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  • richardmitnick 11:40 am on February 15, 2017 Permalink | Reply
    Tags: An entire landscape possibly reshaping itself, An iceberg nearly seven times the size of New York City, Antarctic Peninsula’s Larsen C ice shelf, GIZMODO, Glaciology, How ice shelves break, Iceberg calving on a grand scale, UK-based Project MIDAS monitoring the rift via satellites   

    From GIZMODO: “What Happens When That Enormous Antarctic Ice Shelf Finally Breaks?” 

    GIZMODO bloc

    GIZMODO

    2.15.17
    Maddie Stone

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    Rift in the Larsen C ice shelf photographed by NASA’s IceBridge aerial survey in November 2016. Image: NASA/John Sonntag

    For the past few months, scientists have watched with bated breath as a rift in the Antarctic Peninsula’s Larsen C ice shelf grows longer by the day. Eventually, the rift will make a clean break, expelling a 2,000 square mile chunk of ice into the sea. It’ll be an epic sight to behold—but what happens after the ice is gone?

    Glaciologists, who have been tracking the rift since it first appeared on the Larsen C ice shelf in 2014, are now scrambling to answer that very question. So-called iceberg calving is a natural geophysical process along the Antarctica’s frosty fringes; think of it as the planetary equivalent of your fingernails growing too long and breaking off. But this is one of the largest such events on record, with the potential to dramatically reshape the entire peninsula.

    Moreover, while there’s little direct evidence linking the Larsen C ice shelf breakup to climate change, scientists worry that the processes playing out here could be but a taste of what’s to come for West Antarctica, as rising air and sea temperatures cause this vast, icy mantle to weaken from above and below.

    “What we’re worried about is what we’re seeing here is going to happen everywhere else,” Thomas Wagner, director of NASA’s polar science program told Gizmodo. “[Larsen C] is a natural laboratory for understanding how ice shelves break.”

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    Timelapse of the growing rift in the Larsen C ice shelf captured by ESA’s Sentinel-1 satellite. Image: Project MIDAS

    Over 100 miles long, up to two miles wide, and lengthening at a rate of five football fields per day, the rift in the Larsen C ice shelf has been in and out of the spotlight since it first emerged on the eastern flank of the Antarctic Peninsula in 2014. Since punching its way through a section of softer, more ductile ice, the rift has followed a predictable pattern—periods of quietude, punctuated by sudden growth spurts—that experts say is typical of ice shelf calving. But over the last two months, things have accelerated “quite a lot,” according to Martin O’Leary, a glaciologist with the UK-based Project MIDAS, which is monitoring the rift via satellites. “Now we’re paying attention to every satellite image that comes through to see if it jumps again,” he told Gizmodo.

    Having grown an impressive 17 miles (27 km) since December, the Larsen C rift has about 12 miles (20 km) to go before it reaches the other end of the shelf, snaps off, and spits out an iceberg nearly seven times the size of New York City.

    This could happen any day. “It could go tomorrow, it could go in a year’s time,” O’Leary said, adding that the ice “has to leave eventually.” That’s because additional ice is constantly pushing seaward from the peninsula’s interior, exerting a powerful shear force on the ever-weakening shelf.

    The good news is, we don’t have to worry about Larsen C’s breakup contributing to sea level rise. Ice shelves are, by definition, already sitting on top of water. “It’s already made its sea level rise contribution,” O’Leary said.

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    The ice shelves at the tip of the Antarctic Peninsula have been changing dramatically in recent decades, as illustrated in this composite satellite photo showing the historic ice extent prior to calving events. Image: NASA Earth Observatory

    Aside from possibly setting a few penguins adrift, the real concern with Larsen C’s imminent calving is what it’ll mean for the rest of the shelf—and for the ice currently tethered to land on the Antarctic Peninsula, which can still contribute to sea level rise, albeit probably just a few millimeters. Glaciologists often liken ice shelves to corks in a champagne bottle: remove them, and all the stuff they’ve bottled up starts to escape. This may be especially true for the Larsen C ice shelf, which appears to be snapping off at two crucial pinning points where land meets ice.

    “We expect this to create a new zone where calving happens more readily, now that we’ve removed these pinning points,” Wagner said. “And when these ice shelves break up, the ice behind surges into the ocean, getting thinner.”

    In other words, Larsen C’s soon-to-be iceberg could be the tip of a much larger, proverbial iceberg, of an entire landscape reshaping itself. The changes glaciologists expect around Larsen C jibe with a bigger-picture pattern of ice retreat across the peninsula, including earlier calving events at the neighboring ice shelves Larsen A and B, which scientists have attributed to rising temperatures.

