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  • richardmitnick 9:05 am on July 15, 2016 Permalink | Reply
    Tags: , NatGeo,   

    From NatGeo: “Erupting Volcano Lets Scientists Watch Rare Caldera Collapse” 

    National Geographic

    National Geographics

    July 14, 2016
    Michelle Z. Donahue

    1
    Lava flows from the Bárðarbunga volcano eruption in 2014. Photograph by Tobias Dürig

    As gateways to the seething-hot heart of our planet, volcanoes are feared for their occasionally cataclysmic behavior. From Vesuvius to Krakatau, some of the most devastating eruptions in human memory have one calamitous factor in common: caldera collapse.

    Usually rapid and unannounced, only seven known collapses have occurred since the start of the 20th century, and scientists have been puzzling over the mechanism behind these events for more than a hundred years.

    So when the massive Bárðarbunga volcano in Iceland’s remote southeastern interior started demonstrating caldera formation in slow motion, researchers had an unprecedented opportunity to better understand the process.

    Reporting today in the journal Science, a team of 47 scientists and data modelers from nine countries, led by geophysicist Magnús Gudmundsson of the University of Iceland, describes the evolution of Bárðarbunga’s caldera from August 2014 to February 2015.

    Anatomy of a Disaster

    Caldera collapse happens when a magma chamber deep beneath a volcano drains rather abruptly. The bedrock above pancakes down into the resulting void, creating or deepening a depression in the volcano.

    The exact series of events between a collapse and an eruption is still being sorted out. But a caldera collapse can cause a sudden release of gas, which can explode up and outward, as seen in the big eruptions in recorded history.

    And the biggest danger is simply that the mountain is falling in on itself, which can trigger huge landslides or engulf entire regions.

    Volcanoes can be active for hundreds of thousands of years, and in that time they might experience two or three caldera collapses. So to catch one unfolding bit by bit in Iceland gave scientists the unexpected luxury of time.

    “We could measure everything,” Gudmundsson says of the researchers’ efforts, which included using seismologic and geochemical data, GPS, ground-based surveys, and observations from helicopters and satellites.

    “This is difficult to do when this kind of event typically happens overnight. But because this was happening gradually, we could take measurements many, many times, so we have a time series that allows its evolution to be studied.”

    Nearly 6,600 feet (2,012 meters) tall, Bárðarbunga is Iceland’s second tallest mountain, and its existing caldera is buried beneath 2,600 feet (800 meters) of Vatnajökull glacier ice.

    When the volcano began rumbling in mid-August of 2014, regular earthquakes between magnitude 4.0 and 5.8 swarmed in and around it over the span of two weeks. Beginning initially beneath the caldera itself, the quakes began creeping outward to the southeast before making an abrupt 90-degree turn to the northeast, culminating finally in an eruption 30 miles (48 kilometers) away in the lava fields of Holuhraun.

    By volume of magma displaced from the chamber—equal to about 500 billion gallons of molten rock—it was the largest eruption in Iceland in 230 years, though only a medium-size eruption by typical caldera collapse standards.

    The Bárðarbunga caldera subsided by an additional 213 feet (65 meters) and widened to 42 square miles (110 square kilometers). Thankfully the collapse did not produce an eruption under the ice, which could have resulted in major flooding as well as the release of huge quantities of harmful gases.

    Feeling the Pressure

    Stephanie Grocke, a Smithsonian volcanologist who studies mega-calderas like the one beneath Yellowstone, says that the interdisciplinary team’s work provides an invaluable understanding of how volcanic systems develop and behave.

    “It reveals the story about how the volcano actually evolved in real time,” Grocke says. “It’s super unique, and happened as a function of new technology. It also shows how earthquakes are linked to magma movement. You can follow those dots in seismicity and track how the magma moves through the surface.”

    A lingering question is what drives the initial insult that leads to collapse. It’s possible a buildup of magma in the chamber causes tectonic activity, but it could also be that fault slippage creates a sudden pathway that allows magma to drain rapidly.

    3
    Seen from the north with the sun low in the sky, the main subsidence bowl of the Bárðarbunga caldera becomes more clearly visible under the ice. Photograph by Magnús T. Gudmundsson

    At Bárðarbunga, the team saw that deeply buried ring faults failed, causing earthquakes that opened up an underground dike that magma flowed through until it broke through the surface at distant Holuhraun.

    Gudmundsson says the caldera collapse was then driven by magma leaking away from the overinflated chamber, followed by the roof beginning to break. Once the collapse began, it helped squeeze even more magma out, like a piston in a pipe.

    This so-called lateral flow of magma away from the main volcano body is common with eruptions that result in caldera collapse, Gudmundsson notes. Of the seven known collapses that took place since 1912, all of them had a considerable amount of lateral flow, even under vastly different tectonic conditions.

    Early Warning

    The patterns described at Bárðarbunga can now be used to help calculate the way similar events might happen in the future.

    Understanding the link between earthquakes and magma flow can also help predict where lava, ice flows, or landslides can become an issue for populated areas.

    “It’s extremely helpful for emergency planning and hazard forecasting,” Grocke says. “We use volcanoes’ eruptive histories to forecast how it may behave in the future. If we see a caldera collapse happened in the past, we can assume a volcano would form another one, and a collapse can have links to a lot of other things that can be happening tens of kilometers away from the actual event.”

    That means volcanologists could alert a region to a large or prolonged eruption days or weeks in advance.

    “When we see earthquakes of these magnitudes and are able to monitor the surface [of the volcano], next time it happens we will immediately be able to say that we may have a caldera collapse brewing, and we’re in for a large or long-lived eruption,” Gudmundsson says.

    “By knowing days earlier, we know we have to be on the lookout for something big.”

    See the full article here .

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    The National Geographic Society has been inspiring people to care about the planet since 1888. It is one of the largest nonprofit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, and the promotion of environmental and historical conservation.

     
  • richardmitnick 3:12 pm on June 10, 2016 Permalink | Reply
    Tags: , , , NatGeo   

    From natgeo: “How Much Does the Milky Way Weigh?” 

    National Geographic

    National Geographics

    May 31, 2016
    Michelle Z. Donahue

    1
    The band of the Milky Way stretches over Natural Bridges National Monument in Utah.
    Photograph by Jim Richardson, National Geographic Creative

    Want to start a fight between astrophysicists who study the Milky Way? Ask them to tell you how much the galaxy weighs.

    Now, a new modeling method by researchers at McMaster University in Ontario, Canada, may help put those debates to rest.

    According to the new work, presented May 31 at a Canadian Astronomical Society conference in Winnipeg, the Milky Way contains the same amount of mass as 700 billion suns—and that puts it on the slimmer side of the scale. At the same time, our galaxy seems to contain slightly more dark matter than previously calculated. This mysterious invisible substance is thought to exist in a cloud around the Milky Way.

    Figuring out how much the Milky Way currently weighs can allow cosmologists to get a better handle on our galaxy’s past and future.

