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  • HMS Jr.
    replied
    This neat dude (among esteemed others) says...

    ...not if...just when.

    Leave a comment:


  • GCoyote
    replied
    Originally posted by G David Bock View Post
    ... If "a rock" is on impact course to Earth, the more pieces one can break it up into, the less DEEP and Destructive its impact. Not only is mass and trajectories scattered, but surface area to atmospheric ablation is increased significantly.

    Better many smaller pieces than one large rock!
    The thing about increasing the ablation area is it cuts two ways. That's the same mechanism that rapidly transfers heat to the atmosphere to produce an air burst. If you want to break up an incoming asteroid you'd have to do it far enough away in space and time for the bits to become widely separated so most would miss the Earth.

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  • Bwaha
    replied
    It's being worked on. You should contact your congress critter to get more funding...

    http://www.nasa.gov/mission_pages/as.../#.VCqiU1ePzpE

    Also you personally could get involved.

    Informing NASA’s Asteroid Initiative: A Citizen Forum

    August 28, 2014




    NASA is finding asteroids, including those that might threaten our home planet, and sending humans to explore one. The agency is engaging the public in the Asteroid Grand Challenge to find all asteroid threats to human population and know what to do about them, accelerating NASA's existing planetary defense work. NASA is also developing a first-ever mission to identify, capture and redirect a near-Earth asteroid to a stable orbit around the moon, where astronauts will explore it in the 2020s, returning with samples. This Asteroid Redirect Mission is part of NASA’s plan to advance the new technologies and spaceflight experience needed for humans to pioneer Mars in the 2030s.






    NASA wants to know what the public thinks about how the agency is accomplishing both the Asteroid Grand Challenge and the Asteroid Redirect Mission, what inspires them about exploration, and what they think is valuable in the mission to find, capture, move and explore an asteroid.
    Last year, the agency asked for ideas on how to engage the public directly in the Asteroid Initiative. One highly-rated response to the Asteroid Initiative Request for Information was the Expert and Citizen Assessment of Science and Technology, a consortium of respected universities, science centers and non-governmental organizations. After a presentation at the 2013 Asteroid Initiative Workshop, NASA chose to award the ECAST consortium a cooperative agreement to conduct peer-to-peer deliberations and solicit citizen input on NASA's asteroid initiative.


    http://www.nasa.gov/content/informin...citizen-forum/

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  • G David Bock
    replied
    Originally posted by Pirate-Drakk View Post
    This double vortex system makes me feel much better (I sleep better at night) as it makes very good sense from a physics standpoint (it's a 2-D mushroom cloud). It is also a "relatively" simple computer model to make with meaningful results (unlike complex climate models).





    My initial reaction to this double plume was nuke-missile/anti-missile. This is a terrifying concept. In retrospect I hope it was a "natural" event.

    However, big chunks of rocks hitting the Earth are also a fearsome concept. Typical impact velocities are 20 km/s. "It's not a matter of IF", it's a matter of when/where/how bad we get hit next time....
    Reminds me of an "experiment" conducted several years ago while shooting at a local 'range'/quarry. Took a 12 gauge pump shotgun and three types of rounds where the propellant and projectile (shoot) where all fairly equal.

    TARGET was a round double basin washing machine c. 1930s.

    SHOTS were bird, about 7-8 range, Buck~00, and Slug.

    Bird dented first layer, spare to little penetration.

    Buck~00 (equals about 9 x 9mm Luger., clustered) penetration to second, far-side layers, with dents but no penetration.

    Slug - punched thru all and kept going.

    LESSON LEARNED :

    Mass, concentrated is more destructive than Mass Diffused.

    If "a rock" is on impact course to Earth, the more pieces one can break it up into, the less DEEP and Destructive its impact. Not only is mass and trajectories scattered, but surface area to atmospheric ablation is increased significantly.

    Better many smaller pieces than one large rock!