    Whether or not climate change is playing a direct role in the action on Larsen C, it’s a clearly force to be reckoned with across the Antarctic Peninsula, where average temperatures have risen a staggering 3 degrees Celsius (5.4 degrees Fahrenheit) since pre-industrial times. (Globally-averaged temperatures have risen roughly a single degree Celsius over the same time period.)

    “We may see that one this chunk of [ice] is gone, Larsen C [starts] becoming more vulnerable to climate impacts,” O’Leary said.

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    Bird’s eye view of the Amundsen sea embayment, where major glaciers of the West Antarctic ice sheet empty into the ocean. Pope, Smith, and Kohler glaciers were the focus of this study. Image: NASA/GSFC/SVS

    Most importantly to researchers, the breakup of the Larsen C ice shelf could be a harbinger of what’s to come in other vulnerable parts of West Antarctica, particularly the Amundsen Sea embayment to the south, where warming waters are already causing the enormous Pine Island and Thwaites glaciers to melt and retreat. A summary of a scientific workshop compiled last year by the National Snow and Ice Data Center warns that “a significant retreat of the Thwaites Glacier system would trigger a wider collapse of most of the West Antarctic Ice Sheet.” That entire ice sheet contains enough water to raise global sea level by 3.3 meters (over ten feet), on a timescale of decades to centuries.

    “This is going to happen on other ice shelves,” Wagner said, adding that NASA and others have a unique opportunity with Larsen C, to study a massive iceberg calving event from satellites, airborne surveys like Operation IceBridge, and ground-based data. “We’re gonna watch how the ice shelf responds mechanically [as it breaks]. Larsen C is how we model what’s going to happen to Thwaites.”

    In other words, far more disturbing than the breakup of the Larsen C ice shelf is what it can tell us about our future.

    See the full article here .

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  • richardmitnick 12:45 pm on January 25, 2017 Permalink | Reply
    Tags: , , , , GIZMODO, , The speed of dark   

    From GIZMODO: “What’s the Speed of Dark?” 

    GIZMOGO pictorial
    GIZMODO
    1.24.17
    Sophie Weiner

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    Illustration: Jim Cooke/Gizmodo

    The speed of light is one of the most important constants in physics. First measured by Danish astronomer Olaus Roemer in 1676, it was Albert Einstein who realized that light sets an ultimate speed limit for our universe, of 186,000 rip-roaring miles per second. But while the immutability of lightspeed is drilled into physics students at a young age, Einstein’s laws also state that all motion is relative, which got us thinking: what’s the speed of light’s nefarious doppleganger, darkness?

    We’re not the first to ask this question (shout out comedian Steven Wright) or take it seriously, but in asking scientists and researchers, we left the interpretation of “darkness” open, eliciting some fascinating responses from experts on black holes and quantum physics. It turns out, darkness could be just as fast as light, or it could be infinitely slower—it all depends on your perspective.

    George Musser

    The speed of dark? The easy answer is that it’s just the speed of light. Switch off the sun and our sky would go dark eight minutes later. But easy is boring! For starters, what we commonly call the “speed of light” is the speed of propagation, and that’s not always the deciding factor. A shadow swoops across the landscape at a speed governed by the object that casts it. For instance, as a lighthouse beacon rotates, it lights up the surroundings at regular intervals. The ground speed of its shadow increases with distance from the lighthouse.

    Go far enough away and the shadow will wash over you faster than the propagation speed of light. (This happens for real in rotating neutron stars in the cosmos, with measurable consequences.) All the speed of light means in this case is that there’s a delay: if the lighthouse points toward you at 12 o’clock, you will see the flash a little later. But that doesn’t affect the pace of events you see at your location.

    While we’re at it, is there even such a thing as darkness? If you did switch off the sun, Earth wouldn’t go completely dark. Light from stars, nebulae, and the big bang would fill the sky. The planet and everything on it, including our bodies, would blaze in the infrared. Depending on how, exactly, you’d managed to switch the sun off, it would keep on glowing for eons. As long as we were able to see, we’d see something. No light detector can register total darkness, because, if nothing else, quantum fluctuations produce tiny flashes of light. Even a black hole, the darkest conceivable object, emits some light. In physics, unlike human affairs, light always chases away dark.

