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  • richardmitnick 3:21 pm on April 30, 2019 Permalink | Reply
    Tags: "What ‘Rock Tides’ Reveal About Movements of the Earth", , Discover Magazine,   

    From Discover Magazine: “What ‘Rock Tides’ Reveal About Movements of the Earth” 

    DiscoverMag

    From Discover Magazine

    April 30, 2019
    Rebecca Boyle

    1
    Rock formations in the Atacama Desert. (Credit: Phil Whitehouse via Flickr)

    Earth’s interior teems with movement and heat, a characteristic that manifests in memorable fashion as volcanoes and earthquakes. But even Earth’s more seemingly stable solid rocks move, too. Understanding just how rocks respond when they are pushed and pulled by natural forces, such as tectonic activity, or human-caused forces, like hydraulic fracturing, can make mining, construction, natural gas production and other projects safer. It can also improve geological monitoring in fault zones.

    Now, a new technique uses the fingerprints of the moon, sun and surf to pin down rock behavior.

    Rocks feel solid, but their slight imperfections and cracks give them elastic tendencies, which change when the rock is under some sort of external stress, whether from heat or water or the tidal pull of the moon and sun, said Nicholas van der Elst, a seismologist at the U.S. Geological Survey who was not involved in the new work.

    “For the most part, rocks are elastic in that they change shape when you apply force, but they recover completely when the force is removed. There’s also a small amount of squishy deformation, which takes some time to recover,” he said. These shape changes are captured in a measurement called strain, which can give direct information about rock properties like strength and stiffness. But strain is difficult to measure away from Earth’s surface, van der Elst said.

    Scientists can expose small samples to titanic pressure and heat in lab settings or conduct field measurements of induced seismic activity — like mini-quakes set off by explosive charges — but both these approaches have key limitations such as high costs or questions about how well they replicate the natural environment.

    In the new study [no citation], researchers in Germany were able to link rock strain to seismic velocity changes, using a long-term seismometer station. The seismic velocity measurements serve as a proxy for strain, van der Elst said. And instead of having to squeeze the rock themselves, the scientists let the moon and sun do it for them.

    Christoph Sens-Schönfelder of the GFZ German Research Centre for Geosciences in Potsdam and Tom Eulenfeld of the University of Jena in Germany sifted through 11 years of data from a seismic monitoring station in the Atacama Desert of northern Chile. The Patache station rests on a hillcrest along the Pacific coast, less than 2 kilometers from the shore, in an area where nothing grows save for microbes living in salt rock. The only signs of life are occasional lichen flakes and seabird burrows, and distant lights from copper and salt mines sprinkled through the Atacama. The station keeps tabs on seismic activity in an area known for earthquakes. But it can detect more sensitive ambient movements, too.

    As the moon and sun perpetually tug on Earth, the tides slosh water back and forth all over the planet, causing shorelines to shrink or swell. But not only the water moves: Earth’s insides are strained, too. In this way, the tides serve as a controlled deformation experiment, Sens-Schönfelder said.

    He and Eulenfeld analyzed the Patache recordings for seismic echoes — waves that struck the detector, bounced off the surrounding rock, and then hit the detector again. When they plotted the echo patterns, they could see variations related to the pounding of surf from the Pacific Ocean, a couple kilometers away. They also noticed patterns that repeated every day or half day. They realized the half-day oscillations actually represented two signals, corresponding to 12.42 and 12.56 hours. The 12.42-hour period precisely matches the lunar tide, while the longer oscillation matches the elliptical orbit of Earth’s satellite. The elliptic orbit is the same effect that leads to an occasional “supermoon” when the moon is closer to Earth.

    “We were surprised to see the effects of the tides so clearly,” Sens-Schönfelder said. What’s more, the rocks don’t respond instantaneously, meaning the rock takes some time to relax after it is pushed and pulled.

    The researchers also found something unexpected: The sun was producing a greater effect on the rock tides than they thought it would. Though the sun does contribute to Earth’s tides, its pull is greatly outshone by that of the moon — so why would the one-day seismic signal be so strong? The researchers decided it was related to the sun’s warmth, heating the surface during the day, only to disappear at night and allow the surface to cool and contract.

    “The most surprising thing was that we found an interaction between the tidal and thermal effects. They modulate each other and cause distinct peaks in the spectrum,” Sens-Schönfelder said. The researchers are not sure how these two signals are interacting.

    Van der Elst said the rock deformation and relaxation, or “squishiness,” is faster than the timescales of the tides, which makes it a difficult measurement outside of a controlled lab setting. “It’s a real achievement to have measured this rock property in the field with such precision,” he said.

    Sens-Schönfelder said the researchers were able to separate the effects of temperature and tides by looking at the cycles of the sun and moon — “and the fact that the moon does not cause any heating,” he added. “Disentangling both effects from the sun alone would be much more difficult.”

    Still, the results are precise enough that others should be able to perform similar measurements almost anywhere, and use the signals of the moon and the sun to measure the pulse of the Earth.

    See the full article here .

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  • richardmitnick 8:16 am on April 26, 2019 Permalink | Reply
    Tags: , , , , , Discover Magazine, LIGO Detects Gravitational Waves From Another Neutron Star Merger,   

    From Discover Magazine: “Breaking: LIGO Detects Gravitational Waves From Another Neutron Star Merger” 

    DiscoverMag

    From Discover Magazine

    April 25, 2019

    1
    An artist’s illustration of two colliding neutron stars. (Credit: NASA/Swift/Dana Berry)

    For just the second time, physicists working on the Laser Interferometer Gravitational-Wave Observatory (LIGO) have caught the gravitational waves of two neutron stars colliding to form a black hole.

    The ripples in space time traveled some 500 million light-years and reached the detectors at LIGO, as well as its Italian sister observatory, Virgo, at around 4 a.m. E.T. on Thursday, April 25. Team members say there’s a more than 99 percent chance that the gravitational waves were created from a binary neutron star merger.


