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  • richardmitnick 9:44 am on August 7, 2018 Permalink | Reply
    Tags: , , , , , EarthSky,   

    From EarthSky: “Dark Rift in the Milky Way” 

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    From EarthSky

    August 7, 2018
    Bruce McClure

    Milky Way NASA/JPL-Caltech /ESO R. Hurt

    Standing under a dark sky? Look up! In August, you’ll notice a long, dark lane dividing the bright Milky Way. This Dark Rift is a place where new stars are forming.

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    Thick dust clouds block our night-time view of the Milky Way, creating what is sometimes called the Great Rift or Dark Rift. Image via NASA.

    Have you ever looked up from a dark place on a starry August evening and noticed the dark areas in the Milky Way? For centuries, skywatchers pondered this Great Rift or Dark Rift, as it’s called, but today’s astronomers know it consists of dark, obscuring dust in the disk of our Milky Way galaxy.

    How to see the Dark Rift. The Milky Way is easy to see if you have dark skies. It’s a shining band, stretching across the sky. If you want to see the Dark Rift, that’s easy, too, as long as you realize you aren’t looking for a bright object. You’re looking instead for dark lanes of dust, running the length of the starlit Milky Way band.

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    The Great Rift – also known as the Dark Rift – and the Milky Way pass through the Summer Triangle and above the Teapot asterism in Sagittarius.

    You will be looking south from sometime in June or July (probably) through about October – in a dark sky – and, from a Northern Hemisphere location, you’ll see the Milky Way come off the southern to southeastern horizon. Notice that the Milky Way band looks milky white. The skies aren’t really black like ink between stars in the Milky Way. You will know when you see the Dark Rift because it is as if someone took a marker and colored it darker.

    The Dark Rift begins just above the constellation Sagittarius the Archer. Follow the Milky Way up until you see a black area in the Milky Way just before you get to the constellation Cygnus, which has the shape of a cross.

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    Photo via Manish Mamtani.

    Don’t miss the Milky Way and Great Rift rise. One of the most spectacular sights is to see the Milky Way as it rises. Around 10 p.m. in June, step outside and look in the east to see the phenomena of the Great Rift and the rest of the Milky Way make its dramatic entrance as it rises into the night skies. In July and August, the Great Rift will already be up as darkness falls.

    Make sure you have your binoculars handy to scan the Milky Way. There are many interesting star-forming regions, star clusters and millions of stars that will capture your attention.

    Look in the Great Rift and imagine all the stars that will eventually reveal themselves as the molecular gas dissipates. More about that below.

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    ESA/Planck
    Shown is the interaction between interstellar dust in the Milky Way and the structure of our galaxy’s magnetic field, as detected by ESA’s Planck satellite over the entire sky. Image via ESA on Pinterest.

    ESA/Planck 2009 to 2013

    Molecular dust is the reason it is dark. Stars are formed from great clouds of gas and dust in our Milky Way galaxy and other galaxies. When we look up at the starry band of the Milky Way and see the Dark Rift, we are looking into our galaxy’s star-forming regions. The protostars (newly forming stars) are generating molecular dust that doesn’t allow light in the visual spectrum to shine through.

    However, with the advancement of telescopes that see in different light waves – such as X-rays or infrared – we now know that there’s activity in the area.

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    This painting shows some of the animal shapes that the Incas saw in the Dark Rift of the Milky Way. Image via Coricancha Sun Temple in Cusco/Futurism.

    Ancient cultures focused on the dark not the light areas. You know those paintings where if you look at the light areas you see one thing, but in the dark areas you see something else?

    The Dark Rift is a bit like that. A few ancient cultures in Central and South America saw the dark areas of the Milky Way as constellations. These dark constellations had a variety of myths associated with them. For example, one important dark constellation was Yacana the Llama. It rises above Cuzco, the ancient city of the Incas, every year in November.

    By the way, the other famous area of the sky that is obscured by molecular dust is visible from the Southern Hemisphere. It’s the famous Coalsack Nebula near the Southern Cross, also known as the constellation Crux. The Coalsack is another region of star-forming activity in our night sky – much like the Great Rift.

    Bottom line: On an August night, looking edgewise into our galaxy’s disk, you’ll notice a long, dark lane dividing the bright starry band of the Milky Way. This so-called Dark Rift or Great Rift is a place where new stars are forming.

    See the full article here .


    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.

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  • richardmitnick 12:54 pm on August 2, 2018 Permalink | Reply
    Tags: , , , , , , EarthSky, Life on moon Titan   

    From Astrobiology Magazine via EarthSky: “Where to look for life on Titan” 

    http://www.astrobio.net/

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    From EarthSky

    August 2, 2018
    Paul Scott Anderson

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    Saturn’s largest moon Titan as seen by the Cassini spacecraft. This world’s liquid methane and ethane rivers, lakes and seas might support some kind of life, and scientists now think they know the best places to look. Image via NASA/JPL-Caltech.

    NASA/ESA/ASI Cassini-Huygens Spacecraft

    NASA’s Cassini spacecraft and ESA’s Huygens lander showed that Saturn’s large moon Titan mimics Earth in many ways. But Titan displays different kinds of chemistry in a far colder environment. Given the similarities, the question of life inevitably arises: could Titan support some kind of simple life? Given the differences, scientists ponder the best places to look for Titan life. In late July 2018, a new study published in the peer-reviewed journal Astrobiology and reported on in Astrobiology Magazine suggests the best places on Titan to look for evidence of life.

