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  • richardmitnick 11:18 am on July 16, 2017 Permalink | Reply
    Tags: , , , Citizen Science helps process images, , EarthSky,   

    From EarthSky: “Wow! Juno’s super-close Red Spot images” Do Not Pass This Up 



    July 12, 2017
    Deborah Byrd

    Raw images from the Juno spacecraft’s extremely close sweep past Jupiter’s Red Spot are beginning to come in. NASA invites you to help process them!

    One of the first processed raw map-projected images of Jupiter’s Great Red Spot from Juno’s July 10 flyover, via Jason Major (@JPMajor on Twitter).

    Earlier than expected, the close-ups of Jupiter’s Great Red Spot – made possible by a close sweep past the planet by the Juno spacecraft on July 10 – are beginning to arrive! NASA had said originally not to expect them until July 14, but they started arriving on the 12th! What’s more, NASA has invited “citizen scientists” to help process the images, saying on the JunoCam online database page:

    “This is where we will post raw images. We invite you to download them, do your own image processing, and we encourage you to upload your creations for us to enjoy and share. The types of image processing we’d love to see range from simply cropping an image to highlighting a particular atmospheric feature, as well as adding your own color enhancements, creating collages and adding advanced color reconstruction.”

    The citizen-scientist images, as well as the raw images they used for image processing, can be found at:


    Juno, which began orbiting the giant planet on July 4, 2016, came closer to Jupiter last weekend than any spacecraft ever has. In what scientist call Perijove 7 (a perijove is the spacecraft’s closest point in orbit to Jupiter’s center), Juno came as little as 2,200 miles (3,500 km) above Jupiter’s cloudtops. The probe was slightly higher when it was directly over the Great Red Spot (5,600 miles, or 9,000 km), but, still … awesome images ahead as the processing progresses.

    For now, enjoy these early images!

    Here’s a processed Juno image from Jon M. Greif, who wrote: “The Great Red Spot, a huge storm, the size of 2-3 Earth diameters, that has been raging on the surface of Jupiter for as long as people have studied the planet.”

    This enhanced-color image of Jupiter’s Great Red Spot was created by citizen scientist Gerald Eichstädt using data from the JunoCam imager on NASA’s Juno spacecraft. Image via NASA/ JPL-Caltech/ SwRI/ MSSS/ Gerald Eichstädt.

    Jupiter at Perijove 7, via NASA/ JPL-Caltech/ MSSS/ SwRI/ Kevin M. Gill.

    Bottom line: Raw images from Juno’s July 10 extremely close sweep past Jupiter’s Red Spot are beginning to come in. NASA invites you to help process them!

    See the full article here .

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  • richardmitnick 12:36 pm on July 7, 2017 Permalink | Reply
    Tags: , , , , EarthSky, How do planets form after star death?   

    From EarthSky: “How do planets form after star death?” 



    Astronomers studied the Geminga pulsar (inside the black circle), seen here moving towards the upper left. The orange dashed arc and cylinder show a ‘bow-wave’ and a ‘wake’ which might be key to after-death planet formation. The region shown is 1.3 light-years across. Image via Jane Greaves / JCMT / EAO/ RAS.

    The Royal Astronomical Society’s National Astronomy Meeting is going on this week (July 2-6, 2017) in Yorkshire, England. One interesting presentation comes from astronomers Jane Greaves and Wayne Holland, who believe they’ve found an answer to the 25-year-old mystery of how planets form around neutron stars, essentially dead stars left behind by supernova explosions. These astronomers studied the Geminga pulsar, thought to be a neutron star left by a supernova some 300,000 years ago. This object is known to be moving incredibly fast through our galaxy, and the astronomers have observed a bow-wave, shown in the image above, that might be crucial to forming after-death planets.

    They looked at the extreme environment around a neutron star – the sort of star we typically observe as a pulsar – a super-dense star remnant, left behind by a supernova.

    The first-ever confirmed detection of extrasolar planets – or planets orbiting distant suns – came in 1992, when astronomers found several terrestrial-mass planets orbiting the pulsar PSR B1257+12. Since then they’ve learned that planets orbiting neutron stars are incredibly rare; at least, few have been found.

    The two scientists observed Geminga using the James Clerk Maxwell Telescope (JCMT) near the summit of Mauna Kea in Hawaii.

    East Asia Observatory James Clerk Maxwell telescope, Mauna Kea, Hawaii, USA

    The light the astronomers detected has a wavelength of about half a millimeter, is invisible to the human eye, and struggles to get through the Earth’s atmosphere. They used a special camera system called SCUBA and said:

    What we saw was very faint. To be sure, we went back to it in 2013 with the new camera our Edinburgh-based team had built, SCUBA-2, which we also put on JCMT. Combining the two sets of data helped to ensure we weren’t just seeing some faint artifacts.

    If ALMA data confirm their new model for Geminga, the team hopes to explore some similar pulsar systems, and contribute to testing ideas of planet formation by seeing it happen in exotic environments. Their statement said:

    This will add weight to the idea that planet birth is commonplace in the universe.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    See the full article here .

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  • richardmitnick 11:21 am on July 2, 2017 Permalink | Reply
    Tags: , , , , , EarthSky   

    From EarthSky: “The enduring mystique of Barnard’s Star” 



    June 27, 2017
    Larry Sessions

    Our sun’s closest neighbors among the stars, including Barnard’s Star. Image via NASA PhotoJournal.