    Shot at a Kilonova

    In the moments after the event, a notice went out alerting astronomers around the world to turn their telescopes to the heavens in hopes of catching light from the explosion, which may have formed an extreme object called a kilonova. Kilonovas are 1,000 times brighter than normal novas, and they create huge amounts of heavy elements, like gold and platinum. That brightness makes it easy for astronomers to find these events in the night sky — provided they’ve been given a heads-up and location from LIGO first.

    LIGO’s twin L-shaped observatories — one in Washington state and one in Louisiana — work by shooting a laser beam down the long legs of their “L.”

    Caltech/MIT Advanced aLigo Hanford, WA, USA installation

    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Their experimental setup is precise enough that even the minimal disturbance caused by a passing gravitational wave is enough to trigger a slight change in the laser’s appearance. It made the first ever detection of gravitational waves in 2016. Then it followed up by detecting merging neutron stars in 2017.

    Scientists use any slight delays between when signals reach the detectors to help them better triangulate where the waves originated in the sky. But one of LIGO’s twin detectors was offline Thursday when the gravitational wave reached Earth, making it hard for astronomers to triangulate exactly where the signal was coming from. That sent astronomers racing to image as many galaxies as they could across a region covering one-quarter of the sky.

    And instead of finding one potential binary neutron star merger, astronomers turned up at least two different candidates. Now the question is which, if any, are related to the gravitational wave that LIGO saw. Sorting that out will require more observations, which are already happening around the world as darkness falls.

    “I would assume that every observatory in the world is observing this now,” says astronomer Josh Simon of the Carnegie Observatories. “These two candidates (they’ve) found are relatively close to the equator, so they can be seen from both the Northern and Southern Hemisphere.”

    Simon also says that, as of Thursday afternoon in the United States, telescopes in Europe and elsewhere should be gathering spectra on these objects. His fellow astronomers at the Carnegie Observatories plan to turn their telescopes at Chile’s Las Campanas Observatory to the event as soon as darkness falls Thursday night.

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high

    History-Making Merger

    LIGO’s first detection of a neutron star merger came in August of 2017, when scientists detected gravitational ripples from a collision that occurred about 130 million light years away. Astronomers around the world immediately turned their telescopes to the collision’s location in the sky, allowing them to gather a range of observations from across the electromagnetic spectrum.

    The 2017 detection was the first time an astronomical event had been observed with both light and gravitational waves, ushering in a new era of “multi-messenger astronomy.” The resulting information gave scientists invaluable data on how heavy elements are created, a direct measurement of the expansion of the universe and evidence that gravitational waves travel at the speed of light, among other things.

    This second observation appears to have been slightly too far away for astronomers to get some of of the data they had hoped for, such as how nuclear matter behaves during the intense explosions.

    2
    Researchers at the Laser Interferometer Gravitational-wave Observatory (LIGO) in Livingston, La., recently upgraded the massive instrument. (Ernie Mastroianni/Discover)

    And astronomers still aren’t sure whether the first detection they made came from a typical neutron star merger or whether it was more exotic. But to figure that out, they’d need observations as early as possible, and precious hours have already passed.

    “After the first event, it was clear that a lot of the action was going on immediately after the explosion, so we wanted to get observations as soon as possible,” Simon says. In this case, with one of LIGO’s detectors down, they couldn’t find the object as quickly as they did in 2017.

    So far, one difference is that, unlike last time, astronomers haven’t spotted any signs of gamma-ray bursts, says University of Wisconsin-Milwaukee physicist Jolien Creighton, a LIGO team member.

    But regardless, having additional observations should help us learn more about these extreme cosmic collisions.

    “It gives us a much better handle on the rate of such collisions,” says Stefan Ballmer, associate physics professor at Syracuse University and LIGO member. “The upshot: if we just observe a little longer we will get the strong signal we are hoping for.”

    LIGO just started its third observing run a few weeks ago. And, in the past, these detections were kept a closely guarded secret until they were confirmed, peer-reviewed and published. But with this latest round, LIGO and Virgo have opened their detections up to the public. In this latest run, LIGO has also already detected three potential black hole collisions, bringing its total lifetime haul to 13.

    See the full article here .

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  • richardmitnick 4:37 pm on April 18, 2019 Permalink | Reply
    Tags: "Tiny Star Flares 10 Times Brighter Than the Sun", , , , , Discover Magazine, ESO Next Generation Transit Survey (NGTS) telescope, The tiny star bears the unwieldly name ULAS J224940.13-011236.9   

    From Discover Magazine: “Tiny Star Flares 10 Times Brighter Than the Sun” 

    DiscoverMag

    From Discover Magazine

    April 18, 2019
    Korey Haynes

    1
    This illustration shows an extremely active, tiny star. (Credit: University of Warwick/Mark Garlick)

    On August 13, 2017, the Next Generation Transit Survey (NGTS) telescope spotted an intense solar flare from a tiny star barely bigger than Jupiter.

    ESO Next Generation Transit Survey, an array of twelve 20-centimetre telescopes at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    But despite this sun’s diminutive size, the flare gave off as much energy as 80 billion megatons of TNT. That’s 10 times as powerful as the strongest flare ever observed on our own sun. It’s also the coolest star ever observed to give off such a hot flare, and the spectacular outburst is teaching astronomers the power of small stars.

    Light it Up

    The tiny star bears the unwieldly name ULAS J224940.13-011236.9 and sits 250 light-years from Earth. In fact, classified as an L dwarf, it only barely qualifies as a star. “Any lower in mass and it would definitely be a brown dwarf,” said James Jackman, lead author of the discovery paper, in a press release. Brown dwarfs are sub-stars, too big to count as a planet, but too small to sustain the nuclear fusion in their cores that defines a star. Most telescopes, including NGTS, can’t even see dim little ULAS J2249−0112 during normal times. But the flare lit up the star clearly in the data, boosting it to 10,000 times its normal brightness. Jackman and his team published their findings April 17 in the Monthly Notices of the Royal Astronomical Society Letters.

    Because flares last only a few minutes – this one was visible for 9.5 minutes – it takes luck or a special instrument like NGTS, which looks at wide patches of the sky over quick time intervals, to spot such phenomena.