    Titan is a geological wonderland for planetary scientists. It has rivers, lakes and seas of actual liquid – not water, but the hydrocarbons methane and ethane – and it has mountain ranges, possible ice volcanoes (aka cryovolcanoes) and vast hydrocarbon dunes. There is also evidence for a subsurface ocean of water, similar to those believed to lie beneath the surface of Jupiter’s moon Europa and Saturn’s moon Enceladus.

    Perhaps surprisingly, the research team, led by Catherine Neish, a planetary scientist specializing in impact cratering at the University of Western Ontario, suggested that the best locations to look for life on Titan would not be the lakes or seas. Instead, the new work shows a better place to look would be within impact craters and cryovolcanoes on Titan.

    The scientists reason that these areas are where water ice in Titan’s crust could temporarily melt into a liquid. Water is still the only solvent known to be able to support life as we know it.

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    A large, fairly young crater on Titan, about 25 miles (40 km) in diameter. Such craters could temporarily melt frozen water in the crust, providing an environment for pre-biotic or biotic molecules to form. Image via NASA/JPL-Caltech.

    Various studies have suggested that liquid methane and ethane could support life. But Saturn’s moon Titan – some nine astronomical units farther from the sun than Earth – is very cold, with surface temperatures hovering around -300 degrees Fahrenheit (–179 degrees Celsius). Methane and ethane do remain liquid at Titan’s surface temperature, but it’s too cold there for biochemical processes, at least as far as we know (although that, too, is a matter of debate).

    Titan’s surface is also covered with tholins, which are large, complex organic molecules produced when gases are subjected to cosmic radiation. When mixed with liquid water, tholins can produce amino acids, which are, essentially, life’s building blocks. According to researcher Morgan Cable at NASA’s Jet Propulsion Laboratory in Pasadena, California:

    “When we mix tholins with liquid water, we make amino acids really fast. So any place where there is liquid water on Titan’s surface or near its surface could be generating the precursors to life – biomolecules – that would be important for life as we know it, and that’s really exciting.”

    The temperatures on Titan’s surface are too cold for liquid water, so where could it be found? The answer is Titan’s craters and cryovolcanoes. The processes involved with both of these geologic features can melt water ice into liquid, even if only temporarily.

    But that might be enough for more complex organic molecules like amino acids to form.

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    Sotra Facula is a possible cryovolcano on Titan, one of the few candidates known. Image via NASA/JPL–Caltech/USGS/University of Arizona.

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    Another view of Sotra Facula. This image was built from radar topography with infrared colors overlaid on top. Image via NASA/JPL–Caltech/USGS/University of Arizona.

    Between craters and cryovolcanoes, it would seem that craters would be the most ideal location for pre-biotic or biotic chemistry to occur. As Neish explained:

    “Craters really emerged as the clear winner for three main reasons. One, is that we’re pretty sure there are craters on Titan. Cratering is a very common geologic process and we see circular features that are almost certainly craters on the surface.’

    Neish also noted that craters would produce more liquid water melt than a cryovolcano, so any water would remain liquid for a longer period of time. She also added:

    “The last point is that impact craters should produce water that’s at a higher temperature than a cryovolcano.”

    Warmer water would allow for faster chemical reaction rates, which would help in the creation of prebiotic or even biotic molecules. The largest known craters on Titan are Sinlap (70 miles/112 kms in diameter), Selk (56 miles/90 kms) and Menrva (244 miles/392 kms). These would be the primary locations to look for biomolecules.

    David Grinspoon at the Planetary Science Institute isn’t convinced yet, however. He commented:

    “We don’t know where to search even with results like this. I wouldn’t use it to guide our next mission to Titan. It’s premature.”

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    Titan is well-known for its lakes and seas of liquid methane/ethane, such as Ligiea Mare, shown here. Image via NASA/JPL-Caltech/ASI/Cornell.

    So what about cryovolcanoes? They haven’t actually been confirmed yet to exist on Titan, and if they do, they are more rare than craters (even though craters are also relatively rare on Titan). The most likely feature to be a cryovolcano is a mountain with a caldera on top called Sotra Facula. Other than that, they seem to be few and far between. As Neish said:

    “Cryovolcanism is the harder thing to do and there is very little evidence of it on Titan.”

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    Diagram illustrating how biosignatures could also be transported from the subsurface ocean to the surface of Titan. Image via Athanasios Karagiotas/Theoni Shalamberidze.

    There is also, of course, a possible subsurface ocean of water on Titan, but, if it exists, it is deep below the moon’s surface and inaccessible to any robotic probes in the near future. For now, we can only imagine what might be in that alien abyss.

    The methane/ethane lakes and seas should still be explored too; they are the only other known bodies of liquid on the surface of another moon or planet in the solar system. Methane-based life could theoretically exist in such environments, so it would obviously be a good idea to look, at least.

    Bottom line: Titan is a world that is eerily similar to Earth in some ways, yet still uniquely alien. Whether it supports any kind of life is still a big question, but researchers now think they know the best places to search for it.

    See the full article here .


    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 2:14 pm on June 17, 2018 Permalink | Reply
    Tags: , EarthSky, ,   

    From EarthSky: “Kilauea volcano lava river flows to sea” 

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    From EarthSky

    June 17, 2018
    Adam Voiland/NASA Earth Observatory

    Kilauea volcano’s Fissure 8 has produced a large, channelized lava flow that’s acted like a river, eating through the landscape, finally producing clouds of steamy, hazardous “laze” as hot lava meets the cold ocean.

    Steaming fissures in the Kilauea volcano first began to crack open and spread lava across Hawaii’s Leilani Estates neighborhood on May 3, 2018. Since then, more than 20 fissures have opened on the Kilauea’s Lower East Rift Zone, though most of the lava flows have been small and short-lived.