    Perhaps you know that, over the scale of our human lifespans, the stars appear fixed relative to one another. But Barnard’s Star – sometimes called Barnard’s Runaway Star – holds a speed record of sorts as the fastest-moving star in Earth’s skies. It moves fast with respect to other stars because it’s relatively close, only about 6 light-years away. What does its fast motion mean? It means Barnard’s Star is nearby! It’s only about six light-years away. Relative to other stars, Barnard’s Star moves 10.3 arcseconds per year, or about the width of a full moon in 174 years. This might not seem like much. But – to astronomers – Barnard’s Star is virtually zipping across the sky. Follow the links below to learn more about Barnard’s Star, which has high interest for astronomers and the public alike.

    Barnard’s Star in history and popular culture

    How to see Barnard’s Star

    The science of Barnard’s Star

    Barnard’s star, 1985 to 2005. Most stars are fixed with respect to each other, but – being close to us – Barnard’s Star appears to move. Image via Steve Quirk/ Wikimedia Commons.

    Barnard’s Star in history and popular culture Yerkes Observatory astronomer E. E. Barnard discovered the large proper motion of Barnard’s Star – that is, motion across our line of sight – in 1916.

    He noticed it while comparing photographs of the same part of the sky taken in 1894 and again in 1916. The star appeared in significantly different positions, betraying its rapid motion.

    Later, Harvard astronomer Edward Pickering found the star on photographic plates taken in 1888.

    Barnard’s Star is named for this astronomer, E.E. Barnard, seen here posing with the 36? refractor at Lick Observatory. Image via OneMinuteAstronomer.

    UCO Lick Observatory, Mt Hamilton, in San Jose, California

    The UCO Lick C. Donald Shane telescope is a 120-inch (3.0-meter) reflecting telescope located at the Lick Observatory, Mt Hamilton, in San Jose, California

    UC Observatories Lick Aumated Planet Finder, fully robotic 2.4-meter optical telescope at Lick Observatory, situated on the summit of Mount Hamilton, east of San Jose, California, USA

    Lick Observatory, Mt Hamilton, in San Jose, California

    Barnard’s star came to our attention barely 100 years ago and cannot even be seen with the human eye, so the ancients did not know about it. It doesn’t figure into the lore of any constellation or cultural tradition. But that doesn’t mean that it doesn’t a have certain mystique about it that extends beyond the known facts.

    For example, even as long ago as the 1960s and ’70s – long before successful planet-hunters like the Kepler spacecraft – there were suggestions that Barnard’s Star might have a family of planets. At that time, reported discrepancies in the motion of the star led to a claim that at least one Jupiter-size planet orbits it. Although the evidence was disputed and the claim now largely discredited, there is still a chance of planetary discoveries.

    It’s likely due to this rumor of planets that Barnard’s Star has found a place in science fiction. It’s featured in, for example, The Hitchhiker’s Guide to the Galaxy by Douglas Adams; The Garden of Rama by Arthur C. Clarke and Gentry Lee; and several novels of physicist Robert L. Forward. In these works, the hypothetical planets are locations for early colonization or way-stations for exploration further into the cosmos.

    Barnard’s Star also was the hypothetical target of Project Daedalus, a design study by members of the British Interplanetary Society, in which they envisioned an interstellar craft that could reach its destination within a human lifetime.

    Clearly, Barnard’s Star captures peoples’ imaginations!

    Image via BBC/ Sky at Night/ Paul Wootton. Read more.

    How to see Barnard’s Star. Barnard’s Star is faint; its visual magnitude of about 9.5. Thus this star can’t be seen with the eye alone.

    Whats more, its motion – though large in astronomical terms – is still too slow to be noticed in a single night or even easily across a human lifetime.

    Since Barnard’s Star can’t be seen without powerful binoculars or a telescope, finding it requires both experience and perseverance. It is currently located in the constellation Ophiuchus, which is well placed on June, July and August evenings.

    Because Barnard’s Star is a telescopic object, details on how to observe it are beyond the scope of this article, but Britain’s Sky at Night magazine has a good procedure online here: http://bit.ly/2rZNDe1

    Artist’s concept of a red dwarf star – similar to Barnard’s Star – with a planet of about 12 Jupiter-masses. There has been speculation about planets orbiting Barnard’s Star, but none have been confirmed. Also, Barnard’s Star is thought to be considerably older than our sun, which could affect the potential for finding life there. Image via NASA/ ESA/ G. Bacon (STScI)/ Wikimedia Commons.

    The science of Barnard’s Star. The fame of Barnard’s Star is in its novelty, the fact that it moves fastest through Earth’s skies. But its real importance to astronomy lies in the fact that being so close, it is one of the best sources for studying red dwarfs, the most abundant stars in the universe.

    With only about 14% of the solar mass and less than 20% of the radius, it would take roughly seven Barnard’s Stars to match the mass of our sun, and 133 to match our sun’s volume.

    Like all stars, Barnard’s Star shines via thermonuclear fusion, changing light elements (hydrogen) into more massive elements (helium), while releasing enormous amounts of energy. Even so, the lower mass of Barnard’s Star makes it about 2,500 times less powerful than our sun.

    In other words, Barnard’s Star is much dimmer and cooler than our sun. If it replaced the sun in our solar system, it would shine only about four ten-thousandths as brightly as our sun. At the same time, it would be about 100 times brighter than a full moon. No life on Earth would be possible if we orbited Barnard’s Star instead of our sun, however. The much-decreased stellar heat would plunge Earth’s global temperatures to hundreds of degrees below zero.

    Although very common, red dwarfs like Barnard’s Star are typically dim. Thus they are notoriously faint and hard to study. In fact, not a single red dwarf can be seen with the unaided human eye. But because Barnard’s Star is relatively close and bright, it has become a go-to model for all things red dwarf.