    Darkness isn’t a physical category, but a state of mind. Photons hitting, or not hitting, retinal cells may trigger the experience, but do not explain the subjective experience of darkness, any more than the length of waves explains the experience of color or sound. Our conscious experience changes from moment to moment, but the individual frames of that experience are timeless. In that sense, darkness has no speed.

    And what about speed in general—is there such a thing? It presupposes a framework of space, and scientists see phenomena in quantum physics where spatial concepts seem not to apply—suggesting, to some, that space is derived from a more fundamental level of reality where these is no such as thing as position, distance, or speed. It must be the level that Steven Wright operates on.

    Avi Loeb

    Close to a black hole, matter falls in at a speed that is close to the speed of light. Once it enters the so-called event-horizon of the black holes, nothing can escape. Even light is trapped inside the horizon forever. Hence a black hole can be thought of as the ultimate prison.

    A star like the Sun can be shredded (“spaghettified”) into a stream of gas if it passes too close to a massive black hole, like the one (weighting six billion solar masses) at the center of the Milky Way galaxy.

    As matter falls into the black hole, it often rubs against itself and heats up. As a result it radiates. If the accretion rate is high enough, the force of the radiation flowing out could potentially stop additional matter from falling in. Many of the most massive black holes in the universe, weighting billions of solar masses, are observed to accrete at the maximum possible rate (also called the Eddington limit, after Sir Arthur Eddington who discovered theoretically the maximum radiation output possible for gravity to overcome the radiation force).

    Neil DeGrasse Tyson

    The speed of dark… Consider dark getting erased by light. The light erases it at the speed of light so the speed of dark would be negative the speed of light. If light is a vector, it has magnitude and direction, so… to call it negative means it’s in a negative direction. The dark is receding rather than advancing. I’d call it negative the speed of light.

    Sarah Caudill

    A black hole has gravity so strong that not even light can escape once it has passed the event horizon, an invisible boundary marking the point of no return. Because the black hole has such strong gravity, time dilation will affect observations from outside the strong gravitational field.

    For example, a distant observer watching a glowing object fall into a black hole will see it slow down and fade, eventually becoming so dim it cannot be seen. This observer won’t ever see the object cross the event horizon.

    We can also take the perspective of stuff falling into the black hole, instead of a distant observer. For example, if we take a black hole in the center of a glowing gas cloud, say from a star that has been broken up by passing too close to the black hole, the material will form a flattened disk, known as an accretion disk. This gas will fall into the black hole, but it is not instantaneous. There is a speed limit enforced by the radiation pressure from the hot gas which will fight against the inward force of gravity from the black hole. As the gas falls into the black hole, the black hole grows in size. If a black hole that is 10 times as massive as our Sun is accreting at the maximum allowed rate, in about a billion years it could have reached 100 million times the mass of our Sun.

    David Reitze

    Basically, it depends on whether you’re the matter being consumed by the infinite abyss of a black hole or you’re far enough away to be a dispassionate observer watching someone else falling into the infinite abyss. If you happen to be the unlucky matter falling in, the speed is potentially very large, in principle approaching the speed of light.

    If you’re the observer and you’re far enough away, the speed with which matter is consumed is dramatically slowed down due to an effect known as gravitational time dilation—clocks run slower in gravitational fields, and much slower in the immense gravitational fields near the event horizon of the black hole. By ‘far enough away’, I mean that in your local reference frame, your stationary relative to the black hole (i.e, not getting sucked in) and your local clock is not affected by the gravitational field of the black hole. In fact, to the far away person it will take an infinite amount of time for something to travel to the event horizon of the black hole.

    Niayesh Afshordi

    I believe the speed “of dark” is infinite! In classical physics, the vast darkness of space could be just empty vacuum. However, we have learnt from quantum mechanics that there is no real dark or empty space. Even where there is no light that we can see, electromagnetic field can fluctuate in and out of existence, especially on small scales and short times. Even gravitational waves, the ripples in the geometry of spacetime that were recently observed by the LIGO observatory, should have these quantum fluctuations.

    The problem is that the gravity of these quantum ripples is infinite. In other words, currently there is no sensible theory of quantum gravity that people could agree on. One way to avoid the problem is if the speed “of dark”, i.e. the quantum ripples, goes to infinity (or becomes arbitrarily big) on small scales and short times. Of course, that’s only one possibility, but is a simple (and my favourite) way to understand big bang, black holes, dark energy, and quantum gravity.

    See the full article here .

