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Impact ~ NEO; Near Earth Objects

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  • G David Bock
    replied
    Did a Comet Kill the Woolly Mammoths?
    ...
    Originally published in 2007, Kennett’s controversial Younger Dryas Boundary (YDB) hypothesis suggests that a comet collision precipitated the Younger Dryas period of global cooling, which, in turn, contributed to the extinction of many animals and altered human adaptations.

    The nanodiamond is one type of material that could result from an extraterrestrial collision, and the presence of nanodiamonds along Bull Creek in the Oklahoma Panhandle lends credence to the YDB hypothesis.

    More recently, another group of earth scientists, including UC Santa Barbara’s Alexander Simms and alumna Hanna Alexander, re-examined the distribution of nanodiamonds in Bull Creek’s sedimentological record to see if they could reproduce the original study’s evidence supporting the YDB hypothesis. Their findings appear in the Proceedings of the National Academy of Sciences.

    “We were able to replicate some of their results and we did find nanodiamonds right at the Younger Dryas Boundary,” says Simms, an associate professor in the department of Earth science. “However, we also found a second spike of nanodiamonds more recently in the sedimentary record, sometime within the past 3,000 years.”
    ...
    http://www.theepochtimes.com/n3/4829...olly-mammoths/

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  • G David Bock
    replied
    We Saw It Coming: Dinky Asteroid Hits Earth, Burns Up

    For only the second time in history, an asteroid has hit Earth that was discovered hours before impact. But don’t panic! The asteroid didn’t put a city-sized divot in our planet, it most likely burned up somewhere between Africa and South America over the Atlantic Ocean at midnight EST.
    Top 10 Ways to Stop an Asteroid
    Asteroid 2014 AA, the first asteroid discovery of the year, was spotted by astronomers using the Mt. Lemmon Survey telescope in Arizona. As shrewdly pointed out by Bad Astronomer Phil Plait, the asteroid was the approximate size of a couch — measuring only a couple of meters across. That’s around one-half of a Mini Cooper, whichever takes your fancy. But whatever your preferred size comparison, the outcome was likely the same; the asteroid burned up on atmospheric entry as a meteor.
    This might have provided a nice visual spectacle only a day after New Years, but 2014 AA is notable as being the first pre-impact discovery of an asteroid since 2008.
    ....
    http://news.discovery.com/space/aste...-up-140102.htm

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  • G David Bock
    replied
    That time of year again, the nightly Taurid meteor showers;
    Bright lights in sky probably meteors, Weather Service says
    http://www.latimes.com/local/lanow/l...#axzz2jxdazA8y

    Meteor Shower Lights Up Night Sky Across The West
    ...
    So-called Taurid meteor showers, which seem to come from the direction of the constellation Taurus, will reach their peak this year on Nov. 16 through the early morning of Nov. 17. Observers, aided by a full moon, will see 10 to 20 large fireballs every hour.

    The website PlanetSave.com says the 10-to-20 figure is actually fewer than we normally get in this time period, but that it still promises to be “a pretty good show.”
    ...
    http://losangeles.cbslocal.com/2013/...ross-the-west/

    Wiki page on Taurids;
    http://en.wikipedia.org/wiki/Taurids

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  • G David Bock
    replied
    ^ And from another related article, these excerpts;

    In fact, the U.S. government got a new sense of urgency after Chelyabinsk, quietly holding a disaster drill earlier this year in Washington that was meant to simulate what would happen if a slightly bigger space rock threatened the East Coast.

    In the early part of the drill, when it looked as if the meteor would hit just outside the nation's capital, experts predicted 78,000 people could die. But when the mock meteor ended up in the ocean, the fake damage featured a 49-foot tsunami and shortages of supplies along the East Coast, according to an after-action report obtained by the AP.

    The exercise and the studies show there's a risk from smaller space rocks that strike before they are even detected — not just from the long-seen-in-advance, dinosaur-killing giant ones like in the movie "Armageddon," said Bill Ailor, a space debris expert at the Aerospace Corporation who helped coordinate the federal drill.