    At nearly six light-years’ distance, Barnard’s Star is often cited as the second-closest star to our sun (and Earth). This is true only if you consider the triple star system Alpha Centauri as one star.

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    ESO Pale Red Dot project

    ESO Red Dots Campaign

    Proxima Centauri, the smallest and faintest of Alpha Centauri’s three components, is the closest known star to the sun at just 4.24 light years away. It, too, is a red dwarf. So Barnard’s Star is only the second-closest red dwarf star. It is perhaps more important for astronomical purposes, though, because Proxima is four times fainter and thus harder to study.

    Special thanks to David J. Darling and Jack Schmidling for their help with this article.

    Of course, all stars are moving through the space of our Milky Way galaxy. So even the “fixed” stars move over time. This illustration shows the distances to the nearest stars – including Barnard’s Star – in a time range between 20,000 years in the past and 80,000 years in the future. Image via FrancescoA/ Wikimedia Commons.

    Bottom line: Barnard’s Star is the fastest-moving star in Earth’s skies, in terms of its proper motion. It moves fast because it’s relatively close, only about 6 light-years away.

    See the full article here .

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  • richardmitnick 10:03 am on June 22, 2017 Permalink | Reply
    Tags: , , , , EarthSky, Messier 5 Globular Cluster par excellance   

    From EarthSky: “Messier 5, your new favorite globular cluster” 



    June 22, 2017
    Bruce McClure

    Sure, Messier 13, the Great Hercules cluster is wonderful. But some amateur astronomers say this cluster, Messier 5, is even better.

    Messier 5, as seen by the Hubble Space Telescope. This photo was an Astronomy Picture of the Day in June, 2015. Via HST/ NASA/ ESA/ APOD.

    NASA/ESA Hubble Telescope

    Even with the best of viewing conditions, the globular star cluster Messier 5 – aka M5 – is barely detectable to the unaided eye as a faint star. In binoculars, it appears as a faint, fuzzy star. Ah, but point a small telescope its way! Some amateur observers swear that M5 is the finest globular cluster north of the celestial equator for small telescopes – even better than the celebrated Messier 13, the Great Hercules cluster. Follow the links below to learn more about this wonderful cluster.

    What is Messier 5?

    How to find Messier 5

    Messier 5 in all its glory. Image via Robert (Bob) J. Vanderbei of Princeton University.

    What is Messier 5? Many of the brighter and larger clusters visible from Earth are open star clusters. For example, the Pleiades and the Hyades clusters are open star clusters. Open star clusters are born, and live out their lives, within the galactic disk. They are loose collections of several hundred stars. The ones we know best are relatively nearby, a few hundred light-years away.

    In contrast, Messier 5 is a globular star cluster. Globular clusters reside within the galactic halo – a sphere-shape region of the Milky Way that extends above and below the galactic disk. If we liken the disk to a hamburger, then the bun would be the galactic halo. Globular star clusters contain hundreds of thousands of stars, tightly packed in a symmetrical ball. These clusters are our galaxy’s oldest inhabitants. In other words, they formed first, as the galaxy was forming. Spanning 165 light-years in diameter, M5 is one of the larger globular clusters known. It contains more than 100,000 stars, as many as 500,000 according to some estimates.

    The relatively young stars of open clusters disperse after hundreds of millions of years. The stars in globular clusters still remain intact after many billions of years.

    As you gaze at Messier 5, you’re looking at an object that’s around 13 billion years old, more than twice the age of our solar system, and almost as ancient as the universe itself. Considering that Messier 5 lies some 25,000 light-years distant, we can only imagine what this stellar city would look like if it were at the Pleiades’ distance of 430 light-years!

    Messier 5 is due north of the Libra star Zubeneschamali and east of the constellation Virgo.

    Messier finder chart for Messier 5. Under very good viewing conditions, M5 can be just about glimpsed with the naked eye as a faint point of light. With binoculars, it’s easily visible as small fuzzy patch. A small 80mm (3.1-inch) telescope reveals a bright glowing core wrapped inside a much fainter halo of nebulosity. Image and caption via Free StarCharts.com

    How to find Messier 5. Messier 5 is located in the constellation Serpens Caput (the Serpent’s Head). It is highest up in the south at about 10 p.m (11 p.m. Daylight Saving Time) in mid-June. Because the stars (and star clusters) return to the same place in the sky some 2 hours earlier with each passing month, it’s highest in the sky around 8 p.m. (9 p.m. Daylight Time) in mid-July.

    Using a fist at an arm’s length for a guide, Messier 5 resides a good 2 fist-widths to the southeast of yellow-orange Arcturus, summertime’s brightest star. Messier 5 is also three fist-widths to the east of blue-white Spica, the brightest star in the constellation Virgo.

    Plus, Messier 5 is about one fist-width to the north (above) Zubeneschamali. These stars give you at least a rough idea of Messier 5 whereabouts in the heavens.

    Practiced skygazers star-hop to Messier 5 by way of two faint yet visible Virgo stars: 109 Virginis and 110 Virginis. They draw an imaginary line from 109 Virginis through 110 Virginis, and go twice the distance to land on the star 5 Serpentis. M5 is only 1/3 degree to the northwest (upper right) of this star. The distance from 109 Virginis to Messier 5 spans about 8 degrees of sky. For reference, the width of 4 fingers at an arm length away approximates 8 degrees.

    Some practiced sky gazers star-hop to Messier 5 from the constellation Virgo

    Bottom line: M5, or Messier 5, is a globular star cluster and very beautiful to see. How to find it, here.

    See the full article here .