    “Understanding our galaxy’s mass puts it into a better cosmological context,” says study leader Gwendolyn Eadie, a doctoral candidate at McMaster. For starters, the rate at which stars in any given galaxy form, exist, and die seems to be tied to the overall mass of the galaxy.

    “People who study the evolution of galaxies look at how the mass relates to its evolution,” says Eadie. “If we have a better handle on what the mass of the Milky Way is, we can understand how it and other galaxies form and evolve.”

    Moving Through Dark Matter

    Previous estimates of how much matter the Milky Way contains vary wildly. Some studies report it holds the equivalent of 1 trillion suns, while others say it’s merely 100 billion.

    Those measurements all include the types of matter we can observe or detect directly—dust, planets, moons, stars, and some of the dwarf galaxies orbiting the Milky Way—as well as the galaxy’s dark matter halo.

    Invisible except for its gravitational effects on other objects, dark matter is exceptionally tricky to measure, and Eadie has been working on the problem since she started graduate work studying ancient groups of stars known as globular clusters.

    Eadie ultimately devised a method to measure our galaxy’s dark matter using the known motions and velocities of 89 globular clusters that exist around the Milky Way.

    She used globular clusters because they are dispersed at different distances throughout the galaxy, and because they are relatively large, well defined, and easier to track over time than individual stars. As these clusters orbit the galactic center, dark matter pushes and pulls on them in predictable ways.

    Put together with the known masses of visible objects in the galaxy, her model created a “mass profile” of the Milky Way, which estimates the mass contained within any distance from the galactic center.

    At 700 billion suns, Eadie’s final estimate agrees more closely with the “lighter galaxy” camp, which judges that some of the outer-edge objects, including some large, distant globular clusters and diffuse dwarf galaxies, aren’t truly bound by the Milky Way’s gravity and thus not part of its overall total mass.

    And since the stellar mass of the galaxy is currently estimated at around 60 billion suns, and dust and gas make up about one to three percent of the rest, Eadie’s results suggest that as much as 88 percent of the mass in the Milky Way is comprised of dark matter.

    Hefty Home

    While Eadie’s work isn’t the first to try to estimate the mass of the galaxy, her study combines a wide variety of data sources to yield one of the most thorough analyses to date, says Alan McConnachie, a research officer and instrument specialist at the National Research Council of Canada’s Herzberg Institute for Astrophysics.

    “Figuring out how fast, and in what direction, globular clusters are moving is pretty hard. Combining all of these data together in a consistent model for the Milky Way is a real challenge,” McConnachie says.

    “People sometimes are a bit surprised that we don’t have a better idea of how heavy the Milky Way is, given that it’s the galaxy we live in,” he adds. “This work is a big step toward being able to claim with confidence that we know how massive our home actually is.”

    For Eadie, the result is inspiration to continue astrophysicists’ efforts to pinpoint the nature of dark matter.

    “On the one hand, the visible Milky Way in the night sky is extensive—that stream of stars and dust across the dark sky is beautiful, magnificent, and enormous,” Eadie says. “But the idea that the stuff I’m seeing is only about one-fifth of what’s out there inspires me to figure out what we’re missing.”

    See the full article here .

    Please help promote STEM in your local schools.

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    The National Geographic Society has been inspiring people to care about the planet since 1888. It is one of the largest nonprofit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, and the promotion of environmental and historical conservation.

     
  • richardmitnick 2:51 pm on June 10, 2016 Permalink | Reply
    Tags: 80 Percent of Humankind Can’t See the Milky Way Anymore, , , , NatGeo   

    From natgeo: “80 Percent of Humankind Can’t See the Milky Way Anymore” 

    National Geographic

    National Geographics

    June 10, 2016
    Michelle Z. Donahue

    1
    The Milky Way illuminates the sky over Dinosaur National Monument, which spreads across Colorado and Utah. Photograph by Dan Duriscoe

    The Milky Way galaxy, that torrent of stars that slashes across a deeply darkened night sky, has been a deep well of inspiration from humanity’s earliest days. The ancient Egyptians saw it as a pool of cow’s milk, while in Hindu mythology the arcing galactic arm was likened to a dolphin swimming through the sky. Countless scientists, philosophers, and artists, including Galileo, Aristotle, and Vincent Van Gogh, have drawn upon the galaxy as their muse. (Read “How Much Does the Milky Way Weigh?”)

    But a new atlas of the night sky across the entire globe shows that more than 80 percent of the planet’s land areas—and 99 percent of the population of the United States and Europe—live under skies so blotted with man-made light that the Milky Way has become virtually invisible.

    Fabio Falchi, a researcher at the Light Pollution Science and Technology Institute (ISTIL) in Thiene, Italy, announced Friday the release of a new survey that quantifies nighttime sky quality for every region in the world. Produced using over 35,000 ground-based observations and six months of data from 2014 collected with the Suomi National Polar-orbiting Partnership (NPP) satellite, the atlas is an update to a 2001 work and shows the planet’s darkest and brightest locations in stark contrast.

    NASA/Goddard Suomi NPP satellite
    NASA/Goddard Suomi NPP satellite

    Woe to Singapore, a place of eternal twilight, with the entire population living under skies so bright their eyes cannot fully adjust to night vision, let alone see the Milky Way. Kuwait, Qatar, and the United Arab Emirates have it nearly as bad.

    On the other hand, more than 75 percent of the population of Chad, the Central African Republic, and Madagascar live under near-pristine skies, or places where background light represents less than one percent of the sky’s overall brightness. And according to Falchi’s analysis, residents of the Azores have the distinction of living the farthest from land with unspoiled skies: They’d have to travel nearly 1,100 miles, to the western Sahara, to experience an ancestrally darkened landscape (unless they travel out into the ocean).

    2
    Light pollution clouds the view over Joshua Tree National Park, California. Photograph by Dan Duriscoe

    “In the first atlas we had a hint of what was happening, but these numbers are shocking,” Falchi says. “We have lost the connection with our roots, of literature, of philosophy, of science, of religion—all are connected with the contemplation of the night sky. A new generation can no longer appreciate this beauty.” (“See a Stunning New View of the Milky Way.”)

    Study co-author Dan Duriscoe, a physical scientist with the National Park Service’s Natural Sounds and Night Skies Division, has worked in the Park Service for 36 years and has collected light measurements in national parks since 1994. On the East Coast, apart from a few scattered points in West Virginia, Pennsylvania, and New England, it’s extremely difficult to get to a place with an unfettered view of stars.

    “People could get that experience closer to home decades ago, but now they’re forced out into Utah or Death Valley or Yellowstone, somewhere far from their backyards,” Duriscoe says. “There’s an increased public awareness of how this is a rare experience and becoming one that will cost them some money to go see.”

    High-Tech Eyes on the Sky

    Sweeping over the Earth’s poles 14 times a day, the Suomi satellite generates a complete global set of high-resolution day and night images every 24 hours. Falchi, along with ISTIL colleague Pierantonio Cinzano, worked with data from partners including the National Park Service (NPS) and the National Oceanographic and Atmospheric Administration (NOAA) to produce the atlas. The 2001 atlas looked at only light escaping from Earth into space, while the new data reveal where light is reflected from the sky down to the Earth’s surface. (Read “Graveyard of Stars May Lie at Milky Way’s Center.”)

