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  • richardmitnick 8:12 am on May 1, 2019 Permalink | Reply
    Tags: "One-Third of Exoplanets Could Be Water Worlds With Oceans Hundreds of Miles Deep", , , , , Smithsonian.com   

    From smithsonian.com: “One-Third of Exoplanets Could Be Water Worlds With Oceans Hundreds of Miles Deep” 

    smithsonian
    From smithsonian.com

    4.30.19
    Jason Daley

    2
    NASA

    Scientists often search for water in space because on Earth, anywhere there is water, there is life.

    Rovers on Mars are looking for present-day water or ice as well as signs of ancient rivers and oceans. They’ve scoured the moon looking for signs of ice deep in its craters and even sent a probe to look for ice on a comet. But new research suggests finding cosmic H2O may not be all that difficult outside our own solar system. Simulations based on exoplanet data suggest water worlds covered with deep oceans may actually be rather common throughout our galaxy, according to a new study published this week in PNAS.

    Since 1992, astronomers have catalogued about 4,000 exoplanets orbiting around distant stars. It turns out that most of those planets fall into two size categories: smaller planets with a radius about 1.5 times that of Earth and a mass about five times our planet and larger planets with a radius 2.5 times that of our planet and ten times the mass. Jamie Carter at Forbes reports that researchers believe the planets with smaller radii are rocky worlds. They interpreted the size and mass of the larger planets as a class of planets called gas dwarfs, which have a rocky core surrounded by a halo of gas.

    Using new data about the radii and mass of exoplanets collected by the Gaia space satellite, Harvard planetary scientist Li Zeng and his colleagues gather more details about the exoplanets’ internal structures.

    ESA/GAIA satellite

    They found that those big gas dwarfs are better explained as water worlds. But these are not water worlds like Earth, where despite covering 71 percent of the surface, water only accounts for 0.02 percent of Earth’s mass. Instead, these worlds are made of 25 percent and up to 50 percent water, with strange, vast oceans covering them. It’s possible that up to 35 percent of all known exoplanets are these vast ocean-covered orbs, Li noted at a conference last summer.

    “This is water, but not as commonly found here on Earth,” Li says in a press release. “Their surface temperature is expected to be in the 200 to 500 degree Celsius range. Their surface may be shrouded in a water-vapor-dominated atmosphere, with a liquid water layer underneath. Moving deeper, one would expect to find this water transforms into high-pressure ices before… reaching the solid rocky core. The beauty of the model is that it explains just how composition relates to the known facts about these planets.”

    Li explains George Dvorsky at Gizmodo in an email that these planets may or may not have a defined surface. The oceans could be hundreds of miles deep, calling them: “Unfathomable. Bottomless. Very Deep.” By comparison, the deepest known spot in the Earth’s oceans, Challenger Deep in the Mariana Trench, is less than seven miles deep.

    The weight of all that water would create pressures over a million times that found on the surface of Earth, leading to some very strange phenomenon at the bottom, including the formation of “hot, hard” rock-like phases of ice, like Ice VII.

    So if these water worlds are so common, why don’t we have one like them in our solar system? Zeng tells Carter that it’s possible our planetary system may be an oddball because we have massive gas giants like Jupiter and Saturn floating around.

    “The formation of gas giants and the formation of those close-in super-Earths and sub-Neptunes are somewhat mutually exclusive,” he says. “Our solar system had formed the gas giant Jupiter early on, which probably had prevented or interfered with the formation and growth of super-Earths and sub-Neptunes.”

    In other star systems without a Jupiter-sized planet, the formation of rocky “super-Earths” and water worlds is probably pretty common.

    Sean Raymond, an astronomer at the University of Bordeaux who was not involved in the study, tells Dvorsky the study seems spot on, but cautions that we don’t have direct confirmation of all these water worlds. Our current methods of detecting exoplanets are indirect, and we have to infer what we know from their radius, mass, orbiting time and other data.

    “[The study’s] conclusions are statistical, meaning that the authors are not pointing to specific planets and claiming them to be water worlds but rather focusing on the population as a whole,” he says. “Still, it’s a cool paper and a provocative result.”

    As to whether some form of cosmic-aquatic life may be out there, it’s hard to say. But we may get more information soon when the beleaguered James Webb Space Telescope launches in 2021. That next-gen space scope should be capable of directly detecting water on distant exoplanets.

    See the full article here .

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    Please help promote STEM in your local schools.

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  • richardmitnick 8:59 am on March 14, 2019 Permalink | Reply
    Tags: "Flooding Creates a 10-Mile-Long Lake in Death Valley", , , Smithsonian.com, The rare ephemeral lake was caused when the compacted dry desert soil wasn’t able to absorb the .87 inches of rain that recently fell on the national park.   

    From smithsonian.com: “Flooding Creates a 10-Mile-Long Lake in Death Valley” 

    smithsonian
    From smithsonian.com

    March 13, 2019
    Jason Daley

    The rare ephemeral lake was caused when the compacted, dry desert soil wasn’t able to absorb the .87 inches of rain that recently fell on the national park.

    1
    (Elliot McGucken, http://www.mcgucken.com)

    Most of the time, visitors to Death Valley National Park in southern California don’t expect to see much water. The area is the hottest and driest spot in North America. So it was surprising when, after a massive storm last week, a winding 10-mile-long lake appeared in the park.

    The shallow body of water was discovered by photographer Elliott McGucken on March 7, reports Amy Graff at SFGate.com. After the storm moved through the area, McGucken was planning to visit Badwater Basin to take some photos, hoping that an ephemeral lake had formed in the area. But he couldn’t reach the spot because the other, larger lake along Salt Creek blocked the way.

    It actually turned out to be even better than Badwater Basin. McGucken was able to shoot some once-in-a-lifetime images of the flooding with the surrounding Panamint Mountains reflected in the water. “Nature presents this ephemeral beauty, and I think a lot of what photography is about is searching for it and then capturing it,” he tells Graff.

    While it’s difficult to pin down just how large the lake is, the National Park Service estimates that it stretches about 10 miles. “I believe we would need aerial photos to accurately determine the size. From the road, it looks like it stretched from approximately Harmony Borax Works to Salt Creek right after the rain, which is a little less than 10 road miles,” the park said in a statement emailed to McGucken. “But, the road does curve a bit, so it’s not an entirely accurate guess.”

    According to Pam Wright at Weather.com, the flooding occurred because on March 5 and 6, the Park received .87 inches of rain, almost three times the average for March. The deluge represents about one-third of Death Valley’s total annual precipitation.

    The parched, compacted soil of the desert can be like concrete, and is unable to suck up such a large amount of rain quickly. “Because water is not readily absorbed in the desert environment, even moderate rainfall can cause flooding in Death Valley,” Weather.com meteorologist Chris Dolce explains. “Flash flooding can happen even where it is not raining. Normally dry creeks or arroyos can become flooded due to rainfall upstream.”

    Park officials tell Graff the lake is still present, though it is gradually getting smaller.

    2
    (Elliot McGucken, http://www.mcgucken.com)

    Sadly, the rains have come too late to power a superbloom in Death Valley, reports the NPS. Superblooms occur when the desert gets above average rainfall at the right time in the winter months, leading to an irruption of desert flowers. Currently, a superbloom, the second in two years, is taking place in Anza-Borrego Desert State Park, the state’s largest, which received the right amount of rain early on. Fields of orange poppies, purple sand verbena, white and yellow primroses and other desert wildflowers are blossoming in unison.

    Death Valley experienced a major superbloom in 2005 and it’s latest superbloom was in 2016. Those flowers, however, came with a price. In October 2015, the park experienced the largest flood event in the Valley’s recorded history when between 1 to 2 inches of rain fell over the park. At that time, Badwater Basin, normally a dry lake bed, filled with water. The road to the Scotty’s Castle area of the park was closed, and it is still not expected to reopen until 2020.

    See the full article here .

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    Please help promote STEM in your local schools.

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    Smithsonian magazine and Smithsonian.com place a Smithsonian lens on the world, looking at the topics and subject matters researched, studied and exhibited by the Smithsonian Institution — science, history, art, popular culture and innovation — and chronicling them every day for our diverse readership.

