromeda

    One of Edwin Hubble’s great achievements was the discovery of Cepheid variables in Messier 31, the Andromeda galaxy. Hubble repeatedly photographed Andromeda with the Hooker Telescope. Eventually, he found stars that changed in brightness over a regular period. Performing the calculations, Hubble realized that Messier 31 is not astronomically close to us at all. It’s 2 million light-years away, and it’s a galaxy like our own.

    Hubble, for whom this discovery must have been a monumental shock, surmised that our galaxy was no different from Messier 31 and the others he observed. Thus, he relegated us to a position of lesser importance in the universe. This was as big a revelation and diminution of our position in the universe. It was like when we learned that Earth is not the center of the universe.

    We do not live in a special or privileged location. The universe does not have any vantage points which are superior to others. Wherever you are in the universe and you look up at the stars, you will see the same thing. Your constellations may be different, but no matter in which direction you look, you see galaxies rushing away from you in all directions as the universe expands, carrying the galaxies along with it.

    Until the work by Slipher and Hubble (and others), we did not know the universe was expanding. It took a surprisingly long time for the astronomical community to accept this fact. Even Albert Einstein did not believe it, introducing an arbitrary correction into his calculations on relativity to achieve a static, non-expanding universe. However, Einstein later called this correction his greatest error.

    ______________________________________________________________________________

    Nobel Prize in Physics for 2011 Expansion of the Universe

    4 October 2011

    The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics for 2011

    with one half to

    Saul Perlmutter
    The Supernova Cosmology Project
    The DOE’s Lawrence Berkeley National Laboratory and The University of California-Berkeley,

    and the other half jointly to

    Brian P. SchmidtThe High-z Supernova Search Team, The Australian National University, Weston Creek, Australia.

    and

    Adam G. Riess

    The High-z Supernova Search Team,The Johns Hopkins University and The Space Telescope Science Institute, Baltimore, MD.

    Written in the stars

    “Some say the world will end in fire, some say in ice…” *

    What will be the final destiny of the Universe? Probably it will end in ice, if we are to believe this year’s Nobel Laureates in Physics. They have studied several dozen exploding stars, called supernovae, and discovered that the Universe is expanding at an ever-accelerating rate. The discovery came as a complete surprise even to the Laureates themselves.

    In 1998, cosmology was shaken at its foundations as two research teams presented their findings. Headed by Saul Perlmutter, one of the teams had set to work in 1988. Brian Schmidt headed another team, launched at the end of 1994, where Adam Riess was to play a crucial role.

    The research teams raced to map the Universe by locating the most distant supernovae. More sophisticated telescopes on the ground and in space, as well as more powerful computers and new digital imaging sensors (CCD, Nobel Prize in Physics in 2009), opened the possibility in the 1990s to add more pieces to the cosmological puzzle.

    The teams used a particular kind of supernova, called Type 1a supernova. It is an explosion of an old compact star that is as heavy as the Sun but as small as the Earth. A single such supernova can emit as much light as a whole galaxy. All in all, the two research teams found over 50 distant supernovae whose light was weaker than expected – this was a sign that the expansion of the Universe was accelerating. The potential pitfalls had been numerous, and the scientists found reassurance in the fact that both groups had reached the same astonishing conclusion.

    For almost a century, the Universe has been known to be expanding as a consequence of the Big Bang about 14 billion years ago. However, the discovery that this expansion is accelerating is astounding. If the expansion will continue to speed up the Universe will end in ice.

    The acceleration is thought to be driven by dark energy, but what that dark energy is remains an enigma – perhaps the greatest in physics today. What is known is that dark energy constitutes about three quarters of the Universe. Therefore the findings of the 2011 Nobel Laureates in Physics have helped to unveil a Universe that to a large extent is unknown to science. And everything is possible again.

    *Robert Frost, Fire and Ice, 1920
    ______________________________________________________________________________

    The Milky Way from a distance

    So, what does the Milky Way would look like from the outside? How many spiral arms there are? How big is the galaxy and how many stars does it hold? These were questions still unanswered in the 1920s. It took most of the 20th century after Hubble’s discoveries to piece together those answers through a combination of painstaking work with both Earth- and space-based telescopes.

    So, if you could travel outside our galaxy, what would it look like? A standard analogy compares it to two fried eggs stuck together back-to-back. The yolk of the egg is known as the Galactic Bulge, a huge globe of stars at the center extending above and below the plane of the galaxy.

    Astronomers now think the Milky Way has four spiral arms winding out from its center like the arms of a Catherine wheel. But these arms do not actually meet at the center. A few years ago astronomers discovered that the Milky Way is a barred spiral galaxy. This means a “bar” of stars runs across its center, and the spiral arms extend from either end. Barred spiral galaxies are not uncommon in the universe. But we do not yet understand how that central bar forms.

    New discoveries in the Milky Way

    Only a few years ago, astronomers made another major discovery. The Milky Way is not a flat disk of stars but has a kink running across it like an extended S. Something has warped the disk. At the moment, the finger points at the gravitational influence of the astronomically close Sagittarius dwarf galaxy.

    6
    Sagittarius dwarf galaxy. Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA)

    It’s one of perhaps twenty small galaxies that orbit the Milky Way, like moths around a flame. As the Sagittarius galaxy slowly orbits around us, its gravity has pulled on our galaxy’s stars, eventually creating the warp.

    Other objects are also bound to the Milky Way. A halo of globular clusters surrounds our galaxy. Globular clusters are concentrations of stars that look like fuzzy golf balls. They contain perhaps a million or so extremely ancient stars.

    Discoveries about the Milky Way continue. The study of its nature and origin is accelerating as new astronomical tools become available, such as the European Space Agency’s orbiting Gaia telescope.

    Gaia is making a three-dimensional map of our galaxy’s stars with exquisite and quite unprecedented accuracy. Read more about Gaia’s 3rd data release.

    It’s an extremely exciting time for the study of our galaxy. It is all a far cry from when, thousands of years ago, our ancestors ascribed fantastic beasts and gods to that mysterious band of light they saw as they stood in awe under the starry sky.

    See the full article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
  • richardmitnick 9:28 am on January 25, 2023 Permalink | Reply
    Tags: "Life on Io? An astrobiologist says it’s possible", Dirk Schulze-Makuch, EarthSky,   

    From “EarthSky” : “Life on Io? An astrobiologist says it’s possible” Dirk Schulze-Makuch 

    1

    From “EarthSky”

    1.23.23
    Paul Scott Anderson

    1
    The Galileo spacecraft saw this volcano erupting on Io on June 28, 1997. Astrobiologist Dirk Schulze-Makuch says that despite the hostile surface conditions, it’s possible that microbial life on Io could exist beneath the surface. Image via NASA/ JPL/ DLR.

    Jupiter’s moon Io doesn’t top anyone’s list in the search for extraterrestrial life in our solar system. Io – our solar system’s most volcanically active place – is a hell world. Hundreds of sulfur volcanoes erupt there on a regular basis, covering the entire moon in hot lava and sulfur deposits. But some scientists are rethinking the possibility of life on this hostile world. It would most likely be underground, if it ever existed. Astrobiologist Dirk Schulze-Makuch recently wrote about his own perspective on this intriguing idea in Big Think on January 13, 2023.

    He also tweeted on January 14:

    “There could be or could have been #life in the #subsurface of #Io (the “Pizza Moon”) – an overlooked target for #astrobiology”
    posted at BigThink, direct link at:https://t.co/xTtBFlpb5d #space #science #moon #planet #universe #sciencetwitter #exploration #alien #microbial

    — Dirk Schulze-Makuch (@extreme_microbe) January 14, 2023

    An inhospitable volcanic world

    Life as we know needs heat, water and chemical nutrients. Io has at least one of those … heat. And lots of it, with all those volcanoes and subsurface magma. Maybe even a global magma ocean, according to a recent study. But water and nutrients would seem to be severely lacking.

    The moon is covered in lava flows and sulfur dioxide deposits from ongoing eruptions. There’s also very little atmosphere, and the average surface temperature is -202 degrees Fahrenheit (-130 Celsius), while volcanic hotspots can reach a sizzling 2,900 degrees F (1,600 C). Scientists say that Io may have once had more water, perhaps even similar to the ocean moons Europa and Ganymede. But then it lost all or most of it over billions of years. As Schulze-Makuch wrote:

    “The moon’s surface is constantly being reworked, which means that we see no fresh impact craters. Early in its history, Io may have held as much water as Europa or Ganymede, since it formed in a region of the solar system where water ice was plentiful. In those early days, the combination of liquid water and geothermal heat could have led life to develop. However, due to Jupiter’s unforgiving radiation and tidal heating, Io subsequently lost most if not all of its water, and the surface became uninhabitable.”

    Not exactly the most welcoming place for life, at least as we know it here on Earth. Or is it?

    Life on Io: Maybe not impossible after all?

    These hostile conditions are what we see on the surface. But, what about below the surface? Europa and Ganymede are also desolate and unfriendly to life on their surfaces, but below their icy crusts are global, salty oceans. So what about Io?

    As Schulze-Makuch noted, there may still be water and carbon (at least as carbon dioxide) underground. Io’s volcanoes emit sulfur dioxide, however, so that gas is likely more dominant.

    But could microbes survive in Io’s subsurface, if they ever existed? On Earth, geothermal activity, as from volcanoes, provides energy sources for microbial life. The same could happen on Io, at least theoretically. On Io, reduced sulfur compounds, such as hydrogen sulfide, could provide some of the needed energy for biology. The underground environment could protect any organisms from the powerful radiation from Jupiter that hits Io. But it would also need to be warm enough and contain at least some moisture.

    If there is not enough water, hydrogen sulfide may work as a substitute. Like water, it can dissolve organic compounds. It could also remain liquid in the possible conditions below Io’s surface, scientists say.

    It’s all still a matter of conjecture at this point, but seemingly not impossible. Any life below Io’s surface would probably be quite different than anything on Earth. It would have evolved to survive the unique – and overall still quite hostile – conditions found there.

    Life on Io could hide in lava tubes

    Schulze-Makuch had earlier proposed at a conference in 2004 that microbes on Io might find a home in lava tubes. He also published a paper detailing this idea in 2009, in the Journal of Cosmology [below]. Schulze-Makuch said:

    “At a 2004 conference in Iceland, followed by a paper six years later, I suggested that lava tubes could take over that function. They should be common on Io, given all the volcanic activity. Microbial growth is common in lava tubes on Earth no matter the location and climate, whether it’s ice-volcano interactions in Iceland or hot, sand-floored lava tubes in Saudi Arabia. Lava tubes are the most plausible cave environment for life on Mars, and caves in general are a great model for potential subsurface ecosystems.”