    Not so for Fissure 8. That crack in the Earth has been regularly generating large fountains of lava that soar tens to hundreds of feet into the air. It has produced a large, channelized lava flow that has acted like a river, eating through the landscape as it flows toward the sea.

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    Photo shows Fissure 8 of Kilauea volcano in Hawaii. Fissure 8 fountains reached heights up to 160 feet overnight on Friday. The USGS Hawaiian Volcano Observatory reports that fragments falling from the fountains are building a cinder-and-spatter cone around the vent. USGS image taken June 12, 2018, around 6:10 a.m. HST. View the latest images and videos via USGS.

    While the Fissure 8 lava flow initially remained in relatively narrow channels, it began to widen significantly as it neared the coastline and passed over flatter land. It evaporated Hawaii’s largest lake in a matter of hours, and devastated the communities of Vacationland and Kapoho, destroying hundreds of homes [which probably should never have been built there. Lessons unlearned also in the New Jersey shore communities].

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    May 14, 2018. Image via NASA.

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    June 7, 2018. Image via NASA.

    On June 3, 2018, lava from Fissure 8 reached the ocean at Kapoho Bay on Hawaii’s southeast coast. When the Multi-Spectral Instrument (MSI) on the European Space Agency’s Sentinel-2 satellite captured a natural-color image on June 7 (top image, above), the lava had completely filled in the bay and formed a new lava delta.

    ESA/Sentinel 2

    For comparison, the Landsat 8 image shows the coastline on May 14 (lower image, above).

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    June 15, 2018, photo of Fissure 8. This fissure has produced a lava fountain pulsing to heights of 185 to 200 feet (55 to 60 meters). Spattering has built a cinder cone that partially encircles Fissure 8, now 170 feet (51 meters) tall at its highest point. The steam in the foreground is the result of heavy morning rain falling on warm (not hot) tephra (lava fragments).

    Since May 3, 2018, Kilauea has erupted more than 110 million cubic meters of lava. That is enough to fill 45,000 Olympic-sized swimming pools, cover Manhattan Island to a depth of 7 feet (2 meters), or fill 11 million dump trucks, according to estimates from the U.S. Geological Survey (USGS). However, that is only about half of the volume erupted at nearby Mauna Loa in a major eruption in 1984.

    The new land at Kapoho Bay is quite dynamic, fragile, and dangerous. USGS warns:

    “Venturing too close to an ocean entry on land or the ocean exposes you to flying debris from sudden explosive interaction between lava and water.”

    Since lava deltas are built on unconsolidated fragments and sand, the loose material can abruptly collapse or quickly erode in the surf.

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    This thermal map shows the fissure system and lava flows as of 5:30 p.m. on Saturday, June 9, 2018. The flow from fissure 8 remains active, with the flow entering the ocean at Kapoho. The black and white area is the extent of the thermal map. Temperature in the thermal image is displayed as gray-scale values, with the brightest pixels indicating the hottest areas. Image via USGS.

    The plumes that form where lava meets seawater are also hazardous. Sometimes called laze, these white plumes of hydrochloric acid gas, steam, and tiny shards of volcanic glass can cause skin and eye irritation and breathing difficulties.

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    The ocean entry remains fairly broad with a white steam/laze plume blowing onshore. USGS image taken June 15, 2018.

    See the full article here .


    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 8:41 am on May 17, 2018 Permalink | Reply
    Tags: , , , , EarthSky, , Pale Blue Dot, Wall-E and Eva CubeSats   

    From JPL-Caltech via EarthSky: “Wall-E and Eva set record, snag pic” 

    NASA JPL Banner

    JPL-Caltech

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    From EarthSky

    May 17, 2018
    Deborah Byrd

    The 1st-ever interplanetary CubeSats – nicknamed Wall-E and Eva – are now on their way to Mars. They set a new CubeSat distance record on May 8. Then Wall-E turned back and grabbed an image of the Earth and moon.

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    This is the 1st distant image of the Earth and moon ever captured by a CubeSat. MarCO-B – nicknamed Wall-E by spacecraft engineers at NASA’s Jet Propulsion Laboratory – acquired this image on May 9, 2018. Image via NASA JPL-Caltech.

    The Voyager 1 spacecraft took a classic portrait of Earth – the famous Pale Blue Dot image – from several billion miles away in 1990.

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    Pale Blue Dot. https://photojournal.jpl.nasa.gov/catalog/PIA00452

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    Pale Blue Dot. SETI

    NASA/Voyager 1

    On May 9, 2018, two tiny, boxy spacecraft known as CubeSats – nicknamed Wall-E and Eva by spaceflight engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California – took their own version of a pale blue dot image, capturing Earth and its moon in one shot.

    This is the Mars Cube One or MarCO mission, launched on May 5 along with NASA’s InSight lander. InSight will touch down on Mars this November and study the planet’s deep interior for the first time.

    NASAMars Insight Lander

    The two little spacecraft are the first CubeSats ever to travel to interplanetary space. Most never go beyond Earth orbit; they generally stay below 497 miles (800 km) above the planet. Originally developed to teach university students about satellites, these modular mini-satellites are now a major commercial technology, providing data on everything from shipping routes to environmental changes.

    On May 8, Wall-E and Eva set a new distance record (for CubeSats) when they reached 621,371 miles (~1 million km) from Earth. Then Wall-E – aka Mars Cube One B or MarCO-B – used a fisheye camera to snap its first photo on May 9. That photo – which you see above – is part of the process used by the engineering team to confirm the spacecraft’s high-gain antenna has unfolded properly.