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  • richardmitnick 7:39 am on June 16, 2017 Permalink | Reply
    Tags: Are asteroids hiding among the Taurids?, , , , , EarthSky   

    From EarthSky: “Are asteroids hiding among the Taurids?” 



    June 15, 2017
    Eddie Irizarry

    A Taurid fireball – or exceptionally bright meteor – caught during the 2015 shower by Bill Allen.

    A team of European astronomers has identified a new swarm of meteoroids – icy debris in space, left behind by a comet – related to the Taurid meteor shower. More importantly, this new meteoroid stream might also contain still-undiscovered asteroids, some good-sized, say, a few tens of meters (yards) or even larger. Let’s be clear. We are no more in danger of being hit by a space rock from the newly discovered stream of Taurids than we were before scientists discovered it. So there is no imminent danger here. It simply means that scientists will be searching the newly identified streams of meteoroids, with the goal of detecting any medium-sized or even moderately large asteroids with orbits that might bring them near Earth.

    What are meteoroids? They are typically bits of debris in space, often left behind by comets as they orbit the sun. The Taurid meteor shower, for example, is produced by debris of Comet 2P/Encke. When debris from a comet enters our atmosphere, meteoroids vaporize due to friction with the air, leaving streaks of light in our night sky that we call meteors. Sometimes, a random meteor (usually not associated with one of the annual meteor showers) hits the ground, and then its name changes again to meteorite.

    There are many comets orbiting the sun, leaving debris behind. As Earth orbits the sun, as our planet encounters these small particles left by comets, we see meteor showers. Some meteoroid streams produce only a few visible meteors, but sometimes Earth passes by a denser swarm of particles, thus causing a more impressive or active meteor shower.

    These particles are usually very small, maybe as tiny as sand, or grains of rice, although the sizes do vary. New research suggests some recent Taurid fireballs – or exceptionally bright meteors – were produced by much-larger particles. At least meteor observed in 2015 had an estimated size of about a meter (3.28 feet). Another, very bright meteor – observed in 2015 and recently studied – might have been caused by a space rock 10 times more massive.

    Here’s another Taurid fireball, captured in 2015 by Jeff Dai in Tibet.

    The Taurid meteor shower occurs every year, beginning in late October and extending through November. It usually offers only a few bright meteors. However, 2015 was an exceptional year for the Taurids. In November, 2015, a network of meteor cameras located in Europe detected about 200 fireballs. Of those, 24 were very bright, and 10 were as bright or even brighter than the full moon.

    Bright Taurid meteors were also recorded in Puerto Rico and Thailand, and elsewhere. EarthSky received many photos and videos of the Taurids in 2015.

    Since then, astronomers have made an extensive analysis of some of the incoming 2015 Taurids and found that most of the meteors showed a trajectory or orbit that points to the same new branch of meteoroid material. And hence a new meteoroid stream has been found.

    Then something else got astronomers’ attention. They realized that some large space rocks, including asteroids 2015 TX24 and 2005 UR, share the same orbits as the newly found swarm of Taurid meteoroids. These asteroids are now assumed to be members of the newly detected meteoroid stream. Asteroid 2015 TX24 – discovered on October 8, 2015 – was closest to Earth 20 days later, on October 28, a date very close to the Taurid meteor shower’s enhanced activity in 2015.

    These asteroids are between 200 and 300 meters (656 and 984 feet) in diameter.

    And so it appears likely that the newly discovered meteoroid streams contains other still-undiscovered, but relatively large, space rocks.

    Remember, some Taurid meteors encounter Earth’s atmosphere each year. Is it possible that larger objects in the newly found Taurid meteor stream might also encounter Earth? For this reason, astronomers speak of these objects as potentially hazardous. They say the objects would be large enough to cause some regional damage if they were indeed to strike Earth, but – as yet – no asteroid has been identified as threatening or having a collision course with Earth.

    Clearly, further research and observations are needed.

    Some bright meteors were seen during the enhanced Taurid meteor shower of November, 2015, including this impressive meteor seen in Thailand:

    Another bright Taurid meteor was captured from the Caribbean by the Sociedad de Astronomia del Caribe:

    Bottom line: A new stream of meteoroidal material has been discovered for the Taurids. Some relatively large asteroids are known to be in this same orbit. Could there be potentially hazardous asteroids in the stream as well?

    See the full article here .

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  • richardmitnick 8:07 am on May 20, 2017 Permalink | Reply
    Tags: , , , , , EarthSky, How long to travel to Alpha Centauri?   

    From EarthSky: “How long to travel to Alpha Centauri?” 



    May 16, 2017
    Deborah Byrd

    Artist’s concept via Breakthrough Starshot.

    Outer space is big. Really, really, really big. And that’s why NASA has no plans at present to send a spacecraft to any of the several thousand known planets beyond our solar system. Meanwhile, with respect to star travel, NASA isn’t the only game in town anymore. In April 2016, Russian high-tech billionaire Yuri Milner announced a new and ambitious initiative called Breakthrough Starshot, which intends to pour $100 million into proof-of-concept studies for an entirely new technology for star travel, aimed at unmanned space flight at 20% of light speed, with the goal of reaching the Alpha Centauri system – and, presumably, its newly discovered planet Proxima b – within 20 years. Is it possible? No one knows yet, but Alpha Centauri is an obvious target. It’s the nearest star system to our sun at 4.3 light-years away. That’s about 25 trillion miles (40 trillion km) away from Earth – nearly 300,000 times the distance from the Earth to the sun. Follow the links below to learn more about why star travel is so formidable, and about how we might accomplish it.

    Why won’t a conventional rocket work?

    Warp drive?