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  • richardmitnick 9:30 am on January 9, 2017 Permalink | Reply
    Tags: After More Than 100 Years, , California's Iconic Tunnel Tree Is No More, GIZMODO, The Pioneer Cabin Tree, Yosemite’s Wawona Tunnel Tree   

    From GIZMODO: “After More Than 100 Years, California’s Iconic Tunnel Tree Is No More” 

    GIZMOGO pictorial

    GIZMODO

    1.9.17
    Hudson Hongo

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    Pioneer Cabin Tree. http://www.stancoe.org

    The Pioneer Cabin Tree, a giant sequoia in Calaveras Big Trees State Park that was tunneled through in the 1880s, has fallen due to severe winter weather. It was believed to be hundreds of years old.

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    Calaveras Big Trees Association

    Since it was first hollowed out in imitation of Yosemite’s Wawona Tunnel Tree, thousands of tourists and vehicles have passed through the sequoia. The Wawona tree was killed by the process and later fell during a storm in the 1960s, but the Pioneer Cabin Tree clung on, showing signs of life well into the 21st century.

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    Yosemite’s Wawona Tunnel Tree. Credit: https://www.flickr.com/photos/94207108@N02/24177368222

    “The pioneer cabin tree was chosen because of its extremely wide base and large fire scar,” wrote park interpretive specialist Wendy Harrison in 1990. “A few branches bearing green foliage tell us that this tree is still managing to survive.”

    On Facebook, where the tree’s death was first announced, park visitors shared generations of memories involving the giant sequoia. The Calaveras Big Trees Association, however, offered a simple message about the tree’s return to the earth it sprouted from so many years ago.

    “This iconic and still living tree—the tunnel tree—enchanted many visitors,” wrote the association. “The storm was just too much for it.”

    See the full article here .

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  • richardmitnick 12:54 pm on December 17, 2016 Permalink | Reply
    Tags: GIZMODO, Here's What Would Happen If a Giant Asteroid Struck the Ocean,   

    From GIZMODO: “Here’s What Would Happen If a Giant Asteroid Struck the Ocean” 

    GIZMODO bloc

    GIZMODO

    12.14.16
    Maddie Stone

    1
    Image: Los Alamos National Laboratory

    Seventy percent of Earth’s surface is covered by water, meaning if we were unfortunate enough to be struck by an enormous asteroid, it’d probably make a big splash. A team of data scientists at Los Alamos National Laboratory recently decided to model what would happen if an asteroid struck the sea. Despite the apocalyptic subject matter, the results are quite beautiful.

    Galen Gisler and his colleagues at LANL are using supercomputers to visualize how the kinetic energy of a fast-moving space rock would be transferred to the ocean on impact. The results, which Gisler presented at the American Geophysical Union meeting this week, may come as a surprise to those who grew up on disaster movies like Deep Impact. Asteroids are point sources, and it turns out waves generated by point sources diminish rapidly, rather than growing more ferocious as they cover hundreds of miles to swallow New York.

    The bigger concern, in most asteroid-on-ocean situations, is water vapor.

    “The most significant effect of an impact into the ocean is the injection of water vapor into the stratosphere, with possible climate effects” Gisler said. Indeed, Gisler’s simulations show that large (250 meter-across) rock coming in very hot could vaporize up to 250 metric megatons of water. Lofted into the troposphere, that water vapor would rain out fairly quickly. But water vapor that makes it all the way up to the stratosphere can stay there for a while. And because it’s a potent greenhouse gas, this could have a major effect on our climate.

    Of course, not all asteroids make it to the surface at all. Smaller sized ones, which are much more common in our solar neighborhood, tend to explode while they’re still in the sky, creating a pressure wave that propagates outwards in all directions. Gisler’s models show that when these “airburst” asteroids strike over the ocean, they produce less stratospheric water vapor, and smaller waves. “The airburst considerably mitigates the effect on the water,” he said.

    Overall, Gisler says, asteroids over the ocean pose less of a danger to humans than asteroids over the land. There’s one big exception, however, and that’s asteroids that strike near a coastline.

    “An impact or an airburst [near] a populated shore will be very dangerous,” Gisler said. In that case, the gigantic, city-devouring tsunami every B-list disaster movie has primed you for might actually arrive.

    See the full article here .

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  • richardmitnick 2:11 pm on September 30, 2016 Permalink | Reply
    Tags: , , GIZMODO, Massive Earthquake Along the San Andreas Fault Is Disturbingly Imminent,   

    From GIZMODO: “Massive Earthquake Along the San Andreas Fault Is Disturbingly Imminent” 

    GIZMODO bloc

    GIZMODO

    9.30.16
    George Dvorsky

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    The USGS estimates a 1 in 100 chance of the San Andreas Fault rupturing between now and October 4. (Image: SanAndreasFault.org)

    A series of quakes under the Salton Sea may be a signal that the San Andreas Fault is on the verge of buckling. For the next few days, the risk of a major earthquake along the fault is as high as 1 in 100. Which, holy crap.