    As the paper also notes:

    “Lava tubes on Io may be an ideal habitat for any remaining microbial life, because they provide (1) protection from radiation, (2) insulation to keep temperatures sufficiently high and constant, (3) trap moisture and (4) provide nutrients such as sulfide and H2S that could be oxidized to sulfur dioxide or sulfates.”

    2
    This incredible infrared view of Io – taken by NASA’s Juno spacecraft on July 5, 2022 – shows the many active volcanoes dotting the surface of Jupiter’s moon. Io is our solar system’s most volcanically active body. Image via NASA/ JPL-Caltech/ SwRI/ ASI/ INAF/ JIRAM.

    Juno and Io Volcano Observer

    NASA’s Juno spacecraft has been studying Jupiter since 2016. While Jupiter itself is the main priority, Juno has also taken close looks at some of its larger moons, too, including Io. Indeed, Juno sent back some amazing infrared photos of Io’s erupting volcanoes on July 5, 2022. At the time, Juno passed about 49,700 miles (80,000 km) from Io’s surface. Later this year, it will pass by again, but this time at only about 930 miles (1,500 km) from the moon.

    Juno should be able to provide more clues as to what is happening inside Io, as well as survey its surface in great detail.

    Moreover, the proposed Io Volcano Observer (IVO) could do even more. It is currently under consideration for NASA’s Discovery Program. If selected, it will be a dedicated Io mission, making at least 10 close flybys over four years. Dipping as close as 120 miles (200 km) above the moon, IVO would image about 90% of Io’s colorful surface down to about 900 feet (300 meters) per pixel, and smaller areas down to an incredible 10 feet (3 meters) per pixel. It would also study the heat movement inside Io and take video of the erupting lava and plumes.

    Keeping an open mind

    Schulze-Makuch advises people to remain open-minded about the possibility of life on Io. It may be a long shot, but we could at least look for tentative evidence. He concludes the earlier paper saying:

    “Based on a consideration of possible life-sustaining solvents, organic building blocks, and energy sources, the plausibility of life on Io has to be considered low. Certainly, Europa and also Ganymede are the higher priority targets for astrobiology in the Jovian system. Nevertheless, there could conceivably be a habitable niche in the shallow subsurface, particularly in lava tube caves on Io, an idea which we can not dismiss without further investigation.”

    Journal of Cosmology 2009

    See the full article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
  • richardmitnick 9:31 am on January 18, 2023 Permalink | Reply
    Tags: "What is a variable star?", , , , , , EarthSky, The Australia Telescope National Facility   

    From The Australia Telescope National Facility At CSIRO-Commonwealth Scientific and Industrial Research Organization (AU) Via “EarthSky” : “What is a variable star?” 

    From The Australia Telescope National Facility

    At

    CSIRO bloc

    CSIRO-Commonwealth Scientific and Industrial Research Organization (AU)

    Via

    1

    “EarthSky”

    1.15.23

    Andy Briggs
    EarthSky Voices

    1
    What is a variable star? Astronomers know millions of them, and you might find one in any part of the sky. Among the stars in this image of the central region of the Milky Way galaxy, there are 2 known Cepheid variables. They vary due to internal changes in the star. Image: D. Minniti/ The European Southern Observatory [La Observatorio Europeo Austral] [Observatoire européen austral][Europäische Südsternwarte](EU)(CL)/ VVV consortium.

    3
    Classification diagram for variable stars.

    Many stars are not constant

    When you go out under a starry sky, the stars seem unchanging, eternal, constant. Occasionally you might see a nova or a supernova – apparently “new” stars – but such events usually last only weeks before fading from view, and they are rare (especially supernovae). Apart from those transient reminders that the universe is restless and constantly changing, the stars in the night sky seem to shine with a steady, unwavering light. But many stars are not constant. Their brightness varies over time. We classify a star as a variable star if its light, as seen from the Earth, changes in brightness. A variable star is one that’s known to dim and then brighten again.

    Variable stars aren’t rare or unusual. According to the American Association of Variable Star Observers (AAVSO), astronomers had identified more than 1 million variable stars. It’s not uncommon for amateur astronomers to make interesting and useful scientific discoveries about variable stars. You might wish to join them!

    Most stars fluctuate in brightness

    Most stars have at least some variation in luminosity: our own sun, for example, varies in brightness by a small amount (about 1%) over the course of its 11-year cycle. But unless the fluctuation is large enough to be seen from Earth, the star isn’t classified as variable.

    The changes in brightness of variable stars aren’t generally noticeable to the unaided eye, even if the brightness does change over short timescales (say, hours). To observe most variable stars, you need to monitor the brightness of the star carefully over extended periods of time. But there are examples of stars whose brightness has noticeably faded, over short timescales.

    3
    RS Puppis is a type of variable star known as a Cepheid variable. As variable stars go, Cepheids have a relatively long time between the brightest and least bright state. The brightness from RS Puppis, for example, increases as much as 5 times over 40 days. This Hubble image shows the variable star shrouded by thick, dark clouds of dust. Image: H.Bond/The National Aeronautics and Space Agency/ The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU).

    The dramatic dimming of Betelgeuse

    A famous recent example is the red supergiant star Betelgeuse in the constellation Orion the Hunter. Betelgeuse is one of our sky’s brightest stars. It’s a prominent star, in a noticeable constellation. And there was a worldwide outcry, when, in late 2019, Betelgeuse suddenly began to dim. By February 2020, Betelgeuse was only half as bright as before.

    Betelgeuse is nearing the end of its life. Many are aware that – within the next 100,000 years (soon, from an astronomical perspective) – Betelgeuse might explode as a supernova. Could the dimming be a sign Betelgeuse was about to explode?

    In the end, Betelgeuse did not explode, and its brightness has now returned to normal. Why did it suddenly dim? Astronomers concluded that the bright red supergiant star Betelgeuse literally blew its top in 2019. Betelgeuse lost a substantial part of its visible surface, causing a dust cloud to form and dimming the star as seen from Earth. Betelgeuse is still recovering from that outburst.

    Will Betelgeuse fade noticeably again? It might, but it’s not possible to predict exactly when.

    Do all variable stars brighten and dim due to obscuring clouds of gas? No. There’s more than one reason for a star to change its brightness. That’s why it’s helpful to divide variable stars into categories.

    4
    An example of a star that has changed in brightness but might not be regular, is Betelgeuse. This comparison image shows the star Betelgeuse before and after its unprecedented dimming. These images show how much the star faded and how its apparent shape changed. It is now back to normal brightness. Image via M. Montargès, et al./ ESO.

    Intrinsic variables, like Cepheids

    Intrinsic variable stars change in brightness due to events happening within the star itself.

    Cepheid variables are the most important of this type. These stars are pulsating variable stars. They literally pulse: get bigger and then smaller in size. As they expand and contract, their brightness changes.

    Cepheid variables are named for the first known example of the type, the star Delta Cephei, discovered to be variable in 1874.

    It wasn’t until 1908 that astronomer Henrietta Swan Leavitt discovered a direct relationship between the rate at which a Cepheid fluctuates in brightness and its luminosity or absolute brightness. A street light will appear dimmer as you move farther from it. Likewise, more distant stars appear dimmer than closer stars, assuming both have the same absolute brightness. And that’s why Cepheids are useful. If you see a Cepheid brightening and dimming at a certain rate, you know its true brightness. So you can see how bright it looks and thereby determine its distance.

    Cepheid variables are powerful tools in astronomy. They were an early stepping stone in the establishment of the cosmic distance ladder that now enables astronomers to estimate distances to objects hundreds, thousands, millions and billions of light-years away.

    Cataclysmic variables and novae

    Cataclysmic variable stars are also intrinsic variable stars, but have a different cause for their brightness fluctuations. These aren’t single stars getting bigger and then smaller in size. They are two stars, orbiting close to each other: a binary star system. The star whose brightness fluctuates is a white dwarf, an evolved and compact star. The other star is likely to be more ordinary, except for its closeness to the white dwarf. This closeness means that white dwarf’s gravity deforms the shape of the second star, pulling material off it and forming an accretion disk around the white dwarf. Strong emissions in X-ray and ultraviolet light often betray this disk’s presence.

    As the accretion disk material falls onto its surface, the white dwarf accumulates material from the second, donor star. Once the amount of material falling onto its surface reaches a critical point, runaway nuclear fusion reactions take place around the star. They cause a dramatic brightening of the star, sometimes becoming visible to the unaided eye as a “new” star. Indeed, some single cataclysmic variable events are also called novae, from the Latin word meaning new. Once this conversion has taken place, the fusion reactions end and the star dims to its former brightness.

    If enough mass collects, however, this kind of situation would cause huge thermonuclear explosions that blow the white dwarf apart. They destroy the star, which then becomes known as a Type Ia supernova.

    5
    Credit: Anglo-Australian Observatory

    Supernova 1987A in the Large Magellanic Cloud. The Type II supernova is visible in the left-hand image. The progenitor star is shown in an earlier image on the right.

    Type II supernovae show hydrogen lines in their early spectra. They are all examples of core collapse events with most arising due to a massive progenitor star exhausting its core fuel. Perhaps the best known example of this was Supernova 1987A. This was the first supernova visible to the naked-eye since Kepler’s supernovae of 1604. It took place in the Large Magellanic Cloud, a satellite galaxy of our own about 50,000 pc distant.

    Although we expect two or three stars to go supernova in our galaxy each century, these may not be visible in optical wavebands due to absorption and scattering by the galaxy’s dust lanes so the occurrence of a supernova in an nearby galaxy was a major boon for astronomers. Observations of SN 1987A continue today at many wavebands.

    Other sorts of intrinsic variables

    In addition to the Delta Cepheids, there are approximately 30 sub-groups within the intrinsic variable classification. They differ from one another in the speed of the star’s pulsations, and also its age, type, metallicity and several other factors.

    Thus we have RR Lyrae variables, long-period variables and Mira variables. All of them vary due to internal changes within the stars themselves.

    Extrinsic variables

    Extrinsic variable stars have brightness fluctuations due to external factors. Again, there are many different types, but they break down into two main groups: eclipsing binaries and rotating variables.