    Falchi plans to release a print version of the atlas, and an interactive digital atlas, similar to one from 2006 produced using the 2001 data, is also in the works.

    3
    A map illustrates light pollution in North and South America. Illustration by Fabio Falchi, Google Earth

    Chris Elvidge, a co-author of the study and a scientist with NOAA’s National Centers for Environmental Information, says he expects that the satellite data and analysis will be useful not only for astronomers, who have a vested interest in a dark night sky, but also for biologists studying light impacts on nocturnal organisms, medical researchers interested in the human health effects, and city planners.

    One drawback of the satellite’s imaging instruments is limited detection of the blue and violet parts of the visible spectrum—the very zone where white LEDs would show up on satellite scans. Though highly efficient, white LEDs can be excessively bright, and as municipalities begin to install them in streetlights and for other outdoor purposes, the impact of LEDs may actually worsen overall light pollution in the long run.

    “Several cities have jumped on the LED bandwagon without getting their citizens’ approval,” says Connie Walker, an astronomer with the National Optical Astronomy Observatory in Tucson, Arizona, and a board member of the International Dark-Sky Association. Jurisdictions interested in effectively reducing light pollution can turn to the two atlases to research before-and-after maps, and compare what’s worked and what hasn’t, she says.

    “This atlas affords a consistent way of comparing light pollution in different areas of the world over the last 15 years,” she says.

    4
    This map shows light pollution in the Eastern Hemisphere. Illustration by Fabio Falchi, Google Earth

    Falchi’s work, done completely in his off hours as a labor of love, helps put the extent of the problem into perspective, Duriscoe says.

    “To tackle this on a global scale, nobody else before has attempted it,” he says. “When you can stand back and look at the whole Earth and the impact of our modern lifestyle on the ability of all cultures to enjoy the natural nocturnal environment, it shows how we just take it for granted.”

    Protecting Natural Cycles

    At one time, communities with large telescopes, like the Palomar Observatory outside of San Diego, California, prided themselves on their efforts to protect the night sky, though that attitude seems to have waned over the last several decades, Duriscoe notes. Now, however, with more research emerging about the negative impacts on humans of overexposure to light, there has been an uptick of interest in combating the 24-hour lifestyle.

    Falchi has been personally involved in his own community in changing approaches to outdoor lighting. As the current president of the nonprofit CieloBuio dark skies advocacy organization, he spearheaded a petition effort in the late 1990s to enact lighting reform laws in Lombardia, the region where he lives and works. With controls on the types of new fixtures being installed and limits on light intensity in given areas, despite a twofold increase in the number of new lights, light-pollution levels in the region have remained constant from 2000 to today.

    Though much of Italy is now governed by similar laws, it’s still only a start, Falchi says.

    “This is not a sufficient measure for controlling light pollution, but simply a stop in the increase,” he adds. “For almost all other pollutants—chemical, particulate, carbon monoxide, or anything else, graphs show that almost all of them have decreased over the last 20 years. We need to decrease pollution from light as well.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The National Geographic Society has been inspiring people to care about the planet since 1888. It is one of the largest nonprofit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, and the promotion of environmental and historical conservation.

     
  • richardmitnick 8:48 am on June 5, 2016 Permalink | Reply
    Tags: , , , NatGeo, , Uncertain Future for Earth’s Still Biggest Telescope   

    From nationalgeographics.com: “Uncertain Future for Earth’s Biggest Telescope” 

    National Geographic

    National Geographics

    06/4/2016
    Nadia Drake

    1
    The Arecibo Observatory, easily recognizable from feature films and a symbol of the search for extraterrestrial life, may not be around for much longer. A harsh funding climate is forcing the National Science Foundation to make some hard decisions about which facilities to keep around. (NSF/Wikimedia)

    Tucked into a sinkhole in the Puerto Rican jungle, the world’s largest single-dish radio telescope scans the skies for signs of distant galaxies, elusive gravitational waves, and the murmurs of extraterrestrial civilizations nearly 24 hours a day. For more than a half-century, whether those waves traveled to Earth from the far reaches of our universe or much closer to home, the Arecibo Observatory has been there to catch them.

    But the enormous telescope, with a dish that stretches 1,000 feet across, may not be around for much longer.

    On May 23, the National Science Foundation, which funds the majority of Arecibo’s annual $12 million budget, published a notice of intent to prepare an environmental impact statement related to the observatory’s future.

    That might sound innocuous – after all, isn’t it a good idea to study the context in which our science facilities exist? Yet it’s anything but benign. Putting that environmental assessment together is a crucial step NSF needs to take if it plans to yank funding from the observatory and effectively shut it down.

    “It appears that NSF is following the formal process established, in part, by the National Environmental Policy Act of 1969, for decommissioning of a federal facility,” says Robert Kerr, former director of the observatory. “The good folks at Arecibo are scared to death.”

    The decision to close Arecibo hasn’t been made yet, but the move follows an ominous drumbeat of similar announcements and reports that have accumulated over several years, most urging NSF to send its resources elsewhere. Now, options for Arecibo’s future range from continuing current operations to dismantling the telescope and returning the site to its natural state. It’s a decision NSF hopes to make — with input from the public — by the end of 2017, says Jim Ulvestad, director of NSF’s Division of Astronomical Sciences.

    2
    Above the 1000-foot dish, a 900-ton platform is suspended from three tall towers. (Nadia Drake)

    The most extreme option, which could include explosively demolishing the giant dish, might affect such things as ground water, air quality, and ecosystems – thus the importance of studying the environmental impact of potential futures, especially ones that involve shutting the telescope’s eyes.

    “On a practical level, the telescope would in time — perhaps a short time, given the tropical site — become very unsafe,” says Cornell University’s Don Campbell, a former observatory director. “Short of permanently guarding it, deconstruction would be necessary.”

    Not surprisingly, this notice of intent is causing significant concern among astronomers and the local community. Arecibo is the most sensitive radio telescope in the world; and despite its age, it’s still involved in world-class science, like the search for gravitational waves. Importantly, it also helps boost a sagging local economy, and has inspired many Puerto Ricans to pursue science and think about the mysteries of the universe.

    “Puerto Rico feels a sense of ownership and pride for the observatory,” says Emmanuel Donate, an astronomy graduate student at the University of Georgia who started a petition to keep the observatory funded. “I consider using it, especially in person as I’ve been doing the last couple weeks, one of the highlights of my life and a tremendous personal honor.”

    A Tropical Icon

    Construction at Arecibo began in 1960, when – among other things – the U.S. government wanted to find out if Soviet ICBMs could be detected using charged particles in their atmospheric wakes. The telescope didn’t work well at first, but after a few upgrades it was the most sensitive cosmic radio wave detector in the world. That’s not it’s only trick, though: In addition to collecting photons from space, Arecibo is also capable of sending radio waves into the cosmos, a talent scientists use to scrutinize potentially catastrophic asteroids on Earth-crossing orbits.