    Andy Klesh, the MarCO project’s chief engineer at JPL, said:

    “Consider it our homage to Voyager.”

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    Awesome shot of Insight Mars launch – with the MarCos on board – on May 5, 2018. Despite fog at the launch site, photographer Alex Ustick in California was one of many who caught Insight climbing to space. Notice Jupiter!

    NASA explained Wall-E and Eva’s role in the Insight mission:

    “The MarCO CubeSats will follow along behind InSight during its cruise to Mars. Should they make it all the way to Mars, they will radio back data about InSight while it enters the atmosphere and descends to the planet’s surface. The high-gain antennas are key to that effort; the MarCO team have early confirmation that the antennas have successfully deployed, but will continue to test them in the weeks ahead.

    InSight won’t rely on the MarCO mission for data relay. That job will fall to NASA’s Mars Reconnaissance Orbiter. But the MarCOs could be a pathfinder so that future missions can “bring their own relay” to Mars. They could also demonstrate a number of experimental technologies, including their antennas, radios and propulsion systems, which will allow CubeSats to collect science in the future.”

    Later this month, NASA said, the MarCOs will attempt the first trajectory correction maneuvers ever performed by CubeSats. NASA explained:

    “This maneuver lets them steer towards Mars, blazing a trail for CubeSats to come.”

    See the full article here .

    Please help promote STEM in your local schools.

    stem

    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.

    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge, on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

    Caltech Logo

    NASA image

     
  • richardmitnick 2:22 pm on May 12, 2018 Permalink | Reply
    Tags: , , , , , EarthSky, , ,   

    From Harvard-Smithsonian Center for Astrophysics via EarthSky: “What’s a safe distance between us and a supernova?” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    EarthSky

    May 11, 2018

    And how many potentially exploding stars are located within the unsafe distance?

    A supernova is a star explosion – destructive on a scale almost beyond human imagining. If our sun exploded as a supernova, the resulting shock wave probably wouldn’t destroy the whole Earth, but the side of Earth facing the sun would boil away. Scientists estimate that the planet as a whole would increase in temperature to roughly 15 times hotter than our normal sun’s surface. What’s more, Earth wouldn’t stay put in orbit. The sudden decrease in the sun’s mass might free the planet to wander off into space. Clearly, the sun’s distance – 8 light-minutes away – isn’t safe. Fortunately, our sun isn’t the sort of star destined to explode as a supernova. But other stars, beyond our solar system, will. What is the closest safe distance? Scientific literature cites 50 to 100 light-years as the closest safe distance between Earth and a supernova.

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    Image of remnant of SN 1987A as seen at optical wavelengths with the Hubble Space Telescope in 2011.

    NASA/ESA Hubble Telescope

    This supernova was the closest in centuries, and it was visible to the eye alone. It was located on the outskirts of the Tarantula Nebula in the Large Magellanic Cloud, a satellite galaxy to our Milky Way. It was located approximately 168,000 light-years from Earth. Image via NASA, ESA, and P. Challis (Harvard-Smithsonian Center for Astrophysics).

    What would happen if a supernova exploded near Earth? Let’s consider the explosion of a star besides our sun, but still at an unsafe distance. Say, the supernova is 30 light-years away. Dr. Mark Reid, a senior astronomer at the Harvard-Smithsonian Center for Astrophysics, has said:

    “… were a supernova to go off within about 30 light-years of us, that would lead to major effects on the Earth, possibly mass extinctions. X-rays and more energetic gamma-rays from the supernova could destroy the ozone layer that protects us from solar ultraviolet rays. It also could ionize nitrogen and oxygen in the atmosphere, leading to the formation of large amounts of smog-like nitrous oxide in the atmosphere.”

    What’s more, if a supernova exploded within 30 light-years, phytoplankton and reef communities would be particularly affected. Such an event would severely deplete the base of the ocean food chain.

    Suppose the explosion were slightly more distant. An explosion of a nearby star might leave Earth and its surface and ocean life relatively intact. But any relatively nearby explosion would still shower us with gamma rays and other high-energy radiation. This radiation could cause mutations in earthly life. Also, the radiation from a nearby supernova could change our climate.

    No supernova has been known to erupt at this close distance in the known history of humankind. The most recent supernova visible to the eye was Supernova 1987A, in the year 1987. It was approximately 168,000 light-years away.

    Before that, the last supernova visible to the eye was was documented by Johannes Kepler in 1604. At about 20,000 light-years, it shone more brightly than any star in the night sky. It was even visible in daylight! But it didn’t cause earthly effects, as far as we know.

    How many potential supernovae are located closer to us than 50 to 100 light-years? The answer depends on the kind of supernova.

    A Type II supernova is an aging massive star that collapses. There are no stars massive enough to do this located within 50 light-years of Earth.

    But there are also Type I supernovae – caused by the collapse of a small faint white dwarf star. These stars are dim and hard to find, so we can’t be sure just how many are around. There are probably a few hundred of these stars within 50 light-years.

    The star IK Pegasi B is the nearest known supernova progenitor candidate. It’s part of a binary star system, located about 150 light-years from our sun and solar system.

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    Relative dimensions of IK Pegasi A (left), IK Pegasi B (lower center) and our sun (right). The smallest star here is the nearest known supernova progenitor candidate, at 150 light-years away. Image via RJHall on Wikimedia Commons.