    Breakthrough Starshot

    These 4 conventional spacecraft are headed out of the solar system. A 5th spacecraft, New Horizons, will also eventually leave the solar system.

    NASA/New Horizons spacecraft

    But conventional spacecraft move slowly in contrast to the vast distances between stars. It’ll be tens of thousands of years before one of these craft encounters a star. Image via Wikimedia Commons.

    Why won’t a conventional rocket work? Consider the Space Shuttles, which traveled only a few hundred kilometers above Earth’s surface, into Earth orbit. If Earth were the size of a sand grain, this distance would be about the width of a hair in contrast to a 6-mile (10-km) distance to Alpha Centauri.

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    The Space Shuttles weren’t starships, but we have built starships. Five craft from Earth are currently on their way out of the solar system, headed into interstellar space. They are the two Pioneer spacecraft, the two Voyager spacecraft, and the New Horizons spacecraft. All are moving extremely slowly relative to the speed needed to travel among the stars.

    NASA Pioneer II

    NASA/Voyager 1

    So … consider the two Voyagers – Voyager 1 and Voyager 2 – launched in 1977. Neither Voyagers is aimed toward Alpha Centauri, but if one of them were – assuming it maintained its current rate of speed – it would requires take tens of thousands of years to this next-nearest star. Eventually, the Voyagers will pass other stars. In about 40,000 years, Voyager 1 will drift within 1.6 light-years (9.3 trillion miles) of AC+79 3888, a star in the constellation of Camelopardalis. In some 296,000 years, Voyager 2 will pass 4.3 light-years from Sirius, the brightest star in the sky. Hmm, 4.3 light-years. That’s the distance between us and Alpha Centauri.

    What about the New Horizons spacecraft, the first spacecraft ever to visit Pluto and its moons. NASA’s New Horizons spacecraft travels at 36,373 miles per hour (58,536 km/h). Launched from Earth in mid-January, 2006, it reached Pluto in mid-July, 2015 … nine-and-a-half years later. If New Horizons were aimed toward the Alpha Centauri system, which it isn’t, it would take this spacecraft about 78,000 years to get there.

    So conventional rockets won’t work because they are too slow.

    What a spaceship with warp drive might look like. Credit: Mark Rademaker/Mike Okuda/Harold White/NASA.

    Illustration via the Anderson Institute.

    Warp drive? What if we could travel faster than light? Countless sci-fi books and movies are built around the concept, which brings with its challenges to physicists’ understanding of how space and time actually work. Still, a few years ago, Dr. Harold “Sonny” White – who leads NASA’s Advanced Propulsion Team at Johnson Space Center – claimed to have made a discovery which made plausible the idea of faster-than-light travel, via a concept known as the Alcubierre warp drive.

    This concept is based on ideas put forward by Mexican physicist Miguel Alcubierre in 1994. He suggested that faster-than-light travel might be achieved by distorting spacetime, as shown in the illustration above.

    Harold “Sonny” White has been working to investigate these ideas further. They are highly speculative, but possibly valid, and involve a solution of the Einstein field equations, specifically how space, time and energy interact. In June of 2014, White unveiled images of what a faster-than-light ship might look like. Artist Mark Rademaker based these designs on White’s theoretical ideas. He said creating them took more than 1,600 hours, and they are very cool. See the 2014 faster-than-light spacecraft designs on this Flickr page.

    The video below presents Harold White’s talk at the SpaceVision 2013 Space Conference in November, 2013 in Phoenix. He talks about the concepts and progress in warp-drive development over recent decades.

    One hour

    s it faster-than-light travel possible, via the Alcubierre warp drive? As with conventional propulsion systems, the problem is energy. In this case, it’s the type of energy the warp drive would need. Daily Kos reported:

    In order to form the warp field/bubble, a region of space-time with negative energy density (i.e. repulsing space-time) is necessary. Scientific models predict exotic matter with a negative energy may exist, but it has never been observed. All forms of matter and light have a positive energy density, and create an attractive gravitational field.

    So faster-than-light travel via the Alcubierre warp drive is highly speculative, to say the least.

    With current technologies, it’s not possible.

    However, if it could be accomplished, it would reduce the travel time to Alpha Centauri from thousands of years to just days.

    Want technical details on the Alcubierre warp drive? Read this 2014 article at Daily Kos.

    Or try this January 2017 article on the Alcubierre warp drive, at Phys.org

    NASA has a whole area on its website about faster-than-light travel, in which it basically says … it’s not currently possible.

    Breakthrough Starshot. In April, 2016, Yuri Milner’s organization Breakthrough Initiatives announced a $100 million investment in proof-of concept studies for an all-new way to get to the stars.

    Well, not all new., exactly. The Breakthrough Starshot project relies on technologies that are being tested now, and also on some new technologies that have been around only a few years. But it does put these technologies together in a way that’s entirely new, and extremely visionary.

    The Breakthrough Starshot team has some heavy hitters, including physicist Stephen Hawking and Facebook’s Mark Zuckerberg. It proposes to use the $100 million to learn whether it’s possible to use a 100-gigawatt light beam and light sails to propel some 1,000 ultra-lightweight nanocraft to 20% of light speed. If it’s shown to be possible, such a mission could (hypothetically) reach Alpha Centauri within about 20 years of its launch.

    There are a lot of appealing things about this project. For example, the use of lightsails is currently in the process of being tested by another organization, the Planetary Society, with a publicly funded project called LightSail.

