We can survive killer asteroids — but it won’t be easy
April 4, 2012
(Credit: Don Davis)
More than a thousand known asteroids are classed as “potentially hazardous,” based on size and trajectory, says astronomer Neil deGrasse Tyson in Wired Science.
Currently, it looks doable to develop an early-warning and defense system that could protect the human species from impactors larger than a kilometer wide. … Smaller ones, which reflect much less light and are therefore much harder to detect at great distances, carry enough energy to incinerate entire nations, but they don’t put the human species at risk of extinction.
One killer asteroid we’ve been monitoring is Apophis, which could hit Earth in 2036, likely slamming into the Pacific Ocean. The tsunami it creates will devastate all the coastlines of the Pacific Rim.
The gravitational tractor is a favorite solution. This involves parking a probe in space near the killer asteroid. As their mutual gravity draws the probe to the asteroid, an array of retro rockets fires, instead causing the asteroid to draw toward the probe and off its collision course with Earth.
Comments (15)
by tim333
For serious research and bit of laugh I think we should practice asteroid deflection by nuking one. We’ve got the rockets, we’ve got the nukes, we can do it!
by Chrispium
@LordPenguin The asteroid could be rotating or it could have a fragile surface making it difficult to know where your force vectors are pointing.
From a stationary position near the asteroid you wont have those kinds of problems to contend with. To keep the distance between craft and asteroid you’ll only need a small amount of force so can use very long lasting ion-engines.
As long as you start while the asteroid is a long way from earth you’ll only need to make a very small course correction, which in turn will require only a small amount of energy, meaning even a small lightweight craft of a couple tonnes can do it. Even if the asteroid weighs mega-tonnes.
@R
So your solution to pollution is to cause even more pollution?
To help biodiversity you suggest an extinction event?
Smash the earth to save the earth?
Why would you want an asteroid to do it?
Aren’t you happy that we are already making your wish come true?
by R
Chrispium, you’re right. An asteroid is too messy. A cleaner alternative would be an illness that only affects humans and wipes out 90% of them. Anything that would bring human supply/demand and market based economies to a halt for a long time will do the trick and allow the earth to recover its air, oceans, forests, biodiversity, habitats, etc . Governments and corporations will never accomplish it. An outside event is required.
by R
And for the record, I am neither happy about it nor do I wish it. There just doesn’t appear to be any feasible alternative to save the earth than some kind of natural disaster that shuts down the human activity that’s destroying it.
by Lord Penguin
Why not land on the asteroid and fire the rocket from there? I think the energy required to move something large enough to pull the asteroid away from the gravity between the two objects would be at least as much as directly pushing it.
by Lord Penguin
Also, a laser/solar reflector defense might also work by slowly pushing the rock, especially if we start early. My concern is that it might be used for war.
Asteroids like this one could be used for mining sometime in the future. Having them so close would make getting the resources back down to earth easier, and mining operations could slowly dismantle the rock, and let the small pieces fall to earth and burn up in the atmosphere.
by Dan Robinson
I agree with Lord Penguin that pushing makes more sense than pulling by gravity. For one thing, much of the rocket blast would hit the asteroid, reducing the desired effect. What direction to push? If it’s predicted to hit dead center, almost any direction, with enough force, will mean a miss, but maybe just until next year. If the asteroid is spinning, the only places you might be able to push easily are at the poles. Or maybe anchor the rocket to the asteroid and push intermittently with each rotation. Seems like more unknown danger might be something that we’ve never seen before in a long cometary orbit. Best to keep a fueled rocket ready in orbit. Just thoughts from an amateur.
by kinome79
One I can imagine landing an unmanned aircraft on an asteroid is hard. Two, if you land on it the force of the rockets are being applied to a point on the asteroid and you’d have to put a lot of effort into controlling the direction and rotation of the asteroid where as the force of gravity pulls on the asteroid as a whole.
by R
If the human population were decimated by a very large asteroid then that should be enough to completely shut down market economies and allow the earth to recover its air, oceans, forests, biodiversity, habitats, etc. These types of problems will never be solved by the “collective action” of governments. Global destruction would bring about the necessary changes without so much as even a debate. Besides, the earth doesn’t need 7 billion humans anyway. It can only support about 3 billion sustainably and in total harmony with nature.
by Buffalo Bill
Oh, so you’re pro-mass murder then?
Good to know.
by Bob V
Haven’t you heard, asteroids are a minor concern. The USA is much too busy with issues of contraception, abortion, marriage between one man and one woman, and when life, itself, actually begins.
by GatorALLin
Love to have the world pitch in and contribute to a project like this…. so often it seems a space race of USA vs. the Russians (past) or now vs. China… this project is to protect the entire world of course…so would be cool to see all nations pitching in beyond just cash… I am sure USA could just do this project solo… but would be cool to see what could happen from a positive chance to ALL be on the same side…
by Anonymous
Has anyone determined the minimum size an asteroid must be before we wouldn’t be able to do anything to deflect/destroy it with current technology? or, stated otherwise, how big does one of these things have to be to make whimpering in a corner our only possible option?
by Nick
That is not an option. Impossible is nothing.
by Thomas Jensen
@anonymous. It depends mostly on how early our warning would be. If we have enough time, we can deflect even a massive asteroid, since in space, you can move huge objects with very little force if you’ve got enough time. Don’t have time? Resort to brute force. If something of even modest size is discovered only days before impact, we can only whimper and brace ourselves.