    2
    NASA’s Solar Dynamics Observatory caught an X2.0-class solar flare erupt off our own sun in 2014. (Credit: NASA/SDO)

    NASA/SDO

    Astronomers have spied powerful flares from tiny stars before, but they are rare. In general, smaller stars like this one have fewer, less powerful flares than larger dwarf stars. ULAS J2249−0112 is just the second L-dwarf flare ever seen from the ground and the sixth L-dwarf to be seen flaring at all, and this flare is the brightest yet seen in an ultra-cool star. Astronomers weren’t sure until now that such small, cool stars had enough energy in their chromospheres, or outer layers, to support such powerful flares.

    But the find shows that even tiny stars can pack quite the punch.

    See the full article here .

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  • richardmitnick 1:14 pm on April 17, 2019 Permalink | Reply
    Tags: "What Is the Most Dangerous Volcanic Hazard?", 1 Pyroclastic Flows (also known as hot ash flows or pyroclastic density currents), 2. Ash Fall, 3. Lahars (also known as volcanic mudflows), 4. Tsunamis, 5. Lava Flows, , Discover Magazine,   

    From Discover Magazine: “What Is the Most Dangerous Volcanic Hazard?” 

    DiscoverMag

    From Discover Magazine

    April 17, 2019
    Erik Klemetti

    1
    The 2015 eruption of Calbuco in Chile, with the city of Puerto Montt in the foreground. Wikimedia Commons.

    Volcanoes can be pretty dangerous. Thankfully, we’ve gotten better over the last half century at getting people out of the way of volcanic hazards. However, many hundreds of millions of people still live close enough to volcanoes to feel the impact of an eruption — especially when the volcano decides to have a spectacular eruption.

    There are a lot of misconceptions out there about what the most dangerous aspects of a volcanic eruption might be. I think many people picture lava flows cascading down the sides of a volcano and imagine that the searing rivers of molten rock are what will do you in.

    Well, they’re right in one respect: stay in the path of a lava flow and you will likely cease being alive. But luckily, lava flows are actually pretty easy to avoid as they move rather slowly, rarely up to ~30 km/hr (20 mph) but more likely less than 8 km/hr (5 mph). You can probably out-walk most lava flows.

    So, what is it that makes volcanoes so deadly if it isn’t the copious volumes of lava they can produce? Here’s a little countdown of what I think are the most dangerous volcanic hazards based on the number of deaths associated with them, the potential for damage to houses and infrastructure, the frequency with which they occur and the difficulty of avoiding them.

    5. Lava Flows: After all that pre-amble about lava flows, here they are! Though lava flows may not cause many fatalities, the potential damage to infrastructure and homes is very high. Lava flows are also very common at certain types of volcanoes, so with that combination of frequency and destructiveness, we need to take lava flows seriously. The 2018 eruption at Kīlauea is a perfect example, where there were no fatalities but over 700 homes destroyed. However, the lava can be deadly in rare cases. This can happen when the composition and temperature of the lava means it is especially runny, so it travels fast. An eruption of Nyiragongo in the Democratic Republic of the Congo produced lava flows that moved through the city of Goma killing dozens.

    2
    Lava flow from the 2018 eruption of Kīlauea in Hawaii. USGS/HVO.

    4. Tsunamis: Tsunamis can be generated by geologic events other than eruptions — in fact, they are more common with earthquakes. However, volcanoes can produce these deadly ocean waves when part of the volcano collapses during an eruption. Most recently, the 2018 eruption of Anak Krakatau killed over 420 people when most of the relatively-small cinder cone collapsed during an eruption. The predecessor to Anak Krakatau — Krakatau itself — generated a massive 30-m tsunami when it collapsed into a caldera in 1883. That eruption and tsunami killed over 35,000 people along the Sunda Strait in Indonesia. Other volcanoes, like Unzen in Japan, have had deadly tsunamis as well.

    3
    Anak Krakatau not long after the 2018 collapse that generated a deadly tsunami. Alex Gerst – ISS/ESA.

    3. Lahars (also known as volcanic mudflows): You might be tempted to think mudflows couldn’t be too deadly, but these rivers of volcanic (and other) debris generated by snow and ice melt during an eruption or heavy precipitation on a volcano are very hazardous. Lahars have the consistency of wet cement and they flow at tens of kilometers per hour down river valleys. Many times, that allows for enough forewarning to escape if you are downriver, but the 1985 eruption of Nevado del Ruiz in Colombia proved that a lack of preparation can lead to over 20,000 deaths. Due to their density, lahars can destroy infrastructure and homes and bury towns (and people) rapidly. They can happen without an eruption, such as when old volcanic debris gets mobilized during heavy rain or snow melt. That’s why volcanoes like Mt. Rainier have lahar warning systems for the towns downslope from the volcano.

    4
    The town of Chaitén buried by lahar deposits from the 2008 eruption of Chaitén in Chile. Flickr.

    2. Ash Fall: It might look like snow, but volcanic ash is nasty. It’s made of tiny pieces of volcanic glass and other debris, so if you can imagine inhaling broken glass, well, you get the idea. It can be carried for potentially thousands of kilometers depending on the size of the eruption and winds. When it piles up, the ash can destroy roofs, contaminate water, annihilate vegetation and even block out the sun. If you are unlucky enough to breathe in the ash, it will coat the inside of your lungs and cut them up, people can die from the silica cement in their lungs and/or from more or less drowning in those fluids. Volcanic ash in the atmosphere can disable jet engines, so flying through even dilute ash clouds is a bad idea. Ash fall can be persistent as well, with a volcano producing ash that might accumulate a few millimeters or centimeters thick for months to years — and as I mentioned with lahars, you can get the ash moving again with heavy rains or even with winds.