    3
    The Arecibo Observatory, as seen on Google Earth.

    In the intervening decades, Arecibo has been involved in loads of top-notch science, including work that was awarded a Nobel Prize. But it’s also become a recognizable symbol of humanity’s quest to understand our place in the cosmos (my dad, a former observatory director, used Arecibo to send Earth’s first intentional postcard to the stars in 1974), and is a semi-frequent character in popular films and TV series, including The X-Files, Contact, and GoldenEye.

    To say the telescope is iconic is not an overstatement.

    Stormclouds on the Horizon

    But a frustratingly flatlined budget is forcing the National Science Foundation to ration its resources. To do that, NSF relies on a somewhat contorted process of soliciting input from external reviews and panels, federal advisory boards, and the National Research Council’s decadal surveys, which prioritize science goals for the coming decade.

    “NSF, like most federal science agencies, has much more worthy science proposed to it than it is able to fund,” Ulvestad says. “Within the constraints of its resources, NSF responds as well as possible to those community and governmental science priorities and recommendations.”

    The most recent decadal survey, published in 2010, prioritized science requiring new facilities instead of experiments that could be conducted at places like Arecibo. That survey, in combination with the dismal funding situation, is what’s causing NSF to look for facilities to dump.

    4
    Arecibo’s dish is suspended above the floor of the natural depression it sits in. Beneath it, plants grow like crazy. (Nadia Drake)

    Despite its iconic status, Arecibo is an easy target – newer, shinier telescopes are coming online, and it’s got a relatively small number of users compared to optical telescopes across the United States, many of which are individually less expensive to run.

    Over the past decade, multiple panels have called for severe reductions in funding for the observatory, starting with a 2006 NSF review that recommended finding alternative sources of cash for Arecibo. “The [senior review] recommends closure after 2011 if the necessary support is not forthcoming,” the report says. “This raises the important question of the cost of decommissioning the telescope, which could be prohibitively large.”

    That review was followed by a 2012 assessment of the facilities funded by NSF’s astronomical sciences division. While somewhat less gloomy – the committee recommended keeping the observatory in NSF’s portfolio – the 2012 panel suggested revisiting Arecibo’s funding status later in the decade, “in light of the science opportunities and budget forecasts at that time.”

    NSF followed that review with a 2013 letter saying it would begin studying the costs and impact of decommissioning the giant telescope – a matter that would be complicated by the telescope’s history and location in a region of high biodiversity, “thus these reviews should be started as soon as practicable.”

    The cloudy outlook intensified this year, when NSF’s Astronomy and Astrophysics Advisory Committee urged the agency to proceed with divestment “as fast as is practical.” That was quickly followed by another NSF review that advised a 75% reduction in funding from the agency’s Atmospheric and Geospace Sciences division (AGS), slashing contributions to atmospheric research from $4.1 million to $1.1 million.

    And now, the sky is looking dark indeed.

    “The timing of the federal register announcement in juxtaposition with the AGS review is being received by most as the final death sentence for Arecibo,” Kerr says.

    Ulvestad says that before any such decision is reached, communities that rely on the observatory will have an opportunity to share their concerns. On June 7, the first of these meetings will take place in Puerto Rico, and a public comment period is open until June 23. After the results of the draft environmental impact statement are released, a 45-day public comment period will follow.

    And then? Either the storm will hit or it won’t.

    “To be fair to the NSF, AST and AGS are reacting to a very difficult budget situation — no significant increase in several years and none forecast,” Campbell says.

    Scanning the Cosmos

    Now, Arecibo’s projects include detecting mysterious bursts of radio waves coming from far, far away, testing cosmological models by studying small galaxies in the local universe, and studying those potentially planet-killing asteroids – as well as the moons of distant planets.

    “There is much concern, not just in the small bodies community, but in the planetary science community as a whole regarding the future of Arecibo,” says Nancy Chabot of the Johns Hopkins University Applied Physics Laboratory. Chabot chairs NASA’s Small Bodies Assessment Group, which published a report earlier this year urging NASA to continue supporting the observatory, in the name of preserving “the nation’s science and security interests.”

    Among astronomers, perceptions are that NSF’s move to decommission Arecibo has been gaining momentum as challenges from new facilities arise. One potential thorn in Arecibo’s side is ALMA, the ultrasensitive array of radio telescopes recently completed in the Chilean Atacama.

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array

    Some scientists speculate that with continued resources devoted to ALMA, NSF could be looking to share the relative wealth and spend its money on something other than radio. And that might make sense, especially given that China is nearly done constructing a single-dish radio telescope that will be larger than Arecibo. Called the Five-hundred-meter Aperture Spherical Telescope, the behemoth could possibly open its eyes this fall, though real science observations won’t begin right away.

    FAST Chinese Radio telescope under construction, Guizhou Province, China
    “FAST Chinese Radio telescope under construction, Guizhou Province, China

    Despite its size, FAST won’t necessarily be more sensitive than Arecibo, and it won’t have a built-in radar, which can be used to give the most accurate orbital information for asteroids which might impact the Earth.

    Cornell University’s Jim Cordes points out that newer facilities don’t necessarily have to replace older, high-quality telescopes, especially when those older facilities still provide unique capabilities. They can be complementary, he says, pointing out that scores of similar optical telescopes exist in tandem, such as the two nearly identical Keck telescopes at the summit of Hawaii’s Mauna Kea.

    Keck Observatory, Mauna Kea, Hawaii, USA
    Keck Observatory, Mauna Kea, Hawaii, USA

    “It’s sort of like there’s a disconnect in the way people think about radio telescopes and optical telescopes,” Cordes says.

    More importantly, Cordes notes, some experiments actually require multiple extremely sensitive telescopes. One of these, called NANOGrav, uses Arecibo and a telescope at the National Radio Astronomy Observatory in Green Bank, West Virginia to search for gravitational waves.

    NANOGrave Gravitational waves JPL-Caltech  David Champion
    NANOGrave Gravitational waves JPL-Caltech David Champion

    NRAO/GBT radio telescope
    NRAO/GBT radio telescope

    The project does this by observing pulsars, spinning stellar corpses that act as astronomical clocks. As these dense, dead stars rotate, they emit beams of radio waves that can be detected from Earth; gravitational waves, similar to those detected earlier this year by the LIGO collaboration, sweep through and disrupt the signals coming from those spinning clocks in observable ways…as long as a sharp set of eyes is paying attention.

    A National Inspiration?

    It seems clear that Arecibo won’t go down without a fight, but it’s not exactly clear what form that fight will take. Interestingly, former observatory director Robert Kerr threw one punch by beginning the process for listing Arecibo as a national historic site.

    “It was entirely my intention that the National Historic Registry be an impediment to site closure,” he says, adding that “others assisting with that application may have had other motivations, such as enhanced tourist appeal.”

