OK, so the asteroid ins’t going to hit. Damn. I was so looking forward to not having to engage in human conversation after 2014.
But, let’s say it was going to hit and the world went insane and, using characteristic bad decision-making skills, decided it wanted to survive. Since the thing is only 3/4 of a mile long why not do a space program to line up a bunch of H-bombs along one side and set them off simultaneously? Wouldn’t that cause it to change course? We’d probably still catch a little fudge but, overall, I think our chances would be greatly improved.
There’s something wrong with this plan, isn’t there?
Well, there’s something certainly wrong with all your negativity about humanity, but putting that aside, detonating H-bombs near an asteroid isn’t necessarily the best way to go about it, depending on the rock’s composition. A gentler push over a longer period of time might be worthwhile, as in embedding a spaceship into the side of asteroid and letting it give the rock a gradual push with its engines over a period of several days.
In any event, the matter deserves thorough study and careful, thoughtful decision-making.
Well, sure… but what if there’s no time for that? If a chunk of rock appeared out of left field, with only a few days to respond, I don’t doubt we’d try something… but what options (good or bad) would be available?
The problem is that we really don’t understand the internal make up of asteroids. Some are simply ice and rock, others solid iron/nickel. Are they loose aggregates or solid pieces? Remember no air so no explosive shockwave to knock things over with, you’d be relying solely on vaporized asteroid to move the thing, and the damn thing is huge. Would it simply absorb the energy and fragment into largely intact pieces or would we heat a pocket of ice that would in turn vaporize and nudge the rock into the earth.
As Bryan said, thoughtful consideration is required. Slow and steady might be the best bet.
Oh and before anyone else says it, we could mine the damn things.
On preview I see Engywook post. Basically if we’ve got months to prepare we’re screwed. ICBMs are design to get into space. Besides, remember all the great discussions on using a rocket to hit an ICBM? Image the “ICBM” is traveling at 31 km per second!
Maybe a year or so might give us a chance to modify enough to hit/ablate enough asteroid to get to pass us by. The biggest problem is that we don’t know enough about NEOs. We need to know they’re coming before we can do anything about them
On preview I see Engywook’s post. Basically if we’ve got months to prepare we’re screwed. ICBMs are not designed to travel into space (sub orbital ballistic flight does not count). Besides, remember all the great discussions on using a rocket to hit an ICBM? Image the “ICBM” is traveling at 31 km per second!
If researchers are right and most asteroids are “gravel piles” rather than rocks, it might be impossible to apply thrust with an engine mounted to the asteroid, and certainly impossible to blow them up (except by hitting them with a second asteroid.)
On the other hand, project orion seems tailor made for solving the problem.
In project orion, a-bombs are placed next to heavy tungsten plates, and when each bomb fires, the pulse of vaporized tungsten impacts the bottom of the Orion spacecraft, applying distributed thrust. The Orion study worked out the whole scheme, and showed that ships the size of aircraft carriers were feasible.
So, to deflect an asteriod, just lob a long stream of fractional-kiloton Orion fuel-bombs at it, detonating them at the proper distance to “illuminate” the whole asteroid with hyper-velocity tungsten vapor.
If we had a fleet of nuclear-pulse asteroid mining craft out there already, then pushing asteroids around would become almost trivial. But then it would also become possible to wipe out a whole country by miscalculating an asteroid orbit change. Industrial accident!
Space is weightless in the sense that there’s no gravity but moving objects still have an inertial mass you need to overcome, justthefacts. It’s like trying to push a freighter by swimming against it.
That’s one of those problems with scientific terms vs everyday langauge.
Never forget, given enough time small forces can move large masses. It depends on when and for how long you do it.
Let us take this hunk of rock moving at 31000 m/s and massing at 2.6x10^12 kg. Let us make it move in a straight line (x) for simplicity’s sake and have it 1 AU away from the Earth.
Subject it instantly to 10^6 N of force in the (y) direction. You would have moved the asteroid by ~4500 km in the (y) direction by the time the thing reached Earth. Given the Earth is ~12600 km across that’s pretty impressive work and likely the difference between an unpleasant geology lesson or paying the mortgage.
i’ll trust you math. But if you are going to move an asteroid you would need to position a “rocket type” engine facing down, pointing towards the center of the mass, then “hit the gas”. If not you would just get it to spin, not really change directions. Since i am assuming it would be impossible tell where the true center is i think we would just make it mad by spinning it. You really don’t want an angry asteroid.
That wasn’t the point. You doubted the ability of a small force to move a very massive rock. I showed how it could be done. Besides, so long as the result forces move the thing out of the path of the Earth who cares where it goes? I mean until next time that is.
If you’re objecting to the use of a classic rocket fine, use a mass driver mounted on the surface with a sensor that has it fire only when the orientation is right.
Or use nuclear weapons to flash vaporize the asteroid’s surface layers. The resultant gasses could push it away. Rinse and repeat as needed.
The details of course are complex but that’s were the “thoughtful consideration part comes in”
One idea is to detonate a nuclear weapon a few asteroid radii from the surface. The pressure from the blast is negligible. However, the heat will flash vaporize the surface of the asteroid, and that vapor will expand rapidly. This supplies a push on the asteroid in a similar way as a rocket engine. Some calculations show this to be a good way to divert an asteroid (“Rain of Iron and Ice”, John Lewis-- a good book!). It might even work on a rubble pile.
What about attaching a rocket or detonating a nuke behind the asteroid. Instead of deflecting it or slowing it down, speed it up, so that it intersects Earths orbit a few hours before earth arrives.