    5
    Buildings destroyed by ash fall at Clark Air Base in the Philippines during the 1991 eruption of Pinatubo. USGS.

    1 Pyroclastic Flows (also known as hot ash flows or pyroclastic density currents): If you’re looking for that one-two punch of destruction and potential for major fatalities, it is hard to beat a pyroclastic flow. Imagine a cloud of hot volcanic gases and debris that ranges in size from tiny specks of ash to massive boulders, all moving down a volcano at over 300 km/hr (190 mph) at a temperature over 600ºC. You, your city, everything is toast. Some of the deadliest pyroclastic flows buried Pompeii in 79 A.D., wiped St. Pierre off the map during the 1902 eruption of Pelée, erased towns surrounding El Chichón in Mexico in 1982, snapped enormous trees as they flattened forest at Mount St. Helens in 1980 and buried entire valleys during the 1912 eruption of Novarupta in Alaska and 1991 eruption of Pinatubo. They are landscape-altering events that occur in mere moments. If you don’t get buried in the hot debris, you’ll be sizzled to death in the volcanic gases or choke on the ash.

    6
    Pyroclastic flow from Mount St. Helens in June 1980. USGS.

    Pyroclastic flows are generated a number of ways: a collapsing ash column from an eruption, a collapsing lava dome at the top of a volcano or an explosive eruption that moves sideways. Some recent research on pyroclastic flows suggests that they move so far and fast because they travel on a bed of air like a hovercraft. This allows them to travel tens of kilometers from the volcano and “leap” over obstacles. Even seasoned volcanologists can be caught off guard by unpredictable travel of pyroclastic flows. A 1991 eruption of Unzen killed Maurice and Katja Krafft, famed volcano documentarians, along with USGS volcanologist Harry Glicken. Pyroclastic flows need to be taken seriously because you will not survive being in the path of these clouds of volcanic fury.

    See the full article here .

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  • richardmitnick 9:21 am on March 31, 2019 Permalink | Reply
    Tags: "Here’s What Scientists Hope to Learn as LIGO Resumes Hunting Gravitational Waves", , , Discover Magazine, , Kagra gravitational wave detector,   

    From Discover Magazine: “Here’s What Scientists Hope to Learn as LIGO Resumes Hunting Gravitational Waves” 

    DiscoverMag

    From Discover Magazine

    March 29, 2019
    Korey Haynes

    After a year of downtime to perform hardware upgrades, the Laser Interferometer Gravitational-Wave Observatory (LIGO) is ready for action and will turn on its twin detectors, one in Washington state and the other in Louisiana, on April 1. This time, it will also be joined by the Virgo collaboration based out of Italy, and possibly also by the KAGRA detector in Japan later in the year.


    VIRGO Gravitational Wave interferometer, near Pisa, Italy


    Caltech/MIT Advanced aLigo Hanford, WA, USA installation


    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger

    Gravity is talking. Lisa will listen. Dialogos of Eide

    ESA/eLISA the future of gravitational wave research

    Localizations of gravitational-wave signals detected by LIGO in 2015 (GW150914, LVT151012, GW151226, GW170104), more recently, by the LIGO-Virgo network (GW170814, GW170817). After Virgo came online in August 2018


    Skymap showing how adding Virgo to LIGO helps in reducing the size of the source-likely region in the sky. (Credit: Giuseppe Greco (Virgo Urbino group)

    Combined with the hardware upgrades, scientists expect these updates to allow LIGO to spot more observations and trace their origins more clearly. In 2016, LIGO made history with the first-ever direct detection of gravitational waves, produced in that case by colliding black holes.

    3
    A wrinkle in space-time confirms Einstein’s gravitation. Credit: Astronomy Magazine

    New Hardware

    “Most of the upgrades have been increasing the amount of laser power that’s used,” says Jolien Creighton, a University of Wisconsin Milwaukee professor and member of the LIGO collaboration. “That’s improved the sensitivity.” Each of LIGO’s detector is a giant L-shape, and instruments wait for passing gravitational waves to distort the length of each arm of the detector, measuring them by bouncing lasers across their lengths. Researchers are also pushing the physical limits of the detector, which Creighton says is limited by the quantum uncertainly principle. To increase sensitivity even more, the experiment will “quantum squeeze” the laser beam. “This puts it into an interesting quantum mechanical state that lets us detect the arm length of the detector,” to even greater precision than before.

    The additional detectors from Virgo and KAGRA will let researchers triangulate sources on the sky more accurately than the two LIGO detectors can manage alone. Virgo will be online throughout the whole next year of observing, while KAGRA is still being commissioned, but could join as early as fall of 2018 [? Don’t ask me, I did not write this].


    KAGRA gravitational wave detector, Kamioka mine in Kamioka-cho, Hida-city, Gifu-prefecture, Japan

    New Detections

    The upgraded LIGO will look for many of the same events it did before: collisions of two black holes, two neutron stars, or mixtures of both. Creighton says he’s personally excited about binary neutron stars, because those systems are the mostly likely to have counterparts that can be observed by traditional observatories at the same time, at wavelengths from radio waves to visible light to gamma rays. “Seeing more of those will give us more insight into the natures of gamma ray bursts and the formation of elements of the universe,” Creighton says. He points out the mergers can also teach astronomers how matter behaves when crunched down denser than an atom’s nucleus, a state that only exists in neutron stars. “The way we can probe that is by watching the interactions of neutron stars just before they merge. It’s a fundamental nuclear physics lab in space.”

    Creighton says he’s confident they’ll see many more events from colliding black holes, a phenomenon LIGO has already observed more than once. “We’re hoping to see a binary of a neutron star and a black hole,” Creighton says, but since no one has ever seen one, it’s hard to calculate how common or rare they are, and what the odds are of LIGO spotting one in the next year. But LIGO will be peering farther into the universe, “so even rare things should start to be observed,” Creighton says.

    Other possible objects LIGO might spy would be a supernova explosion, or an isolated neutron star spinning rapidly. “If it’s not perfectly symmetric, then that rotating distortion would produce gravitational waves,” Creighton says. The signal would be weak but constant, so the longer LIGO looks, the more likely finding a source like this becomes. Even more subtle would be a skywide, low-level reverberation from the Big Bang, similar to the microwave background that exists in radiation, and which researchers suspect might also exist in gravitational waves.

    “There’s always the hope that we’ll see something entirely unexpected,” Creighton adds. “Those are the things that you really can’t predict in any way.”

    LIGO’s upcoming run will last for roughly a year, at which point it will undergo more upgrades for a year, and then hopefully start the cycle over again, prepared to witness even more spectacular and invisible events.

    See the full article here .