    And NASA, which funds the planetary radar experiments at Arecibo, also may have something to say about NSF shutting down the facility. It’s also possible that another institution, or someone with enough spare cash might decide to step in.

    “I hope that they do find another institution to contribute to the costs but it will depend on the conditions,” Campbell says. “The alternative is grim for science, for Puerto Rico and, especially given Puerto Rico’s current situation, for the Observatory’s local staff. The staff are an incredible hard working and supportive group.”

    Indeed, generations of Puerto Ricans have visited the observatory, in addition to those who have worked, studied, and lived there.

    “I grew up in the city of Arecibo, I grew up knowing that in the mountains south of the city great science was being done,” says Pablo Llerandi-Román, a geologist at the University of Puerto Rico, Rio Piedras. For Llerandi, science became more than just a subject in school when he visited the observatory as a student and talked with the researchers on site. “If Arecibo shuts down,” he says, “A major aspect of my arecibeño and Puerto Rican scientist pride would be lost.”

    Carlos Estevez Galarza, a student at the University of Puerto Rico, says he hopes Puerto Ricans will one day be as celebrated for their commitment to science as they are for their passions for arts and sports – and he thinks the observatory plays an important role in that.

    “The Arecibo Observatory and its staff were the only ones who believed in me, when no one did,” Galarza says. He worked as a student research assistant at the observatory, studying Mars, and has since presented his work at international conferences and submitted his first paper to a science journal.

    “The most important thing about my experience at the Arecibo Observatory is that I found my purpose,” he continues. “There are many talented Puerto Rican students who deserve the chance that I had.”

    One of those students is still in high school. Now 16, Wilbert Andres Ruperto Hernandez wanted to be an astronaut as a kid – and he wanted to get some hands-on experience in science and engineering. So he enrolled in the Arecibo Observatory Space Academy, which offers high school students the opportunity to design experiments, then collect and analyze data. Now, Hernandez says, he wants to study mechanical engineering or space sciences in college, and has discovered a yearning to understand how the universe works – something that emerged while working with and talking to scientists at the observatory.

    “The fact that we have yet to discover and learn more about ourselves, where we live in and all the things that surround us, motivates me the most to investigate and study these fields,” he says. “Being part of Arecibo Observatory and AOSA has been the greatest experience in my life.”

    See the full article here .

    Please help promote STEM in your local schools.

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    The National Geographic Society has been inspiring people to care about the planet since 1888. It is one of the largest nonprofit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, and the promotion of environmental and historical conservation.

     
  • richardmitnick 7:14 am on May 28, 2016 Permalink | Reply
    Tags: , , NatGeo, What Went Wrong on Everest This Season?   

    From NatGeo: “What Went Wrong on Everest This Season” 

    National Geographic

    National Geographics

    May 24, 2016
    Kat Long

    1
    A shot from Garrett Madison’s successful 2016 Everest expedition; Photograph courtesy Garrett Madison from Instagram

    Garrett Madison had high hopes for the 2016 climbing season on Mount Everest.

    The veteran mountaineering guide, who is president and founder of Madison Mountaineering in Seattle, had survived the devastating avalanche at Everest Base Camp, triggered by the magnitude 7.8 earthquake that rocked the Himalayas on April 25, 2015. At least 20 other climbers and Sherpas had perished. The previous year, Madison had watched an avalanche bury 16 Nepali mountain workers in the Khumbu Icefall, and he had helped dig out the victims.

    Madison returned this year “to remember what a beautiful climb it can be” and to lead others toward Everest’s peak. With an international team of 15 Sherpas, seven clients, and four other guides, Madison summited the world’s tallest mountain—for his seventh time—on May 18.

    But they changed their plans for summiting neighboring Lhotse the following day after a Sherpa who was fixing ropes died in a fall. Three more climbers died from altitude-related conditions on Everest, while two climbers went missing and are presumed to have died on the mountain. Many more climbers have been evacuated by helicopter for pulmonary edema, frostbite, and other illnesses.

    Madison spoke with National Geographic Adventure about what’s gone wrong this year, how climbers can ensure their own health and safety, and why choosing the right expedition company for an Everest ascent can be a matter of life and death.

    Why do you think so many climbers have lost their lives this season?

    I don’t know what happened in each case; I’ve only heard rumors. On the day we summited Everest, while we were on our way down, we looked over to Lhotse, which is the nearest peak to Everest. We could see a line of climbers going up the Lhotse face, but as they were going up, they turned around. I couldn’t figure out why they turned around—they were only a few hundred meters from the top.

    [Later we heard] that the Sherpa who died on Lhotse fell at that moment. They’re supposed to use modern safety equipment. No one knows why he fell, but the climbers turned around, most likely because no one continued fixing the ropes.

    That night we had a team talk, and we discussed the fact that there had been a sad accident. We didn’t feel like it was ethical to continue our plan to climb Lhotse the following day. It just didn’t seem right.

    This is speculation, but it’s possible that the Sherpa was piecing together ropes from the last time Lhotse was climbed, in 2013, with new ropes from this season, and perhaps the old rope broke. Nobody knows for sure. But all teams have backed off from climbing Lhotse this year because of the death as well as the uncertain safety of the ropes.

    In past seasons, climbers have died because of sudden storms and unpredictable weather. But weather has been good lately, right?

    The weather been very good this season. But when I think about mountain conditions, I always have to anticipate bad conditions and be prepared for them. There are some things you can’t anticipate—with an icefall or an avalanche, you’re in the wrong place at the wrong time, and it can take you out.

    In general, mountaineering is dangerous because the weather can change suddenly. In 2012, on May 20, which is the day we summited Everest and came down OK, four other climbers behind us on other teams didn’t make it.

    Has the growing number of climbers and different outfitters made Everest less safe?

    What we’re seeing now with recent Western climbers is people getting in over their heads. A lot of climbers are buying into logistics support—that includes permits, maybe a camping setup, some oxygen, some Sherpa support—but they don’t climb together as a true team. They’re individuals going up and down the mountain who are sharing logistics and services. When they get into trouble, they’re on their own. They don’t have [a] support network in place to get them down the mountain to save them.

    That’s a lot of what I’ve seen on Everest, these ragtag groups of amateur climbers who get in over their heads and don’t have a support network, i.e., a professional mountain guide, to make decisions and intervene and try to save them. If I have a client who’s struggling, we try not to get to the point where they are incapacitated and helpless. I try to address problems lower on the mountain and head off issues before they become life threatening. That’s why three of our folks went home [before ascending the summit].

    I feel like a lot of people don’t know when to stop pushing themselves, and they don’t have a guide who can tell them when it’s far enough and what’s too much. It’s like swimming out into the ocean—you don’t want to get so far out that you can’t swim back. I see a lot of amateur climbers without the knowledge and experience pushing themselves so far that they can’t get back down.

    That’s what we saw in 2012: Four climbers couldn’t get back down from summit day to high camp. And that’s what we’re seeing now: Climbers can get down to high camp, but they’re so wiped out that they’re dying that night of cerebral edema or other causes—no one’s really sure what at this point.