     
  • richardmitnick 11:18 am on March 13, 2019 Permalink | Reply
    Tags: "Streams of Stars Snaking Through the Galaxy Could Help Shine a Light on Dark Matter", Adrian Price-Whelan calls GD-1 "the Goldilocks stream" because it's in just the right place., , , At about 33000 light-years (10 kiloparsecs) GD-1 is the longest stellar stream in the galactic halo, , , Dark matter makes up the bulk of the mass in the universe but it has never been directly observed, , , , scores of dark matter seeds are scattered through galaxies like the Milky Way, Smithsonian.com, The stellar stream known as GD-1 is a thin flow of material tucked inside the Galactic halo   

    From smithsonian.com: “Streams of Stars Snaking Through the Galaxy Could Help Shine a Light on Dark Matter” 

    smithsonian
    From smithsonian.com

    March 12, 2019
    Nola Taylor Redd

    When the Milky Way consumes another galaxy, tendrils of stellar streams survive the merger, containing clues about the universe’s mysterious unseen matter.

    1
    An ultraviolet image of the Andromeda galaxy, the closest major galaxy to the Milky Way, taken by NASA’s Galaxy Evolution Explorer space telescope. Like our own galaxy, Andromeda is a spiral galaxy with a flat rotating disk of stars and gas and a concentrated bulge of stars at the center. (NASA/JPL-Caltech)

    When a small galaxy strays too close to the Milky Way, the gravity from our larger galaxy reels it in. Gas and stars are ripped from the passing galaxy as it falls inward toward its doom, creating streams of material that stretch between the galactic pair. These streams continue to tear away stars until the infalling object has been completely consumed. After the merger is over, some of the only remaining signs of the devoured object are the stellar streams snaking through the Milky Way, a small sample of stars from a galaxy long gone.

    In addition to being a record of the past, one of these streams may provide the first direct evidence for small scale clusters of dark matter—the elusive material that is believed to account for 85 percent of all matter in the universe. A recent analysis of a trail of stars reveals that it interacted with a dense object in the last few hundred million years. After ruling out the most likely suspects, the researchers determined that the relatively recently made gap in the stream may have been caused by a small clump of dark matter. If confirmed, the eddies of this stellar stream could help scientists sort through the competing theories about dark matter and perhaps even close in on the characteristics of the mysterious material.

    The stellar stream known as GD-1 is a thin flow of material tucked inside the Galactic halo, the loose collection of stars and gases surrounding the disk of the Milky Way. Using data released last April from the European Space Agency’s Gaia space telescope, which is in the process of assembling the most detailed map of the Milky Way’s stars ever made, astronomers were able to use precise positional data to reconstruct the movement of the stars in GD-1.

    ESA/GAIA satellite

    Torn from a cloud of material, the stream is the last remnant of an object that was likely consumed by our galaxy in the last 300 million years—an eyeblink on astronomical timescales.

    Gaia found two small breaks in the stream, the first unambiguous observation of gaps in a stellar stream, as well as a dense collection of stars called a spur. Together, these features suggest that a small but massive object shook up the material of the stream.

    “I think this is the first direct dynamical evidence for the small-scale [structure] of dark matter,” says Adrian Price-Whelan, an astronomer at the Flatiron Institute in New York. Working with Ana Bonaca of the Harvard-Smithsonian Center for Astrophysics, Price-Whelan investigated the newfound structures in GD-1 to determine their source and presented the results earlier this year at the winter meeting of the American Astronomical Society.

    At about 33,000 light-years (10 kiloparsecs), GD-1 is the longest stellar stream in the galactic halo. While Price-Whelan and his colleagues were able to use models to show that one of the gaps formed during the generation of the stream, the other gap remained a mystery. However, along with the puzzle, Gaia also revealed a solution: the spur.

    When an object travels past or through a stellar stream, it disrupts the stars. Price-Whelan compares the disruption to a strong jet of air blowing across a stream of water. The water—or stars—plume outward along the path of the disruptor, creating a gap. Some move so fast that they escape the stream and go flying off into space, lost forever. Others are pulled back into the stream to form eddy-like features astronomers call spurs. After a few hundred million years, most spurs merge back into the stream, and only the gap remains, though some can be longer-lived.

    When it comes to spotting structures in stellar streams, Price-Whelan calls GD-1 “the Goldilocks stream” because it’s in just the right place. GD-1 is within the stars of the Milky Way, but moving in the opposite direction, making it easier for astronomers to pick out the stars in the stream from the surrounding objects. “At any given location, it’s moving differently from the way most of the other stars in that part of the sky are moving,” Price-Whelan says.

    The researchers modeled what type of objects could be responsible for the relatively newborn spur spotted in GD-1. They determined that the responsible object had to weigh in with a mass somewhere between 1 million and 100 million times the mass of the sun. Stretching only about 65 light-years (20 pc) in length, the object would have been incredibly dense. The interaction between the stream and the dense object would have likely happened within the last few hundred million years out of the 13.8-billion-year lifetime of the universe.

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

    Dark matter isn’t the only object that could have disrupted the stellar stream. A globular cluster or dwarf galaxy swooping nearby could also have created the gap and spur. Price-Whelan and his colleagues turned their eyes toward all known such objects and calculated their orbits, finding that none came close enough to GD-1 in the last billion years to shake things up. A chance encounter with a primordial black hole could have sent the stream’s stars flying, but it would have been an extremely rare event.

    According to dark matter simulations that allow for small structures, scores of dark matter seeds are scattered through galaxies like the Milky Way. A stream like GD-1 is expected to encounter at least one such seed within the last 8 billion years, making dark matter a far more likely perturber based on encounter rates than any other object.

    Dark matter makes up the bulk of the mass in the universe, but it has never been directly observed. The two leading theories for its existence are the warm dark matter model and the Lambda cold dark matter model (ΛCDM), which is the model preferred by most scientists.

    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex Mittelmann Cold creation

    Under ΛCDM, dark matter forms clumps that can be as large as a galaxy or as small as a soda can. Warm dark matter models suggest that the material has less massive particles and lacks the can-sized structures that the ΛCDM model suggests. Finding evidence for small scale structures of dark matter could help weed out certain models and start to narrow in on some of the characteristics of the tantalizing stuff.

    “Streams might be the only avenue that we could [use to] study the lowest mass end of what dark matter is doing,” Price-Whelan says. “If we want to be able to confirm or reject or rule out different theories of dark matter, we really need to know what’s happening at [the low] end.”

    Gaia’s data helped identify the stars of the spur, but it’s not detailed enough to compare the velocity differences between them and the stars in the stream, which could help confirm that dark matter perturbed the structure. Price-Whelan and his colleagues want to use NASA’s Hubble Space Telescope to further study the movement of the faint stars in GD-1. Although Gaia has opened the door to wide-scale examination of the movement of stars across the Milky Way, Price-Whelan says that it can’t compete with the HST when it comes to very faint stars. “You can drill much deeper when you have a dedicated telescope like Hubble,” he says.

    The differences in how the stars of the stream and spur move could help astronomers determine how much energy the perturbing object carried, as well as allow researchers to calculate its orbit. These pieces of information could be used to track down the disruptive dark matter clump and study its immediate environment.

    In addition to making a more in-depth study of GD-1, astronomers plan to apply the same techniques enabled by Gaia’s data to some of the more than 40 other streams surrounding the Milky Way. Spotting spurs and gaps in other streams and tying them to dark matter could further improve our understanding of how the mysterious substance interacts with the visible galaxy.

    After decades of puzzling over the mystery of dark matter, the gaps and spurs in stellar streams like GD-1 may finally help to reveal the secrets of the substance that makes up most of the universe. “This is one of the most exciting things that has come out of Gaia,” Price-Whelan says.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Smithsonian magazine and Smithsonian.com place a Smithsonian lens on the world, looking at the topics and subject matters researched, studied and exhibited by the Smithsonian Institution — science, history, art, popular culture and innovation — and chronicling them every day for our diverse readership.