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  • richardmitnick 3:21 pm on March 19, 2019 Permalink | Reply
    Tags: , Bezymianny volcano, Discover Magazine, , Sheveluch volcano, The Kamchatka Peninsula in far eastern Russia is one of the most active volcanic areas on Earth.,   

    From Discover Magazine: “Two Russian Volcanoes Erupting in Tandem” 

    DiscoverMag

    From Discover Magazine

    March 19, 2019
    Erik Klemetti

    1
    The long ash plume from Bezymianny seen stretching across the Pacific Ocean on March 17, 2019 by Terra’s MODIS imager. The smaller plume from Sheveluch can be seen just above the darker Bezymianny plume. NASA.

    NASA Terra MODIS schematic

    NASA Terra satellite

    The Kamchatka Peninsula in far eastern Russia is one of the most active volcanic areas on Earth. It isn’t surprising to find multiple volcanoes erupting each week and this week is no exception. Two side-by-side volcanoes — Bezymianny and Sheveluch — were simultaneously erupting over the weekend (above). The eruption at Bezymianny was big enough to cause some air travel over the peninsula to change their flight paths to avoid the ash, but that’s business-as-usual in Kamchatka.

    2
    Bezymianny volcano

    3
    Sheveluch volcano

    Kamchakta is remote and fairly sparsely populated. Only about 1600 people live within 30 kilometers of Sheveluch and only 47 within 30 kilometers of Bezymianny. The monitoring of the volcanoes in Kamchatka is done by KVERT (Kamchatka Volcanic Eruption Response Team) with help from the Alaska Volcano Observatory. The low hazard for people on the ground is balanced by higher hazard for people in aircraft that traverse the airspace over and near the peninsula.

    Most of this traffic is from the Americas and Europe to eastern Asia, so someone flying from Seattle to Hong Kong might be in the path of an erupting volcano even if their destinations are thousands of kilometers from the action. Ash is very bad for jet aircraft, so avoiding ash plumes is vital, which means the Volcanic Ash Advisory Centers have to use satellite data and ground observations to warn airlines and air traffic controllers about potential ash plumes.

    That makes Kamchatka a real problem. Not only are the volcanoes remote and challenging to monitor, but they also tend towards explosive eruptions. Case in point the eruption of Bezymianny on March 16. That blast sent ash to 15 kilometers (50,000 feet), well above where commercial air traffic flies. The ash drifted east over the Pacific Ocean and ended up causing flights in the Aleutians as far east as Unalaska (2000 kilometers away!) to be cancelled. Trans-Pacific flights had to follow some different routes as well to avoid the ash.

    Although Kamchatka doesn’t have a lot of people to watch the volcanoes erupt, KVERT does operate a bunch of webcams to watch the eruptions. Bezymianny has three pointed at the volcano as does Sheveluch. This means you can see some of their giant explosions while sitting across the globe. Even at night you can spot activity, like a glowing lava dome on Sheveluch (below). Both the eruption at Bezymianny and Shiveluch are caused by lava domes forming and then getting destroyed as the pressure building underneath the dome gets to high, causing the dome to “pop” like a cork (if the cork also shattered into tiny pieces). The sticky lava erupted at these volcanoes leads to these explosive eruptions.

    There aren’t many truly “remote” places on Earth these days, so volcanoes in areas where people are rare can still be a big hazard. 100 years ago, we might not have even known eruptions like these at Bezymianny and Sheveluch were even happening unless someone happened to be nearby or notice ash falling on their town. Thanks to all the satellites watching the planet, we now know a lot more about how volcanically active the Earth is.

    See the full article here .

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  • richardmitnick 11:02 am on March 2, 2019 Permalink | Reply
    Tags: A moon’s gravitational forces aren’t strong enough to create tectonic plates but a nearby star could do the trick, , , , , Discover Magazine, new research indicates that spotting evidence of volcanic activity on a planet close to a red dwarf may be both a good sign of tectonic activity and a higher chance of extraterrestrial life, , The researchers argue that a planet orbiting close to its host star can experience stresses from that host’s gravitational pull. Those stresses then weaken the outer crust aiding or generating plate   

    From Discover Magazine: “How Plate Tectonics Could Make Harsh Alien Planets More Friendly to Life” 

    DiscoverMag

    From Discover Magazine

    March 1, 2019
    Ramin Skibba

    1
    Planets orbiting close to red dwarf stars risk getting hit by violent flares. (Credit: NASA, ESA and D. Player (STScI))

    Shifting, slipping and colliding tectonic plates played an essential role in the emergence and evolution of life on Earth.

    Such tectonic activity generated volcanoes that spewed carbon dioxide and other gases into the air. Rain brought the gases down to Earth, where they were pushed underground again by moving plates. For billions of years the cycle has regulated the climate and stabilized the temperature, which helped enable life to arise.

    Plate tectonics like what’s seen on Earth seems rare — no other world in our solar system has tectonic activity currently — but scientists now argue there could be a different way to generate an active crust on alien worlds.

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

    The researchers argue that a planet orbiting close to its host star can experience stresses from that host’s gravitational pull. Those stresses then weaken the outer crust, aiding or generating plate tectonics similar to those seen on Earth. That process could increase the likelihood of life developing on these planets.

    “We’re the first people to actually apply this calculation to other planetary systems,” said J.J. Zanazzi, an astrophysicist at the University of Toronto. Zanazzi and Amaury Triaud, an astronomer at the University of Birmingham in the U.K. are publishing their findings in the journal Icarus.

    The way a nearby star could stress a planet’s crust is similar to how the moon creates tides in the Earth’s oceans. A moon’s gravitational forces aren’t strong enough to create tectonic plates, but a nearby star could do the trick.

    “To get plate tectonics, we need these tidal forces to be acting for geologic times and to be strong enough to weaken the crust,” said Bradford Foley, a Penn State University geophysicist. If a world’s host star stretches, flexes and squeezes its crust enough for millions of years, plates could develop and start moving.