    The main star in the system – IK Pegasi A – is an ordinary main sequence star, not unlike our sun. The potential Type I supernova is the other star – IK Pegasi B – a massive white dwarf that’s extremely small and dense. When the A star begins to evolve into a red giant, it’s expected to grow to a radius where the white dwarf can accrete, or take on, matter from A’s expanded gaseous envelope. When the B star gets massive enough, it might collapse on itself, in the process exploding as a supernova.

    What about Betelgeuse? Another star often mentioned in the supernova story is Betelgeuse, one of the brightest stars in our sky, part of the famous constellation Orion. Betelgeuse is a supergiant star. It is intrinsically very brilliant.

    RIGEL-BETELGEUSE-ANTARES Digital image ©Michael Carroll

    Such brilliance comes at a price, however. Betelgeuse is one of the most famous stars in the sky because it’s due to explode someday. Betelgeuse’s enormous energy requires that the fuel be expended quickly (relatively, that is), and in fact Betelgeuse is now near the end of its lifetime. Someday soon (astronomically speaking), it will run out of fuel, collapse under its own weight, and then rebound in a spectacular Type II supernova explosion. When this happens, Betelgeuse will brighten enormously for a few weeks or months, perhaps as bright as the full moon and visible in broad daylight.

    When will it happen? Probably not in our lifetimes, but no one really knows. It could be tomorrow or a million years in the future. When it does happen, any beings on Earth will witness a spectacular event in the night sky, but earthly life won’t be harmed. That’s because Betelgeuse is 430 light-years away.

    How often do supernovae erupt in our galaxy? No one knows. Scientists have speculated that the high-energy radiation from supernovae has already caused mutations in earthly species, maybe even human beings.

    One estimate suggests there might be one dangerous supernova event in Earth’s vicinity every 15 million years. Another says that, on average, a supernova explosion occurs within 10 parsecs (33 light-years) of the Earth every 240 million years. So you see we really don’t know. But you can contrast those numbers to the few million years humans are thought to have existed on the planet – and four-and-a-half billion years for the age of Earth itself.

    And, if you do that, you’ll see that a supernova is certain to occur near Earth – but probably not in the foreseeable future of humanity.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
  • richardmitnick 1:27 pm on May 12, 2018 Permalink | Reply
    Tags: , , , , EarthSky, , What will happen when our sun dies?   

    From University of Manchester via EarthSky: “What will happen when our sun dies? 

    U Manchester bloc

    From University of Manchester

    EarthSky

    Deborah Byrd
    Eleanor Imster

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    An example of a planetary nebula, Abell 39. Five billion years from now, our own sun will look like this, when it goes through the planetary nebula stage of star death. Image via WIYN/NOAO/NSF/University of Manchester.

    NOAO WIYN 3.5 meter telescope at Kitt Peak, AZ, USA, Altitude 2,096 m (6,877 ft)


    NOAO WIYN 3.5 meter telescope at Kitt Peak, AZ, USA, Altitude 2,096 m (6,877 ft)

    NOAO WIYN Telescope, Kitt Peak National Observatory, Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O’odham Nation, 88 kilometers (55 mi) west-southwest of Tucson, Arizona, Altitude 2,096 m (6,877 ft)

    What does death mean, for the sun? It means our sun will run out of fuel in its interior. It’ll cease the internal thermonuclear reactions that enable stars to shine. It’ll swell into a red giant, whose outer layers will engulf Mercury and Venus and likely reach the Earth. Life on Earth will end. If the sun were more massive – estimates vary, but at least several times more massive – it would explode as a supernova. So … no supernova. But what? What happens next? An international team of astronomers recently used a new stellar data-model that predicts the life cycle of stars to answer this question.

    Their research is published in the peer-reviewed journal Nature Astronomy. It suggests that the sun is almost exactly the lowest mass star that – at the end of its life – produces a visible, though faint, planetary nebula.

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    Artist’s concept of our sun as a red giant. Image via Chandra X-ray Observatory.

    NASA/Chandra X-ray Telescope

    The name planetary nebula has nothing to do with planets. It describes a massive sphere of luminous gas and dust, material sloughed off an aging star. In the 1780s, William Herschel called these spherical clouds planetary nebulae because, through his early telescope, planetary nebulae looked round, like the planets in our solar system.

    Astronomers already knew that 90 percent of all stars end their active lives as planetary nebulae. They were reasonably sure our sun would meet this fate. The key word here is visible. For years, scientists thought the sun has too low mass to create a visible planetary nebula.

    Albert Zijlstra of the University of Manchester in England is a co-author of the study. He said in a statement:

    “When a star dies it ejects a mass of gas and dust – known as its envelope – into space. The envelope can be as much as half the star’s mass. This reveals the star’s core, which by this point in the star’s life is running out of fuel, eventually turning off and before finally dying.

    It is only then the hot core makes the ejected envelope shine brightly for around 10,000 years – a brief period in astronomy. This is what makes the planetary nebula visible. Some are so bright that they can be seen from extremely large distances measuring tens of millions of light-years, where the star itself would have been much too faint to see.”

    Will that be the fate of our sun? Will it – at the end of its life – become briefly visible to alien astronomers on planets millions of light-years away? These astronomers say no. They say their new models predict our sun at the end of its life, though forming a planetary nebula, will remain faint.

    By the way … what next? Eventually, the planetary nebula will disperse and fade. With its thermonuclear fuel gone, the sun will no longer be able to shine. The immensely high pressures and temperatures in its interior will slacken. The sun will shrink down to become a dying ember of a star, known as a white dwarf, only a little larger than Earth.

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    Artist’s concept of our sun as a white dwarf. Image via Chandra X-ray Observatory.