    Eclipsing binaries are systems containing two orbiting stars. As seen from the Earth, one star passes in front of the other, causing the eclipsed star’s brightness to fluctuate regularly. A famous example of this type of variable is Algol in the constellation Perseus. Another group of eclipsing variable stars is the W Ursae Majoris variables, where binary stars are situated so close to each other that they whip around each other in less than a day, and the surfaces of the two stars are so close that they are nearly touching!

    Rotating variables, on the other hand, are variable stars where the brightness fluctuates due to phenomena associated with their rotation. There are many kinds of rotating variables, for example stars with huge sunspots on their surface which, as these rotate into view of the Earth, block and dim the light from the star.


    Algol Eclipsing Binary Star With Lightcurve.

    What is a variable star?

    The study of variable stars can reveal much about the nature, history and future of stars. There are many astronomers – both amateur and professional – who study them. And organizations such as the AAVSO serve as collectors and collators of variable star observations.

    Variable stars show that you don’t always need sophisticated and expensive technology to do useful and valuable science. On a base level, all you need is your eyes, although telescopes and equipment can more precisely measure the brightness of a star. But all you really need is the ability to estimate the brightness of a star by comparing it to that of others. This is an acquired skill that comes from practice.

    See the full EarthSky article here .
    See the ATNF article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Australia Telescope National Facility

    About ATNF

    CSIRO’s radio astronomy observatories are collectively known as The Australia Telescope National Facility. The ATNF is operated and managed by the Space and Astronomy business unit of CSIRO — Australia’s national science agency. The business unit was until May 2021 known as CSIRO Astronomy and Space Science. The facility supports Australia’s research in radio astronomy and can be used by researchers from institutions all over the world.

    ATNF’s Headquarters are located in the Sydney suburb of Marsfield, with offices also located in the Perth suburb of Kensington, and at the MRO Support Facility in Geraldton.

    Our vision

    We operate world-class radio astronomy facilities for users from across Australia and around the world. We are global leaders in technology and research, exploiting the world’s premier radio quiet site. We attract and retain the best staff.

    Our mission

    To develop and operate world-class National Facilities in radio astronomy:

    Operate the ATNF as a financially viable and user‑focused research facility for the benefit of the Australian and international communities
    Play a key role in the international Square Kilometre Array (SKA) project, covering in-country operations, science leadership and technology development
    Deliver world-class science through exploitation of our southern location and technological advantages
    Develop, apply and commercialise our innovative technologies and big data processing techniques
    Foster a diverse and creative workforce.

    Our telescopes

    Parkes Observatory is home to the CSIRO Parkes 64-metre radio telescope [below]. This telescope has been successfully operated since 1961. Upgrades to accommodate a 13-beam focal plane array have maintained its international standing as a state-of-the-art instrument.

    CSIRO’s Australia Telescope Compact Array [below] is located at the Paul Wild Observatory near the town of Narrabri. Each of these antennas has a reflecting surface with a diameter of 22 metres. A further 22-metre antenna, known as the CSIRO Mopra telescope, is located near Coonabarabran.

    The Australian Square Kilometre Array Pathfinder (ASKAP) [below], is located at the Murchison Radio-astronomy Observatory in Western Australia. ASKAP is made up of 36 antennas, each 12 metres in diameter, working together as a single instrument.

    CSIRO also manages the astronomy use of the Canberra Deep Space Communication Complex 70-m [below] and 34-m antennas at Tidbinbilla. NASA/JPL-Caltech makes approximately 5% of 70-m antenna time available to astronomical research programs.

    In addition to operating independently, the ATNF radio telescopes can be used together (and sometimes in conjunction with other antennas in Australia and New Zealand) as a long baseline array for a technique known as Very Long Baseline Interferometry (VLBI).

    Technical research and development supporting upgrades of the ATNF, as well as for the new ASKAP instrument, are conducted at CSIRO Space and Astronomy headquarters at Marsfield.

    CSIRO campus

    CSIRO-Commonwealth Scientific and Industrial Research Organization (AU ), is Australia’s national science agency and one of the largest and most diverse research agencies in the world.

    CSIRO works with leading organizations around the world. From its headquarters in Canberra, CSIRO maintains more than 50 sites across Australia and in France, Chile and the United States, employing about 5,500 people.

    Federally funded scientific research began in Australia 104 years ago. The Advisory Council of Science and Industry was established in 1916 but was hampered by insufficient available finance. In 1926 the research effort was reinvigorated by establishment of the Council for Scientific and Industrial Research (CSIR), which strengthened national science leadership and increased research funding. CSIR grew rapidly and achieved significant early successes. In 1949 further legislated changes included renaming the organization as CSIRO.

    Notable developments by CSIRO have included the invention of atomic absorption spectroscopy; essential components of Wi-Fi technology; development of the first commercially successful polymer banknote; the invention of the insect repellent in Aerogard and the introduction of a series of biological controls into Australia, such as the introduction of myxomatosis and rabbit calicivirus for the control of rabbit populations.

    Research and focus areas

    Research Business Units

    As at 2019, CSIRO’s research areas are identified as “Impact science” and organized into the following Business Units:

    Agriculture and Food
    Health and Biosecurity
    Data 61
    Energy
    Land and Water
    Manufacturing
    Mineral Resources
    Oceans and Atmosphere

    National Facilities
    CSIRO manages national research facilities and scientific infrastructure on behalf of the nation to assist with the delivery of research. The national facilities and specialized laboratories are available to both international and Australian users from industry and research. As at 2019, the following National Facilities are listed:

    Australian Animal Health Laboratory (AAHL)
    Australia Telescope National Facility – radio telescopes included in the Facility include the Australia Telescope Compact Array, the Parkes Observatory, Mopra Radio Telescope Observatory and the Australian Square Kilometre Array Pathfinder.

    STCA CSIRO Australia Compact Array (AU), six radio telescopes at the Paul Wild Observatory, is an array of six 22-m antennas located about twenty five kilometres (16 mi) west of the town of Narrabri in Australia.

    CSIRO-Commonwealth Scientific and Industrial Research Organization (AU) Parkes Observatory [Murriyang, the traditional Indigenous name], located 20 kilometres north of the town of Parkes, New South Wales, Australia, 414.80m above sea level.

    NASA Canberra Deep Space Communication Complex (AU), Deep Space Network. Credit: NASA.

    CSIRO Canberra campus (AU).

    ESA DSA 1, hosts a 35-metre deep-space antenna with transmission and reception in both S- and X-band and is located 140 kilometres north of Perth, Western Australia, near the town of New Norcia.

    CSIRO-Commonwealth Scientific and Industrial Research Organization (AU) CSIRO R/V Investigator.

    UK Space NovaSAR-1 satellite (UK) synthetic aperture radar satellite.

    CSIRO Pawsey Supercomputing Centre AU)

    Magnus Cray XC40 supercomputer at Pawsey Supercomputer Centre Perth Australia.

    Galaxy Cray XC30 Series Supercomputer at at Pawsey Supercomputer Centre Perth Australia.

    Pausey Supercomputer CSIRO Zeus SGI Linux cluster.

    Others not shown

    SKA

    SKA- Square Kilometer Array.



    SKA Square Kilometre Array low frequency at the Inyarrimanha Ilgari Bundara Murchison Widefield Array, Boolardy station in outback Western Australia on the traditional lands of the Wajarri peoples.

    EDGES telescope in a radio quiet zone at the Inyarrimanha Ilgari Bundara Murchison Radio-astronomy Observatory in Western Australia, on the traditional lands of the Wajarri peoples.

     
  • richardmitnick 9:29 am on January 8, 2023 Permalink | Reply
    Tags: "How far away is Betelgeuse - the famous doomed star?", , , , , , EarthSky, , Gaia space telescope, Hipparcos space telescope, ,   

    From The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne] [Europäische Weltraumorganization](EU) Via “EarthSky” : “How far away is Betelgeuse – the famous doomed star?” 

    ESA Space For Europe Banner

    European Space Agency – United Space in Europe (EU)

    From The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne] [Europäische Weltraumorganization](EU)

    Via

    1

    “EarthSky”

    1.8.23

    1
    The ALMA telescope in Chile captured this image of the red giant Betelgeuse at sub-millimeter wavelengths. It shows something we almost never see, a section of hot gas slightly protruding from the red giant star’s extended atmosphere (around 8 o’clock). Whoa! It just looks unstable! Image via ALMA.

    How far away is doomed Betelgeuse?

    Betelgeuse, the bright red star in the constellation Orion the Hunter, is in the end stage of its stellar life. Someday, it will explode as a supernova. In late 2019 and early 2020, Betelgeuse suddenly and unexpectedly dimmed. Some joked it might soon explode! It didn’t, but still … what if it did? When Betelgeuse goes supernova, will it affect earthly life? How far away is Betelgeuse?

    The good news is that if Betelgeuse explodes, it is close enough to put on a spectacular light show but far enough to not cause us on Earth any harm. To answer the distance question first, Betelgeuse is approximately 724 light-years away. But getting that answer, even for a relatively nearby star, is surprisingly difficult.

    New measurement techniques

    It’s only in the last 30 years that astronomers have obtained more accurate measurements for the distance to Betelgeuse and other nearby stars. New technologies explain this advance. It began in 1989, when the European Space Agency (ESA) launched a space telescope called Hipparcos, named after the famous Greek astronomer Hipparchus.

    Over several years of observations, the Hipparcos space telescope provided “parallax” and distance data for more than 100,000 relatively nearby stars.

    3
    When viewed from 2 locations, there is a slight shift in the position of a nearby star with respect to distant background stars. For observations on Earth, taken 6 months apart, the separation between those 2 locations is the diameter of Earth’s orbit. The angle alpha is the parallax angle. Image via P.wormer/ Wikimedia Commons.

    Those measurements became the basis for most of the estimated distances to stars that you see today.

    The original Hipparcos data gave a parallax of 7.63 milliarcseconds for Betelgeuse; that’s about one-millionth the width of the full moon. Computations based on that parallax yielded a distance of about 430 light-years.

    Measurement errors

    But Betelgeuse is what’s known as a variable star. That means its brightness fluctuates with time. That said, the excitement over Betelgeuse’s dimming was because it was the biggest dip in brightness ever observed. And therein began the difficulty in estimating Betelgeuse’s distance.

    Subsequent studies found an error in the methods used for reducing the Hipparcos data for variable stars. An effort to correct those errors gave a parallax of 5.07 milliarcseconds. That changed Betelgeuse’s estimated distance from 430 light-years to about 643 light-years, plus or minus 46 light-years.