    Is that partly because some guides on Everest lack the experience to be able to help their clients if they’re in danger?

    Well, I wouldn’t refer to those individuals as guides. I’d say some group leaders, or business owners who offer services on Everest—they’re not in the business of guiding. They’re providing services and logistics for climbers who want to come up and make their own attempt. So, there really isn’t any guidance there. It’s just, “For x amount of dollars”—which is a lot less than I charge—”we’ll give you the permit, the oxygen, some Sherpa support, some food, everything you need to make an attempt on Everest.” But that’s it.

    For many people, the discount in money is a big deal, and maybe they think it’s the right thing for them. But I think a lot of people get in over their heads, and unfortunately they pay the price. That’s what we’ve seen happen this year.

    As a guide, what is your role in helping your clients when they’re ailing?

    We had a member with pulmonary edema at Camp 2, and we immediately addressed that with medications and supplemental oxygen. We helped him get to Base Camp. Helicopter rescues are available; because of advances in technology we can evacuate people from Camp 2. But we’d rather have them walk down under their own power. That was the end of the expedition for him, though, because it takes a while to recover from pulmonary edema.

    As a guide, my role is dealing with these issues as they come up and helping them get down safely. I’m responsible for my clients’ lives. I feel compelled to ensure that they return to their families and loved ones. That’s a special service that’s part of our expedition. If you sign up with us, that is part of the deal, you’re a part of our team. But on the other end of the spectrum, with these logistics support companies, no one’s looking out for you.

    For some climbers who do have a lot of experience, logistics support is all they need and want. They don’t need a guide. I think that’s fine for some people, but for others, they should have a lot more supervision and guidance so they can get down alive.

    Because there’s no regulation of Everest in terms of guides services, anybody can offer an Everest climb, so there’s a whole spectrum of services and packages available, from the ultra bare-bones, low-end basic program to the ultra high-end program, which is kind of where we are. Climbers have to make educated decisions about who they decide to go with, based on their ability and skill set.

    Do you think in the future there will be more regulation of these companies on Everest?

    Perhaps eventually, but I think it will be a long time coming. The Nepalese government makes money off the number of climbers who decide to try Everest, at $11,000 per foreign climber. If they start to regulate how things are done, I think that will diminish the number of climbers, which diminishes the royalty fee the government gets. Right now, I think they want as many people as possible to climb, and they accommodate every type of service those climbers want. That’s what they’re focused on.

    What has the mood been like between the Western climbers and the Nepali workers there? Some have said they’re dissatisfied with the working conditions on Everest. Are the relationships positive?

    Oh yeah, very good. Relations are great—in fact, the media always blows [any conflict] way out of proportion. It’s not representative at all of the cohesive relationship between foreign climbers and Nepali high-altitude workers.

    I think the economic part is certainly a big reason why Sherpas and other castes in Nepal work in the mountains. They’ve got to feed their families somehow, and it certainly can be a way to do that. But I feel like all the Sherpas that we climb with really enjoy climbing in the mountains, and they love climbing on Everest.

    The reason I started working as a guide in 1999 on Mount Rainier is because I love being in the mountains and sharing that with other climbers. I found a way to do that and actually make a living at it. I remember thinking, Wow, this is as good as it gets! I’m living my dreams, my passion, and I’m getting paid for it.

    I think a lot of the Sherpas, if not all of them, feel the same way. It’s their identity; it’s in their blood. All the guys I climb with on our team are very happy to be climbing, and the camaraderie that we share is really powerful.

    There have been reports of some climbers taking oxygen tanks and tents from other climbers. Have you heard anything about that?

    I heard some rumors. I think what happens is that people get into trouble. People go up high, and they become incapacitated and desperate. They just want to survive. They do whatever they have to, meaning they’ll take somebody’s oxygen, which is cached up high, or they’ll get into someone’s tent, or they’ll take someone’s food. It happens on every mountain all over the world when people get desperate for their lives.

    I think we see it on Everest because there are a lot of people up there for a very short period of time, a very small window. There are a lot of amateur climbers who do get into trouble, and they’re just trying to survive. I mean, if I was in that situation, I’d probably do everything that I could to try to help myself survive. I’ve been fortunate not to have been in that situation.

    If I did need to take someone else’s oxygen or use their tent for shelter, I hope that I would at least be able to let them know. Maybe I could talk to them by radio so they didn’t get there and find their oxygen gone or their tent occupied. I think it’s just a condition of human nature that when people get into trouble, they do whatever they can to survive.

    What could climbers do to increase their own safety and avoid that kind of survival situation?

    I just hope climbers do a lot of research before gong to Everest, and make very informed decisions about the selection of the companies that they go with. I wish [climbers] had some coaching, or some screening process to help them not go so far, or be with somebody who could make decisions for them. It’s just really sad to see people push themselves beyond their ability, become incapacitated, and then not have the support to help them get down. That’s my main thought and takeaway from this season.

    Now that your whole team has summited together, are you planning on retiring from Everest?

    No, I think I’ll come back one more time. Our next big project is K2, and I have to be in Islamabad by June 12 to start that expedition, so for me, it’s one mountain at a time. I’ve got a few climbers who really want to go to Everest next year, so I’m planning on another trip in 2017. I’d like to climb it a few more times.

    But this season, it was great to have a safe, successful, drama-free expedition, especially after the last two years. Sometimes you get lucky.

    See the full article here .

    Please help promote STEM in your local schools.

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    The National Geographic Society has been inspiring people to care about the planet since 1888. It is one of the largest nonprofit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, and the promotion of environmental and historical conservation.

     
  • richardmitnick 10:30 am on December 15, 2015 Permalink | Reply
    Tags: , , , NatGeo   

    From nationalgeographic.com: “Space Rocks Delivered One-Two Punch to Ancient Earth” 

    National Geographic

    National Geographics

    December 15, 2015
    Nadia Drake

    1
    A double asteroid impact in an ancient sea, around 460 million years ago, created two crater remnants near Lockne, Sweden.No image credit

    Scientists link a rare, double impact crater in central Sweden to a 470-million-year-old cataclysm in the asteroid belt.

    Around 470 million years ago, what is now central Sweden was covered in a shallow, ancient sea inhabited by tiny, plankton-like organisms. The placid scene would soon be scarred by one of the largest cataclysms in the last billion years.

    That’s because far away, trouble was brewing. In the main asteroid belt, between Mars and Jupiter, two space rocks were about to collide.

    2
    The inner Solar System, from the Sun to Jupiter. Also includes the asteroid belt (the white donut-shaped cloud), the Hildas (the orange “triangle” just inside the orbit of Jupiter), the Jupiter trojans (green), and the near-Earth asteroids. The group that leads Jupiter are called the “Greeks” and the trailing group are called the “Trojans” (Murray and Dermott, Solar System Dynamics, pg. 107).

    When they slammed together, the collision shattered a 200-kilometer-wide asteroid, sending fragments ricocheting through space—some of which headed right for planet Earth.