     
  • richardmitnick 10:42 am on January 16, 2019 Permalink | Reply
    Tags: , , , , Disintegrating Planets Could Be the Key to Discovering What Worlds Are Made Of, Smithsonian.com   

    From smithsonian.com: “Disintegrating Planets Could Be the Key to Discovering What Worlds Are Made Of” 

    smithsonian
    From smithsonian.com

    January 15, 2019
    Nola Taylor Redd

    1
    The artist’s concept depicts a comet-like tail of a possible disintegrating super Mercury-size planet candidate as it transits its parent star named KIC 12557548. At an orbital distance of only twice the diameter of its star, the surface temperature of the potential planet is estimated to be a sweltering 3,300 degrees Fahrenheit. (NASA / JPL-Caltech)

    The exoplanet Kepler-1520b is so close to its host star that it completes an orbit in just over half a day. At this close proximity, Kepler-1520b is tidally locked in a gravitational stability, keeping one half of the planet facing the star and the other half facing away at all times. Unfortunately for Kepler-1520b, this arrangement turns the star-facing side of the planet into a churning mass of molten rock and magma seas, slowly boiling off into space.

    Even though Kepler-1520b is not long for this galaxy, astronomers are eager to learn more about the disintegrating world, positioned about 2,000 light-years from Earth. The planets’ comet-like tail of dust and debris could provide insight into the fundamental formation process of all planets in the galaxy. New telescopes, such as NASA’s James Webb Space Telescope scheduled to launch in 2021, may be able to probe the cloud behind Kepler-1520b and two other slowly disintegrating worlds.

    NASA/ESA/CSA Webb Telescope annotated

    “The composition in an exoplanet system could be substantially different from the solar system,” says Eva Bodman, an exoplanet researcher at Arizona State University. As more and more exoplanets are discovered, astronomers are struck by how unique our solar system looks from other planets orbiting other stars. Bodman set out to determine if it was possible to measure the composition of a small, rocky, disintegrating exoplanet by studying the debris traveling in its wake. But there was a problem.

    Spotting the fingerprint of rocky elements requires studying the worlds in infrared. Ground-based telescopes aren’t sensitive enough to spot them, leaving only NASA’s soon-retiring Spitzer Space Telescope and SOFIA, a telescope carried above the atmosphere on board a Boeing 747.

    NASA/Spitzer Infrared Telescope

    NASA/DLR SOFIA

    Neither instrument has the range to look for the rocky material, Bodman says. But James Webb, designed to study exoplanets in infrared as well as ancient galaxies and the most distant objects of the universe, should be able to peer through the clouds of debris and identify some of their ingredients.

    “Webb would be able to measure the relative abundances of different minerals,” Bodman says. “From that, we can infer the geochemistry of the interior of these planets was before they started disintegrating.” Bodman and her team’s findings on the feasibility of studying disintegrating exoplanets were published in The Astronomical Journal late last year.

    In 2012, scientists reviewing data from NASA’s Kepler space telescope found signs of a world being slowly shredded by heat and pressure, Kepler-1520b. Two more shredded planets were found in the following years among the thousands of exoplanets discovered by Kepler and its extended mission, K2. Circling their stars in just a handful of hours, these rocky bodies boast temperatures as high as 4,200 degrees Celsius (7,640 degrees Fahrenheit) on the superheated regions facing the stars.

    The extreme temperatures drive the planet’s dissolution. “The atmosphere is just rock vapor,” Bodman says. “It’s the sheer heat of the planet that’s pushing off this rock vapor atmosphere.”

    Radiation produced by the stars pushes against the planet’s vaporized atmospheres, creating a cloudy tail. Although Kepler wasn’t able to directly measure how large the shrouded planets were, simulations suggest that they are between the size of the moon and Mars. Any more compact, and the disintegration process shuts down.

    These objects were not always so small and shriveled, however. Kepler-1520b and the two other objects like it are thought to have formed as gas giants, after which they migrated in toward their host stars and were stripped all the way down to the rocky core.

    In recent years, exoplanet scientists have made great strides studying the atmospheres of large, gaseous planets orbiting other stars. Most of that material is rich in hydrogen and helium and can be identified using NASA’s Hubble Space Telescope. But the rocky materials fall on a different part of the spectrum, “in wavelengths that Hubble can’t currently reach,” says Knicole Colon, a research astrophysicist at NASA’s Goddard Space Flight Center in Maryland who has studied the disintegrating planet K2-22. “With James Webb, we’d be able to go out to those wavelengths.”

    Using Webb to hunt for materials such as iron, carbon and quartz, astronomers would gain a better understanding about what’s going on inside distant worlds. “If we were able to detect any of these features, we could say with some certainty what these rocky bodies are made off,” Colon says. “That could definitely be very informative for understanding rocky exoplanets in general.”

    Planets form from the cloud of dust and gas leftover after the birth of a star. Scientists think the worlds of the solar system were created by a process known as pebble accretion, in which small bits of dust and gas come together to make larger and larger objects. Eventually, the cores of the gas giants grow massive enough to attract leftover gas, forming their thick atmospheres. But the exact steps remain difficult to pin down.

    The interiors of planets around other stars would vary depending on the elements found in that particular environment. Sorting through these differences could help researchers better understand those tantalizing first steps of planet formation.

    “There’s no reason that the solar system should be different from exoplanets, and vice versa,” Colon says. “We’re all planets, so we all formed in possibly similar ways. Understanding these planets is another step in the process to the bigger picture.”

    But even with similar formation processes, Bodman suspects that planets around other stars might not look so familiar. “The composition in an exoplanet system could be substantially different from the solar system,” she says.

    Although Webb will only be able to tease out information about exoplanet composition, advanced instruments may one day allow disintegrating planets to reveal even more about themselves. As the planets erode away, astronomers could get an unprecedented look at their interiors, possibly down to the core. “In theory, we could know more about these exoplanets than even about the Earth, and definitely more than the other planets in the solar system,” Bodman says.

    Unlike stars, which can shine for tens of billions of years, shredded worlds only stick around for a relatively short time. Simulations suggest that planets like K2-22 only have about 10 million years before they are completely destroyed. And because all three worlds orbit stars that are billions of years old, they probably haven’t been in their current positions for very long.

    Bodman and Colon both think the doomed planets probably formed far out in their system and then migrated inward over time. Interactions with other planets could have hurled them on their fateful trajectories, although all three of these disintegrating planets are the only known satellites of their host stars. Bodman says it is likely the worlds have only recently begun a close orbit of their stars, but how they got there remains an open question.

    The short lifetime of a disintegrating planet—only a blip in the longer life of a star—is probably why so few of these worlds have been found. “They’re definitely rare,” Bodman says.

    Both women agree that there is a good chance that another one or two disintegrating exoplanets are contained in the Kepler data, especially the most recent results from K2. And the recently launched Transiting Exoplanet Survey Satellite (TESS), which has already found hundreds of new planets, will produce even more.

    “I think it’ll take some time to sift through everything, but I’m hoping we find more,” Colon says.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Smithsonian magazine and Smithsonian.com place a Smithsonian lens on the world, looking at the topics and subject matters researched, studied and exhibited by the Smithsonian Institution — science, history, art, popular culture and innovation — and chronicling them every day for our diverse readership.

     
  • richardmitnick 10:51 am on January 9, 2019 Permalink | Reply
    Tags: , , , China’s Chang’e-4 lander, , , Smithsonian.com   

    From smithsonian.com: “Best Photos From China’s Far Side Moon Landing” 

    smithsonian
    From smithsonian.com

    January 7, 2019
    Jason Daley
    All photos from China National Space Admimmistration

    3
    Yutu-2 rover leaves the Chang’e-4 lander

    1
    Yutu-2 sets off.

    2
    First images

    4
    Close shot of Yutu-2 rover specialized wheel.

    China’s Chang’e-4 lander reached the Von Kármán crater near the moon’s South Pole on Wednesday, marking the first time a human craft has visited the lunar far side.

    The first upclose images of the far side’s surface came in shortly after via a satellite called “Queqiao,” report Steven Lee Myers and Zoe Mou at The New York Times.

