Saturday, October 26, 2013

Boston University on how to prevent asteroid impacts

In Eclipse and asteroid DOOM, I pointed out the latest news about the risks of asteroids colliding with the Earth.  That same week, Boston University posted How to catch an asteroid by Rich Barlow, which described how "BU astronomers ponder how to save the Earth."  Here are the relevant excerpts.
Last February’s atmospheric blowup of a meteor over Russia injured 1,500 people, mostly from glass smashed by the blast, whose force was estimated at 30 times that of the atom bomb dropped on Hiroshima. A month later, the US Senate heard former astronaut Edward Lu advocate for beefing up asteroid detection, warning that the casualties in Russia would have been incalculably greater had the meteor exploded closer to a big city. The Russian rock, a NASA scientist noted at the hearing, snuck by Earth’s telescopes, whose sites are set on projectiles much larger than that 60-foot-diameter meteor.

Is NASA worried? Sufficiently so that it has announced an asteroid Grand Challenge, inviting ideas from the global scientific community about how to spot and stop asteroids that threaten our planet.
How exactly does one stop an asteroid? First, Hughes says, we should distinguish between planet-killers—asteroids so massive that we could kiss our posteriors good-bye—and smaller, potential city-killers like the Russian meteor. The former, he says, are hard to miss. Current scopes pick up 95 percent of those believed to be lurking near us, none of which currently threaten Earth, and improved technology will move that detection rate closer to 100 percent. Hughes and Andrew West, a CAS assistant professor of astronomy, concur that strikes from such monster rocks happen only once in tens of millions of years.

City-killers, the asteroids small enough to go undetected by telescopes, strike once every 1,000 years. That sounds disturbing, but Hughes points out that “tsunamis, super storms, and major earthquakes also can come close to obliterating cities or even small countries, and they happen far more frequently than once a millennium, so are a far more dangerous threat.” It’s better to invest in preparing for those more likely catastrophes, he says. “I don’t think detecting small asteroids should be a NASA priority.”

West agrees, saying that given Earth’s vast uninhabited real estate, from oceans to wilderness, “the real chances of them hitting a populated city…are very small.”

But Hughes also knows that human nature is easily frazzled by even the most unlikely events: “Tell people about a risk they’ve never heard about or thought about, and they get excited.”

Obviously, he notes, the best scenario would provide lots of warning—“ideally a decade or more”—of a coming collision, and the astronomer thinks such lead times are becoming possible as scientists’ ability to calculate orbits improves. The hard part is figuring out what to do once the heavenly threat is identified. Hughes’ preferred approach would be to knock it off course by hijacking its steering.
There is more, but in the spirit of showing instead of telling, I present the three videos that accompany the article, narrated by Professor Hughes.

Using Explosives to Move an Asteroid

Jeffrey Hughes explains how Hollywood's explosive solution to an asteroid may not be the best idea to avoiding destruction.
Using a Laser to Save the World from Asteroids

Jeffrey Hughes explains how lasers may one day save the world from an asteroid doomsday scenario.
Using Rockets to Save the Earth from Asteroids

Jeffrey Hughes explains how we might use rockets to save the earth from an asteroid impact--by pushing back.
Here's to there being spacefaring nations around capable of dealing with the threat when it arises--and it will arise.

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