    But the most appealing thing is that the Breakthrough Starshot project is truly innovative, yet still grounded in current, cutting-edge science and technology. Just realize that all existing spacecraft are huge and clunky in contrast to the gram-scale nanostarships – dubbed StarChips – being proposed by Breakthrough Starshot. Can tiny, light ships – on sails pushed by a light beam – fly 1,000 times faster than the fastest spacecraft built up to now? That’s what Breakthrough Starshot is exploring with its ongoing proof-of-concept studies.

    Starshot envisions launching a mothership carrying the 1,000 tiny spacecraft to a high-altitude orbit. Each craft is a gram-scale wafer, carrying cameras, photon thrusters, power supply, navigation and communication equipment, and “constituting a fully functional space probe,” the Starshot team has said.

    Mission controllers would deploy the nanocraft – send them on their way – one by one. A ground-based laser array called a light beamer would be used to focus light on the sails of the ships, to accelerate individual craft to the target speed “within minutes.”

    The plan is to stick four cameras (two-megapixels each) on the nanocraft, allowing for some elementary imaging. The data would be transmitted back to Earth using a retractable meter-long antenna, or perhaps even using the lightsail to facilitate laser-based communications that could focus a signal back towards Earth.

    The original idea was to send the spacecraft flying through the Alpha Centauri system without slowing down. After all, how can they slow down? It turns out someone has already figured out a possible way. In early 2017 two scientists announced the results of their study of a possible braking method, using the radiation and gravity of the Alpha Centauri stars themselves. We don’t know yet if such a thing can work, but it’s heartening to see scientists getting involved in this idea!

    Clearly, the Breakthrough Starshot project is one that’s worth watching.

    On April 20 and 21, 2017, Breakthrough Initiatives held the second of what it says will be an annual conference – called Breakthrough Discuss – aimed at bringing together leading astronomers, engineers, astrobiologists and astrophysicists. This year, they held the conference at Stanford University and focused it on discoveries of potentially habitable planets in nearby star systems, including Alpha Centauri. Videos related to discussions at the conference are archived on Breakthrough’s Facebook page, if you’re interested.

    Illustration via FutureHumanEvolution.com

    Bottom line: At 4.3 light-years away, the Alpha Centauri system is the nearest star system to our Earth and sun, but getting there would be extremely difficult.

    See the full article here .

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  • richardmitnick 12:37 pm on May 14, 2017 Permalink | Reply
    Tags: , , EarthSky, , What’s a safe distance between us and a supernova?   

    From EarthSky: “What’s a safe distance between us and a supernova?” 



    May 7, 2017

    Artist’s illusration of a supernova, or exploding star, via http://SmithsonianScience.org

    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 years as the closest safe distance between Earth and a supernova. Follow the links below to learn more.

    What would happen if a supernova exploded near Earth?

    How many potential supernovae are located closer to us than 50 to 100 light-years?

    What about Betelgeuse?

    Betelgeuse and Bellatrix: Orion’s Shoulders

    How often do supernovae erupt in our galaxy?

    This image shows the remnant of Supernova 1987A seen in light of very different wavelengths. ALMA data (in red) shows newly formed dust in the centre of the remnant. Hubble (in green) and Chandra (in blue) data show the expanding shock wave.
    Date 6 January 2014
    Source http://www.eso.org/public/images/eso1401a/
    Author ALMA (ESO/NAOJ/NRAO)/A. Angelich. Visible light image: the NASA/ESA Hubble Space Telescope. X-Ray image: The NASA Chandra X-Ray Observatory

    NASA/ESA Hubble Telescope

    NASA/Chandra Telescope

    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 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.

    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.

    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 speaking), 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 knowns. 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. Read more about Betelgeuse as a supernova.

    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 a few million years for the time 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.

    Bottom line: Scientific literature cites 50 to 100 years as the closest safe distance between Earth and a supernova.

    See the full article here .

    See the full article <a href="http://1 EarthSky See the full article here . Please help promote STEM in your local schools. STEM Icon Stem Education Coalition

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  • richardmitnick 9:25 am on May 1, 2017 Permalink | Reply
    Tags: , , , Chariklo rings, , EarthSky,   

    From EarthSky: “Simulating the smallest ring world’ 



    April 30, 2017
    Deborah Byrd

    Chariklo is the smallest space body known to have rings. A new supercomputer simulation by Japanese researchers suggests a life expectancy for the rings of only 1 to 100 years.

    The Center for Computational Astrophysics in New York said on Friday (April 28, 2017) that Japanese researchers have modeled the two known rings around 10199 Chariklo, a possible dwarf planet orbiting the sun between the major planets Saturn and Uranus. They say it’s the first time an entire ring system has been simulated using realistic sizes for the ring particles while also taking into account collisions and gravitational interactions between the particles. They also created the visuals on this page, including the video above, which lets you dive into Chariklo’s ring system. Note that Chariklo itself is really potato-shaped and no doubt pocked with craters; the round, smooth shape in the video is for purposes of the simulation.

    These researchers’ work is published in the peer-reviewed March 2017 edition of The Astrophysical Journal Letters.

    Chariklo is a tiny world.

    An artist’s rendering of the minor planet 10199 Chariklo, with rings.
    Observations at many sites in South America, including ESO’s La Silla Observatory, have made the surprise discovery that the remote asteroid Chariklo is surrounded by two dense and narrow rings. This is the smallest object by far found to have rings and only the fifth body in the Solar System — after the much larger planets Jupiter, Saturn, Uranus and Neptune — to have this feature. The origin of these rings remains a mystery, but they may be the result of a collision that created a disc of debris. This artist’s impression shows a close-up of what the rings might look like.
    ESO/L. Calçada/M. Kornmesser/Nick Risinger (skysurvey.org)

    Its estimated size about 200 miles (334 km) by about 140 miles (226 km) by about 100 miles (172 km). Our solar system’s major outer planets (Jupiter, Saturn, Uranus, Neptune) all are known to have rings. These planets’ rings are composed of particles estimated to range from inches to several feet (centimeters to meters) in size. Chariklo’s gravitational attraction is small relative to the major planets, so its rings – which were discovered in 2014 – are likely only temporary.