    But wait, there’s more. In 2017, astronomers published new calculations that further refined Betelgeuse’s parallax to 4.51 milliarcseconds [The Astronomical Journal (below)]. This new analysis of data from Hipparcos also included observations from several ground-based radio telescopes [un-cited]. That placed Betelgeuse at a distance of about 724 light-years, or, more accurately, between 613 and 881 light-years, when data uncertainties are included.

    Why Gaia can’t measure the distance of Betelgeuse

    You might know that the European Space Agency’s Gaia astrometry mission has the goal of making a three-dimensional map of our Milky Way galaxy.

    With Gaia’s 3rd data release in June 2022, ESA said it now had estimates for nearly 2 billion stars in the galaxy.

    Yet Betelgeuse is not one of those stars, and astronomers can’t use Gaia to find a more precise distance for Betelgeuse. The reason is that Betelgeuse is too bright for the spacecraft’s sensors.

    4
    A map of Orion the Hunter, showing the location of Betelgeuse. Image via IAU/ Sky & Telescope magazine/ Wikimedia Commons.

    More about parallax

    Have you ever viewed a nearby object from two different locations and noticed how its position changed with respect to distant landmarks? That is the effect called parallax. Astronomers obtain measurements of a nearby star’s position in the sky relative to distant background stars six months apart. During that time, Earth has traveled to the opposite side of its orbit. Thus, two locations are about 186 million miles (300 million km) apart, or the diameter of Earth’s orbit. The difference in the nearby star’s relative position at the two locations enables astronomers to derive a parallax angle and calculate a distance to the nearby star.

    Ancient Greek astronomers understood the concept of parallax, but they lacked the technology to make very fine angular measurements on the sky. As a result, all measurements of stellar parallax failed until German astronomer Friedrich Bessel succeeded in 1838. He used a telescope, and even though his two observing locations were on opposite sides of Earth’s orbit, he was barely able to make out a tiny angular displacement. But it was enough to determine a distance of 11 light-years to the nearby star 61 Cygni.

    Limits of using parallax

    From Bessel’s time until Hipparcos’ launch in 1989, astronomers compiled only a few thousand parallaxes. The process was difficult for a number of factors. The extremely small angles involved, imperfections in the instruments, and the murkiness of Earth’s own atmosphere all hinder measurements. The atmosphere distorts observations from the Earth, even from very clear and dark locations such as deserts and mountaintops.

    Hipparcos, in obtaining observations from space starting in 1989, pushed past the limitations imposed by Earth’s atmosphere to get positional data of stars at unprecedented accuracy for that time. Astronomers are continuing to refine these measurements with new innovations in instruments and data analysis, using ground- and space-based observatories.
    ________________________________________________________________

    Want to keep track of how bright or dim Betelgeuse is on any given day? Follow the Betelgeuse Status account on Mastodon.

    Science paper:
    The Astronomical Journal
    See the science paper for instructive material with images and data tables.

    See the full article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.


    five-ways-keep-your-child-safe-school-shootings


    Please help promote STEM in your local schools.

    Stem Education Coalition

    The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC (NL) in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the
    European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

    ESA’s space flight programme includes human spaceflight (mainly through participation in the International Space Station program); the launch and operation of uncrewed exploration missions to other planets and the Moon; Earth observation, science and telecommunication; designing launch vehicles; and maintaining a major spaceport, the The Guiana Space Centre [Centre Spatial Guyanais; CSG also called Europe’s Spaceport) at Kourou, French Guiana. The main European launch vehicle Ariane 5 is operated through Arianespace with ESA sharing in the costs of launching and further developing this launch vehicle. The agency is also working with The National Aeronautics and Space Agency to manufacture the Orion Spacecraft service module that will fly on the Space Launch System.

    The agency’s facilities are distributed among the following centres:

    ESA European Space Research and Technology Centre (ESTEC) (NL) in Noordwijk, Netherlands;
    ESA Centre for Earth Observation [ESRIN] (IT) in Frascati, Italy;
    ESA Mission Control ESA European Space Operations Center [ESOC](DE) is in Darmstadt, Germany;
    ESA -European Astronaut Centre [EAC] trains astronauts for future missions is situated in Cologne, Germany;
    European Centre for Space Applications and Telecommunications (ECSAT) (UK), a research institute created in 2009, is located in Harwell, England;
    ESA – European Space Astronomy Centre [ESAC] (ES) is located in Villanueva de la Cañada, Madrid, Spain.
    European Space Agency Science Programme is a long-term programme of space science and space exploration missions.

    Foundation

    After World War II, many European scientists left Western Europe in order to work with the United States. Although the 1950s boom made it possible for Western European countries to invest in research and specifically in space-related activities, Western European scientists realized solely national projects would not be able to compete with the two main superpowers. In 1958, only months after the Sputnik shock, Edoardo Amaldi (Italy) and Pierre Auger (France), two prominent members of the Western European scientific community, met to discuss the foundation of a common Western European space agency. The meeting was attended by scientific representatives from eight countries, including Harrie Massey (United Kingdom).

    The Western European nations decided to have two agencies: one concerned with developing a launch system, ELDO (European Launch Development Organization) , and the other the precursor of the European Space Agency, ESRO (European Space Research Organization) . The latter was established on 20 March 1964 by an agreement signed on 14 June 1962. From 1968 to 1972, ESRO launched seven research satellites.

    ESA in its current form was founded with the ESA Convention in 1975, when ESRO was merged with ELDO. ESA had ten founding member states: Belgium, Denmark, France, West Germany, Italy, the Netherlands, Spain, Sweden, Switzerland, and the United Kingdom. These signed the ESA Convention in 1975 and deposited the instruments of ratification by 1980, when the convention came into force. During this interval the agency functioned in a de facto fashion. ESA launched its first major scientific mission in 1975, Cos-B, a space probe monitoring gamma-ray emissions in the universe, which was first worked on by ESRO.

    ESA50 Logo large

    Later activities

    ESA collaborated with National Aeronautics Space Agency on the International Ultraviolet Explorer (IUE), the world’s first high-orbit telescope, which was launched in 1978 and operated successfully for 18 years.

    ESA Infrared Space Observatory.

    European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU)/National Aeronautics and Space Administration Solar Orbiter annotated.

    A number of successful Earth-orbit projects followed, and in 1986 ESA began Giotto, its first deep-space mission, to study the comets Halley and Grigg–Skjellerup. Hipparcos, a star-mapping mission, was launched in 1989 and in the 1990s SOHO, Ulysses and the Hubble Space Telescope were all jointly carried out with NASA. Later scientific missions in cooperation with NASA include the Cassini–Huygens space probe, to which ESA contributed by building the Titan landing module Huygens.

    ESA/Huygens Probe from Cassini landed on Titan.

    As the successor of ELDO, ESA has also constructed rockets for scientific and commercial payloads. Ariane 1, launched in 1979, carried mostly commercial payloads into orbit from 1984 onward. The next two versions of the Ariane rocket were intermediate stages in the development of a more advanced launch system, the Ariane 4, which operated between 1988 and 2003 and established ESA as the world leader in commercial space launches in the 1990s. Although the succeeding Ariane 5 experienced a failure on its first flight, it has since firmly established itself within the heavily competitive commercial space launch market with 82 successful launches until 2018. The successor launch vehicle of Ariane 5, the Ariane 6, is under development and is envisioned to enter service in the 2020s.

    The beginning of the new millennium saw ESA become, along with agencies like National Aeronautics Space Agency, Japan Aerospace Exploration Agency (JP), Indian Space Research Organization (IN), the Canadian Space Agency(CA) and Roscosmos (RU), one of the major participants in scientific space research. Although ESA had relied on co-operation with NASA in previous decades, especially the 1990s, changed circumstances (such as tough legal restrictions on information sharing by the United States military) led to decisions to rely more on itself and on co-operation with Russia. A 2011 press issue thus stated:

    “Russia is ESA’s first partner in its efforts to ensure long-term access to space. There is a framework agreement between ESA and the government of the Russian Federation on cooperation and partnership in the exploration and use of outer space for peaceful purposes, and cooperation is already underway in two different areas of launcher activity that will bring benefits to both partners.”

    Notable ESA programs include SMART-1, a probe testing cutting-edge space propulsion technology, the Mars Express and Venus Express missions, as well as the development of the Ariane 5 rocket and its role in the ISS partnership. ESA maintains its scientific and research projects mainly for astronomy-space missions such as Corot, launched on 27 December 2006, a milestone in the search for exoplanets.

    On 21 January 2019, ArianeGroup and Arianespace announced a one-year contract with ESA to study and prepare for a mission to mine the Moon for lunar regolith.

    Mission

    The treaty establishing the European Space Agency reads:

    The purpose of the Agency shall be to provide for and to promote, for exclusively peaceful purposes, cooperation among European States in space research and technology and their space applications, with a view to their being used for scientific purposes and for operational space applications systems…

    ESA is responsible for setting a unified space and related industrial policy, recommending space objectives to the member states, and integrating national programs like satellite development, into the European program as much as possible.

    Jean-Jacques Dordain – ESA’s Director General (2003–2015) – outlined the European Space Agency’s mission in a 2003 interview:

    “Today space activities have pursued the benefit of citizens, and citizens are asking for a better quality of life on Earth. They want greater security and economic wealth, but they also want to pursue their dreams, to increase their knowledge, and they want younger people to be attracted to the pursuit of science and technology. I think that space can do all of this: it can produce a higher quality of life, better security, more economic wealth, and also fulfill our citizens’ dreams and thirst for knowledge, and attract the young generation. This is the reason space exploration is an integral part of overall space activities. It has always been so, and it will be even more important in the future.”