    As they traveled through the inner solar system, a portion of these pulverized bits and pieces re-congealed, forming what’s known as a rubble pile asteroid—a type of space object that is exactly what it sounds like. But this rocky swarm wasn’t like most of the others: It had a small, orbiting companion.

    And when that twosome finally plowed into the ancient Swedish sea after a 12-million-year journey, it left a distinctive double crater. Or rather, a double crater that would have been distinctive had the smaller of the two punches not remained hidden until just a few years ago.

    “We are quite convinced that the two craters were formed at the same time,” says Erik Sturkell of the University of Gothenburg, who presented the story Monday at the American Geophysical Union’s annual meeting.

    Double Whammy

    Binary craters aren’t exceptionally common on Earth, even though roughly 15 percent of asteroids in Earth-crossing orbits are thought to have a companion in tow. That’s because “getting two distinct nearby craters that are well dated has been hard to accomplish,” says Bill Bottke of the Southwest Research Institute.

    Today, these two 458-million-year-old craters—Lockne and Målingen—are set amidst forests and farmlands.

    3
    Lockne crater location

    Lockne, the larger of the two, is about 7.5 kilometers across and was created as the rubble pile asteroid collided with Earth. About 16 kilometers away is Målingen, which is just 0.7 kilometers across and made by the smaller companion.

    2
    This double crater on Mars was created by two nearly simultaneous impacts.
    Photograph by NASA/JPL-Caltech/University of Arizona

    Scientists aren’t sure precisely how big the two asteroids were, but they estimate the bigger one was at least 600 meters across, and the smaller was at least 150 meters across. Rubble pile asteroids create craters that are a bit different than the scars left behind by dense, intact impactors.

    “The fragments separate but maintain their trajectory,” Sturkell explains. “The effect on the target area can be compared to that of a shotgun blast rather than a single rifle bullet—a shallow, widespread, but still coherent crater.”

    Cataclysmic Breakup

    The fossilized remains of those hapless, plankton-like organisms helped the team determine how long ago planet Earth had gotten punched.

    But, how did scientists link these craters with that 470-million-year-old cataclysm?

    For starters, the asteroids that gouged these double pockmarks into Earth are a particular type of space rock called an L chondrite—something that is rich in olivine and relatively iron-poor. Sprinkled all over the planet are craters of similar ages, made from the same type of asteroid…and there are too many similarly aged craters, with similar fingerprints, to be explained by normal cratering rates.

    In addition, more than 100 fossilized meteorites have been uncovered from Sweden, China, and Russia. These small, preserved fragments arrived on Earth around the same time, and all except one are L chondrites. What’s more, the fragments bear the signature of an ancient collision that occurred about 470 million years ago—before they barreled into Earth.

    3
    Families of asteroids are created when space rocks collide.
    Illustration by NASA/JPL-Caltech

    The only way that pattern could emerge is if a mishap of cosmic proportions destroyed a parent space rock and sent shrapnel flying through the solar system.

    “It probably went through a supercatastrophic disruption event,” Bottke says, noting that, in addition to the cataclysmic breakup, research suggests the parent asteroid happened to be in a spot where gravitational nudges from Jupiter could efficiently send fragments flying toward Earth.

    “A lot of this material was able to get to Earth very quickly,” he says.

    But not all the fragments left their home: Today, the shards from that collision that still live in the main belt are known as the Gefion family. “There is a lot of cool stuff related to this particular event,” Bottke says. “The question is whether this event had other implications, say for life on Earth.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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    The National Geographic Society has been inspiring people to care about the planet since 1888. It is one of the largest nonprofit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, and the promotion of environmental and historical conservation.

     
  • richardmitnick 4:02 pm on September 8, 2015 Permalink | Reply
    Tags: , , NatGeo   

    From NatGeo: “Is Earth as Special as We Think?” 

    National Geographic

    National Geographics

    September 07, 2015
    Maya Wei-Haas

    You might be surprised at some of the factors that made Earth a cozy place for life to set up shop.

    1
    Earth’s sunlit face captured this summer by cameras aboard the DSCOVR satellite. This pretty blue marble may be ripe for life, but it may not be so special. Photograph by NASA

    Maybe Earth isn’t so special. “We could have easily been standing on Venus having this conversation,” says Mark Jellinek, a geologist who studies how planets form.

    I envision standing under Venus’ thick atmosphere of greenhouse gases, broiling on the dusty planet’s surface. Temperatures there soar high enough to melt lead. Sure, Venus and Earth are often said to be the most comparable planets—similar in size, makeup, and distance from the sun—but “easily” seems like a stretch.

    Or maybe not. According to recent research, if we restart the “experiment” of our solar system, seemingly insignificant early changes—like internal heat, climate, or water content—could completely reroute planetary history, says Adrian Lenardic, a planetary scientist at Rice University.

    Maybe a rewind would lead to life on Venus instead of Earth; or maybe life on neither. After all, scientists are now learning, there might be much more to our balmy climate than Earth’s perfectly-sized bulk circling our fiery sun at just the right distance. We cannot ignore a planet’s history: “How it got to be where it is; how it started out; how it evolved over time,” Lenardic explains.

    On Earth, that tipping point could have been a period of intense meteorite impacts, argues Jellinek, of the University of British Columbia, in a recent study in the journal Nature Geoscience. These impacts would have helped exfoliate heat-producing radioactive elements on Earth’s surface, allowing the planet to cool, and meanwhile jump starting a driver of Earth’s internal thermostat, known as plate tectonics.

    Habitability is also not permanent.

    On Mars, the river channels and dried lake beds discovered there suggest the now-dusty planet had an ancient watery past. Perhaps life once creeped in those waters. And who knows? “Venus could have been a very habitable planet for quite some time,” says Lenardic. (Learn fun facts about Venus.)

    So what is the latest recipe for a habitable planet? The ingredients might surprise you.

    2
    Venus is similar in size and distance from the sun, making it one of the most comparable planets to Earth. But unlike our humble home, Venus’s surface sizzles at temperatures over 880 degrees Fahrenheit (470 degrees Celsius).
    Photograph by NASA

    Oven Temperature

    To host an Earth-like menagerie and luscious vegetation, scientists have long said that planets need to fall within the so-called habitable zone. This swath of space exists at a “Goldilocks” distance from a star, where a planet is warmed just enough for liquid water to flow.

    “At some level, no one argues with that,” says Lenardic. The idea is rather intuitive: Approach a sizzling star too closely, and the planet incinerates; move too far away and the world freezes over.

    But it’s more complicated than that. For instance: how far from a star is the habitable zone? That depends how hot the star is.

    And then there’s the size of the planet. Too small and the planet’s atmosphere escapes its gravity and is lost to space. Too large and the atmosphere becomes thick and “puffy,” says Cowan, with potential to become a freezing giant like Neptune and Uranus.