    Leave a comment:


  • Pirate-Drakk
    replied
    This double vortex system makes me feel much better (I sleep better at night) as it makes very good sense from a physics standpoint (it's a 2-D mushroom cloud). It is also a "relatively" simple computer model to make with meaningful results (unlike complex climate models).





    My initial reaction to this double plume was nuke-missile/anti-missile. This is a terrifying concept. In retrospect I hope it was a "natural" event.

    However, big chunks of rocks hitting the Earth are also a fearsome concept. Typical impact velocities are 20 km/s. "It's not a matter of IF", it's a matter of when/where/how bad we get hit next time....
    Attached Files

    Leave a comment:


  • GCoyote
    replied
    Chelyabinsk: Portrait of an asteroid airburst

    A pretty good and reasonably non-technical article on what we've learned since our most recent cosmic wake-up-call.

    With Chelyabinsk, scientists can, for the first time, link the damage from an impact event to a well- determined impact energy in order to assess the future hazards of asteroids to lives and property. Using methods of quantitative risk assessment, one can estimate the range of probabilities of various events and the consequences of those events. Asteroid impacts represent a classic low-probability, high-consequence risk: very unlikely but potentially catastrophic. 14 Moreover, the greatest contributor to long-term risk is from the most improbable but largest impacts, which can lead to civilization collapse or even human extinction. Fortunately, the largest are also the easiest to discover, and about 90% of nearby objects greater than 1 km in diameter have been cataloged. And because none are on a collision course, the assessed risk from large asteroids has dropped since the survey began by more than an order of magnitude.
    http://scitation.aip.org/content/aip...1063/PT.3.2515

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  • G David Bock
    replied
    Originally posted by GCoyote View Post
    So other than being lucky, the last paragraph sums it well;

    "So Earth has the technology, potentially. What it needs is time. According to Yeomans, using today’s technology means we’d need a decade’s head start to deflect an asteroid. The harder we look, the better off we’ll be."

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  • GCoyote
    replied
    Saving the Earth by Inches per Second

    Just continuing the thread -

    ... Will we be able to turn it away before it strikes? According to Don Yeomans, manager of NASA’s Near Earth Object program at the Jet Propulsion Laboratory in Pasadena, Calif., there are only three ways to increase our chances against an asteroid aimed at Earth: “Find it early; find it early; find it early.”
    https://www.asme.org/engineering-top...hes-per-second

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  • Bwaha
    replied
    NASA is on the hunt for an asteroid to capture with a robotic spacecraft, redirect to a stable orbit around the moon, and send astronauts to study in the 2020s -- all on the agency's human Path to Mars. Agency officials announced on Thursday recent progress to identify candidate asteroids for its Asteroid Redirect Mission (ARM), increase public participation in the search for asteroids, and advance the mission's design.
    NASA plans to launch the ARM robotic spacecraft in 2019 and will make a final choice of the asteroid for the mission about a year before the spacecraft launches. NASA is working on two concepts for the mission: the first is to fully capture a very small asteroid in open space, and the second is to collect a boulder-sized sample off of a much larger asteroid. Both concepts would require redirecting an asteroid less than 32 feet (10 meters) in size into the moon’s orbit. The agency will choose between these two concepts in late 2014 and further refine the mission’s design.


    http://www.nasa.gov/press/2014/june/.../#.U6g_nEBfV8c


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  • GCoyote
    replied
    Or alternatively, be used to capture asteroids that could then be reprocessed into construction materials without having to lift them out of a gravity well.

    Leave a comment:


  • G David Bock
    replied
    How NASA's Asteroid Mission Will Head Off 'Armageddon'

    Experts say it’s just a matter of time before a killer asteroid comes hurtling toward us – but NASA is making progress on plans to grab a space rock and test technologies that could someday save the world.
    The space agency’s Asteroid Retrieval Mission aims to net an asteroid by the mid-2020s so that scientists can run experiments on it.

    ...
    http://www.nbcnews.com/science/space...geddon-n136041

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  • G David Bock
    replied
    Chelyabinsk Asteroid Hit Another Asteroid First

    http://www.nbcnews.com/science/space...-first-n113501

    Leave a comment:


  • G David Bock
    replied
    Twice each year, Earth passes thru the debris cloud known as the Taurid Meteor Stream/Comet Encke. Following illustration shows;


    http://www.enterprisemission.com/ima...id-stream1.gif
    http://www.enterprisemission.com/oh_my_god.htm

    A couple of footnotes about the above. The July transit has the TMS coming from the Sun direction and is mostly a daytime event, the November transit, coming from the outer reaches of the Solar System is a night-time event. Prior to the 15 day calendar adjustment a couple of centuries ago, that Nov. transit was actually the last half of October, might put an interesting insight to some of the Halloween "traditions"/concepts.
    Last edited by G David Bock; 25 Apr 14, 15:54.

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  • G David Bock
    replied
    Asteroids Whack Earth More Often Than Thought

    EXCERPT:
    A global network that listens for telltale traces of nuclear weapons tests detected 26 explosions between 2000 and 2013 caused not by nuclear explosions but by asteroids blasting apart in the atmosphere, a video visualization released on Tuesday shows.
    Only one impact, the 2013 strike over Chelyabinsk, Russia, caused widespread injuries and damages on the ground, but the study is a somber reminder that Earth's lucky days may be numbered.
    "Most of the impacts are too small and too high up to cause major damage ... but it does show you ... an asteroid large enough to destroy a city is likely to occur about once every century or so," Ed Lu, a former NASA astronaut who now oversees the asteroid-hunting B612 Foundation, told reporters on a conference call.
    ...
    http://news.discovery.com/space/aste...ght-140422.htm

    Another related article;
    'The only thing preventing a catastrophe from a city-killer size asteroid is blind luck': Nasa astronauts to reveal evidence that large-scale asteroids have hit Earth 10 times more often than previously thought over past decade
    http://www.dailymail.co.uk/sciencete...y-thought.html

    And while on subject of impacts;
    Ancient plants 'frozen in time' by space impacts
    http://www.bbc.com/news/science-environment-27075508
    Last edited by G David Bock; 24 Apr 14, 16:03.

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  • G David Bock
    replied
    Dinosaur-Killing Asteroid Triggered Lethal Acid Rain

    The oceans soured into a deadly sulfuric-acid stew after the huge asteroid impact that wiped out the dinosaurs, a new study suggests.
    Eighty percent of the planet's species died off at the end of the Cretaceous Period 65.5 million years ago, including most marine life in the upper ocean, as well as swimmers and drifters in lakes and rivers. Scientists blame this mass extinction on the asteroid or comet impact that created the Chicxulub crater in the Gulf of Mexico.
    A new model of the disaster finds that the impact would have inundated Earth's atmosphere with sulfur trioxide, from sulfate-rich marine rocks called anhydrite vaporized by the blast. Once in the air, the sulfur would have rapidly transformed into sulfuric acid, generating massive amounts of acid rain within a few days of the impact, according to the study, published today (March 9) in the journal Nature Geoscience.

    The model helps explain why most deep-sea marine life survived the mass extinction while surface dwellers disappeared from the fossil record, the researchers said. The intense acid rainfall only spiked the upper surface of the ocean with sulfuric acid, leaving the deeper waters as a refuge. The model could also account for another extinction mystery: the so-called fern spike, revealed by a massive increase in fossil fern pollen just after the impact. Ferns are one of the few plants that tolerate ground saturated in acidic water, the researchers said.
    The Chicxulub impact devastated the Earth with more than just acid rain. Other killer effects included tsunamis, a global firestorm and soot from burning plants. [The 10 Best Ways to Destroy Earth]
    ...
    cont'd
    http://www.livescience.com/43960-ast...ification.html

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