    Bottom line: A study suggests our sun is about the lowest mass star that – at the end of its life – produces a visible, though faint, planetary nebula. What that is … and more on the fate of our sun, here.

    See the full article here .

    Please help promote STEM in your local schools.

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    U Manchester campus

    The University of Manchester (UoM) is a public research university in the city of Manchester, England, formed in 2004 by the merger of the University of Manchester Institute of Science and Technology (renamed in 1966, est. 1956 as Manchester College of Science and Technology) which had its ultimate origins in the Mechanics’ Institute established in the city in 1824 and the Victoria University of Manchester founded by charter in 1904 after the dissolution of the federal Victoria University (which also had members in Leeds and Liverpool), but originating in Owens College, founded in Manchester in 1851. The University of Manchester is regarded as a red brick university, and was a product of the civic university movement of the late 19th century. It formed a constituent part of the federal Victoria University between 1880, when it received its royal charter, and 1903–1904, when it was dissolved.

    The University of Manchester is ranked 33rd in the world by QS World University Rankings 2015-16. In the 2015 Academic Ranking of World Universities, Manchester is ranked 41st in the world and 5th in the UK. In an employability ranking published by Emerging in 2015, where CEOs and chairmen were asked to select the top universities which they recruited from, Manchester placed 24th in the world and 5th nationally. The Global Employability University Ranking conducted by THE places Manchester at 27th world-wide and 10th in Europe, ahead of academic powerhouses such as Cornell, UPenn and LSE. It is ranked joint 56th in the world and 18th in Europe in the 2015-16 Times Higher Education World University Rankings. In the 2014 Research Excellence Framework, Manchester came fifth in terms of research power and seventeenth for grade point average quality when including specialist institutions. More students try to gain entry to the University of Manchester than to any other university in the country, with more than 55,000 applications for undergraduate courses in 2014 resulting in 6.5 applicants for every place available. According to the 2015 High Fliers Report, Manchester is the most targeted university by the largest number of leading graduate employers in the UK.

    The university owns and operates major cultural assets such as the Manchester Museum, Whitworth Art Gallery, John Rylands Library and Jodrell Bank Observatory which includes the Grade I listed Lovell Telescope.

     
  • richardmitnick 12:37 pm on May 12, 2018 Permalink | Reply
    Tags: , EarthSky, ,   

    From EarthSky: “Hawaii’s erupting Kilauea volcano” 

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    From EarthSky

    Eleanor Imster
    Deborah Byrd

    Kilauea is one of the world’s most active volcanoes. Here are images and video from its ongoing eruption in Hawaii.

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    The Verge 6 days ago

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    The lava lake at the summit of Kilauea, via @USGSVolcanoes on Twitter.

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    NASA’s Terra satellite acquired this image on May 6, 2018. Massive sulfur dioxide plumes from Kilauea volcano are shown here in yellow and green. A smaller, but thicker, sulfur dioxide gas plume can be seen coming from Kilauea. The prevailing trade winds blow the plumes to the southwest, out over the ocean. Image via NASA/METI/AIST/Japan Space Systems/Japan ASTER Science Team.

    NASA/Terra satellite

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    Looking up the slope of Kilauea, a shield volcano on the island of Hawaii. Puu_Oo_looking_up_Kilauea.jpg

    UPDATE May 12, 2018 from the Hawaiian Volcano Observatory/ USGS: Volcanic unrest in the lower East Rift Zone of Kilauea Volcano continues. While no lava has been emitted from any of the 15 fissure vents since May 9, earthquake activity, ground deformation, and continuing high emission rates of sulphur dioxide indicate additional outbreaks of lava are likely. The location of future outbreaks is not known with certainty, but could include areas both uprift (southwest) and downrift (northeast) of the existing fissures, or resumption of activity at existing fissures. Communities downslope of these fissures could be at risk from lava inundation.

    Lava and sulfur dioxide gas are continuing to spew from Kilauea volcano on Hawaii’s Big Island, where flows of lava across a rural neighborhood have caused evacuations. By late Tuesday (May 8, 2018), some 104 acres were covered by lava. Hawaii Civil Defense said that 35 structures — including at least 26 homes — had been destroyed.

    A total of 12 volcanic fissures had formed as of late Tuesday. Residents were voicing frustration and anxiety against a backdrop of flowing lava and hazardous fumes.

    May 4, 2018 Third Leilani Eruption from Mick Kalber on Vimeo.

    Videographer Mick Kalber was on the ground in Leilani Estates on May 5, where he told captured the dramatic video above and told this story:

    “This is a killer video! And may be one of the last ground level shots I’ll be able to get before I have to evacuate … After all the lava drained out of the Pu’u ‘O’o Vent (the main vent of the 35 year long current eruption) last Monday [April 30, 2018], the contents moved down the East rift zone, causing hundreds of earthquakes as far away as Kapoho, some 15 miles downslope. All week, a new eruption had been forecast … cracks appeared on roadways, as the Earth began to swell. And then, on Thursday afternoon [May 3, 2018], Pele (the Volcano Goddess) made her appearance in the lower part of Leilani Estates Subdivision. At first, fountains of lava shot up into the air … but within a few hours, she had settled down into a lava flow that now threatens dozens of nearby homes, and a geothermal power plant just a quarter mile downslope. That flow has now stopped… but several more continue to pop out nearby. I live in the subdivision, and we are continually experiencing rolling earthquakes … it ain’t over till it’s over!”

    Meanwhile, the video below, also from Mick Kalber, shows the view from the air:

    May 6, 2018 HUGE Fissure Eruption from Mick Kalber on Vimeo.