    Most stars burn so bright, however, that a planet close enough to experience tidal plate tectonics would get too hot for life. Fainter red dwarf stars provide a fruitful compromise, since the range of distances where a planet would have star-generated tides could overlap with that of the “habitable zone,” the region around a star that’s not too hot or too cold for life and allows for liquid water on the planet’s surface.

    But not just any closely orbiting planet will do. The tidal stresses need to cause some plates to gradually move beneath others — a process called subduction — and for that to happen, the stresses need to vary. This can happen if the orbit is a bit noncircular or if the same side of the planet doesn’t always face the star. Zanazzi and Triaud identified more than 40 potential planets with the necessary characteristics, many of them discovered by astronomers using NASA’s Kepler space telescope.

    NASA/Kepler Telescope, and K2 March 7, 2009 until November 15, 2018

    The list also included planets orbiting TRAPPIST-1, an ultracool red dwarf star that astronomers recently discovered was surrounded by seven planets.

    A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres. NASA


    The TRAPPIST-1 star, an ultracool dwarf, is orbited by seven Earth-size planets (NASA).

    ESO Belgian robotic Trappist National Telescope at Cerro La Silla, Chile


    ESO Belgian robotic Trappist-South National Telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    Most of the more than 40 worlds that the researchers identified orbit red dwarf stars more closely than Mercury orbits our sun and make a complete trip around their stars in less than 10 days.

    “If these planets have plate tectonics, it offers a way to stabilize the amount of carbon dioxide in the planet’s atmosphere and not have the planet undergo a runaway greenhouse effect,” Zanazzi said, referring to Venus, whose atmosphere became clogged with carbon dioxide, eventually causing its oceans to boil away.

    Telescopes scheduled to become operational in the 2020s, like NASA’s James Webb Space Telescope and the European Southern Observatory’s Extremely Large Telescope in northern Chile, are designed to probe distant planets’ atmospheres for a variety of life-friendly signatures, including indicators of volcanoes, like sulfur dioxide.

    NASA/ESA/CSA Webb Telescope annotated

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

    But just because volcanoes are there doesn’t mean astronomers will be able to notice. “Sulfur dioxide gets washed out efficiently from the atmosphere, so you need explosive volcanoes to shoot it up high enough,” said Lisa Kaltenegger, an astronomer at Cornell University in Ithaca, New York.

    After an eruption, sulfur dioxide usually dissipates and disappears from the atmosphere in a matter of months — a tiny window of time. To belch out sulfur dioxide at levels that astronomers could detect, she argues, a planet would have to have numerous simultaneously or frequently erupting volcanoes, like on early Earth, or one 10 times more powerful than the massive 1991 eruption of Mount Pinatubo in the Philippines.

    The worlds that host life, especially the kind that might be detectable from this solar system, likely make up just a fraction of all the inhabited planets. “We are limited to finding gases in the atmosphere, but life could develop underground or in an ocean,” Kaltenegger said. Such aliens would give few, weak signs of their existence to Earthling astronomers so far away.

    Nonetheless, the new research indicates that spotting evidence of volcanic activity on a planet close to a red dwarf may be both a good sign of tectonic activity and a higher chance of extraterrestrial life.

    See the full article here .

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  • richardmitnick 1:53 pm on February 21, 2019 Permalink | Reply
    Tags: , , , , Discover Magazine, M31N 2008-12a-GK Persei is a prime example of a nova remnant, , White dwarf   

    From Discover Magazine: “This Star Has Exploded Annually For Millions of Years” 

    DiscoverMag

    From Discover Magazine

    February 20, 2019
    Jake Parks

    1
    GK Persei, seen above, is a prime example of a nova remnant. Unlike supernovae, which blow stars apart from within, novae explosions occur on the surfaces of accreting white dwarfs. Though the previous record for largest nova remnant is about 3.5 light-years wide, researchers recently discovered M31N 2008-12a, a nova remnant that spans over 400 light-years.
    (Credit: X-ray: NASA/CXC/RIKEN/D.Takei et al; Optical: NASA/STScI; Radio: NRAO/VLA)

    NASA/Chandra X-ray Telescope

    NASA/ESA Hubble Telescope

    NRAO/Karl V Jansky Expanded Very Large Array, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)

    Astronomers have discovered a star in the Andromeda galaxy that has been regularly erupting for the past million years, leaving behind one of the biggest shells of ejected material scientists have ever seen.

    Andromeda Galaxy Adam Evans

    Andromeda Nebula Clean by Rah2005 on DeviantArt

    The new research, which was published last month in the journal Nature, not only marks the first discovery of such a super-remnant in another galaxy, it also paves the way for detecting a potentially massive population of repeatedly exploding stars, called recurrent novae, which may help shed light on how the universe has changed over time.

    Swing Your Partner

    The star responsible for this expansive remnant, which stretches over 400 light-years across, is actually from one of the most diminutive types of star: a white dwarf. These stellar corpses are left behind after a smallish star dies and blows off its outer layers, leaving behind only its dense core.

    But in the case of this remnant, catchily named M31N 2008-12a, the culprit is not your ordinary white dwarf. This tiny star has a dance partner.

    As the white dwarf and its nearby companion star orbit each other, the white dwarf rapidly siphons hydrogen from its buddy. As this unspent hydrogen fuels reaches the surface, it’s heated and compressed thanks to the white dwarf’s intense gravitational pull. Eventually, the hydrogen reaches a breaking point and spontaneously fuses to create helium, resulting in a powerful surface explosion we call a nova.

    This burst of fusion causes the white dwarf to temporarily brighten up to a millionfold as it ejects material outward at about 3 percent the speed of light. In the case of M31N 2008-12a, over time, these repeated explosions have created an extensive and ever-expanding cocoon of gas and dust around the white dwarf.

    According to the study, “Larger than almost all known remnant of even supernova explosions, the existence of this shell demonstrates that the nova M31N 2008-12a has erupted with high frequency for millions of years.”

    It Keeps Going, and Going…

    The massive size of the remnant is not its only claim to fame. Indeed, M31N 2008-12a also now holds the title of most frequently recurring nova, as it erupts at least once a year. “When we first discovered that M31N 2008-12a erupted every year, we were very surprised,” said co-author Allen Shafter of San Diego State University in a press release. This is because most recurrent novae only explode about once a decade.