    Activities

    According to the ESA website, the activities are:

    Observing the Earth
    Human Spaceflight
    Launchers
    Navigation
    Space Science
    Space Engineering & Technology
    Operations
    Telecommunications & Integrated Applications
    Preparing for the Future
    Space for Climate

    Programs

    Copernicus Programme
    Cosmic Vision
    ExoMars
    FAST20XX
    Galileo
    Horizon 2000
    Living Planet Programme
    Mandatory

    Every member country must contribute to these programs:

    Technology Development Element Program
    Science Core Technology Program
    General Study Program
    European Component Initiative

    Optional

    Depending on their individual choices the countries can contribute to the following programs, listed according to:

    Launchers
    Earth Observation
    Human Spaceflight and Exploration
    Telecommunications
    Navigation
    Space Situational Awareness
    Technology

    ESA_LAB@

    ESA has formed partnerships with universities. ESA_LAB@ refers to research laboratories at universities. Currently there are ESA_LAB@

    Technische Universität Darmstadt (DE)
    École des hautes études commerciales de Paris (HEC Paris) (FR)
    Université de recherche Paris Sciences et Lettres (FR)
    The University of Central Lancashire (UK)

    Membership and contribution to ESA

    By 2015, ESA was an intergovernmental organization of 22 member states. Member states participate to varying degrees in the mandatory (25% of total expenditures in 2008) and optional space programs (75% of total expenditures in 2008). The 2008 budget amounted to €3.0 billion whilst the 2009 budget amounted to €3.6 billion. The total budget amounted to about €3.7 billion in 2010, €3.99 billion in 2011, €4.02 billion in 2012, €4.28 billion in 2013, €4.10 billion in 2014 and €4.33 billion in 2015. English is the main language within ESA. Additionally, official documents are also provided in German and documents regarding the Spacelab are also provided in Italian. If found appropriate, the agency may conduct its correspondence in any language of a member state.

    Non-full member states
    Slovenia
    Since 2016, Slovenia has been an associated member of the ESA.

    Latvia
    Latvia became the second current associated member on 30 June 2020, when the Association Agreement was signed by ESA Director Jan Wörner and the Minister of Education and Science of Latvia, Ilga Šuplinska in Riga. The Saeima ratified it on July 27. Previously associated members were Austria, Norway and Finland, all of which later joined ESA as full members.

    Canada
    Since 1 January 1979, Canada has had the special status of a Cooperating State within ESA. By virtue of this accord, The Canadian Space Agency [Agence spatiale canadienne, ASC] (CA) takes part in ESA’s deliberative bodies and decision-making and also in ESA’s programs and activities. Canadian firms can bid for and receive contracts to work on programs. The accord has a provision ensuring a fair industrial return to Canada. The most recent Cooperation Agreement was signed on 15 December 2010 with a term extending to 2020. For 2014, Canada’s annual assessed contribution to the ESA general budget was €6,059,449 (CAD$8,559,050). For 2017, Canada has increased its annual contribution to €21,600,000 (CAD$30,000,000).

    Enlargement

    After the decision of the ESA Council of 21/22 March 2001, the procedure for accession of the European states was detailed as described the document titled The Plan for European Co-operating States (PECS). Nations that want to become a full member of ESA do so in 3 stages. First a Cooperation Agreement is signed between the country and ESA. In this stage, the country has very limited financial responsibilities. If a country wants to co-operate more fully with ESA, it signs a European Cooperating State (ECS) Agreement. The ECS Agreement makes companies based in the country eligible for participation in ESA procurements. The country can also participate in all ESA programs, except for the Basic Technology Research Programme. While the financial contribution of the country concerned increases, it is still much lower than that of a full member state. The agreement is normally followed by a Plan For European Cooperating State (or PECS Charter). This is a 5-year programme of basic research and development activities aimed at improving the nation’s space industry capacity. At the end of the 5-year period, the country can either begin negotiations to become a full member state or an associated state or sign a new PECS Charter.

    During the Ministerial Meeting in December 2014, ESA ministers approved a resolution calling for discussions to begin with Israel, Australia and South Africa on future association agreements. The ministers noted that “concrete cooperation is at an advanced stage” with these nations and that “prospects for mutual benefits are existing”.

    A separate space exploration strategy resolution calls for further co-operation with the United States, Russia and China on “LEO” exploration, including a continuation of ISS cooperation and the development of a robust plan for the coordinated use of space transportation vehicles and systems for exploration purposes, participation in robotic missions for the exploration of the Moon, the robotic exploration of Mars, leading to a broad Mars Sample Return mission in which Europe should be involved as a full partner, and human missions beyond LEO in the longer term.”

    Relationship with the European Union

    The political perspective of the European Union (EU) was to make ESA an agency of the EU by 2014, although this date was not met. The EU member states provide most of ESA’s funding, and they are all either full ESA members or observers.

    History

    At the time ESA was formed, its main goals did not encompass human space flight; rather it considered itself to be primarily a scientific research organization for uncrewed space exploration in contrast to its American and Soviet counterparts. It is therefore not surprising that the first non-Soviet European in space was not an ESA astronaut on a European space craft; it was Czechoslovak Vladimír Remek who in 1978 became the first non-Soviet or American in space (the first man in space being Yuri Gagarin of the Soviet Union) – on a Soviet Soyuz spacecraft, followed by the Pole Mirosław Hermaszewski and East German Sigmund Jähn in the same year. This Soviet co-operation programme, known as Intercosmos, primarily involved the participation of Eastern bloc countries. In 1982, however, Jean-Loup Chrétien became the first non-Communist Bloc astronaut on a flight to the Soviet Salyut 7 space station.

    Because Chrétien did not officially fly into space as an ESA astronaut, but rather as a member of the French CNES astronaut corps, the German Ulf Merbold is considered the first ESA astronaut to fly into space. He participated in the STS-9 Space Shuttle mission that included the first use of the European-built Spacelab in 1983. STS-9 marked the beginning of an extensive ESA/NASA joint partnership that included dozens of space flights of ESA astronauts in the following years. Some of these missions with Spacelab were fully funded and organizationally and scientifically controlled by ESA (such as two missions by Germany and one by Japan) with European astronauts as full crew members rather than guests on board. Beside paying for Spacelab flights and seats on the shuttles, ESA continued its human space flight co-operation with the Soviet Union and later Russia, including numerous visits to Mir.

    During the latter half of the 1980s, European human space flights changed from being the exception to routine and therefore, in 1990, the European Astronaut Centre in Cologne, Germany was established. It selects and trains prospective astronauts and is responsible for the co-ordination with international partners, especially with regard to the International Space Station. As of 2006, the ESA astronaut corps officially included twelve members, including nationals from most large European countries except the United Kingdom.

    In the summer of 2008, ESA started to recruit new astronauts so that final selection would be due in spring 2009. Almost 10,000 people registered as astronaut candidates before registration ended in June 2008. 8,413 fulfilled the initial application criteria. Of the applicants, 918 were chosen to take part in the first stage of psychological testing, which narrowed down the field to 192. After two-stage psychological tests and medical evaluation in early 2009, as well as formal interviews, six new members of the European Astronaut Corps were selected – five men and one woman.

    Cooperation with other countries and organizations

    ESA has signed co-operation agreements with the following states that currently neither plan to integrate as tightly with ESA institutions as Canada, nor envision future membership of ESA: Argentina, Brazil, China, India (for the Chandrayan mission), Russia and Turkey.

    Additionally, ESA has joint projects with the European Union, NASA of the United States and is participating in the International Space Station together with the United States (NASA), Russia and Japan (JAXA).

    European Union
    ESA and EU member states
    ESA-only members
    EU-only members

    ESA is not an agency or body of the European Union (EU), and has non-EU countries (Norway, Switzerland, and the United Kingdom) as members. There are however ties between the two, with various agreements in place and being worked on, to define the legal status of ESA with regard to the EU.

    There are common goals between ESA and the EU. ESA has an EU liaison office in Brussels. On certain projects, the EU and ESA co-operate, such as the upcoming Galileo satellite navigation system. Space policy has since December 2009 been an area for voting in the European Council. Under the European Space Policy of 2007, the EU, ESA and its Member States committed themselves to increasing co-ordination of their activities and programs and to organizing their respective roles relating to space.

    The Lisbon Treaty of 2009 reinforces the case for space in Europe and strengthens the role of ESA as an R&D space agency. Article 189 of the Treaty gives the EU a mandate to elaborate a European space policy and take related measures, and provides that the EU should establish appropriate relations with ESA.

    Former Italian astronaut Umberto Guidoni, during his tenure as a Member of the European Parliament from 2004 to 2009, stressed the importance of the European Union as a driving force for space exploration, “…since other players are coming up such as India and China it is becoming ever more important that Europeans can have an independent access to space. We have to invest more into space research and technology in order to have an industry capable of competing with other international players.”

    The first EU-ESA International Conference on Human Space Exploration took place in Prague on 22 and 23 October 2009. A road map which would lead to a common vision and strategic planning in the area of space exploration was discussed. Ministers from all 29 EU and ESA members as well as members of parliament were in attendance.

    National space organizations of member states:

    The Centre National d’Études Spatiales(FR) (CNES) (National Centre for Space Study) is the French government space agency (administratively, a “public establishment of industrial and commercial character”). Its headquarters are in central Paris. CNES is the main participant on the Ariane project. Indeed, CNES designed and tested all Ariane family rockets (mainly from its centre in Évry near Paris)
    The UK Space Agency is a partnership of the UK government departments which are active in space. Through the UK Space Agency, the partners provide delegates to represent the UK on the various ESA governing bodies. Each partner funds its own programme.
    The Italian Space Agency A.S.I. – Agenzia Spaziale Italiana was founded in 1988 to promote, co-ordinate and conduct space activities in Italy. Operating under the Ministry of the Universities and of Scientific and Technological Research, the agency cooperates with numerous entities active in space technology and with the president of the Council of Ministers. Internationally, the ASI provides Italy’s delegation to the Council of the European Space Agency and to its subordinate bodies.
    The German Aerospace Center (DLR)[Deutsches Zentrum für Luft- und Raumfahrt e. V.] is the national research centre for aviation and space flight of the Federal Republic of Germany and of other member states in the Helmholtz Association. Its extensive research and development projects are included in national and international cooperative programs. In addition to its research projects, the centre is the assigned space agency of Germany bestowing headquarters of German space flight activities and its associates.
    The Instituto Nacional de Técnica Aeroespacial (INTA)(ES) (National Institute for Aerospace Technique) is a Public Research Organization specialized in aerospace research and technology development in Spain. Among other functions, it serves as a platform for space research and acts as a significant testing facility for the aeronautic and space sector in the country.

    National Aeronautics Space Agency

    ESA has a long history of collaboration with NASA. Since ESA’s astronaut corps was formed, the Space Shuttle has been the primary launch vehicle used by ESA’s astronauts to get into space through partnership programs with NASA. In the 1980s and 1990s, the Spacelab programme was an ESA-NASA joint research programme that had ESA develop and manufacture orbital labs for the Space Shuttle for several flights on which ESA participate with astronauts in experiments.

