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Nuking an asteroid out of the sky to protect the Earth is great fodder for the silver screen. However, new research suggests that simply exploding a threatening space rock may not save us quite as simply as we expect.
Scientists find rogue asteroids roaming our solar system often -- just last month they discovered one that could strike the Earth -- and one of the ways to deal with these potential threats is to impact them, knocking them off course. NASA is currently planning an asteroid redirect mission where it'll send a kamikaze spacecraft into the moonlet of an asteroid known as Didymos, barreling into the rock to shoo it away.
Yet, we haven't had a lot of opportunities to study asteroids up close, so we can't appreciate exactly how they are structured or how they might be destroyed. It has been believed that bigger asteroids may be easier to destroy because they would be more likely to have cracks and weaknesses that make them easy to blow apart. Thus, if an asteroid were to threaten our peaceful existence, what should we do?
"Are we better off breaking it into small pieces, or nudging it to go a different direction? And if the latter, how much force should we hit it with to move it away without causing it to break?" asks Charles El Mir, lead author on the study, in a press release. Those questions are exactly what he and a team at Johns Hopkins University set out to answer.
Their findings, published in an upcoming issue of the journal Icarus, are based on computer simulations of asteroid impacts. They plugged in parameters that digitally recapitulated a small asteroid, about 1 kilometer wide, impacting a large asteroid, about 25 times bigger, while travelling at 5 kilometers per second.
A previous model had shown that the large asteroid was obliterated by this type of collision -- but the Johns Hopkins team found an entirely different endgame. According to their modelling, the asteroid would greatly fracture in the fractions of a second after an impact. [...] Over the hours after an impact though, the team showed the large asteroid broke apart into smaller pieces but wasn't entirely obliterated as previous research had shown. The fragments that flew off the asteroid were then pulled back together by the damaged asteroid core, due to the overwhelming effect of gravity.
(Score: 0) by Anonymous Coward on Friday March 08 2019, @05:48PM (3 children)
Asteroids come in a few flavors and how we deal with them is going to largely depend on what flavor they are.
#1 The large rocky asteroids. They should be deflected not destroyed. Because as the article says, if you blow them up, they will just turn into the 3rd type which are damn near impossible to deal with. The best solution would be to put them into earth orbit where they could serve as mining colonies and orbital construction platforms. Their gravity might be enough to disrupt space debris and function as a vacuum cleaner for all the space junk in LEO. Could also disrupt normal satellites as well. But maybe we could put them in orbit around Luna and have our very own moonmoons.
#2 Dirty snowballs. These are comets and comet like objects. They are hard to deal with because the frozen shit unfreezes as it gets closer to the sun and begins outgassing, turning the thing into a rocket with randomly firing engines. Deflecting these won't do anything because their movement is going to be random. The best option is to heat them, forcing them to outgas in the direction we want them to go. That's going to require a fleet of landers with RTGs, solar panels and other strong sources of heat. It will have to be direct heat too because convection doesn't exist in the vacuum of space.
#3 Standard rubble pile. You really can't do much with these. Imagine a large landslide gaining speed and energy as it rushes down a mountain side. That's what this is. It obeys the same physics and because it is a collection of gravitationally bound smaller solid objects, behaving in a fluid like manner. Anything you do to try and disrupt it would to add to the mess. Blowing it up is a really bad idea, you just make a lot of smaller but still rather huge rocks whilst imparting a nuclear bomb's worth of kinetic energy to the mass. You can't attach solar sails because there's nothing to attach to. You can't deflect it with a nuclear blast ahead or to the side, but the nuclear energy might be able to slow the pile down for awhile. Best bet is to literally build a network of something like cubesats to land on the components and trebuchet the constituents away. It would have the same effect as forced outgasing for the dirty snowballs.
(Score: 0, Interesting) by Anonymous Coward on Friday March 08 2019, @06:07PM (2 children)
This doesnt exist. Every mission to a comet shows a hard as rock and dark as coal object. Philae already bounced off due to this assumption, now you are putting the entire earth at risk.
(Score: 0) by Anonymous Coward on Friday March 08 2019, @06:27PM
Ooops I think you're right, my bad!
Still using RTGs to force it to outgas in the direction we want, essentially piloting it around the solar system and maybe crashing it into venus or the sun is the best bet since the rocket fuel is inside the rock, we just need to assert control.
https://m.xkcd.com/2115/ [xkcd.com]
(Score: 0) by Anonymous Coward on Friday March 08 2019, @06:53PM
At worst the parent should be modded +1 funny or maybe even +1 insightful. Why decided he was trolling? He's right, I made a mistake in my dirty snowball analysis. Age related memory problems, had to update my knowledge. Still it was a good reply and doesn't seem to be trolling at all.