    The United States Geological Survey has been tracking a series of earthquakes near Bombay Beach, California. This “earthquake swarm” is happening under the Salton Sea, and over 140 events have been recorded since Monday September 26. The quakes range from 1.4 to 4.3 in magnitude, and are occurring at depths between 2.5 to 5.5 miles (4 to 9 km).

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    Quakes recorded under the Salton Sea on September 27, 2016. (Image: USGS)

    For seismologists, these quakes could represent some seriously bad news. The swarm is located near a set of cross-faults that are connected to the southernmost end of the San Andreas Fault. Troublingly, some of these cross-faults could be adding stress to the San Andreas Fault when they shift and grind deep underground. Given this region’s history of major earthquakes, it’s got some people a bit nervous.

    Calculations show that from now until October 4, the chance of a magnitude 7 or greater earthquake happening along the Southern San Andreas Fault is as high as 1 in 100, and as low as 1 in 3,000. On the plus side, the likelihood of it happening decreases with each passing day. These estimates are based on models developed to assess the probabilities of earthquakes and aftershocks in California.

    “Swarm-like activity in this region has occurred in the past, so this week’s activity, in and of itself, is not necessarily cause for alarm,” cautions the USGS.

    That being said, this is only the third swarm that has been recorded in this area since sensors were installed in 1932, and it’s much worse than the ones recorded in 2001 and 2009. This particular stretch of the San Andreas Fault hasn’t ruptured since 1680, and given that big quakes in this area happen about once every 150 to 200 years, this fault line is considerably overdue.

    A big fear is that the rupturing of the southern portion of the San Andreas fault could cause a domino effect along the entire stretch, cracking the fault from Imperial County through to Los Angeles County. Another possibility is that the Salton Sea swarm could cause the nearby San Jacinto fault system to rupture, which would in turn trigger the collapse of the San Andreas Fault.

    Should the Big One hit, it won’t be pretty. Models predict a quake across the southern half of California with a magnitude around 7.8. Such a quake would cause an estimated 1,800 deaths, 50,000 injuries, and over $200 billion in damage.

    But as the USGS researchers point out, this is far from an inevitability. The swarm under the Salton Sea may subside, or fail to influence the gigantic fault nearby. Moreover, the estimates provided by the scientists are exactly that—estimates. The science of earthquake prediction is still very much in its infancy, and these models are very likely crunching away with insufficient data. No need to panic just yet.

    See the full article here .

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  • richardmitnick 9:11 pm on September 12, 2016 Permalink | Reply
    Tags: , , GIZMODO,   

    From GIZMODO: “We Were Wrong About Where the Moon Came From” 

    GIZMODO bloc

    GIZMODO

    9.12.16
    Ria Misra

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    Artist’s concept of moon-Earth crash (Image: Dana Berry/SwRI)

    The moon is our almost constant frenemy in space, lighting our nights and spoiling our star-views in equal turns. But now, new measurements from Apollo-era moon rocks suggest that the moon and Earth had a much more savage past than we knew.

    A new paper out today in Nature says that the moon formed as a result of a more violent space collision than previously believed. Since the 1970s, many researchers have championed a theory in which the moon was created from thrown-off debris when a Mars-sized body grazed Earth in a relatively low-contact collision. Instead, the researchers say new evidence shows that the impact was more “like a sledgehammer hitting a watermelon.”

    The old theory of the moon’s origin—in which it formed from debris from a grazing collision—neatly explains both the moon’s size and orbital position. But a test on some lunar rocks from the Apollo mission revealed something odd which that theory couldn’t explain.

    “We’re still remeasuring the old Apollo samples from the the ‘70s, because the tech has been developing in recent years. We can measure much smaller differences between Earth and the moon, so we found a lot of things we didn’t find in the 1970s,” Kun Wang, an assistant professor at Washington University who is the lead author of the paper told Gizmodo. “The old models just could not explain the new observations.”

    If the four-decade old theory were correct, then researchers would expect to find that well over half of the moon’s material had come from that Mars-sized body that scraped Earth to form the moon. But the researchers weren’t finding signs of that in the samples; instead, chemical analyses on the samples were returning isotopic compound readings that were nearly identical.