    Discoveries from NASA’s Kepler telescope—launched in 2009 to seek out worlds ripe for life—show that a planet up to 1.5 Earth radii may be habitable, says Nick Cowan, a planetary scientist at McGill University.

    NASA Kepler Telescope
    Kepler

    Of the 1,030 planets (and counting) Kepler has identified, a handful meet the Goldilocks standards for both size and distance, with Kepler 452b perhaps the most similar to Earth.

    But these qualities alone do not make a habitable place. And a growing cohort of scientists believe the recipe is much more complex.

    3
    Kepler 186f was the first Earth-like planet identified in the habitable zone of its star. Just 1.1 times the size of Earth, this planet could support liquid water on its surface, according to experts.
    Illustration by NASA

    A Perfect Crust

    Earth’s outer surface is flexible: It pulls and pushes, driven by the churning inner Earth, known as mantle convection. Sometime in geologic history—it is much debated when—this tug-of-war cracked the surface into a series of creeping plates.

    But why do they matter? The plates are part of Earth’s thermostat. Their collisions stoke volcanic eruptions, which “burp” the greenhouse gasses necessary for atmosphere. And as Earth gets “hot under the collar,” the collisions pull extra gas back down into its depths, says Cowan.

    Earth is the only planet known with a system of actively creeping plates, a process called tectonics, and according to Jellinek, it is what truly sets us apart.

    3
    The tectonic plates of the world were mapped in the second half of the 20th century.

    Recent computer simulations show that even on Mars, with the perfect mix of gases in the sky, an active tectonic system would leave the surface of the planet quite livable, says James Kasting, a planetary scientist at Penn State, who helped shape the modern idea of a habitable zone.

    All The Right Stuff

    But what causes the plates to move in the first place? It’s all in the ingredients.

    When planets first form from a condensing cloud of dust, they sizzle with heat from the molten inner core, and radiate heat from radioactive surface elements. When hot, the surface bends and flexes. But like a candy bar in the freezer, the planet toughens as it cools, and when frozen threatens to break your teeth before it yields.

    Jellinek argues that the Earth eventually arrived at a happy temperature, cool enough for the crust to break, thanks to an intense meteorite shower that rained down on our infant planet for its first 20-30 million years, shaving some heat-producing radioactive elements from the planet’s surface.

    Venus may be an example of what happens when temperatures run high, he says. Instead of Earth’s minutely creeping plates, Venus’ surface is too hot and “runny” to break. Eventually heat builds up until “the whole surface caves in on itself,” says Jellinek. Catastrophic volcanism ensues, forcing the planet into a hothouse state.

    But if Venus had been the target of the early meteorite shower instead of Earth, would that have changed the history of life as we know it? According to Jellinek this may be the case. But not all scientists agree. Kasting argues that our neighbor Venus is just too close to the sun to sustain liquid water.

    Tiny and freezing, Mars is the other extreme: its surface never broke.

    When looking at ingredients, we also can’t stop skin-deep. The roiling convection in the inner earth drives the shifting plates. So if the planet’s minerals are too dense, they’ll “gum up your mantle convection and slow it down,” says Cayman Unterborn, a graduate student at Ohio State University.

    Remember the diamond planet? That dense, carbon filling prevents convection from ever starting, says Unterborn.

    Testing the Recipe

    Which of these factors is most important for habitability? It’s tough to say.

    The most crippling problem in creating a recipe for life is the lack of Earth-twins to study. “You’re testing against this solar system and assuming it is universal,” says Lenardic.

    Until NASA’s Kepler spacecraft launched in 2009 to seek out habitable worlds, scientists assumed that our solar system was a blueprint for other worlds.

    What we found was that “our solar system is a freak,” says Cowan. “Eventually we might discover that some of the stuff we found based on Earth is just not true,” he says.

    For instance, take Earth’s magnetic field, which is widely thought to help hold onto our atmosphere. Though it probably helps shield us from solar winds and flares, is it truly important for habitability? The evidence is lacking, according to Jellinek and Lenardic.

    The answers lie out there, somewhere, in the star-studded galaxy.

    A world of new possibilities is on the horizon. NASA’s James Webb telescope will launch in 2018—but even this advanced scope will be limited to searching in our backyard, says Cowen, about ten light-years from Earth.

    NASA Webb Telescope
    Webb

    To really get to the nitty-gritty details, we need to turn to the “next, next generation” of telescopes, says Cowen: HDST, LUVOIR, and ATLAST to name a few. These mega-scopes—as wide as five buses end to end—could squint at Earth-twin candidates much farther away, even roughly mapping clouds, continents, and oceans on their surface.

    Though a launch before the 2030s is unlikely, the possibilities are tantalizing.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The National Geographic Society has been inspiring people to care about the planet since 1888. It is one of the largest nonprofit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, and the promotion of environmental and historical conservation.

     
  • richardmitnick 7:23 pm on July 19, 2015 Permalink | Reply
    Tags: , , , NatGeo   

    From NatGeo: “The Kepler Mission – Finding the Next Earth…” Video 

    National Geographic

    National Geographics

    This is an excellent video about Kepler and includes a section on the James Webb Space Telescope which will search in the infrared.

    Join astronomers in a race to find a planet that can sustain life. Amid all the space in the universe, is there another world like ours? Astronomers studying.

    This is an excellent video about Kepler and includes a section on the James Webb Space Telescope which will search in the infrared.

    NASA Webb Telescope

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The National Geographic Society has been inspiring people to care about the planet since 1888. It is one of the largest nonprofit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, and the promotion of environmental and historical conservation.

     
  • richardmitnick 7:39 am on March 27, 2015 Permalink | Reply
    Tags: , , NatGeo   

    From NatGeo: A Hundred Million Stars in Three Minutes 

    National Geographic

    National Geographics

    In January 2015, NASA released the largest image ever of the Andromeda galaxy, taken by the Hubble telescope.

    NASA Hubble Telescope
    NASA/ESA Hubble

    Totaling 1.5 billion pixels and requiring 4.3 gigabytes of disk space, this photo provides a detailed glimpse at the sheer scale of our nearest galactic neighbor. By zooming into the incredible shot, filmmaker Dave Achtemichuk creates an unforgettable interactive experience.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The National Geographic Society has been inspiring people to care about the planet since 1888. It is one of the largest nonprofit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, and the promotion of environmental and historical conservation.

     
  • richardmitnick 1:30 pm on March 21, 2015 Permalink | Reply
    Tags: , , NatGeo   

    From NatGeo: “A Hundred Million Stars in 3 Minutes” 

    National Geographic

    National Geographics

    In January 2015, NASA released the largest image ever of the Andromeda galaxy, taken by the Hubble telescope. Totaling 1.5 billion pixels and requiring 4.3 gigabytes of disk space, this photo provides a detailed glimpse at the sheer scale of our nearest galactic neighbor. By zooming into the incredible shot, filmmaker Dave Achtemichuk creates an unforgettable interactive experience.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The National Geographic Society has been inspiring people to care about the planet since 1888. It is one of the largest nonprofit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, and the promotion of environmental and historical conservation.

     
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