    In robotic science mission and exploration missions, NASA has been ESA’s main partner. Cassini–Huygens was a joint NASA-ESA mission, along with the Infrared Space Observatory, INTEGRAL, SOHO, and others.

    National Aeronautics and Space Administration/European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU)/ASI Italian Space Agency [Agenzia Spaziale Italiana](IT) Cassini Spacecraft.

    European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU) Integral spacecraft

    European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne] [Europäische Weltraumorganization] (EU)/National Aeronautics and Space AdministrationSOHO satellite. Launched in 1995.

    Also, the Hubble Space Telescope is a joint project of NASA and ESA.

    National Aeronautics and Space Administration/European Space Agency[La Agencia Espacial Europea] [Agence spatiale européenne] [Europäische Weltraumorganization](EU) Hubble Space Telescope

    ESA-NASA joint projects include the James Webb Space Telescope and the proposed Laser Interferometer Space Antenna.

    National Aeronautics Space Agency/European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne] [Europäische Weltraumorganization]Canadian Space Agency [Agence Spatiale Canadienne](CA) James Webb Space Telescope annotated. Scheduled for launch in December 2021.

    Gravity is talking. Lisa will listen. Dialogos of Eide.

    The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU)/National Aeronautics and Space Administration eLISA space based, the future of gravitational wave research.

    NASA has committed to provide support to ESA’s proposed MarcoPolo-R mission to return an asteroid sample to Earth for further analysis. NASA and ESA will also likely join together for a Mars Sample Return Mission. In October 2020 the ESA entered into a memorandum of understanding (MOU) with NASA to work together on the Artemis program, which will provide an orbiting lunar gateway and also accomplish the first manned lunar landing in 50 years, whose team will include the first woman on the Moon.

    NASA ARTEMIS spacecraft depiction.

    Cooperation with other space agencies

    Since China has started to invest more money into space activities, the Chinese Space Agency[中国国家航天局] (CN) has sought international partnerships. ESA is, beside, The Russian Federal Space Agency Государственная корпорация по космической деятельности «Роскосмос»](RU) one of its most important partners. Two space agencies cooperated in the development of the Double Star Mission. In 2017, ESA sent two astronauts to China for two weeks sea survival training with Chinese astronauts in Yantai, Shandong.

    ESA entered into a major joint venture with Russia in the form of the CSTS, the preparation of French Guiana spaceport for launches of Soyuz-2 rockets and other projects. With India, ESA agreed to send instruments into space aboard the ISRO’s Chandrayaan-1 in 2008. ESA is also co-operating with Japan, the most notable current project in collaboration with JAXA is the BepiColombo mission to Mercury.

    European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU)/Japan Aerospace Exploration Agency [国立研究開発法人宇宙航空研究開発機構](JP) Bepicolumbo in flight illustration. Artist’s impression of BepiColombo – ESA’s first mission to Mercury. ESA’s Mercury Planetary Orbiter (MPO) will be operated from ESOC Germany.

    ESA’s Mercury Planetary Orbiter (MPO) will be operated from ESOC Germany.

    Speaking to reporters at an air show near Moscow in August 2011, ESA head Jean-Jacques Dordain said ESA and Russia’s Roskosmos space agency would “carry out the first flight to Mars together.”

     
  • richardmitnick 8:41 am on January 5, 2023 Permalink | Reply
    Tags: "Black holes are time machines with a catch", , , , , , EarthSky, The Australian Catholic University (AU)   

    From The Australian Catholic University (AU) Via “EarthSky” : “Black holes are time machines with a catch” 

    From The Australian Catholic University (AU)

    Via

    1

    “EarthSky”

    1.5.23
    Sam Baron

    Black holes form natural time machines that allow travel to both the past and the future. But don’t expect to be heading back to visit the dinosaurs any time soon. At present, we don’t have spacecraft that could get us anywhere near a black hole. But, even leaving that small detail aside, attempting to travel into the past using a black hole might be the last thing you ever do.

    What are black holes?

    A black hole is an extremely massive object that typically forms when a dying star collapses in on itself. Like planets and stars, black holes have gravitational fields around them. A gravitational field is what keeps us stuck to Earth, and what keeps Earth revolving around the sun.

    As a rule of thumb, the more massive an object is, the stronger its gravitational field. Earth’s gravitational field makes it extremely difficult to get to space. That’s why we build rockets: We have to travel very fast to break out of Earth’s gravity. The gravitational field of a black hole is so strong that even light can’t escape it. That’s impressive, since light is the fastest thing known to science!

    Incidentally, that’s why black holes are black: We can’t bounce light off a black hole the way we might bounce a flashlight off a tree in the dark.

    Stretching space

    Albert Einstein’s general Theory of Relativity tells us matter and energy have a curious effect on the universe. Matter and energy bend and stretch space. The more massive an object is, the more it stretches and bends the space around it.

    A massive object creates a kind of valley in space. When objects come near, they fall into the valley. That’s why, when you get close enough to any massive object, including a black hole, you fall toward it. It’s also why light can’t escape a black hole: The sides of the valley are so steep that light isn’t going fast enough to climb out.

    The valley created by a black hole gets steeper and steeper as you approach it from a distance. The point at which it gets so steep that light can’t escape is the event horizon. Event horizons aren’t just interesting for would-be time travelers: They’re also interesting for philosophers, because they have implications for how we understand the nature of time.

    Black holes stretching time

    When space is stretched, so is time. A clock that is near a massive object will tick slower than one that is near a much less massive object. A clock near a black hole will tick very slowly compared to one on Earth. One year near a black hole could mean 80 years on Earth, as you may have seen illustrated in the movie Interstellar.

    In this way, you could use black holes to travel to the future. If you want to jump into the future of Earth, simply fly near a black hole and then return to Earth. If you get close enough to the center of the black hole, your clock will tick slower, but you should still be able to escape so long as you don’t cross the event horizon.

    Loops in time

    What about the past? This is where things get truly interesting. A black hole bends time so much that it can wrap back on itself.

    Imagine taking a sheet of paper and joining the two ends to form a loop. That’s what a black hole seems to do to time. This creates a natural time machine. If you could somehow get onto the loop, which physicists call a closed time-like curve, you would find yourself on a trajectory through space that starts in the future and ends in the past.

    Inside the loop, you would also find that cause and effect get hard to untangle. Things that are in the past cause things to happen in the future, which in turn cause things to happen in the past!

    The catch

    So, you’ve found a black hole and you want to use your trusty spaceship to go back and visit the dinosaurs. Good luck.

    There are three problems. First, you can only travel into the black hole’s past. That means that if the black hole was created after the dinosaurs died out, then you won’t be able to go back far enough.

    Second, you’d probably have to cross the event horizon to get into the loop. This means that to get out of the loop at a particular time in the past, you’d need to exit the event horizon. That means traveling faster than light, which we’re pretty sure is impossible.

    Third, and probably worst of all, you and your ship would undergo spaghettification. Sounds delicious, right? Sadly, it’s not. As you crossed the event horizon you would be stretched flat, like a noodle. In fact, you’d probably be stretched so thin that you’d just be a string of atoms spiraling into the void.

    So, while it’s fun to think about the time-warping properties of black holes, for the foreseeable future that visit to the dinosaurs will have to stay in the realm of fantasy.

    See the full article here.

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    PENTAX DIGITAL CAMERA

    The Australian Catholic University is a public university in Australia. It has seven Australian campuses and also maintains a campus in Rome.

    Australian Catholic University was opened on 1 January 1991 following the amalgamation of four Catholic tertiary institutions in eastern Australia:

    Catholic College of Education Sydney, New South Wales
    Institute of Catholic Education, Victoria
    McAuley College, Queensland
    Signadou College of Education, Australian Capital Territory

    These institutions had their origins in the mid-1800s, when religious orders and institutes became involved in preparing teachers for Catholic schools and, later, nurses for Catholic hospitals. Through a series of amalgamations, relocations, transfers of responsibilities and diocesan initiatives, more than 20 historical entities have contributed to the creation of the university.

     
  • richardmitnick 10:05 am on January 4, 2023 Permalink | Reply
    Tags: "A large volcanic outburst on Jupiter’s moon Io", , EarthSky, ,   

    From “EarthSky” : “A large volcanic outburst on Jupiter’s moon Io” 

    1

    From “EarthSky”

    1.4.23
    Deborah Byrd

    1
    IoIO image of Jovian sodium nebula in outburst – corresponding with the large volcanic outburst on Io – in fall, 2022. Image via Jeff Morgenthaler/ Planetary Science Institute.

    A large volcanic outburst on Io

    The Planetary Science Institute said yesterday (January 3, 2023) that astronomer Jeff Morgenthaler discovered a large volcanic outburst on Jupiter’s moon Io last fall. It was the largest yet, he said. Morgenthaler has been remotely operating a new observatory he set up in 2017, in the desert near Tucson, Arizona.

    2
    Here’s the IoIO telescope, set up to be operated remotely from the desert near Tucson. A bright emission line of ionized sulfur is used to monitor material in Jupiter’s magnetosphere. Morgenthaler said: “The bright, extended nature of these emissions make them easily accessible to small-aperture telescopes developed for the high-end amateur astronomy market.” This telescope caught another large eruption on Io in 2018. And it has recorded images of Mercury’s sodium tail, and Comet NEOWISE in sodium. Image via Planetary Science Institute.

    His goal is to monitor changes in volcanic activity on Io. He has seen some sort of outburst nearly every year, but the outburst of northern hemisphere autumn, 2022, was the largest so far. Morgenthaler said his observations can be reproduced by any ambitious amateur astronomer.

    Io is the innermost of Jupiter’s four large moons and is the most volcanically active body in our solar system. It orbits so close to Jupiter that it is subject to gravitational stresses – or tidal forces – from the giant planet. Essentially, Jupiter squeezes Io like a rubber ball, creating Io’s volcanoes.

    Morgenthaler was using the Planetary Science Institute’s IoIO observatory. NASA and the National Science Foundation provide the funding for IoIO, which stands for Io Input/Output. Morgenthaler commented:

    One of the exciting things about these observations is that they can be reproduced by almost any small college or ambitious amateur astronomer. Almost all of the parts used to build IoIO are available at a high-end camera shop or telescope store.

    How IoIO works

    The Planetary Society explained:

    “IoIO uses a coronagraphic technique which dims the light coming from Jupiter to enable imaging of faint gases near the very bright planet. A brightening of two of these gases, sodium and ionized sulfur, began between July and September 2022 and lasted until December 2022. The ionized sulfur, which forms a donut-like structure that encircles Jupiter and is called the Io plasma torus, was curiously not nearly as bright in this outburst as previously seen.”