    "The biggest hazard from asteroids right now is the city-busting airbursts, not the civilization-busting impacts from 1-kilometer-diameter objects that has so far been the target of most astronomical surveys," Purdue University astronomer Jay Melosh, who wasn't part of the studies, wrote in an email. "Old-fashioned civil defense, not Bruce Willis and his atom bombs, might be the best insurance against hazards of this kind."
    ...
    NASA also got a wake-up call this week on those bigger space rocks that astronomers thought they had a handle on, discovering two 12-mile-wide space rocks and a 1.2-mile-wide asteroid that had escaped their notice until this month.

    The three objects won't hit Earth, but their discovery raises the question of how they weren't seen until now.

    The last time a 12-mile-wide rock had been discovered was about 30 years ago, and two popped into scientists' view just now, NASA asteroid scientist Donald Yeomans said. He said NASA had thought it had already seen 95 percent of the large space rocks that come near Earth.
    ....
    http://news.msn.com/science-technolo...-may-be-bigger

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  • GCoyote
    replied
    Risk of massive asteroid strike underestimated

    From the BBC

    An international team looked at the last 20 years of data collected from sensors used by the US government and infrasound sensors positioned around the globe.
    ...
    The researchers found that during this time about 60 asteroids up to 20m in size had smashed into the Earth's atmosphere: far more than was previously thought.
    More - http://www.bbc.co.uk/news/science-environment-24839601

    Link to the original article in Nature - http://www.nature.com/news/risk-of-m...imated-1.14114

    Leave a comment:


  • G David Bock
    replied
    Asteroid threat in 2032? Don't panic, but don't brush it off

    A big asteroid sailed past Earth last month, and astronomers haven't yet totally excluded the possibility that it'll hit us when it comes around in 2032. If the past is any guide, we won't have to worry about asteroid 2013 TV135 — but it's a reminder that we'll have to fend off a killer space rock one of these days.

    Ukrainian astronomers discovered 2013 TV135 just 10 days ago, well after the asteroid had its close encounter with Earth on Sept. 16. Actually, it wasn't all that close: The distance was 4.2 million miles (6.7 million kilometers), or about 17 times as far away as the moon. But based on the rough estimates of its orbital path, experts rated its chances of colliding with Earth during a follow-up encounter in 2032 at 1 in 63,000.
    ...
    Nukes or not, asteroid defense is an international issue well worth contemplating: A space rock that's 1,300 feet (400 meters) wide could destroy a region or set off a huge tsunami if there were a direct hit. The asteroid that caused a meteor blast over Russia earlier this year, injuring more than 1,600 people, was a mere 17 meters (54 feet) wide when it hit Earth's atmosphere.
    ...
    ...But for now, the big challenge is to identify and characterize near-Earth objects on a timely basis. The fact that 2013 TV135 was discovered only after last month's close encounter demonstrates how far we have yet to go.
    http://www.nbcnews.com/science/aster...-it-8C11418631

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  • G David Bock
    replied
    A real nuclear deterrent: US, Russia may team up to use weapons against asteroids

    http://investigations.nbcnews.com/_n...id=msnhp&pos=1

    Leave a comment:


  • GCoyote
    replied
    Makes sense. Those impact rates are only estimates and we'd expect to revise those estimates as we get more data.

    Leave a comment:


  • G David Bock
    replied
    Russian Meteor Explosion Might Mean Earth Gets Hit More Often Than We Think

    EXCERPT:
    ...
    “When an asteroid explodes, its momentum is conserved and that explosion continues down toward the Earth,” Boslough said.

    For that reason, the people who live in Chelyabinsk explosion are very lucky to be alive, he added. If the bollide had come into the atmosphere at a less steep angle, its blast would have been aimed right at the ground, likely doing much more damage.

    That an airburst continues traveling in the same direction as a meteorite was only appreciated starting in the 1990s, particularly after the impact of Shoemaker-Levy 9 on Jupiter. This understanding has led to revisions in estimates of the size of the asteroid that exploded over the Siberian tundra in 1908. This blast, known as the Tunguska event, flattened trees over a 2,000-square-kilometer area.