    They started to do more and more advanced tests to try and pinpoint any differences in the signatures. They finally found one—but one that suggested that the samples’ origins were even more tightly connected than previously expected.

    The isotope signatures were the same, except for more of a heavy-potassium isotope in the lunar samples which would have required incredibly hot temperatures to separate out. A violent collision between the Earth and the Mars-sized impactor could have caused those incredibly high temperatures. In this model, the temperatures were so high and the force so powerful that the impactor and even much of Earth vaporized on contact. That vapor then expanded out over an area 500 times the size of the Earth before finally cooling and condensing into the moon.

    “We need a much, much bigger impact to form a moon according to our study,” explained Wang. “The giant impact itself should be called extremely giant impact. The amount of energy required isn’t even close.”

    This new data doesn’t just change our conception of how the moon was formed, though. It also suggests an early solar system that was much more volatile than we knew—and it could be just the beginning of what new analyses on old lunar samples could teach us.

    “Everything we know about the early solar system is from our study of meteorites and lunar samples, all those really really old rocks,” said Wang. “It has changed our understanding of the early solar system, it’s much more violent than we thought.”

    The researchers will continue to study the Apollo lunar samples to try and pull yet more clues from them. Even now, they suspect that these samples that we’ve been holding on to for decades could have more secrets to reveal.

    See the full article here .

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  • richardmitnick 4:39 pm on August 30, 2016 Permalink | Reply
    Tags: , , GIZMODO, ,   

    From GIZMODO: “How We’ll Get Our First Big Clue About Life on Proxima b” 

    GIZMODO bloc

    GIZMODO

    1
    Artist’s concept of Proxima b orbiting Proxima Centauri. (Image: ESO./L. Calçada/Nick Resigner)

    Last week, astronomers announced that our nearest neighboring star hosts an Earth-sized planet in the habitable zone—an exciting prospect for alien life, and a possible second home for humanity. But before we assemble the interstellar welcoming party to greet our cosmic neighbors, we need to figure out whether Proxima b is capable of supporting life at all. Thanks to the James Webb Space Telescope, that question could be answered in less than three years.

    NASA/ESA/CSA Webb Telescope annotated
    NASA/ESA/CSA Webb Telescope annotated

    “It is controversial whether or not life can exist in low mass star systems like Proxima Centauri,” Harvard astronomer Avi Loeb told Gizmodo. “Some people have argued that such planets cannot have an atmosphere.”

    That’s why Loeb, along with Harvard astronomer Laura Kreidberg, has just submitted a paper to Astrophysical Journal Letters describing how we can use the JWST—the highly-anticipated successor to Hubble that launches in 2018—to answer this critical question within just a few days of observation.

    The concern that Proxima b may be a dead, airless world stems from the fact that it orbits its dim red dwarf star, Proxima Centauri, at a distance of just 4.6 million miles. (Earth, for comparison, is 93 million miles from the Sun.) This tight orbit affords Proxima b enough sunlight for Earth-like temperatures and liquid water, but it also subjects the planet to powerful, atmosphere-stripping solar winds. What’s more, it virtually ensures that Proxima b is tidally locked, with a permanent dayside and a permanent nightside. Unfortunately, models suggest that the atmospheres of tidally locked planets may be prone to sudden collapse, as volatile gases freeze out on the nightside.

    But atmospheres can also be replenished through volcanic activity, and on planets with strong magnetic fields, they’re less likely to escape. Since we know nothing of Proxima b’s volcanic activity or magnetic field strength, we can’t even make an educated guess about its prospects of having an atmosphere. But we’re dying to know, because an atmosphere means oceans are possible, and the two together mean life is.

    That’s where the JWST comes in. As Loeb and Kreidberg discuss in their paper, the key to sniffing out Proxima b’s atmosphere lies in the planet’s infrared heat signature. And it just so happens that Hubble’s successor is highly attuned to the infrared part of the spectrum.

    “As Proxima b moves about its star, there is no day-night variation,” Loeb explained. “The day side is hot and the night side is cold. But the temperature difference between day and night depends on whether the planet is bare rock, or if it has an atmosphere or ocean, because these redistribute heat.”

    In other words, the temperature difference between Proxima b’s day side and its night side will be larger if there is no atmosphere. In fact, the day side will re-emit all of the energy it absorbs from Proxima Centauri as a blackbody, and we can calculate exactly how much blackbody radiation there should be. The night side, on the other hand, will be hell frozen over.

