What To Do About an Asteroid That Has a 1 In 625 Chance of Hitting Us In 2040? 412
The Bad Astronomer writes "The asteroid 2011 AG5 is 140 meters across: football-stadium-sized. Its orbit isn't nailed down well enough to say yet, but using what's currently known, there's a 1 in 625 chance it will impact the Earth in 2040. It's behind the Sun until September 2013, and more observations taken then will probably reduce the odds of impact to something close to 0. But does it make sense to wait until then to start investigating a mission to deflect it away our planet? Astronomers are debating this right now, and what they conclude may pave the way for how we deal with an asteroid threat in the future."
Slow it down or speed it up just slightly (Score:5, Interesting)
I saw a recent idea that involved painting it white in order to decrease absorptivity.
Re:I don't see the problem. (Score:5, Interesting)
It's too small to be a civilization-killer. We're only talking a gigaton-range boom when it impacts.
Yeah, it would suck to be under it, or even within a couple hundred miles of it, but beyond that, it's mostly just a lightshow and something to keep the bookies busy.
Attach a solar sail (Score:5, Interesting)
And let the solar wind push it out. You only need to alter its orbit by 5 minutes in the next 22 years to miss completely.
Re:I don't see the problem. (Score:5, Interesting)
That would depend on what it's made of. If it's a dirty snowball (mostly ice, with some small rock debris), it'd fall apart when it hit the atmosphere, and make for a pretty light show.
We've identified what we believe to be other rarer objects. Say it was a chunk of something like BPM 37093. I suspect that would be dangerous on reentry. I'm not a geologist, so I won't attempt to guess what would happen to it. Would it shatter, melt, or remain one relatively solid mass the whole way down.
If so, I don't think it would be an ELE. Tragic? Possibly, depending on where it hit. Catastrophic? probably not. Despite the way things look in population centers, there are vast areas of relatively uninhabited land around the world. If it hit the water, it may cause a tsunami wave. Depending on where that wave makes landfall, it could disrupt anywhere from dozens to millions of people.
Re:Idiots! (Score:5, Interesting)
The Mayan calendar was more accurate... 365.2420 days, vs. Gregorians 365.2425, when the actual value was 365.2422.
Re:I will be doing one thing about it. (Score:0, Interesting)
I'll be dead by then, so let world fry. With Climate Change, right wing religious nut jobs and the Big Brother state, the world will be ready for a nice cleansing.
Re:Attach a solar sail (Score:4, Interesting)
Well then use a real sail. http://en.wikipedia.org/wiki/Magnetic_sail [wikipedia.org]
Sample calculations in the article provide 70n of thrust at 1AU, over 28 years would result in a displacement of 6 822 402 370 meters. The earth is 12 756 000 meters in diameter. This means that it would miss by 534 earth-diameters. Depending on which direction it is we're either really safe or more screwed. Note I did not take into account orbital mechanics, and only did a linear calculation. I think the odds would be even in better favor if we got the sail on it and it orbited closer to the sun where the magnetic pressure is higher.
Given that magsails are 1/10000th the power of a solar sail, I still think the sail idea has it licked.
Re:I will be doing one thing about it. (Score:4, Interesting)
Re:I will be doing one thing about it. (Score:4, Interesting)
Humanity won't be in risk from this but if it crashes in a densely populated area like US east coast, central Europe, India or China then the death toll can be considerable. 100 million dead is a possibility.
No way. That's a third of the US population. Can't think of any place in the world where the population is packed densely enough to cause those kinds of casualties.
Striking rock, an iron meteorite would create a crater no more than 4km across. At 10 kilometers distance, well built structures would remain standing. You'd get dead people from flying glass and random rocks, but that's about it. At 20km, you should have no casualties at all, except maybe a few hundred dying from the resultant earthquake. Even if it hit Delhi (one of the top 10 densest cities in the world, population 12 million), I wouldn't expect more than 5 million casualties as a maximum, and probably far fewer.
Re:Astrometrics ain't like quantum mechanics boy.. (Score:2, Interesting)
A coin flip is exactly as probabilistic an event as this possible impact.
Erm, nope. A coin flip is an exact statement about the probability of a random event, the chance of an asteroid impact represents our ignorance of the true state. One is frequentist probability, the other is a Bayesian posterior probability.