    But despite the fact that the white dwarf has spent the past million years or so exploding annually, researchers don’t think it will last forever. Once the white dwarf surpasses the Chandrasekhar limit — which is about 1.4 times the mass of the sun — it will irreparably blow itself apart as a supernova or collapse down into a neutron star.

    According to theory, white dwarfs that are approaching the Chandrasekhar limit should undergo frequent novae explosions, resulting in gigantic remnants. And because that’s exactly what astronomers see happening around M31N 2008-12a, they think this star may be priming up for a supernova explosion itself. However, you and I likely will not be around to witness it.

    “In less than 40,000 years,” the study says, “the underlying composition of the white dwarf will be revealed incontrovertibly when either a type Ia supernova or an accretion-induced collapse of the white dwarf to a neutron star is observed.”

    If the researchers are able to find other examples of huge remnants around different novae, they think they may learn a bit about type Ia supernovae. Because type Ia supernovae have very predictable brightnesses (which is why they’re called standard candles), by studying them, researchers can pin down cosmic distances with extreme accuracy. Ultimately, this helps them better understand how the universe grows and evolves over time.

    “They are, in effect, the measuring rods that allow us to map the visible universe,” said Shafter. “Despite their importance, we don’t fully understand where they come from.”

    So for now, Shafter and his colleagues are working hard to determine whether super-remnants like M31N 2008-12a are the exception, or the rule. And if they’re as common as some think, then the next step becomes improving our ability to spot them.

    See the full article here .

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

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  • richardmitnick 2:28 pm on February 19, 2019 Permalink | Reply
    Tags: "Extreme Radiation Could Strip Exoplanets of their Atmospheres", , , , , Discover Magazine, , The exoplanet WASP-69b   

    From IAC via Discover Magazine: “Extreme Radiation Could Strip Exoplanets of their Atmospheres” 

    IAC

    From Instituto de Astrofísica de Canarias – IAC

    via

    DiscoverMag

    Discover Magazine

    December 6, 2018
    Amber Jorgenson

    1
    This artist illustration shows WASP-69b, which sits about 163 light years from Earth, orbiting its host star. (Credit: Gabriel Perez Diaz, SMM (IAC))

    If orbiting just 4 million miles from your fiery host star wasn’t bad enough, things might have just gotten even worse.

    New research shows that stars emitting high levels of ultraviolet (UV) radiation could strip the atmospheres of their ultra-close exoplanets. While observing gas giants that orbit exceptionally close to their host stars, astronomers found that those bombarded with radiation were losing helium from their atmospheres. These results, which were published in multiple studies today in the journals Science and and Astronomy & Astrophysics, could help researchers understand the evolution of planetary atmospheres, and also determine if extreme radiation could be peeling gas giants’ layers of clouds away to leave them as barren, rocky objects.

    Follow the Trail

    Astronomers from the Instituto de Astrofísica de Canarias (IAC) in the Canary Islands came across this strange phenomenon when they observed the exoplanet WASP-69b pass in front of its host star. During its transit, which takes just 3.9 days, the Jupiter-sized planet caused the star’s light to briefly dim, allowing researchers to home in on the orbiting object.

    Planet transit. NASA/Ames

    They used the CARMENES instrument at Spain’s Calar Alto Observatory to break down the planet’s light into visible and near infrared wavelengths — revealing the chemical elements that make up its atmosphere. It was then that they noticed a strange, comet-like tail of particles escaping from the planet.

    CARMENES spectrograph, mounted on the Calar Alto 3.5 meter Telescope, located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in Sierra de Los Filabres


    Calar Alto 3.5 meter Telescope, located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in Sierra de Los Filabres

    “We observed a stronger and longer-lasting dimming of the starlight in a region of the spectrum where helium gas absorbs light,” said the WASP-69b study’s lead author, Lisa Nortmann of the IAC, in a news release. “The longer duration of this absorption allows us to infer the presence of a tail.”

    This loss of helium, the second-most abundant element in gas giants, wasn’t an isolated incident, either. Using similar methods, the team studied four other planets that orbit extremely close to their host stars: gas giant KELT-9b, Neptune-sized GJ 436b, and hot Jupiter’s HD 189733b and HD 209458b.

    While helium wasn’t seen leaving the atmospheres of KELT-9b, GJ 436b or HD 209458b, the group did see a balloon of helium surrounding, and escaping from, HD 189733b.

    Wondering why these two planets were losing parts of their outer atmospheres, they turned to ESA’s Multi-Mirror X-Ray Mission (ESA XMM-Newton) for data about their host stars.

    ESA/XMM Newton

    The results showed that both HD 189733b and WASP-69b’s host stars were dangerously active — expelling much more UV radiation than the other host stars.

    And in yet another instance, astronomers from the University of Geneva detected a balloon of helium escaping the atmosphere of HAT-P-11b, whose nearby host star also emits high amounts of UV radiation. Their results were published today in the journal Science.

    Gas Giant Annihilation?

    These correlations lead researchers to believe that massive amounts of UV radiation are energizing helium particles, causing them to escape from the atmosphere and fly out into space. And once these gaseous envelopes have been completely stripped, all that’s left are the dense, rocky corpses of former gas giants. Follow-up studies will be needed to verify this theory, but thankfully, infrared spectrographs like CARMENES are making atmospheric observations a bit easier.

    “In the past, studies of atmospheric escape, like the one we have seen in WASP-69b, were based on space-borne observations of hydrogen in the far ultraviolet, a spectral region of very limited access and strongly affected by interstellar absorption,” said University of Hamburg researcher Michael Salz, who authored the Astronomy & Astrophysics paper about HD 189733b. “Our results show that helium is a very promising new tracer to study atmospheric escape in exoplanets.”

    And if this theory proves true, astronomers could use it to further compare the atmospheres of exoplanets, gain insight into their evolutions and shed light on the peculiar planets that sit a little too close to their host stars.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Instituto de Astrofísica de Canarias(IAC) is an international research centre in Spain which comprises:

    The Instituto de Astrofísica, the headquarters, which is in La Laguna (Tenerife).
    The Centro de Astrofísica en La Palma (CALP)
    The Observatorio del Teide (OT), in Izaña (Tenerife).