    If the temperature difference between day and night is less extreme, we can infer the presence of an atmosphere. Conveniently, it won’t take long for the JWST to measure IR emissions from both faces of Proxima b as it orbits its star—an entire year only takes 11.2 Earth days.

    If Proxima b does have an atmosphere, the next step will be figuring out what it’s made of. We’ll specifically want to look for things like oxygen, water vapor, and methane, which could indicate habitable conditions if not active biological processes. This, however, requires us to catch starlight as it bounces off or filters through the planet’s atmosphere—an extraordinarily difficult thing to do. While the JWST might be able to detect a few compounds including ozone, full atmospheric analysis will have to wait for future ground-based observatories like the Extremely Large Telescope, which is expected to see first light in the mid-2020s.

    “The important thing is that in a couple of years, we should be able to start learning about the atmosphere [of Proxima b],” Loeb said. “If there is one, it’s quite likely there’d be a call for a special mission to study just this planet.”

    As we continue building the tools to study Proxima b from Earth, Loeb is already thinking about how we might pay the planet a visit. He’s chairing the advisory committee for Breakthrough Starshot, a billionaire-backed effort to develop tiny, laser-propelled spacecraft that can travel at up to 20 percent the speed of light. While Breakthrough Starshot was initially packaged as a voyage to the nearby binary star system Alpha Centauri, the discovery of Proxima b changes everything.

    “I think it’s extremely important, psychologically, to have a target,” Loeb said. “If you ask a person to build a ship without knowing where it will sail, it’s quite different than if you have a destination in mind. The fact that we now have a target, in the habitable zone, is very exciting.”

    See the full article here .

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  • richardmitnick 12:53 pm on July 27, 2016 Permalink | Reply
    Tags: , , , GIZMODO,   

    From GIZMODO: “Heating of Jupiter’s upper atmosphere above the Great Red Spot” 

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    GIZMODO

    7.27.16
    Ria Misra

    1
    Artist’s concept of heating above the Great Red Spot (Image: Karen Teramura, UH IfA with James O’Donoghue and Luke Moore)

    There’s a mystery above Jupiter. The planet is five times farther from the sun than Earth is—and yet has similar atmospheric temperatures to our own. So where’s all that extra heat coming from? It turns out, Jupiter may have a second heat source in its Big Red Spot.

    In a new paper out today in Nature, researchers from Boston University explain how they constructed a heat-map of the atmosphere using infrared emissions thrown off by the planet. With that heat map, researchers were able to trace the temperature spike to its source. The highest temperatures were consistently over the planet’s Great Red Spot, an ever-present storm system larger than two Earths.

    Researchers had previously flagged the turbulent storm as a potential heat source but, until this study, had no way to back up their hunch. Now that this team pinned the heat to a likely source, though, researchers have even more questions.

    The precise mechanism by which the storm system’s heat transfer works, for instance, has yet to be uncovered. Equally intriguing is the question of what will happen to Jupiter’s atmosphere as the Great Red Spot changes. This “perpetual hurricane,” as researchers describe it, has raged for centuries at least—but that doesn’t mean it’s going to keep on going forever. Previous studies have shown that the giant spot appears to be steadily shrinking with age.

    If the Great Red Spot is indeed one of the primary heat sources for the planet, then it would make sense to see Jupiter cool down as it shrinks. If nothing else, a gradual cooling of the planet’s temperature would confirm that scientists have indeed solved the mystery of Jupiter’s extra heat.

    See the full article here .

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  • richardmitnick 6:26 am on July 26, 2016 Permalink | Reply
    Tags: , First American to Receive Double Hand Transplant Reveals It Was Unsuccessful, GIZMODO,   

    From GIZMODO: “First American to Receive Double Hand Transplant Reveals It Was Unsuccessful” 

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    GIZMODO

    7.25.16
    Eve Peyser

    1
    Image: AP

    Jeff Kepner, the first American to receive a double hand transplant, wishes they could be removed.

    In an interview with TIME published today he revealed that the transplant was unsuccessful and he has never been able to utilize his hands.

    “I sit in my chair all day and wear my TV out,” he said.

    Kepner had his hands amputated in 1999 after his strep throat infection caused sepsis. Before he received the hand transplant in 2009, he used prosthetics which allowed him to not only hold down a job, but even drive a car.

    Kepner figured if the transplant was unsuccessful, he could simply get them removed and go back to prosthetics. The doctor who oversees Kepner’s case, Vijay Gorantla, told TIME that “it’s uncertain if Kepner would be able to use prosthetics if the hands were removed, and that rigorous physical therapy would be required.”