    Morgenthaler explained:

    “This could be telling us something about the composition of the volcanic activity that produced the outburst or it could be telling us that the torus is more efficient at ridding itself of material when more material is thrown into it.”

    Morgenthaler’s work involves studying changes in volcanic activity on Io to measure properties of Jupiter’s magnetosphere. A major goal of the project is to learn why ionized material from Io sticks close to Jupiter, rather than being flung out by Jupiter’s rapid rotation.

    What these observations mean for Juno

    While Morgenthaler has been scrutinizing Io from the ground, NASA’s Juno mission has been studying Jupiter from orbit.

    Juno has been orbiting Jupiter since 2016. Juno flew past Jupiter’s second moon outward, Europa, during the recent Io outburst. It is gradually approaching Io for a close flyby December 2023. The Planetary Society said:

    Several of Juno’s instruments are sensitive to changes in the plasma environment around Jupiter and Io that can be traced directly to the type of volcanic activity observed by IoIO.

    So, Juno’s measurements might be able to tell us if this volcanic outburst had a different composition than previous ones.

    More IoIOs?

    Morgenthaler said having one or more copies of IoIO running somewhere else would be very helpful in avoiding weather gaps and could potentially provide more time coverage each night of Jupiter’s highly dynamic Io plasma torus and sodium nebula. He said:

    “It would be great to see another IoIO come on line before Juno gets to Jupiter next December.”

    In addition to observing the Jovian sodium nebula, IoIO also observes Mercury’s sodium tail, bright comets and transiting extra-solar planets.

    3
    IoIO time sequence of singly ionized sulfur in the Io plasma torus, showing how the structure rotates with Jupiter’s powerful magnetic field which, like Earth’s, is not perfectly aligned with the rotation axis of the planet. Image via Jeff Morgenthaler/ PSI.

    See the full article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
  • richardmitnick 12:19 pm on December 18, 2022 Permalink | Reply
    Tags: "Meteorites May have Needed This 1 Thing to Help Bring About Life on Earth", , , , , , EarthSky, , Yokohama National University [横浜国立大学](JP)   

    From Yokohama National University [横浜国立大学](JP) Via “EarthSky” : “Meteorites May have Needed This 1 Thing to Help Bring About Life on Earth” 

    1

    From Yokohama National University [横浜国立大学](JP)

    Via

    1

    From “EarthSky”

    12.18.22
    Russell McLendon

    1
    (Dneutral Han/Moment/Getty Images)

    Earth is the only planet in the Universe known to host life, but even it was desolate at first. About 4 billion years ago, something happened to give our sterile rock the building blocks of life.

    Amino acids [PNAS (below)], for example, needed to exist before Earth could have proteins, a vital component of all life forms. The origins of Earth’s amino acids remain murky, but some scientists suspect these organic compounds were delivered from space by meteorites.

    In a new study [ACS Central Science (below)], researchers reveal details about how that could have happened, supporting the idea that meteorites helped establish life on Earth [PNAS (below)].

    The study shows how a certain class of meteorites called chondrites could produce their own amino acids thanks to reactions powered by gamma rays from the meteorites themselves.

    Meteorites are chunks of ancient debris left over from the Solar System’s infancy that crash onto a planet or moon. Different types of meteorites feature different materials.

    Chondrites are stony meteorites embedded with mysterious spheres known as chondrules. Made primarily of silicate minerals, chondrules are among the oldest objects in the Solar System.

    Meteorites have bombarded Earth since the beginning, and some of the early barrages may have included carbonaceous chondrites [Nature Communications (below)] – a relatively rare subcategory of chondrite that holds significant amounts of water [Space Science Reviews (below)] and small molecules, including amino acids.

    Such meteorites could have given Earth vital ingredients for life, but how did those ingredients get onto a meteorite [Science Advances (below)]. in the first place?

    We still aren’t sure, but the new study illuminates how chondrites (or their parent bodies) are at least theoretically capable of synthesizing these compounds.

    Led by cosmochemist Yoko Kebukawa from Yokohama National University in Japan, the researchers sought to resolve questions from previous lab experiments [Science Advances (below)] investigating the potential formation of amino acids on carbonaceous chondrites [Life (below)].

    Those experiments showed that simple molecules like ammonia and formaldehyde could generate amino acids, but only in the presence of heat and liquid water. In the new study, researchers examine a possible heat source from the meteorite: gamma rays.

    Early carbonaceous chondrites are known to have contained aluminum-26, a radioactive element that can release gamma radiation as it decays. Kebukawa and her colleagues decided to test whether this could provide the heat needed to form amino acids.

    Researchers dissolved ammonia and formaldehyde in water, sealed the resulting solution inside glass tubes, and then exposed the tubes to high-energy gamma rays from decaying cobalt-60.

    As the dose of gamma radiation increased, so did the production of α-amino acids like alanine, glycine, α-aminobutyric acid, and glutamic acid, along with β-amino acids like β-alanine and β-aminoisobutyric acid.

    The researchers note that these amino acids could help explain the presence of these amino acids on carbonaceous chondrites that have fallen to Earth, such as Australia’s famous Murchison meteorite.

    2
    Murchison meteorite at the The National Museum of Natural History (Washington)

    Loaded with “presolar” silicon carbide particles (meaning they’re older than the Sun [PNAS (below)]), the Murchison meteorite exploded in the sky over Murchison, Victoria, on 28 September 1969. It was a widely observed event; people collected a trove of fragments from the area afterward. It has since become one of the most studied space rocks in history.

    Among many interesting finds, the Murchison meteorite was packed with amino acids. Scientists have so far identified more than 70 amino acids from the meteorite, only 19 of which are known from Earth, according to Museums Victoria.

    This has stirred widespread fascination, suggesting that life on Earth’s basic chemical building blocks can also easily form elsewhere.

    3
    A meteor with outsides fused in the heat of hitting Earth’s atmosphere and its organic-rich grainier inside. (Steve Jurvetson/Flickr/CC BY 2.0)

    In the new study, Kebukawa and her colleagues investigated how amino acids might arise on a meteorite like this and how long it might take.

    Based on their results, plus the expected dose of gamma radiation from decaying aluminum-26 in meteorites, they estimate it would take between 1,000 and 100,000 years for this process to generate the amount of alanine and β-alanine found on the Murchison meteorite.

    Although we still have a lot to learn about abiogenesis, or the spontaneous generation of life, the researchers say this study shows how reactions sparked by gamma rays can produce amino acids on a meteorite, potentially contributing to the origin of life on Earth.

    The study was published in ACS Central Science [below].

    Science papers:
    PNAS 2017
    ACS Central Science
    PNAS
    Nature Communications 2019
    Science Advances 2018
    Science Advances 2017
    Life 2021
    PNAS
    See the above science papers for instructive material with images.
    Space Science Reviews 2019

    See the full article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
  • richardmitnick 10:32 am on December 18, 2022 Permalink | Reply
    Tags: "1st TRAPPIST-1 results from Webb Space Telescope", , , , EarthSky, , ,   

    From “EarthSky” And The NASA/ESA/CSA James Webb Space Telescope: “1st TRAPPIST-1 results from Webb Space Telescope” 

    1

    From “EarthSky”

    And

    NASA Webb Header

    National Aeronautics Space Agency/European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU)/ Canadian Space Agency [Agence Spatiale Canadienne](CA) James Webb Infrared Space Telescope annotated, finally launched December 25, 2021, ten years late.

    12.17.22
    Paul Scott Anderson

    Webb’s 1st observations of TRAPPIST-1

    1
    Artist’s concept of the intriguing TRAPPIST-1 exoplanet system, just 39 light-years from Earth. It has 7 Earth-sized rocky planets, at least 3 of which are potentially habitable. Webb has taken its 1st look at these fascinating worlds, and researchers just announced the initial findings. Image via NASA/ JPL-Caltech/ Nature [below].

    Webb began observing the nearby and fascinating TRAPPIST-1 exoplanet system last June. And now the initial highly-anticipated first results are in [Nature (below)]. Astronomer Björn Benneke of the University of Montreal announced them on December 13, 2022, at the Space Telescope Science Institute symposium in Baltimore, Maryland. As Benneke said to the audience of astronomers:

    “We’re in business.”

    And veteran science journalist Alexandra Witze then reported on Benneke’s announcement in Nature [below], the next day. The associated science papers have not been published yet, but will be starting in early 2023.

    Why the hubbub? The fact is that TRAPPIST-1 is one of the most eagerly anticipated targets for Webb. The system contains no fewer than seven rocky planets, all similar in size to Earth. At least three of the planets are in this star’s habitable zone, where temperatures could allow liquid water to exist. The other planets are also close to the habitable zone. All at only 39 light-years away.

    The new Webb findings are preliminary. So they don’t answer the question of whether any of the seven rocky planets – all similar in size to Earth – could support life … yet. But they do show the potential for Webb to study this beguiling nearby system.

    TRAPPIST-1b and TRAPPIST-1g

    The initial observations focused on two of the planets, TRAPPIST-1b and TRAPPIST-1g. Planet b is the closest to the star and planet g is the second farthest (with TRAPPIST-1h being the farthest).

    3
    TRAPPIST-1b

    4
    TRAPPIST-1g

    See the full article for this thorough going explication of the Trappist-1 system

    TRAPPIST-1g is the largest of the planets, with a radius 1.154 times that of Earth. The results, so far, indicate that it is unlikely to have a deep primordial hydrogen atmosphere. Larger gas and ice giants, like Jupiter or Neptune in our own solar system, tend to have such atmospheres. This means that TRAPPIST-1g could have a thinner, more terrestrial-type atmosphere, like that of Earth, Venus or Mars. If so, that would be good for the prospects of possible life, since those are secondary atmospheres, ones that have undergone significant chemical alterations over millions or billions of years. For example, Earth’s primarily nitrogen atmosphere is largely due to life processes changing it over time.

    More observations needed

    More observations will be needed, however, to determine just what TRAPPIST-1g’s atmosphere is like, if it does have one. This is because the TRAPPIST-1 planets are small, close to their star and far away (39 light-years). Even with Webb it requires several orbits of the planet, where it transits in front of its star, to analyze the atmosphere in detail. Larger exoplanets, like WASP-39b, are easier to study.