    Scientists in the mid-20th century used nuclear blast comparisons to estimate Tunguska’s power. To make trees fall down over that large an area, a nuclear weapon would have to be 10 to 20 megatons. Now knowing how asteroid impact bursts can deliver more energy to the ground, the Tunguska bollide estimate has gotten smaller, suggesting that an object of roughly 100,000 tons entered the atmosphere and delivered a blast of between 3 and 5 megatons.

    Tunguska and Chelyabinsk are thought to be among the most powerful asteroid impacts in recent history. That both would come within about 100 years of one another is slightly worrying to scientists like Boslough.
    ...
    http://www.wired.com/wiredscience/20...equent-impact/

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  • G David Bock
    replied
    Astronauts auction own artifacts to 'save the world' from asteroids

    http://www.nbcnews.com/science/astro...ids-6C10547244

    Leave a comment:


  • G David Bock
    replied
    NASA Radar Shows Near-Earth Asteroid Bringing Its Own Moon

    ...
    PASADENA (CBSLA.com) — A mile-long asteroid set to pass safely by Earth on Friday appears to be bringing along a companion.
    Radar imagery showed that asteroid “1998 QE2″ is a binary asteroid, according to researchers at Jet Propulsion Laboratory (JPL) in Pasadena.
    About 16 percent of asteroids that are about 655 feet or larger are binary or triple systems, according to JPL.
    Data shows the main body of the asteroid is approximately 1.7 miles in diameter and has a rotation period of less than four hours. Radar imagery also shows the space rock has several dark surface features that suggest large concavities.
    The preliminary estimate for the size of the asteroid’s satellite, or moon, is approximately 2,000 feet wide, researchers said. The moon appears in JPL images as a small, bright object orbiting 1998 QE2.
    ...
    http://losangeles.cbslocal.com/2013/...-its-own-moon/

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  • G David Bock
    replied
    Latest updates;
    Asteroid 1998 QE2's close encounter generates a wave of attention online

    http://cosmiclog.nbcnews.com/_news/2...on-online?lite

    Leave a comment:


  • GCoyote
    replied
    Meteor crashes into moon's surface causing flash – video

    http://www.guardian.co.uk/science/vi...ce-flash-video

    From the site:

    A Nasa telescope captures the moment a 40kg (88lb) rock crashes into the moon's surface on Friday. The impact caused a flash 10 times brighter than any other Nasa has seen since it began monitoring the lunar surface eight years ago. Nasa's Lunar Reconnaissance Orbiter satellite is now hunting for the newly-formed crater, which scientists believe could be up to 20m (66ft) in width

    Leave a comment:


  • G David Bock
    replied
    Dark, massive asteroid to fly by Earth on May 31

    It's 1.7 miles long. Its surface is covered in a sticky black substance similar to the gunk at the bottom of a barbecue. If it impacted Earth it would probably result in global extinction. Good thing it is just making a flyby.
    Asteroid 1998 QE2 will make its closest pass to Earth on May 31 at 1:59 p.m. PDT.
    Scientists are not sure where this unusually large space rock, which was discovered 15 years ago, originated from. But the mysterious sooty substance on its surface could indicate it may be the result of a comet that flew too close to the sun, said Amy Mainzer, who tracks near-Earth objects at Jet Propulsion Laboratory in La Cañada Flintridge. It might also have leaked out of the asteroid belt between the orbits of Mars and Jupiter, she said.
    ...
    At its closest approach the asteroid will still be 3.6 million miles from our planet (about 15 times the distance between the Earth and the moon), but it will be close enough for these powerful radar antennas to see features as small as 12 feet across.
    ...
    http://www.latimes.com/news/science/...0,548201.story

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  • GCoyote
    replied
    Russian Meteor without the Hype

    http://video.pbs.org/video/2358778286

    Much better than the 'instant science' special the History Channel did. The close up of the infra sound system was interesting.

    Leave a comment:

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