    Queqiao Relay Satellite China

    The Guardian reports that, about 12 hours after the landing, a small rover named Yutu-2, or Jade Rabbit-2, left the Chang’e-4 spacecraft and began exploring the crater, which is part of the South Pole-Aitken basin, one of the largest known impact structures in our solar system.

    Chang’e-4 weighs about four metric tons and carries eight instruments on board, including an infrared spectrometer, panoramic camera and lunar penetrating radar, writes Andrew Jones at Smithsonian.com. It will also collect mineral and geological samples of the moon’s surface as well as investigate the impact of solar wind on the moon. The craft even has its own little farm, or lunar biosphere, aboard—the first of its kind. Part of an experiment designed by university students, it contains silkworm eggs, potato seeds and Arabidopsis, a model organism used in space plant studies.

    Because the far side of the moon is shielded from the radio signals coming from Earth, Chang’e-4 will conduct low frequency radio experiments using a new technique. Astronomers plan to connect a radio instrument on the landing craft with one aboard the Queqiao satellite and use the dual-system as a radio telescope—free from noisy radio interference that is common closer to Earth, reports Michael Greshko at National Geographic.

    “This will allow us for the first time to do radio observation at low frequencies that are not possible from Earth, from close to the moon and on the moon,” Radboud University astronomer Marc Klein Wolt, who leads the project, tells Greshko. “This will pave the way for a future large radio facility on the moon to study the very early universe in the period before the first stars were formed.”

    While such experiments are valuable, the landing is also considered an important accomplishment for the Chinese space program, which is quickly catching up to the decades-old United States and Russian space programs. Landing on the far side required a high level of technical expertise and unique communications solutions, Smithsonian.com’s Jones points out.

    “This is a major achievement technically and symbolically,” Namrata Goswami, an independent space analyst, tells The New York Times. “China views this landing as just a stepping stone, as it also views its future manned lunar landing, since its long-term goal is to colonize the moon and use it as a vast supply of energy.”

    In the last two decades, China has ramped up its space program, launching two space stations and sending dozens of satellites into space. Besides the U.S. and Russia, it is the only nation to send its own astronauts into space. It first visited the near side of the moon in 2013 with its Chang’e-3 lander and rover. Later in 2019, the nation plans to land Chang’e-5 on the near side of the moon and then send a sample of the moon’s surface back to Earth. In 2022, China is slated to launch another space station into orbit and has plans to establish a lunar colony later in that decade.

    While the success of Chang’e-4 is being universally celebrated by the scientific community, space policy expert Wendy Whitman Cobb at The Conversation wonders whether its an indication of second space race. The U.S. recently announced a 10-year, $2.6 billion effort to return to the moon and construct an orbiting space station. Russia has also announced intentions to send missions to the moon in the near future.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Smithsonian magazine and Smithsonian.com place a Smithsonian lens on the world, looking at the topics and subject matters researched, studied and exhibited by the Smithsonian Institution — science, history, art, popular culture and innovation — and chronicling them every day for our diverse readership.

     
  • richardmitnick 11:17 am on December 4, 2018 Permalink | Reply
    Tags: 40000000000000000000000000000000000000000000000000000000000000000000000000000000000000 photons over 13.7 billion years, , , , EBL-extragalactic background light, Looking at blazars ranging in age from 2 million to 11.6 billion years old, , Smithsonian.com, This Is How Much Starlight the Universe Has Produced   

    From smithsonian.com: “This Is How Much Starlight the Universe Has Produced” 

    smithsonian
    From smithsonian.com

    4,000,000,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000,000,000,000,000,000,000,000,000,000,000 photons over 13.7 billion years.

    December 3, 2018
    Jason Daley

    1
    Extragalactic Background Light ( Fermi-LAT)

    NASA/Fermi LAT


    NASA/Fermi Gamma Ray Space Telescope

    Since the first stars first started flickering about 100 million years after the Big Bang our universe has produced roughly one trillion trillion stars, each pumping starlight out into the cosmos. That’s a mind-boggling amount of energy, but for scientists at the Fermi Large Area Telescope Collaboration it presented a challenge. Hannah Devlin at The Guardian reports that the astronomers and astrophysicists took on the monumental task of calculating how much starlight has been emitted since the universe began 13.7 billion years ago.

    So, how much starlight is there? According to the paper in the journal Science, 4×10^84 photons worth of starlight have been produced in our universe, or 4,000,000,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000,000,000,000,000,000,000,000,000,000,000 photons.

    To get to that stupendously ginormous number, the team analyzed a decades worth of data from the Fermi Gamma-ray Space Telescope, a NASA project that collects data on star formation. The team looked specifically at data from the extragalactic background light (EBL) a cosmic fog permeating the universe where 90 percent of the ultraviolet, infrared and visible radiation emitted from stars ends up. The team examined 739 blazars, a type of galaxy with a supermassive black hole in its center that shoots out streams of gamma-ray photos directly toward Earth at nearly the speed of light. The objects are so bright, even extremely distant blazars can be seen from Earth. These photons from the shiny galaxies collide with the EBL, which absorbs some of the photons, leaving an imprint the researchers can study.

    Looking at blazars ranging in age from 2 million to 11.6 billion years old allowed the researchers to use the sensitive instruments on the Fermi telescope to analyze their light, measuring how much radiation it lost as it moved through the EBL. This let them create an accurate measure of the density or thickness of the EBL over time, essentially creating a history of starlight in the universe since, in deep space, distance and time are almost the same thing.

    “By using blazars at different distances from us, we measured the total starlight at different time periods,” co-author Vaidehi Paliya of Clemson University says in a press release. “We measured the total starlight of each epoch – one billion years ago, two billion years ago, six billion years ago, etc. – all the way back to when stars were first formed. This allowed us to reconstruct the EBL and determine the star-formation history of the universe in a more effective manner than had been achieved before.”

    Researchers have tried to measure the EBL in the past, but were unable to get past the localized dust and starlight close to Earth, making it almost impossible to collect good data on the EBL. The Fermi telescope, however, finally allowed the team to minimize that interference by looking at gamma rays. The data they collected is in line with previous estimates for the density of the EBL.

    The study shows that the peak of star formation in the universe took place about 11 billion years ago. Over time, it has slowed drastically, but stars are still forming, with about seven new stars lighting up in the Milky Way every year alone.

    The study was not just an exercise in smashing the zero key either. Ryan F. Mandelbaum at Gizmodo reports that the measurement gives scientist an upper limit to the number of galaxies that were floating around 12 billion years ago during the Epoch of Reionization, the period when dark matter, hydrogen and helium first coalesced into stars and ordinary matter. It’s also possible that the EBL measurement could help develop new ways to look for unknown particle types.

    Clemson astrophysicist and lead author Marco Ajello says in the release that the study is also good step toward understanding the universe’s earliest days

    “The first billion years of our universe’s history are a very interesting epoch that has not yet been probed by current satellites,” he says. “Our measurement allows us to peek inside it. Perhaps one day we will find a way to look all the way back to the big bang. This is our ultimate goal.”

    See the full article here .

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  • richardmitnick 9:50 am on July 18, 2018 Permalink | Reply
    Tags: , , , , Dana Berry, , Smithsonian.com,   

    From smithsonian.com: “The Supernova That Launched a Thousand Gorgeous Space Images” Dana Berry 

    smithsonian
    From smithsonian.com

    July 17, 2018
    Casey Rentz

    1
    Berry started his career colorizing actual telescope data. His more recent work includes this artistic impression of a black hole at the heart of galaxy NGC 1068. The material trapped around the black hole is moving so fast that the light itself is either compressed to blue where the material is coming toward the viewer, or stretched to red, where it is rushing away from the viewer. (Dana Berry / SkyWorks / NRAO / NSF)

    In 1990, Dana Berry was messing around with a precursor to the software program Photoshop at NASA’s Space Telescope Science Institute, where he worked as a science visualizer.