    Although Chariklo is small, and although its gravity is relatively weak, its rings are as opaque as those around Saturn and Uranus. Thus, the researchers said, Chariklo offered an ideal chance to model a complete ring system.

    The team said their simulation revealed information about the size and density of the particles in the rings. They found that Chariklo’s inner ring should be unstable without help. So – the researchers said – the ring particles must be much smaller than previously thought. Or it means that an undiscovered shepherd satellite around Chariklo is stabilizing the ring.

    Visualization constructed from simulation of Chariklo’s double ring. Note that Chariklo itself is really potato-shaped and no doubt pocked with craters; the round, smooth shape here is for purposes of the simulation. Image via Shugo Michikoshi, Eiichiro Kokubo, Hirotaka Nakayama, 4D2U Project, NAOJ/ CFCA.

    The researchers – Shugo Michikoshi (Kyoto Women’s University/University of Tsukuba) and Eiichiro Kokubo (National Astronomical Observatory of Japan, or NAOJ) modeled Chariklo’s rings using the supercomputer ATERUI*1 at NAOJ. They calculated the motions of 345 million ring particles with the realistic size of a few meters taking into account the collisions and mutual gravitational attractions between the particles.

    Chariklo is the largest member of a class known as the Centaurs, orbiting between Saturn and Uranus in the outer solar system. These bodies are categorized like asteroids, but, whereas most asteroids lie in the asteroid belt between Mars and Jupiter – closer to the sun – Centaurs may have come from the Kuiper Belt, which is visualized as extending from the orbit of the outermost major planet Neptune to approximately 50 Earth-sun units (AU) from our sun. Centaurs have unstable orbits that cross the giant planets’ orbit. Chariklo’s orbit gazes that of Uranus. Because their orbits are frequently perturbed, Centaurs like Chariklo are expected to only remain in their orbits only for millions of years, in contrast to our Earth and the other major planets which have been orbiting for billions of years around our sun.

    The new computer visualization suggests that the density of Chariklo’s ring particles must be less than half the density of Chariklo itself. And they show a striped pattern forming in the inner ring due to interactions between the particles. They use the term “self-gravity wakes” for this pattern (see the image below). These self-gravity wakes accelerate the break-up of the ring, the researchers said.

    But perhaps the most surprising result of the new study is a recalculated life expectancy for Chariklo’s rings. The study suggests the rings may be able to reamin around Chariklo for only one to 100 years! That’s much shorter than previous estimates, and it’s less than an eye-blink in astronomical terms.

    So what we are seeing with Chariklo and its ring system is likely a very temporary and dynamic situation. Things in space tend to happen on a vastly-longer timescales than we humans are used to, but sometimes things do happen on human timescales. Chariklo’s rings may be an example!

    Simulation of Chariklo’s ring system. The researchers said they used a ring particle density equal to half of Chariklo’s density, in order to maintain the rings’ overall structure. In the close-up view (right) complicated, elongated structures are visible. These structures are called self-gravity wakes. The numbers along the axes indicate distances in km. Image via Shugo Michikoshi / CFCA.

    See the full article here .

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  • richardmitnick 12:58 pm on April 18, 2017 Permalink | Reply
    Tags: , , , , , , EarthSky   

    From EarthSky: “Who needs dark energy?” 



    April 17, 2017
    Brian Koberlein

    Dark energy is thought to be the driver for the expansion of the universe. But do we need dark energy to account for an expanding universe?

    Image via Brian Koberlein/ One Universe at a Time.

    Our universe is expanding. We’ve known this for nearly a century, and modern observations continue to support this. Not only is our universe expanding, it is doing so at an ever-increasing rate. But the question remains as to what drives this cosmic expansion. The most popular answer is what we call dark energy. But do we need dark energy to account for an expanding universe? Perhaps not.

    The idea of dark energy comes from a property of general relativity known as the cosmological constant. The basic idea of general relativity is that the presence of matter https://briankoberlein.com/2013/09/09/the-attraction-of-curves/. As a result, light and matter are deflected from simple straight paths in a way that resembles a gravitational force. The simplest mathematical model in relativity just describes this connection between matter and curvature, but it turns out that the equations also allow for an extra parameter, the cosmological constant, that can give space an overall rate of expansion. The cosmological constant perfectly describes the observed properties of dark energy, and it arises naturally in general relativity, so it’s a reasonable model to adopt.

    In classical relativity, the presence of a cosmological constant simply means that cosmic expansion is just a property of spacetime. But our universe is also governed by the quantum theory, and the quantum world doesn’t play well with the cosmological constant. One solution to this issue is that quantum vacuum energy might be driving cosmic expansion, but in quantum theory vacuum fluctuations would probably make the cosmological constant far larger than what we observe, so it isn’t a very satisfactory answer.

    Despite the unexplainable weirdness of dark energy, it matches observations so well that it has become part of the concordance model for cosmology, also known as the Lambda-CDM model. Here the Greek letter Lambda is the symbol for dark energy, and CDM stands for Cold Dark Matter.