    While his life might improve if they were to partially amputate the transplanted hands, Kepner is tired of the relentless surgeries. “I am not going through all those operations again,” he said.

    Dr. W.P. Andrew Lee, the surgeon who performed the transplant, said that Kepner’s case is unusual. “The other three patients have had significant functional return in their hands and have been able to resume completely independent living, including driving, working, and going to school,” he explained.

    Since Kepner’s 2009 transplant has rendered him “0% functional,” his wife—who cares for him full-time—has set up a GoFundMe page to cover the years of medical bills.

    See the full article here .

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  • richardmitnick 9:58 am on July 22, 2016 Permalink | Reply
    Tags: , GIZMODO, , We’ll Only Have a Year to Prepare For a Cataclysmic Super-Eruption   

    From GIZMODO: “We’ll Only Have a Year to Prepare For a Cataclysmic Super-Eruption” 

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    GIZMODO

    7.21.16
    George Dvorsky

    1
    Image: GFZ German Research Centre for Geosciences

    Volcanic super-eruptions are bad. Like really bad. Scientists warn of such a potentially civilization-ending catastrophe in our future, but as a new study shows, we’ll only have a year to prepare once the signs of an impending eruption become visible.

    A new microscopic analysis of quartz crystals taken from the site of a massive volcanic eruption that occurred 760,000 years ago in eastern California suggests we’ll only have about a year’s worth of advance warning before a devastating super-eruption. In a paper published in PLOS ONE, Guilherme Gualda from Vanderbilt University and Stephen Sutton from the University of Chicago show that super-eruptions don’t require much time to blow their tops, even though they’re tens of thousands of years in the making.

    2
    The Long Valley Caldera in eastern California, the result of a super-eruption 760,000 years ago. (Image: NASA/JPL)

    Unlike “conventional” eruptions, these explosions are among the most devastating on the planet, unleashing destruction that can flatten continents, trigger new ice ages, and potentially put an end to human civilization as we know it. They happen when the magma in the mantle rises into the crust, but is unable to breach the surface. The ensuing pressure builds and builds in an ever-growing magma pool until the crust can no longer contain the pressure. The results of the ensuing explosion are nothing short of catastrophic. In the most severe cases, a supervolcano can eject upwards of 1,000 cubic kilometers of ash into the sky.

    Our planet has experienced several super-eruptions in the recent geological past. The Taupo Volcanic Zone in New Zealand erupted 26,500 years ago, and Campi Flegrei in Italy erupted 40,000 years ago. Other noteable super-eruptions include Indonesia’s Toba super-eruption in Sumatra 75,000 years ago and the Tambora eruption in 1815. Wyoming’s Yellowstone has super-erupted three times in the past million years, and there’s fear it could happen again. As these episodes show, super-eruptions are still a part of Earth’s geological fabric. It’s not a matter of if they’ll happen again, but when.

    As these timelines suggest, super-eruptions evolve over relatively long timescales. But as the new study by Gualda and Sutton shows, the final stage doesn’t take very long at all.

    “The evolution of a giant, super-eruption-feeding magma body is characterized by events taking place at a variety of time scales,” noted Gualda in a release. It typically takes tens of thousands of years to “prime” the crust with the requisite amounts of magma. Once these pools are established, the giant magma bodies swell and fester for a few millennia or even just a few centuries. “Now we have shown that the onset of the process of decompression, which releases the gas bubbles that power the eruption, starts less than a year before eruption,” said Gualda.

    3
    A quartz crystals used in the analysis. (Image: Guilherme Gualda/Vanderbilt University)

    Gualda and Sutton reached this conclusion by analyzing small quartz crystals in pumice taken from the site of the Long Valley Caldera that formed nearly a million years ago. This allowed the researchers to measure the distinctive surface rims found at the sites of super-eruptions. By measuring the size and growth rates of these rims, the researchers were able to determine the length of time it took for an explosion to happen once the collapse phase begins. Analysis showed that more than 70 percent of rim growth times were less than a year, indicating that quartz rims mostly grow in the days and months prior to an eruption.

    According to the researchers, we’ll likely be able to detect the signs of a pending super-eruption by noticing the bloating effects of the expanding magma body on the surface. More work is needed to know more about these warning signs, but this new study suggests that these signals will start to appear within a year of an eruption. And they’ll intensify as the explosion gets closer.

    See the full article here .

    Please help promote STEM in your local schools.

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