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## Paintball Pellets As a Tool To Deflect Asteroids153

SternisheFan sends this quote from an article at MIT's Technology Review: "In the event that a giant asteroid is headed toward Earth, you’d better hope that it’s blindingly white. A pale asteroid would reflect sunlight — and over time, this bouncing of photons off its surface could create enough of a force to push the asteroid off its course. How might one encourage such a deflection? The answer, according to an MIT graduate student: with a volley or two of space-launched paintballs. Sung Wook Paek, a graduate student in MIT’s Department of Aeronautics and Astronautics, says if timed just right, pellets full of paint powder, launched in two rounds from a spacecraft at relatively close distance, would cover the front and back of an asteroid, more than doubling its reflectivity, or albedo. The initial force from the pellets would bump an asteroid off course; over time, the sun’s photons would deflect the asteroid even more."
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## Paintball Pellets As a Tool To Deflect Asteroids

• #### Re:Why worry (Score:4, Insightful)

on Saturday October 27, 2012 @05:05PM (#41792137)

That's true, but there's something more unnerving about losing the entire human race.

• #### Probability and magnitude are both relevant (Score:5, Insightful)

on Saturday October 27, 2012 @05:05PM (#41792139)

The chance of getting killed by a car when crossing the road is orders of magnitude larger than the chance of getting killed by an asteroid.

True. However one asteroid can kill all of us, unlike one car.

The probability of an event must be combined with the magnitude of an event when assessing the risk.

• #### Re:Why worry (Score:5, Insightful)

on Saturday October 27, 2012 @05:40PM (#41792321)

Your point is valid, except that the problem with estimates like that is while they are useful for estimating the risk, they don't say much about whether an asteroid of the required size is actually on its way. In other words, we don't get a do-over if the rock shows up earlier than we thought it would. Not to mention that rocks of the necessary size could be generated by the effects of a collision with another body which then suddenly expels a rock on a collision course with Earth. In that situation, we may well not see it coming until just before the window in which we need to take action to deflect it.

Existential threats like asteroid impacts are situations that you start planning to deal with as soon as you have the knowledge to do so. There is really no reason not to, since given the extreme consequences, it doesn't seem particularly absurd to maintain those plans in a constant state of revision. We know that an asteroid of sufficient size is going to hit again. It's only a matter of time. Maybe that time is a million years from now, maybe it's a week from now. I grant that we shouldn't be building an expensive specialized asteroid defense grid or mineshaft shelter/habitats right now, but an actual plan that could be feasible in the event that we end up with an unforeseen visitor is the right thing to do. In this case, scientists realize that it is very easy to miss Earth if you poke at the asteroid just a little bit when it is far enough out. It's a reasonable plan that really should not require that much expenditure to make happen, if required.

• #### Re:why not a simple rocket (Score:4, Insightful)

on Saturday October 27, 2012 @05:53PM (#41792419) Homepage

Actually 'landing' on it would be a huge problem. An asteroid is not typically one large smooth rock, after all. And it will definitely be 'tumbling' in relation to you as well. So it would be a very difficult docking maneuver on an uncertain surface. And remember these things arent large enough to generate enough gravity to notice either. So it's basically all in zero-g.

Spraying a load of paint at it would be orders of magnitutude easier, and still wouldnt exactly be easy.

• #### Re:Too tenuous (Score:5, Insightful)

on Saturday October 27, 2012 @05:57PM (#41792461)

That's a long shot plan right there.

I think sending Bruce Willis with a thermonuclear device and a boatload of family drama might work even better.

Modded funny but is actually insightful. What would happen is that the chance of the giant asteroid actually hitting the earth will start out less than certain, so the large expense of sending a mission to deflect it far from earth using a gentle push would result in debate and delay. Then the odds of impact will increase, but the expense of the mission will still be high. We will piss and moan, and a loud minority of self-anointed space experts who begin to say that the rock is actually going to miss, that it is all a liberal/conservative/alien conspiracy, that there is really no asteroid, etc. will get a lot of press. Finally the thing will be visible from earth and the shit will hit the fan but by then it will be too late to use mild persuasion, and we will have to send up whoever passes for Bruce Willis with a crapload of nukes. We will blow it into chunks, maybe even into gravel whose kinetic energy strips away the atmosphere.

• #### Re:Why worry (Score:5, Insightful)

on Saturday October 27, 2012 @06:14PM (#41792563)

Problem is, the herd thinning would not be done by brains power but by purchasing power. Now imagine an Earth where only managers and bankers will survive. The living will envy the dead.

It is much harder to find a job than to keep one.

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