    Space Telescope Science Institute operated for NASA by AURA

    The Hubble Telescope had launched that year, and all around him, the Institute’s scientists were busy analyzing and releasing about a half dozen deep space images. But all were grainy and monochrome—not exactly ideal for conveying the dazzling mystery of the cosmos.

    One day, astrophysicist Eric Chaisson walked over to Berry’s office with a picture of a supernova exploding. It was a remarkable event to be caught on camera, but the black-and-white palette did it no justice. Chaisson suggested that Berry colorize the image, mostly for the wow-factor. He argued that color was scientifically justifiable since the supernova actually did reflect colored light, but Hubble’s camera was only set to capture light at 5007 angstroms.

    Berry sat down to his Silicon Graphics Iris 3130 computer—bigger than a mini-fridge with less computing power than the original iPhone—and began toying with the image.

    2
    Silicon Graphics Iris 3130

    “I frankly couldn’t believe my good fortune that I was doing this,” Berry says now.

    In keeping with Chaisson’s request, he colored the blob in the center pink because to represent hydrogen, which glows magenta when it burns in the laboratory. He colored the ring yellow because it emitted sulfur, which burns yellow in the lab. He colored the two stars on either side a kind of pool blue because hot stars burn either blue or white/blue. Berry was tempted to add small, distant stars in the background like you would see if the camera could’ve focused on the whole scene at once, but decided against it: “I handled that image as gingerly as I could, as if the scientific data was holy in a way,” he says.

    3
    Berry shooting Hubble’s Amazing Universe for National Geographic in 2008. (Dana Berry)

    Berry’s admiration for NASA exploration went deep. When he was young, he followed the Apollo missions with great zeal. One day he and his father learned that one of the Apollo capsules would reenter the atmosphere and splash down over the Atlantic somewhere between their hometown, Myrtle Beach, SC, and Puerto Rico. They drove to the beach and looked out over the ocean for hours. Once, they swore they saw a white streak grace the sky. Berry was also inspired by Carl Sagan’s 1980 documentary Cosmos. In college, he majored in art but took as many astronomy courses as he could. In astronomy, “I could see these things I was reading about,” he says.

    In 1987, he had graduated and was making PowerPoint graphics for businesses when he saw an ad for the job at the Space Telescope Science Institute. They were looking for a computer scientist, but he interviewed anyway and, as he puts it, “talked his way into the job.” When the first images started coming through, he and everyone at the Institute immediately started contemplating how they could be best used.

    At the time, the space program was facing significant challenges. By the time Hubble launched, it had cost more than $2 billion and had the unfortunate timing of being the next big project to come after the space shuttle Challenger, which had exploded over onlookers in Florida. Everyone was watching Hubble. To add to the anxiety, scientists discovered post-launch that Hubble’s main mirror had a manufacturing defect.

    News media ridiculed NASA, and Hubble became the butt of Jay Leno’s late-night jokes. “What sound does a space turkey make? Hubble, Hubble, Hubble,” the comedian quipped on an early 1990’s broadcast.

    The first Hubble color image of Supernova 1987A, colored by Berry, was released to news media on August 29, 1990, and immediately mesmerized astronomy lovers and piqued the interest of the general public.

    4
    A String of ‘Cosmic Pearls’ Surrounds an Exploding Star

    6
    Hubble’s first colorized space image was this image of a supernova taken with the European Space Agency’s Faint Object Camera on August 23, 1990. (Dana Berry / Space Telescope Science Institute)

    The chatter among scientists was not all positive, though, Berry recalls. Some said the picture was not strictly accurate; artistic license had been taken with the color additions.

    But beyond translating the science, Supernova 1987A and other images served another key purpose as well. They showed off what Hubble could do—that is, capture amazing images that ground telescopes couldn’t—and re-ignited the public interest in space exploration. “The value of the public outreach was not understood in the general scientific community,” Berry says, “but that changed and I think Hubble was a catalyst for that change.”

    Other institutions took notice. After several years at the Space Telescope Science Institute, Berry took a job at Tufts University and then at NASA’s Chandra X-ray Observatory, which is headquartered at the Smithsonian Astrophysical Observatory, where he used similar techniques to color images of supernova, nebulae and planets. Sometimes the pictures were taken differently—through color filters or at multiple wavelengths—but for most of them, Berry relied on his trusty Photoshop to make them pop. Sometimes multiple images needed to be patched together or layered on top of one another to remove a cosmic glare and Berry did that, too. For Chandra, he also made animations of black holes and of the Chandra spacecraft itself, which are still used there today.

    By this time, these institutions employed entire teams of science visualizers. Kimberly Arcand, now Visualization Lead at Chandra, recalls working with Berry for an animation of Cassiopeia A, a supernova remnant.

    7
    A false color image of Cassiopeia A (Cas A) using observations from both the Hubble and Spitzer telescopes as well as the Chandra X-ray Observatory (cropped).
    9 June 2005
    http://gallery.spitzer.caltech.edu/Imagegallery/image.php?image_name=ssc2005-14c
    Author Oliver Krause (Steward Observatory) George H. Rieke (Steward Observatory) Stephan M. Birkmann (Max-Planck-Institut fur Astronomie) Emeric Le Floc’h (Steward Observatory) Karl D. Gordon (Steward Observatory) Eiichi Egami (Steward Observatory) John Bieging (Steward Observatory) John P. Hughes (Rutgers University) Erick Young (Steward Observatory) Joannah L. Hinz (Steward Observatory) Sascha P. Quanz (Max-Planck-Institut fur Astronomie) Dean C. Hines (Space Science Institute) Courtesy NASA/JPL-Caltech.

    “I definitely looked up to Dana as to what was possible in a career,” she says. Arcand is using the same decades-old data to make significantly more cutting-edge animations of Cassiopeia A in virtual reality.

    After Chandra, Berry landed a job as lead animator at Wilkinson Microwave Anisotropy Probe, which brought back images in microwaves and whose scientists won the 2018 Breakthrough Prize for their detailed maps of the early universe. Meanwhile, the Hubble images, now colored by Berry’s successor and visualization savant Zolt Levay and his team, started to look more and more like paintings. Pillars of Creation, a mélange of 32 different images taken in 1995 by four different Hubble cameras, used a similar technique similar to what Berry used on his first job: green for Hydrogen, red for ionized sulfur, blue for ionized oxygen.

    Pillars of Creation. in the Eagle Nebula, NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

    Eagle Nebula NASA/ESA Hubble Public Domain

    Pillars is now the most recognizable of all the Hubble images. And the technique of using art to communicate science had caught on: beyond still images, animation presented an opportunity for TV networks like Discovery, National Geographic and the Smithsonian to make more enthralling space documentaries, and Berry was interested in that direction as well. In the 2000s, Berry got a call from Steve Burns at Discovery Channel who was looking for someone to help produce the 25th-anniversary edition of Carl Sagan’s Cosmos, the iconic documentary he had admired as a kid.

    Berry was jazzed. “I had basically been asked to clean up the Mona Lisa,” he recalls.

    Berry combed through the film, cutting outdated bits and updating several animations. Ann Druyan argued that some animations should stay no matter what, like the line drawing of evolution through all of time. “Starting documentary work wasn’t the same cold splash that landing the job at Space Telescope was, but I felt pretty excited nevertheless,” he says. He finished the update in a mere 3 months.

    After Cosmos, Berry worked on an episode of The Universe series for The History Channel in 2008 and published the book Smithsonian Intimate Guide to the Cosmos in 2008. In the same year, he wrote and produced the documentary Hubble’s Amazing Universe for the TV show Naked Science, and in 2009 wrote and directed Alien Earths for National Geographic, which garnered an Emmy nomination.

    n 2014, Berry was asked to work on a few mini-segments for the new Cosmos: A Spacetime Odyssey with Neil DeGrasse Tyson. His role would be pre-visualization: thinking about how to illustrate DNA dividing, water evaporating, and other things happening on a molecular scale. Dozens of other science visualizers and graphics people worked on the documentary. When it was released, Cosmos: A Space-time Odyssey became the most watched series ever for National Geographic International.