    In this model there is a simple way to describe the overall shape of the cosmos, known as the Friedmann–Lemaître–Robertson–Walker (FLRW) metric. The only catch is that this assumes matter is distributed evenly throughout the universe. In the real universe matter is clumped together into clusters of galaxies, so the FLRW metric is only an approximation to the real shape of the universe. Since dark energy makes up about 70% of the mass/energy of the universe, the FLRW metric is generally thought to be a good approximation. But what if it isn’t?

    A new paper argues just that. Since matter clumps together, space would be more highly curved in those regions. In the large voids between the clusters of galaxies, there would be less space curvature. Relative to the clustered regions, the voids would appear to be expanding similarly to the appearance of dark energy. Using this idea the team ran computer simulations of a universe using this cluster effect rather than dark energy. They found that the overall structure evolved similarly to dark energy models.

    That would seem to support the idea that dark energy might be an effect of clustered galaxies.

    It’s an interesting idea, but there are reasons to be skeptical. While such clustering can have some effect on cosmic expansion, it wouldn’t be nearly as strong as we observe. While this particular model seems to explain the scale at which the clustering of galaxies occur, it doesn’t explain other effects, such as observations of distant supernovae which strongly support dark energy. Personally, I don’t find this new model very convincing, but I think ideas like this are certainly worth exploring. If the model can be further refined, it could be worth another look.

    Paper: Gabor Rácz, et al. Concordance cosmology without dark energy. Monthly Notices of the Royal Astronomical Society Letters: DOI: 10.1093/mnrasl/slx026 (2017)

    Dark Energy Camera [DECam], built at FNAL

    DECam at Cerro Tololo, Chile, housing DECam

    See the full article here .

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  • richardmitnick 12:38 pm on April 15, 2017 Permalink | Reply
    Tags: , , , , EarthSky, , Is there life on Saturn’s moon?,   

    From EarthSky: “Is there life on Saturn’s moon?” 


    April 15, 2017
    Daniela Breitman

    Enceladus, one of 62 moons in a confirmed orbit around Saturn, has been in the spotlight since the Cassini spacecraft began orbiting Saturn, weaving among its moons and rings, in 2004. It was only when Cassini turned its instruments toward Enceladus that we learned of the moon’s powerful geysers and subsurface saltwater ocean. This week, scientists made another fascinating announcement about this Saturn moon. They say they now have strong evidence for a habitable area on the floor of Enceladus’ ocean. Their paper on this subject was published in the peer-reviewed journal Science on April 13, 2017.

    The ocean of Enceladus is covered by a layer of surface ice. The moon’s geysers emerge from the subsurface ocean through cracks in the ice. When the Cassini spacecraft flew through plumes of gas and icy particles that make up Enceladus’ geysers on October 28, 2015, it detected a significant amount of molecular hydrogen. Scientists confirmed this week that the best explanation for this observation is that hydrothermal reactions occurring on Enceladus’ ocean floor. They may be similar to hydrogen-generating interactions taking place at Earth’s hydrothermal vents.

    This discovery means the small, icy moon Enceladus might have a source of chemical energy that could be useful for living microbes, if any exist there.

    Scientists have suggested that water interacts with the rocky core of Enceladus, thereby producing hydrogen. The detection of molecular hydrogen in the plumes of Enceladus supports this idea. Image via NASA.

    Hydrothermal vents are common on Earth. They are fissures in the ocean crust through which geothermally heated water escapes. In other words, they are regions where water interacts with Earth’s magma. Earthly hydrothermal vents are home to many fascinating bacteria. Yellowstone’s Grand Prismatic Spring is an example of a hydrothermal area with a rich bacterial life.

    Life has not been discovered beneath the icy crust of Enceladus. But the detection of hydrogen is strong evidence that all the necessary conditions for life are present. Hunter Waite of the Southwest Research Institute in San Antonio and lead author of the new Enceladus study, said in a statement:

    Although we can’t detect life, we’ve found that there’s a food source there for it. It would be like a candy store for microbes.

    Microbes on Enceladus could produce their energy through a chemical reaction known as methanogenesis, which consists of burning hydrogen and carbon dioxide dissolved in the ocean water to form methane and water.

    This reaction is at the core of the development of life on Earth.

    The so-called tiger stripes and geysers of Enceladus, photographed by the Cassini-Huygens probe in October, 2015. Image via NASA.

    NASA/ESA/ASI Cassini Spacecraft

    ESA Huygens Probe from Cassini landed on Titan

    This Cassini image from 2005 shows Enceladus’ geysers – backlit – spewing into space. By flying the craft through the plume from geysers like this one, scientists obtained evidence for molecular hydrogen, possibly produced via hydrothermal processes on the floor on Enceladus’ ocean. Image via NASA.

    Scientists considered other explanations for Cassini spacecraft’s 2015 detection of molecular hydrogen within Enceladus’ geysers, for example, hydrogen leaking from the moon’s rocky core in ways other than hydrothermal reactions. The scientists who’ve studied these observations most closely, however, now feel that hydrothermal reactions are the best explanation.

    Liquid water, an energy source, and the right chemicals (carbon, hydrogen, nitrogen, oxygen, phosphorus and sulphur) are the three main requirements for life as we know it. Now scientists discovered all of these life-ingrediants – except phosphorus and sulphur – on Enceladus.

    The paper published in Science presents a detailed analysis of the possibility of methanogenesis on Enceladus. The calculations are inconclusive as to whether methanogenesis is happening or not around the hydrothermal vents of Enceladus. Nevertheless, this discovery is a big step in characterising the habitability of the ocean of Enceladus.

    Bottom line: In April, 2017, scientists announced that molecular hydrogen in the plumes of Enceladus, one of Saturn’s moons, may be due to methanogenesis, a process that implies microbial life.

    See the full article here .

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