    The eruptive activity began on April 30, 2018, when the floor of Kilauea’s crater began to collapse. Earthquakes followed, including one that measured magnitude +6.9, a very strong earthquake. All the while, lava was being pushed into new underground areas that eventually broke through the ground in such areas as the Leilani Estates (population 1,560 at the 2010 census) near the town of Pahoa, Hawaii.

    Evacuations in Leilani Estates began on May 4.

    The USGS is doing a good job following the volcano on Twitter.

    Follow @UGSGVolcanoes on Twitter.

    Kilauea is one of the world’s most active volcanoes, and it’s the youngest and southeastern-most volcano on Hawaii’s Big Island. Eruptive activity along the East Rift Zone has been continuous since 1983.

    Bottom line: Images from the May 2018 eruption of Kilauea volcano on Hawaii’s Big Island.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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 8:04 am on May 3, 2018 Permalink | Reply
    Tags: , EarthSky, , ,   

    From University of Illinois via EarthSky: “Ample warning for supervolcanos?” 

    U Illinois bloc

    University of Illinois

    EarthSky

    May 3, 2018
    Eleanor Imster

    3
    llinois geology professor Patricia Gregg, right, and graduate student Haley Cabaniss have developed the first quantitative model that could help predict supervolcano eruptions.
    Photo by L. Brian Stauffer

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    A supervolcano is a large volcano that has had an eruption of magnitude 8, which is the largest value on the Volcanic Explosivity Index (VEI). This means the volume of deposits for that eruption is greater than 240 cubic miles (1,000 cubic km). No image credit.

    No need to panic about an imminent supervolcano eruption, not from the Yellowstone supervolcano or another other similar system around the globe. That’s according to a new study published in the peer-reviewed journal Geophysical Research Letters on April 19, 2018. The study says that geological signs pointing to a catastrophic supervolcano eruption would be clear far in advance.

    Scientists had thought that these huge volcanoes gradually built up more and more molten rock until the pressure got to be too much. But they are now realizing that much of the period between eruptions — as much as a million years — is probably quiet. To help understand how to forecast supervolcano eruptions, a team of geologists quantified the effects of tectonic stress on the rocks that house these sleeping giants.

    Geologist Patricia Gregg of University of Illinois is a co-author on the study. She explained in a statement:

    “Supervolcanos tend to occur in areas of significant tectonic stress, where plates are moving toward, past or away from each other.”

    Haley Cabaniss, a PhD student at University of Illinois, is the study’s first author. Her work focuses on computer modeling of 3-D magma reservoirs of volcanos, in order to determine the how systems fail and ultimately. She explained how the models used in this study showed that tectonic stress does have a profound effect on the stability of supervolcanoes, but that these stresses aren’t the only factor to cause an eruption. She said:

    “Any tectonic stress will help destabilize rock and trigger eruptions, just on slightly different timescales. The remarkable thing we found is that the timing seems to depend not only on tectonic stress, but also on whether magma is being actively supplied to the volcano.”

    The researchers found that, in any given tectonic setting, the magma reservoirs inside supervolcanoes appear to remain stable for hundreds to thousands of years while new magma is being actively suppled to the system. Gregg said:

    “We were initially surprised by this very short timeframe of hundreds to thousands of years. But it is important to realize that supervolcanoes can lay dormant for a very long time, sometimes a million years or more. In other words, they may remain stable, doing almost nothing for 999,000 years, then start a period of rejuvenation leading to a large-scale eruption.”

    The researchers unexpectedly found that their models could help forecast supervolcano eruption timing and inform experts on what to expect, geologically, well before an eruption. Gregg acknowledged that people tend to panic whenever they hear that Yellowstone or, say, the Taupo Volcanic Zone in New Zealand, experience any change in seismic or geyser activity.

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    Bay of Plenty, North Island, New Zealand, from the Bay of Plenty coast to Mounts Tongariro, Ngauruhoe, and Ruapehu (at bottom of picture). Also shows Lake Taupo and the Rotorua Lakes. This scene was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA’s Terra satellite, on October 23, 2002.BayofPlentyA2002296.jpg

    NASA/Terra satellite

    But she said this new research suggests that the precursors to catastrophic eruption will be far greater and long-lasting than anything yet documented. She said:

    “When new magma starts to rejuvenate a supervolcano system, we can expect to see massive uplift, faulting and earthquake activity, far greater than the meter-scale events we have seen in recent time. We are talking on the range of tens to hundreds of meters of uplift. Even then, our models predict that the system would inflate for hundreds to thousands of years before we witness catastrophic eruption.”

    Cabaniss added:

    “It is also important to note that our research suggests that the whole rejuvenation-to-eruption process will take place over several or more human lifetimes. Our models indicate that there should be plenty of warning.”

    Bottom line: Before a supervolcano erupts, many warning signs will appear first, says a new study.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    U Illinois campus

    The University of Illinois at Urbana-Champaign community of students, scholars, and alumni is changing the world.

    With our land-grant heritage as a foundation, we pioneer innovative research that tackles global problems and expands the human experience. Our transformative learning experiences, in and out of the classroom, are designed to produce alumni who desire to make a significant, societal impact.

     
  • richardmitnick 8:31 am on April 27, 2018 Permalink | Reply
    Tags: Andrea Ghez/Keck Observatory/UCLA Galactic Center Group, , , , , EarthSky, , Unseen siblings for Milky Way’s supermassive black hole?   

    From EarthSky: “Unseen siblings for Milky Way’s supermassive black hole?” 