    6
    WASP-39b. Credit: NASA.

    The same is even more true for TRAPPIST-1b, since it is a little smaller and the closest to its star. As Witze wrote:

    Olivia Lim of the University of Montreal showed two Webb observations of the innermost planet in the system, TRAPPIST-1b. She, too, has not been able to tease out a signal indicating the planet’s atmosphere just yet. But preliminary studies suggest that it, like planet 1g, probably doesn’t have a puffy, hydrogen-rich atmosphere.

    A TRAPPIST-1 family portrait

    While these first results may not sound too exciting, rest assured that much more is coming about all seven planets. In fact, as Knicole Colon, an astronomer at NASA’s Goddard Space Flight Center, noted:

    “Within the next year we’ll have a family portrait.”

    It will be interesting to see just how many of the seven planets do actually have atmospheres (if any) and how they compare to each other. There is some concern that at least some of the planets may have lost their atmospheres. This is due to the fact that they orbit a red dwarf star.

    7
    A Chandra satellite x-ray image of the closest star to the Sun: the red dwarf, Proxima Centauri.
    Credit: NASA/CXC/SAO

    Red dwarfs are known for being highly active, emitting intense solar flares that can strip a planet of its atmosphere if it is too close. This is still a subject of much debate, however. A study from 2021 [MNRAS (below)] showed that many red dwarf planets may actually be safe from solar flares after all.

    TRAPPIST-1 at the 241st Meeting of the American Astronomical Society

    There will also be updates about both TRAPPIST-1b and TRAPPIST-1g given at the upcoming 241st Meeting of the American Astronomical Society in Seattle, Washington (January 8-12, 2023).

    From the abstract for TRAPPIST-1b:

    “In this talk, we present the first high-precision transit spectra of the warm Earth-sized planet TRAPPIST-1b based on two transit observations using NIRISS [below] in SOSS mode on the James Webb Space Telescope. TRAPPIST-1b is the most favorable Earth-sized planet for characterization via transmission spectroscopy among all exoplanets. As such, our observations have the sensitivity to detect a wide range of atmospheres, providing unprecedented insight into the potentially secondary atmosphere on a rocky Earth-sized planet outside the solar system.”

    From the abstract for TRAPPIST-1g:

    “The rocky exo-Earth TRAPPIST-1g is particularly well-suited for this kind of first study because the low stellar insolation can allow for habitable conditions on its surface, while the small host star strongly amplifies the observable spectroscopic transit signature compared to planets orbiting sun-like stars. Here, we present the first high-precision JWST transmission spectrum of a habitable-zone exo-Earth, the planet TRAPPIST-1g, covering the full spectra range between 0.6-5.3µm, obtained through two JWST transits observations using the NIRSpec [below] PRISM BOTS mode.”

    The sensitivity of these observations is sufficient to detect secondary terrestrial atmospheres of a wide range of compositions, with molecular bands of CO2, H2O, CH4, NH3, and SO2 plausibly directly detectable if present.

    2023 should be an interesting and exciting year for anyone who has been following the discovery and subsequent studies of the TRAPPIST-1 system. What will Webb discover?

    Science article:
    Nature
    See the article for instructive material with images.

    Science paper:
    MNRAS
    See the science paper for instructive material with images and tables.

    See the full article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Webb is a large infrared telescope with a 6.5-meter primary mirror. Webb was finally launched December 25, 2021, ten years late. Webb will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.

    Webb is the world’s largest, most powerful, and most complex space science telescope ever built. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it.

    Webb was formerly known as the “Next Generation Space Telescope” (NGST); it was renamed in Sept. 2002 after a former NASA administrator, James Webb.

    Webb is an international collaboration between National Aeronautics and Space Administration, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center managed the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute operates Webb.

    Several innovative technologies have been developed for Webb. These include a folding, segmented primary mirror, adjusted to shape after launch; ultra-lightweight beryllium optics; detectors able to record extremely weak signals, microshutters that enable programmable object selection for the spectrograph; and a cryocooler for cooling the mid-IR detectors to 7K.

    There are four science instruments on Webb: The Near InfraRed Camera (NIRCam), The Near InfraRed Spectrograph (NIRspec), The Mid-InfraRed Instrument (MIRI), and The Fine Guidance Sensor/ Near InfraRed Imager and Slitless Spectrograph (FGS-NIRISS).

    Webb’s instruments are designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range. It will be sensitive to light from 0.6 to 28 micrometers in wavelength.
    National Aeronautics Space Agency Webb NIRCam.

    The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganization](EU) Webb MIRI schematic.

    Webb has four main science themes: The End of the Dark Ages: First Light and Reionization, The Assembly of Galaxies, The Birth of Stars and Protoplanetary Systems, and Planetary Systems and the Origins of Life.

    Launch was December 25, 2021, ten years late, on an Ariane 5 rocket. The launch was from Arianespace’s ELA-3 launch complex at European Spaceport located near Kourou, French Guiana. Webb is located at the second Lagrange point, about a million miles from the Earth.

    ESA50 Logo large

    Canadian Space Agency

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
  • richardmitnick 9:52 am on December 16, 2022 Permalink | Reply
    Tags: "The Orion Nebula is a starry nursery", , , , , EarthSky, Harvard-Smithsonian Center for Astrophysics in Cambridge Mass., Messier 42 - the Orion Nebula., , Steward Observatory at University of Arizona, The Trapezium   

    From “EarthSky” : “The Orion Nebula is a starry nursery” 

    1

    From “EarthSky”

    12.16.22
    Bruce McClure

    1
    Rudy Kokich in Virginia took this composite image of the Orion Nebula in January 2021. Rudy wrote: “The Orion Nebula is one of the most familiar celestial objects, easily visible to the unaided eye below the 3 stars of Orion’s Belt. It’s a large cloud of dust and gas, about 25 light-years in extent, partially illuminated by emission and reflection components.” Thank you, Rudy!

    Orion the Hunter is the most noticeable of all constellations. The three stars of Orion’s Belt jump out at you as a short, straight row of medium-bright stars, midway between Orion’s two brightest stars, Betelgeuse and Rigel.

    2
    Light from the star Rigel reflects off the dust composing the Witch Head Nebula. (Image credit: Rogelio Bernal Andreo / NASA)

    Once you find the Belt stars, you can also locate the Orion Nebula, otherwise known as Messier 42. When you look at it, you’re gazing toward a stellar nursery, a place where new stars are born.

    How to locate the Orion Nebula

    If you want to find this famous nebula, first you have to locate the constellation Orion.

    3
    Orion the Hunter – visible to both hemispheres – rises in the east on December evenings. Chart via Chelynne Campion/ EarthSky.

    Fortunately, that’s easy, if you’re looking at the right time of year. The Northern Hemisphere winter months (Southern Hemisphere summer months) are the perfect time to come to know Orion.

    First, look for the three medium-bright stars in a short, straight row. These stars represent Orion’s Belt.

    Next, if you look closely, you’ll notice a curved line of stars “hanging” from the three Belt stars. These stars represent Orion’s Sword. Look for the Orion Nebula about midway down in the Sword of Orion.

    As a general rule, the higher the constellation Orion is in the sky, the easier it is to see the Orion Nebula. From Northern Hemisphere locations, Orion is due south and highest in the sky around midnight in the middle of December. The stars return to the same place in the sky some four minutes earlier each night, or two hours earlier each month. So look for Orion to be highest up around 10 p.m. in mid-January and 8 p.m. in mid-February.

    Another time people notice Orion is around the months of August and September, when this constellation appears in the east before dawn.

    A globe of luminescent fog

    Most nebulae – clouds of interstellar gas and dust – are difficult if not impossible to see with the unaided eye or even binoculars. But the Orion Nebula is in a class nearly all by itself. It’s visible to the unaided eye on a dark, moonless night. To me, it looks like a star encased in a globe of luminescent fog. The star-gazing aficionado Stephen James O’Meara described it as:

    ” … angel’s breath against a frosted sky.”

    In a dark-sky location, observe the Orion Nebula for yourself to see what it looks like. A backyard telescope, or even binoculars, will do wonders to showcase one of the greatest celestial treasures in the winter sky.

    6
    Parisa Bajelan took this photo on November 17, 2017, from Iran and shared it with EarthSky. Parisa wrote: “Lut Desert is one of the hottest and darkest areas on earth. Lut Desert National Park has many wonders, spectacular wildlife, geo-tourism attractions, well-designed eco-resorts, a marvelous starry sky and adventure recreation activities as well.” Thank you, Parisa! Can you see the expanded glow around one of the Sword stars? That’s Messier 42, the Orion Nebula.

    Science and the Orion Nebula

    According to modern astronomers, the Orion Nebula is an enormous cloud of gas and dust, one of many in our Milky Way galaxy. It lies roughly 1,300 light-years from Earth.

    At some 30 to 40 light-years in diameter, this great nebulous cocoon is giving birth to perhaps a thousand stars. A young open star cluster, whose stars were born together in the gas cloud and are still loosely bound by gravity, appears within the nebula. Some people refer to it as the Orion Nebula Star Cluster. In 2012, an international team of astronomers suggested this cluster in the Orion Nebula might have a black hole at its heart.

    Through small telescopes you can see the four brightest stars in the Orion Nebula, known as the Trapezium.

    7
    Two views of the Trapezium cluster in the Orion Nebula, from the Hubble Space Telescope. The image on the left, an optical spectrum image taken with Hubble’s WFPC2 camera, shows a few stars shrouded in glowing gas and dust.

    On the right, an image taken with Hubble’s NICMOS infrared camera penetrates the haze to reveal a swarm of stars as well as brown dwarfs. Source: http://hubblesite.org/newscenter/newsdesk/archive/releases/2000/19

    Credits for near-infrared image: K.L. Luhman (Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.)/NASA; ; and G. Schneider, E. Young, G. Rieke, A. Cotera, H. Chen, M. Rieke, R. Thompson (Steward Observatory, University of Arizona, Tucson, Ariz.)

    Credits for visible-light picture: NASA, C.R. O’Dell and S.K. Wong (Rice University)

    The light of the young, hot Trapezium stars illuminate the Orion Nebula. These stars are only a million or so years old, babies on the scale of star lifetimes.

    But most of the stars in this emerging cluster are veiled behind the Orion Nebula itself, the great stellar nursery in Orion’s Sword.

    The Orion Nebula’s position is Right Ascension: 5h 35m; Declination: 5 degrees 23′ south.

    See the full article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: