We really need to figure out how to stop a killer asteroid, scientists say

Nov 26, 2016

By Sarah Kaplan

Imagine if scientists found out that a massive asteroid was on a collision course with Earth and would strike somewhere near Los Angeles by September 2020. What could humanity do?

Not much. At least, that was the result of a day-long tabletop exercise coordinated by NASA and FEMA late last month. In their hypothetical scenario, the space agency concluded that the 330-foot space rock was approaching too quickly to mount a deflection mission. The team from FEMA was left to figure out how to evacuate millions of people from Southern California.

This was a purely fictional exercise. NASA has discovered some 17,000 potentially hazardous near-Earth objects, but none of them is projected to come close to Earth in the next hundred years. No human that we know of has been killed by a meteorite or the effects of an impact, and the likelihood that this could happen to any of us is very, very slim. The chance of an impact big enough to destroy our planet is even smaller. Remember that Earth has suffered only one mass extinction-inducing impact that we know of in its 4.6 billion-year history, and even that asteroid didn’t end life entirely. Our planet is pretty resilient.


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3 comments on “We really need to figure out how to stop a killer asteroid, scientists say

  • @OP – This was a purely fictional exercise. NASA has discovered some 17,000 potentially hazardous near-Earth objects, but none of them is projected to come close to Earth in the next hundred years.

    However there are thousands of smaller asteroids which have not yet been detected and tracked, but which could cause massive Tunduska type damage {which Flattened 2,000 km² (770 sq mi)}, from airbursts.

    No human that we know of has been killed by a meteorite or the effects of an impact, and the likelihood that this could happen to any of us is very, very slim.

    Actually thought it may be true of any particular individual, this is not correct.
    Recent investigations into airburst explosions have shown that because of the density of many asteroids, major damage can be caused by bodies three times smaller than previously thought.
    Whole cities could be wiped out at relatively short notice!

    Also, because they have very dark surfaces, smaller asteroids are difficult to spot at a distance!



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  • @OP – link – “New NEOs [near-Earth objects] are now being discovered at the rate of some four per day,” Alan Harris, a letter signatory and senior scientist at German Aerospace Center, noted at a news conference. “We need a coordinated international strategy for near-Earth object impact mitigation.”

    Many asteroid researchers say that the Chelyabinsk meteor strike, which injured at least 1,200 people in the Ural Mountains in Russia in 2013, was something of a wake up call. It’s estimated that the rock weighed about 10 tons and was about 65 feet across when it broke up in the sky above the city of Chelyabinsk. That no one died is largely a product of the remote location and incredible luck.

    There are thousands of un mapped NEOs much bigger than that, but smaller than the 17,000 really big ones, referred to in the OP.

    An analysis of the meteor published later that year suggested that dangerous strikes could be more common than many of us realized.

    Indeed so!



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  • There are various proposed possible means of deflection, if the asteroids or comets are found soon enough.

    http://www.planetary.org/explore/projects/laser-bees/

    A New Way to Deflect a Dangerous Asteroid

    What do we do if an asteroid is found to be on a collision course with Earth? At this point, the answer is not clear, so The Planetary Society has partnered with researchers to discover ways to protect Earth when we one-day find a dangerous space rock.

    We’ve been working with a team at the University of Strathclyde and the University of Glasgow in Scotland to study a new technique which uses concentrated light to gently move an asteroid — a project we called “Mirror Bees” — using mirrors on several spacecraft swarming around an asteroid to focus sunlight onto a spot on the asteroid. As part of the initial Mirror Bees project, researchers found that lasers are more effective than mirrors and can be used from greater distances. So, now the project is called “Laser Bees.”

    The researchers at the University of Strathclyde and the University of Glasgow, under the leadership of Massimiliano Vasile, became interested in this approach when they set out to compare nine approaches to planetary defense. To their surprise, one of their results was that Mirror Bees would work more quickly and effectively than all but nuclear warheads. (But unlike the use of nuclear explosions, there would be no risk of breaking a huge asteroid into any number of equally deadly smaller asteroids, nor would the procedure face as many political and bureaucratic hurdles.)

    What Are Laser Bees

    This technique involves many small spacecraft — each carrying a laser — swarming around a near-Earth asteroid.
    The spacecraft could precisely focus their powerful lasers pumped by sunlight onto a tiny spot on the asteroid, vaporizing the rock and metal, and creating a jet plume of super-heated gases and debris.
    The asteroid would become the fuel for its own rocket — and slowly, the asteroid would move into a new trajectory.




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