    1

    EarthSky

    April 27, 2018
    Eleanor Imster

    Our Milky Way galaxy is known to have a supermassive black hole at its heart. Could more supermassive black holes be lurking unseen at our galaxy’s outskirts?

    Nowadays, astronomers think that nearly all large galaxies have supermassive black holes at their cores. Our own Milky Way’s central black hole is called Sgr A* (pronounced Sagittarius A-star), and it’s the focus of many fascinating studies.

    SGR A* , the supermassive black hole at the center of the Milky Way. NASA’s Chandra X-Ray Observatory

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    Artist’s concept of the orbit of the star S2 (sometimes S0-2), shown in light blue. In the next few months, this star is expected to plunge near a gigantic black hole in our galaxy. Image via S. Sakai/Andrea Ghez/Keck Observatory/UCLA Galactic Center Group.

    This week (April 24, 2018), astrophysicists announced the results of a new study based not on observations, but on a state-of-the-art cosmological simulation, called Romulus. The simulation showed that galaxies might contain more than one supermassive black hole. In fact, a galaxy with a mass like that of our Milky Way should host several, these scientists said. The extra supermassive black holes might “wander” throughout a galaxy, remaining far from its center. If it’s true, then could our own Milky Way galaxy’s supermassive black hole have an unseen sibling or two?

    How did these extra supermassive black holes get into the Milky Way? These scientists – led by Michael Tremmel at Yale – think the sibling black holes, if they exist, indicate mergers between our Milky Way and other galaxies in the early universe. If a smaller galaxy joined ours, it might have deposited its own central supermassive black hole within our galaxy. When the universe was young, this might have happened several times.

    The new study was published April 24 in the Astrophysical Journal, a peer-reviewed journal. Tremmel was speaking of the computer simulation when he said:

    “In this study, we’re looking at how supermassive black holes move through their galaxies. If we look at massive galaxies the size of the Milky Way, we find that, on average, these galaxies host several supermassive black holes within them, wandering about the galaxy on scales of several thousand light-years from the center of the galaxy.”

    So, theoretically, multiple supermassive black holes – wandering supermassive black holes – within galaxies are possible. But no one has yet discovered them. Tremmel said that, in the next several decades, gravitational wave telescopes in space should be able to detect the black hole mergers that would cause galaxies to have more than one supermassive black hole. Perhaps this is a normal part of galaxy evolution.

    Could we find one of our Milky Way’s sibling black holes now? Probably not. Tremmel said that, since wandering supermassive black holes are predicted to exist far from the centers of galaxies and outside of galactic disks, they’re unlikely to be accreting more gas. Since it’s the accretion of matter that causes all the observable activity near a black hole, any sibling supermassive black holes for our Milky Way or other galaxies would effectively be invisible. Tremmel said:

    “We are currently working to better quantify how we might be able to infer their presence indirectly.”

    If they exist, could unseen supermassive black holes in our Milky Way galaxy somehow affect us? No. Tremmel explained:

    “It is extremely unlikely that any wandering supermassive black hole will come close enough to our sun to have any impact on our solar system. We estimate that a close approach of one of these wanderers that is able to affect our solar system should occur every 100 billion years or so, or nearly 10 times the age of the universe.”

    An extremely unlikely encounter indeed!

    Bottom line: Astronomers ran a sophisticated computer simulation called Romulus to learn that galaxies like our Milky Way might contain multiple supermassive black holes. Thus our Milky Way’s central supermassive black hole might have unseen siblings.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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 12:45 pm on April 21, 2018 Permalink | Reply
    Tags: , , , , , Christian Sasse, , EarthSky,   

    From EarthSky: “Milky Way spins across the sky” 

    1

    EarthSky

    April 16, 2018
    Deborah Byrd


    This composite – centered on celestial south – is made of images taken hourly from outside the dome of the Anglo-Australian Telescope at Siding Spring Observatory.

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    Composite image by Christian Sasse.

    Christian Sasse emailed EarthSky on April 11, 2018, from Australia’s Siding Spring Observatory and wrote:

    “A spectacular night at the Anglo-Australian Telescope (3.9-meter [13-foot] mirror). This composite – made of images taken every hour from 7 p.m. until midnight – shows the apparent movement of the Milky Way across the sky. See Jupiter on the left, leaving a discrete trail as it moves towards the dome until midnight. Top is location of the celestial South Pole.”


    AAO Anglo Australian Telescope near Siding Spring, New South Wales, Australia, Altitude 1,100 m (3,600 ft)

    Siding Spring Mountain with Anglo-Australian Telescope dome visible near centre of image at an altitude of 1,165 m (3,822 ft)

    As you can see, Christian has a novel approach to acquiring photographic images of star trails. His images have been featured in National Geographic and Nature. His Ph.D. in optics has helped shape his photography. You can visit him on his Facebook page, or on YouTube, or on Twitter (@sassephoto).

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    Article by Christian Sasse, originally published at his blog, The Cosmic Clock.

    The Earth rotates or spins on its axis about every 24 hours, causing an apparent movement of the stars overhead by about one-quarter of a degree per minute. If we leave a camera in a fixed position and point upwards, open the shutter in bulb mode and let the Earth rotate under the stars, we will create an image with star trails. Similarly we could take shorter exposures and superimpose (stack) the images with image processing software.

    Most images of star trails taken in the Northern Hemisphere show a pattern similar to the one below taken in Arches National Park, Utah, in spring of 2016.

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    Star trails at Arches National Park via Christian Sasse

    Bottom line: Milky Way composite image by Christian Sasse.

    Read more about Christian Sasse’s photographic process: A novel approach to star trails

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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.

     
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