    Today, there are frequently scientists who take issue with how science-minded films portray concepts like multi-dimensional worlds, time travel, and end-of-universe scenarios. But the value of using art for science outreach is indisputable. “Hubble set the bar, and established astronomy outreach as a really valid thing to do,” says Arcand. Another early colleague of Berry’s at The Space Telescope Science Institute, Ray Villard, now News Director there, agrees. “The success of the Hubble pictures is that they present the awe and wonder of the universe without scaring some people away with scientific terminology,” he says.

    Berry is thankful for witnessing the growth of science visualization as a beloved profession. “One of the legacies of Hubble was the fact that art was brought into the service of science,” he says. “There will never be another big science project that doesn’t benefit from visualization tools.”

    See the full article here .

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  • richardmitnick 8:58 am on April 23, 2018 Permalink | Reply
    Tags: , , , Everything You Ever Wanted to Know About Earth’s Past Climates, , , Smithsonian.com   

    From Smithsonian.com: “Everything You Ever Wanted to Know About Earth’s Past Climates” 

    smithsonian
    Smithsonian.com

    April 16, 2018
    Rachel E. Gross

    They have a lot to tell us about our future.


    1:23:37

    In Silent Spring, Rachel Carson considers the Western sagebrush. “For here the natural landscape is eloquent of the interplay of forces that have created it,” she writes. “It is spread before us like the pages of an open book in which we can read why the land is what it is, and why we should preserve its integrity. But the pages lie unread.” She is lamenting the disappearance of a threatened landscape, but she may just as well be talking about markers of paleoclimate.

    To know where you’re going, you have to know where you’ve been. That’s particularly true for climate scientists, who need to understand the full range of the planet’s shifts in order to chart the course of our future. But without a time machine, how do they get this kind of data?

    Like Carson, they have to read the pages of the Earth. Fortunately, the Earth has kept diaries. Anything that puts down yearly layers—ocean corals, cave stalagmites, long-lived trees, tiny shelled sea creatures—faithfully records the conditions of the past. To go further, scientists dredge sediment cores and ice cores from the bottom of the ocean and the icy poles, which write their own memoirs in bursts of ash and dust and bubbles of long-trapped gas.

    In a sense, then, we do have time machines: Each of these proxies tells a slightly different story, which scientists can weave together to form a more complete understanding of Earth’s past.

    In March, the Smithsonian Institution’s National Museum of Natural History held a three-day Earth’s Temperature History Symposium that brought teachers, journalists, researchers and the public together to enhance their understanding of paleoclimate. During an evening lecture, Gavin Schmidt, climate modeler and director of NASA’s Goddard Institute for Space Studies, and Richard Alley, a world-famous geologist at Pennsylvania State University, explained how scientists use Earth’s past climates to improve the climate models we use to predict our future.

    Here is your guide to Earth’s climate pasts—not just what we know, but how we know it.

    How do we look into Earth’s past climate?

    It takes a little creativity to reconstruct Earth’s past incarnations. Fortunately, scientists know the main natural factors that shape climate. They include volcanic eruptions whose ash blocks the sun, changes in Earth’s orbit that shift sunlight to different latitudes, circulation of oceans and sea ice, the layout of the continents, the size of the ozone hole, blasts of cosmic rays, and deforestation. Of these, the most important are greenhouse gases that trap the sun’s heat, particularly carbon dioxide and methane.

    As Carson noted, Earth records these changes in its landscapes: in geologic layers, fossil trees, fossil shells, even crystallized rat pee—basically anything really old that gets preserved. Scientists can open up these diary pages and ask them what was going on at that time. Tree rings are particularly diligent record-keepers, recording rainfall in their annual rings; ice cores can keep exquisitely detailed accounts of seasonal conditions going back nearly a million years.

    1
    Ice cores reveal annual layers of snowfall, volcanic ash and even remnants of long-dead civilizations. (NASA’s Goddard / Ludovic Brucker)

    What else can an ice core tell us?

    “Wow, there’s so much,” says Alley, who spent five field seasons coring ice from the Greenland ice sheet. Consider what an ice core actually is: a cross-section of layers of snowfall going back millennia.

    When snow blankets the ground, it contains small air spaces filled with atmospheric gases. At the poles, older layers become buried and compressed into ice, turning these spaces into bubbles of past air, as researchers Caitlin Keating-Bitonti and Lucy Chang write in Smithsonian.com. Scientists use the chemical composition of the ice itself (the ratio of the heavy and light isotopes of oxygen in H2O) to estimate temperature. In Greenland and Antarctica, scientists like Alley extract inconceivably long ice cores—some more than two miles long!

    Ice cores tell us how much snow fell during a particular year. But they also reveal dust, sea salt, ash from faraway volcanic explosions, even the pollution left by Roman plumbing. “If it’s in the air it’s in the ice,” says Alley. In the best cases, we can date ice cores to their exact season and year, counting up their annual layers like tree rings. And ice cores preserve these exquisite details going back hundreds of thousands of years, making them what Alley calls “the gold standard” of paleoclimate proxies.

    Wait, but isn’t Earth’s history much longer than that?

    Yes, that’s right. Paleoclimate scientists need to go back millions of years—and for that we need things even older than ice cores. Fortunately, life has a long record. The fossil record of complex life reaches back to somewhere around 600 million years. That means we have definite proxies for changes in climate going back approximately that far. One of the most important is the teeth of conodonts—extinct, eel-like creatures—which go back 520 million years.

    But some of the most common climate proxies at this timescale are even more miniscule. Foraminifera (known as “forams”) and diatoms are unicellular beings that tend to live on the ocean seafloor, and are often no bigger than the period at the end of this sentence. Because they are scattered all across the Earth and have been around since the Jurassic, they’ve left a robust fossil record for scientists to probe past temperatures. Using oxygen isotopes in their shells, we can reconstruct ocean temperatures going back more than 100 million years ago.

    “In every outthrust headland, in every curving beach, in every grain of sand there is a story of the earth,” Carson once wrote. Those stories, it turns out, are also hiding in the waters that created those beaches, and in creatures smaller than a grain of sand.

    2
    Foraminifera. (Ernst Haeckel)

    How much certainty do we have for deep past?

    For paleoclimate scientists, life is crucial: if you have indicators of life on Earth, you can interpret temperature based on the distribution of organisms.

    But when we’ve gone back so far that there are no longer even any conodont teeth, we’ve lost our main indicator. Past that we have to rely on the distribution of sediments, and markers of past glaciers, which we can extrapolate out to roughly indicate climate patterns. So the further back we go, the fewer proxies we have, and the less granular our understanding becomes. “It just gets foggier and foggier,” says Brian Huber, a Smithsonian paleobiologist who helped organize the symposium along with fellow paleobiologist research scientist and curator Scott Wing.

    How does paleoclimate show us the importance of greenhouse gases?

    Greenhouse gases, as their name suggests, work by trapping heat. Essentially, they end up forming an insulating blanket for the Earth. (You can get more into the basic chemistry here.) If you look at a graph of past Ice Ages, you can see that CO2 levels and Ice Ages (or global temperature) align. More CO2 equals warmer temperatures and less ice, and vice versa. “And we do know the direction of causation here,” Alley notes. “It is primarily from CO2 to (less) ice. Not the other way around.”

    We can also look back at specific snapshots in time to see how Earth responds to past CO2 spikes. For instance, in a period of extreme warming during Earth’s Cenozoic era about 55.9 million years ago, enough carbon was released to about double the amount of CO2 in the atmosphere. The consequentially hot conditions wreaked havoc, causing massive migrations and extinctions; pretty much everything that lived either moved or went extinct. Plants wilted. Oceans acidified and heated up to the temperature of bathtubs.

    Unfortunately, this might be a harbinger for where we’re going. “This is what’s scary to climate modelers,” says Huber. “At the rate we’re going, we’re kind of winding back time to these periods of extreme warmth.” That’s why understanding carbon dioxide’s role in past climate change helps us forecast future climate change.

    That sounds pretty bad.

    Yep.

    I’m really impressed by how much paleoclimate data we have. But how does a climate model work?