    These centres, with all the facilities they bring together, make up the European Northern Observatory(ENO).

    The IAC is constituted administratively as a Public Consortium, created by statute in 1982, with involvement from the Spanish Government, the Government of the Canary Islands, the University of La Laguna and Spain’s Science Research Council (CSIC).

    The International Scientific Committee (CCI) manages participation in the observatories by institutions from other countries. A Time Allocation Committee (CAT) allocates the observing time reserved for Spain at the telescopes in the IAC’s observatories.

    The exceptional quality of the sky over the Canaries for astronomical observations is protected by law. The IAC’s Sky Quality Protection Office (OTPC) regulates the application of the law and its Sky Quality Group continuously monitors the parameters that define observing quality at the IAC Observatories.

    The IAC’s research programme includes astrophysical research and technological development projects.

    The IAC is also involved in researcher training, university teaching and outreachactivities.

    The IAC has devoted much energy to developing technology for the design and construction of a large 10.4 metre diameter telescope, the ( Gran Telescopio CANARIAS, GTC), which is sited at the Observatorio del Roque de los Muchachos.

    Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level

     
  • richardmitnick 1:29 pm on February 19, 2019 Permalink | Reply
    Tags: "First Evidence of a Giant Exoplanet Collision", , , , , Discover Magazine, , Kepler-107 system, Kepler-107b and Kepler-107c, The innermost planet Kepler-107b is about 3.5 times as massive as Earth while Kepler-107c which sits farther out is a whopping 9.4 times as massive as Earth, The researchers argue that the denser planet Kepler-107c likely experienced a massive collision with a third unknown planet at some point in its past, Though astronomers have never confirmed a collision between exoplanets in another star system before there is evidence that a similar cosmic crash occurred in our own solar system [Earth and Thea whic   

    From Discover Magazine: “First Evidence of a Giant Exoplanet Collision” 

    DiscoverMag

    From Discover Magazine

    February 18, 2019
    Jake Parks

    1
    A planetary collision is exactly as bad as you would imagine. Unlike an asteroid impact, there’s not just a crater left behind. Instead, such a massive crash causes the surviving world to be stripped of much of its lighter elements, leaving behind an overly dense core. [Thea crashes into Earth] (Credit: NASA/JPL-Caltech)

    For the first time ever, astronomers think they’ve discovered an exoplanet that survived a catastrophic collision with another planet. And according to the new research, which was published Feb. 4, in the journal Nature Astronomy, the evidence for the impact comes from two twin exoplanets that seem to be more fraternal than identical.

    Mass Matters

    The pair of planets in question orbit a Sun-like star (along with two other planets) in the Kepler-107 system, which is located roughly 1,700 light-years away in the constellation Cygnus the Swan.

    Known as Kepler-107b and Kepler-107c, these planets have nearly identical sizes (both have a radius of roughly 1.5 times that of Earth), yet one planet is nearly three times as massive as the other. The innermost planet, Kepler-107b, is about 3.5 times as massive as Earth, while Kepler-107c, which sits farther out, is a whopping 9.4 times as massive as Earth.

    This means the inner planet, Kepler-107b, has an Earth-like density of around 5.3 grams per cubic centimeter, while the more distant Kepler-107c has a density of around 12.6 grams per cubic centimeter — which is extremely dense, even for an alien world. (For reference, water has a density of 1 gram per cubic centimeter.)

    This perplexing density discrepancy left researchers scratching their heads. How could two equally sized exoplanets in the same system (and at nearly the same orbital distance) have such different compositions?

    The Cause

    To determine exactly why Kepler-107c is so dense, first the researchers considered what they already knew. Previous research has shown that intense stellar radiation can strip the atmosphere from a planet that sits too near its host star. But if the innermost planet lost its lighter atmospheric elements, it should be more dense than its twin, not less. According to the study, this would “make the more-irradiated and less-massive planet Kepler-107b denser than Kepler-107c,” which is clearly not the case.

    However, there is another way that a planet can lose a lot of mass: by getting smacked with another planet. And this is exactly what the researchers think happened to Kepler-107c.

    The researchers argue that the denser planet, Kepler-107c, likely experienced a massive collision with a third, unknown planet at some point in its past. Such a gigantic impact, the study says, would have stripped the lighter silicate mantle from Kepler-107c, leaving behind an extremely dense, iron-rich core. According to the study, Kepler-107c could be as much as 70 percent iron.

    Because the mass and radius of Kepler-107c matches what would be expected from a giant planetary impact, the researchers are fairly confident that the collisional scenario they’ve outlined in their paper is accurate; however, they still need to confirm their hypothesis. If proven correct, this new find would become the first-ever evidence of a planetary collision outside our solar system.

    Closer to Home

    Though astronomers have never confirmed a collision between exoplanets in another star system before, there is evidence that a similar cosmic crash occurred in our own solar system. In fact, a leading theory about the formation of the Moon is that it formed when a small protoplanet [Thea, roughly the size of Mars] rammed into early Earth.

    By analyzing lunar samples returned by the Apollo missions, scientists learned that the composition of Moon rocks is very similar to that of Earth’s mantle. Furthermore, the Moon is severely lacking in volatile elements, which boil away at high temperatures. Taken together, along with a few other lines of evidence, this indicates the Moon may have formed when a very large object (roughly the size of Mars) struck Earth with a glancing blow early in the solar system’s history, some 4.6 billion years ago.

    This mash-up melted and tore off some of the outer layers of Earth, which may have temporarily formed Saturn-like rings around our planet. Over time, much of this ejected material drifted back to Earth’s surface, but there was still enough debris left in orbit that it eventually coagulated and formed the Moon.

    With the discovery of Kepler-107c, it seems planet-shattering impacts are not just a sci-fi trope, but instead may occur much more frequently than we once thought. And with the long-anticipated launch of the James Webb Space Telescope coming up in March 2021, it may only be a few more years until they start to reveal themselves en masse, so be sure to stay tuned.

    See the full article here .

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

    Please help promote STEM in your local schools.

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