    Great question! In science, you can’t make a model unless you understand the basic principles underlying the system. So the mere fact that we’re able to make good models means that we understand how this all works. A model is essentially a simplified version of reality, based on what we know about the laws of physics and chemistry. Engineers use mathematical models to build structures that millions of people rely on, from airplanes to bridges.

    Our models are based on a framework of data, much of which comes from the paleoclimate proxies scientists have collected from every corner of the world. That’s why it’s so important for data and models to be in conversation with each other. Scientists test their predictions on data from the distant past, and try to fix any discrepancies that arise. “We can go back in time and evaluate and validate the results of these models to make better predictions for what’s going to happen in the future,” says Schmidt.

    Here’s a model:

    3

    It’s pretty. I hear the models aren’t very accurate, though.

    By their very nature, models are always wrong. Think of them as an approximation, our best guess.

    But ask yourself: do these guesses give us more information than we had previously? Do they provide useful predictions we wouldn’t otherwise have? Do they allow us to ask new, better questions? “As we put all of these bits together we end up with something that looks very much like the planet,” says Schmidt. “We know it’s incomplete. We know there are things that we haven’t included, we know that we’ve put in things that are a little bit wrong. But the basic patterns we see in these models are recognizable … as the patterns that we see in satellites all the time.”

    So we should trust them to predict the future?

    The models faithfully reproduce the patters we see in Earth’s past, present—and in some cases, future. We are now at the point where we can compare early climate models—those of the late 1980s and 1990s that Schmidt’s team at NASA worked on—to reality. “When I was a student, the early models told us how it would warm,” says Alley. “That is happening. The models are successfully predictive as well as explanatory: they work.” Depending on where you stand, that might make you say “Oh goody! We were right!” or “Oh no! We were right.”

    To check models’ accuracy, researchers go right back to the paleoclimate data that Alley and others have collected. They run models into the distant past, and compare them to the data that they actually have.

    “If we can reproduce ancient past climates where we know what happened, that tells us that those models are a really good tool for us to know what’s going to happen in the future,” says Linda Ivany, a paleoclimate scientist at Syracuse University. Ivany’s research proxies are ancient clams, whose shells record not only yearly conditions but individual winters and summers going back 300 million years—making them a valuable way to check models. “The better the models get at recovering the past,” she says, “the better they’re going to be at predicting the future.”

    Paleoclimate shows us that Earth’s climate has changed dramatically. Doesn’t that mean that, in a relative sense, today’s changes aren’t a big deal?

    When Richard Alley tries to explain the gravity of manmade climate change, he often invokes a particular annual phenomenon: the wildfires that blaze in the hills of Los Angeles every year. These fires are predictable, cyclical, natural. But it’d be crazy to say that, since fires are the norm, it’s fine to let arsonists set fires too. Similarly, the fact that climate has changed over millions of years doesn’t mean that manmade greenhouse gases aren’t a serious global threat.

    “Our civilization is predicated on stable climate and sea level,” says Wing, “and everything we know from the past says that when you put a lot of carbon in the atmosphere, climate and sea level change radically.”

    Since the Industrial Revolution, human activities have helped warm the globe 2 degrees F, one-quarter of what Schmidt deems an “Ice Age Unit”—the temperature change that the Earth goes through between an Ice Age and a non-Ice Age. Today’s models predict another 2 to 6 degrees Celsius of warming by 2100—at least 20 times faster than past bouts of warming over the past 2 million years.

    ______________________________________________________________
    From NASA Earth Observatory

    How is Today’s Warming Different from the Past?

    Earth has experienced climate change in the past without help from humanity. We know about past climates because of evidence left in tree rings, layers of ice in glaciers, ocean sediments, coral reefs, and layers of sedimentary rocks. For example, bubbles of air in glacial ice trap tiny samples of Earth’s atmosphere, giving scientists a history of greenhouse gases that stretches back more than 800,000 years. The chemical make-up of the ice provides clues to the average global temperature.

    See the Earth Observatory’s series Paleoclimatology for details about how scientists study past climates.

    3
    Glacial ice and air bubbles trapped in it (top) preserve an 800,000-year record of temperature & carbon dioxide. Earth has cycled between ice ages (low points, large negative anomalies) and warm interglacials (peaks). (Photograph courtesy National Snow & Ice Data Center. NASA graph by Robert Simmon, based on data from Jouzel et al., 2007.)

    Using this ancient evidence, scientists have built a record of Earth’s past climates, or “paleoclimates.” The paleoclimate record combined with global models shows past ice ages as well as periods even warmer than today. But the paleoclimate record also reveals that the current climatic warming is occurring much more rapidly than past warming events.

    As the Earth moved out of ice ages over the past million years, the global temperature rose a total of 4 to 7 degrees Celsius over about 5,000 years. In the past century alone, the temperature has climbed 0.7 degrees Celsius, roughly ten times faster than the average rate of ice-age-recovery warming.

    4
    Temperature histories from paleoclimate data (green line) compared to the history based on modern instruments (blue line) suggest that global temperature is warmer now than it has been in the past 1,000 years, and possibly longer. (Graph adapted from Mann et al., 2008.)

    Models predict that Earth will warm between 2 and 6 degrees Celsius in the next century. When global warming has happened at various times in the past two million years, it has taken the planet about 5,000 years to warm 5 degrees. The predicted rate of warming for the next century is at least 20 times faster. This rate of change is extremely unusual.

    See the full NASA Earth Observatory article here .
    ______________________________________________________________

    Of course there are uncertainties: “We could have a debate about whether we’re being a little too optimistic or not,” says Alley. “But not much debate about whether we’re being too scary or not.” Considering how right we were before, we should ignore history at our own peril.

    ______________________________________________________________

    See the full article here .

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  • richardmitnick 12:56 pm on January 20, 2018 Permalink | Reply
    Tags: , , Geology Makes the Mayon Volcano Visually Spectacular—And Dangerously Explosive, Smithsonian.com, Strombolian eruptions,   

    From smithsonian.com: “Geology Makes the Mayon Volcano Visually Spectacular—And Dangerously Explosive” 

    smithsonian
    smithsonian.com

    January 19, 2018
    Maya Wei-Haas

    What’s going on inside one of the Philippines’ most active volcanoes?

    1
    Lava cascades down the slopes of the erupting Mayon volcano in January 2018. Seen from Busay Village in Albay province, 210 miles southeast of Manila, Philippines. (AP Photo/Dan Amaranto)

    Last weekend, the Philippines’ most active—and attractive—volcano, Mount Mayon, roared back to life. The 8,070-foot volcano began releasing spurts of incandescent molten rock and spewing clouds of smoke and ash into the sky, causing over 30,000 local residents to evacuate the region. By the morning of January 18, the gooey streams of lava had traveled almost two miles from the summit.

    Though the images of Mount Mayon are startling, the volcano isn’t truly explosive—yet. The Philippine Institute of Volcanology and Seismology (PHIVolcs), which monitors the numerous volcanoes of the island chain, has set the current warning level at a 3 out of 5, which means that there is ”relatively high unrest.” At this point, explosive eruption is not imminent, says Janine Krippner, a volcanologist and postdoctoral researcher researcher at Concord University. If the trend continues, however, an eruption is possible in the next few weeks.

    Located on the large island of Luzon, Mount Mayon is known for its dramatically sloped edges and picturesque symmetry, which makes it a popular tourist attraction; some climbers even attempt to the venture to its smouldering rim. “It’s gorgeous, isn’t it?” marvels Krippner. But that beauty isn’t entirely innocuous. In fact, Krippner explains, the structure’s symmetrical form is partly due to the frequency of the volcano’s eruptions.

    “Mayon is one of the most active volcanoes—if not the most active volcano—in the Philippines, so it has the chance to keep building its profile up without eroding away,” she says. Since its first recorded eruption in 1616, there have been roughly 58 known events—four in just the last decade—which have ranged from small sputters to full-on disasters. Its most explosive eruption took place in 1814, when columns of ash rose miles high, devastated nearby towns and killed 1200 people.

    Many of these eruptions are strombolian, which means the cone emits a stuttering spray of molten rock that collects around its upper rim. (Strombolian eruptions are among the less-explosive types of blasts, but Mayon is capable of much more violent eruptions as well.) Over time, these volcanic rocks “stack up, and up, and up,” says Krippner, creating extremely steep slope. That’s why, near the top of the volcano, its sides veer at angles up to 40 degrees—roughly twice the angle of the famous Baldwin street in New Zealand, one of the steepest roads in the world.

    So why, exactly, does Mayon have so many fiery fits? It’s all about location.

    The islands of the Philippines are situated along the Ring of Fire, a curving chain of volcanism that hugs the boundary of the Pacific Ocean and contains three-fourths of all the world’s volcanoes. What drives this region of fiery activity are slow-motion collisions between the shifting blocks of Earth’s crust, or tectonic plates, which have been taking place over millions of years. The situation in the Philippines is in particularly complex, explains Ben Andrews, director of Smithsonian’s Global Volcanism Program. “It’s a place where we have a whole bunch of different subduction zones of different ages that are sort of piling together and crashing together,” he says. “It gets pretty hairy.”

    As one plate thrusts beneath another, the rocks begin to melt, fueling the volcanic eruption above. Depending on the composition of the melting rock, the lava can be thin and runny, or thick and viscous. This viscosity paired with the speed at which the magma rises determines the volcano’s explosivity, says Andrews: The thicker and quicker the lava, the more explosive the blast. Mayon produces magma of intermediate composition and viscosity, but it differs from eruption to eruption.

    Think of a volcanic eruption like opening a shaken bottle of soda, says Andrews. If you pop off the cap immediately, you’re in for a spray of sugary carbonated liquid to the face, just like the sudden release of gas and molten rock that builds under a plug of viscous magma. But if you slow down and let a little air out first—like the gases that can escape from liquid-y magma—a violent explosion is less likely.

    News outlets have been reporting on an “imminent explosion,” warning that Mayon will erupt within days. But given its activity so far, it’s not yet clear if, or when, Mayon will erupt. Volcanoes are extremely hard to predict as the magma is constantly changing, says Krippner.

    Since the volcano began belching, small pyroclastic flows—avalanches of hot rocks, ash and gas—have also tumbled down its flanks. Though dangerous, these pyroclastic flows have the potential to be much more devastating. Previously at Mayon, says Krippner, these flows have been clocked in at over 60 meters per second. “They’re extremely fast and they’re extremely hot,” she says. “They destroy pretty much everything in their path.”

    If the eruption continues, one of the biggest dangers is an explosive blast, which could produce a column of volcanic ash miles high. The collapse of this column can send massive, deadly pyroclastic flows racing down the volcano’s flanks. The last time Mayon burst in an explosive eruption was in 2001. With a roar like a jet plane, the volcano shot clouds of ash and molten rock just over six miles into the sky.

    Also of concern is the potential for what are known as lahars, or flows of debris. The volcanic rumblings have been actively producing volcanic ash, a material that’s more like sand than the kind of ash you see when you burn wood or paper, notes Krippner. A strong rain—as is frequent on these tropical islands—is all that’s needed to turn these layers of debris into a slurry and send it careening down the volcano’s slopes, sweeping with it anything that gets in its way. Mayon’s steep sides make it particularly susceptible to these mudflows.

    Residents suffered the full potential for destruction of Mayon’s lahars in November of 2006 when a typhoon swept the region, bringing with it heavy rain that saturated built up material. A massive lahar formed, destroying nearby towns and killing 1,266 people.

    Both Krippner and Andrews stress that local residents are in good hands under PHIVolcs’ careful watch. The researchers have installed a complex network of sensors that monitor Mayon’s every tremble and burp and are using their vast amounts of knowledge garnered from past events to interpret the volcano’s every shiver.

    And as Krippner notes, “it’s still got two more levels to go.” If PHIVoics raises the alert level to a 4 or 5, she says, “that could mean something bigger is coming.”

    See the full article here .

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  • richardmitnick 6:45 pm on November 27, 2017 Permalink | Reply
    Tags: Smithsonian.com, Stratovolcano, The Geology of Bali’s Simmering Agung Volcano,   

    From smithsonian.com: “The Geology of Bali’s Simmering Agung Volcano” 

    smithsonian
    smithsonian.com

    11.27.17
    Jason Daley

    The high viscosity magma of stratovolcanoes like Agung makes them extremely explosive—and potentially deadly.

    1
    Mount Agung (MAGMA Indonesia)

    Bali authorities have issued evacuation orders for 100,000 people living within a six-mile radius of volcanic Mount Agung, the highest point on the Indonesian island.

    Trouble has been brewing at the volcano for quite some time. Researchers recorded seismic activity at Agung beginning in August, with the unrest increasing in the following weeks, according to the Earth Observatory of Singapore. On September 22, authorities raised to the volcano’s status to level 4, its highest warning category. Then, last Tuesday the volcano began emitting plumes of smoke and mudflows streamed through local waterways. Over the weekend, the ash cloud reached 30,000 feet and magmatic eruptions began, reports the Associated Press. About 59,000 travelers are currently stuck on the island after the ash caused the international airport to close.

    While authorities tell the AP they don’t expect a major eruption, the activity changed early this morning from emission of steam to magma. So officials are playing it safe. Last time Agung erupted in 1963, an estimated 1,100 people died. And since the 1963 catastrophe, population density has only intensified on Agung’s slopes.

    So what makes Agung so dangerous? Blame its geology.

    Agung is what’s known as a stratovolcano. Also known as composite volcanoes, these formations occur at tectonic subduction zones, areas where two tectonic plates meet and one plate slides underneath another, geophysicist Jacqueline Salzer at the German Research Centre for Geosciences tells Fabian Schmidt at Deutsche Welle.

    The tectonic plates of the world were mapped in 1996, USGS.

    The lava in those areas is usually thick and sticky, causing pressures to build within the steep cones, which results in highly explosive—and deadly—eruptions.

    As Janine Krippner, a volcanologist at the University of Pittsburgh, writes for the BBC, Agung has gone through the predictable stages of a waking volcano. In August, small earthquakes were measured, but the mountain appeared unchanged. Then, in September, as rising magma heated the interior of the cone, plumes of steam were observed as the water in the mountain heated up.

    Beginning last week, steam-driven or phreatic eruptions began. During this time, steam inside the volcano built up pressure causing small explosions to shoot ash, crystals and rock into the air. Now the magma has reached the surface—the point at which it is called lava—and its glow can be seen at the top of the mountain.

    Authorities are hopeful the eruption won’t continue further but if it does, several types of disasters could unfold. The cloud of gas and steam will blow off larger pieces of the mountain off, shooting rock “bombs” into the air. Actual lava flows could also stream down the mountain for several miles. But the most dangerous element of the eruption is the pyroclastic flow, an explosion of hot gas and debris that follows valleys or low-lying areas. These flows can race down the mountain at 50 miles per hour, destroying everything in its path.

    Another major concern is lahars which occur when volcanic debris and ash mixes with water, creating a slurry the consistency of wet concrete. Lahars can rush down slopes at up to 120 miles per hour and swell in volume, destroying any villages or structures in its path.

    According to John Seach at VolcanoLive, during the 1963 Agung eruption, 820 people were killed by pyroclastic flows, 163 died from falling ash and rock and 165 were killed by lahars.

    The 1963 eruption also had global consequences. Alle McMahon at the Australia Broadcasting Corporation reports that the sulphur dioxide blown into the atmosphere by that event temporarily cooled the Earth by 0.1-0.4 degrees Celsius by reflecting some of the sun’s ultraviolet radiation.

    If Agung does have another major eruption, this miniscule amount of cooling is likely too small to be noticed. But the immediate consequences of such an eruption can be deadly, so authorities are encouraging locals to heed the evacuation notices.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Smithsonian magazine and Smithsonian.com place a Smithsonian lens on the world, looking at the topics and subject matters researched, studied and exhibited by the Smithsonian Institution — science, history, art, popular culture and innovation — and chronicling them every day for our diverse readership.

     
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