What If? Asteroid impact in 5 years

[JagerIV]

Tomorrow, a fast moving object out past Jupiter is noticed, that seems to have a fairly high chance of impact (10%, with large error bars) in 5 years. The object is massive, about 50 km wide and moving very quickly, suggesting an origin outside the solar system. The object is predicted to be over a 100x heavier and moving significantly faster than the dinosaur killer.

As the object gets closer, the certainty of impact, increases, reaching about 90% by the start of the last year before impact.

1) What would people in general do?

2) What would you do?

 

[Francis Urquhart]

What would people in general do?

Probably every permutation of actions imaginable. Ranging from denial to paralysed fear to "let's party like there's no tomorrow (because there isn't)" Democrats will start to impeach PDJT for collusion with the asteroid.

What would you do?

Last day, go down to my deep bunker, sit on the throne, put my head between my knees and kiss my ass goodbye.

 

[Deleted member]

China and Russia collaborate on a ground launched Orion to take it out.

 

[Bacle]

5 years lead time...get a mapped trajectory, crash-build a gav tractor and/or nuke pulse pusher/launcher, and start to move the bitch so it either ends up out of the solar system, in the sun, or in a gas giant.

 

[Deleted member]

The nuclear pulse pusher is easiest, we get it spaceborne from direct ground launch, zero-zero with the impactor and then start thrusting it out of the way. We only have to input trivial speed in the right direction to make its interaction with Earth a gravitational slingshot instead of an impact. We may have our heads in the sand but China and Russia won’t.

 

[JagerIV]

5 years lead time...get a mapped trajectory, crash-build a gav tractor and/or nuke pulse pusher/launcher, and start to move the bitch so it either ends up out of the solar system, in the sun, or in a gas giant.

I'm not sure you really have the time to do that to such a large object. Something that size weighs something like 100 trillion tons.

 

[Bacle]

I'm not sure you really have the time to do that to such a large object. Something that size weighs something like 100 trillion tons.

So grav tractor on one side, hit the opposite side with nukes, and push that bitch enough to miss Earth.

 

[Deleted member]

I'm not sure you really have the time to do that to such a large object. Something that size weighs something like 100 trillion tons.

My quick back of the envelop calculation says an Orion will accelerate that mass to 0.28m/s after ten days of continuous firing using up all of its nuclear charge fuel after take-off, acceleration, and de-acceleration to contact taking all in all about ninety days to intercept off Jupiter. Assuming it is still a year out, that gives us 8,830 klicks of positional change from the imparted velocity by the time it reaches the position that Earth should be in. That clears the Earth and its atmosphere by 2,400 klicks; what that means is that we can still engineer a miss by a single Orion if it launches as little as one year before the impact. Which is nice since that means if the project is started a year after detection, we have three years to complete construction and we only have to commit to the ground launch when we have 90% confidence of the impact. Since an Orion can be built to submarine standards and we already have the nukes, three years is a perfectly plausible construction engineering schedule.

 

[JagerIV]

Your talking about an extremely powerful Orion from what I can tell: intercepting something out near Jupiter for example takes a minimum of 1-2 years even with energetic transfer orbits with delta vs of 30-40 km, which is the extreme of Orion designs I have seen.

10 days of continuous firing with an Orion is something like, assuming a pulse every 2 seconds, is about 400-500 thousand bombs. Each pulse unit is like 100 kg, so your discussing some 40-50 thousand tons of bombs. And this has to be the payload to get to the Asteroid. Getting it to the Asteroid I think requires a mass ratio of 2, so your talking about another 500-1000 thousand bombs.

At least that's my quick look at things.

Assuming 100 Trillion tons, you need to apply about 50 petajoules of energy to move it about 1 m/s. Which isn't actually that much looking it up. I mean, it still is, but a megaton is only about 4 petajoules, so if you could apply about 12.5 megatons to the asteroid in a solid push in the right direction, it would move out of the way. The problem is trying to get that applied as a push, rather than having it go into simply vaporizing the top cm of it into plasma or breaking rocks.

 

[Deleted member]

It assumes a slower firing rate of much larger bombs. The physics package of a small bomb can be made into a large bomb without much effort -- and unfortunately anything beyond that statement (and the fact that it's obviously true because of dial-a-yield) is not a talk-about subject. The intercept was on the basis of continuous acceleration for several days at each end of the approach, at one gravity.

 

[Deleted member]

Huh. It's interesting, you're right; I was focused on solving the wrong problem.

 

[Scottty]

If there's only a 10% probability of impact, you might want to refine the predictions a bit. Would be a shame if your change to the orbit of the asteroid ended up causing the impact rather than preventing it.

 

[Deleted member]

If there's only a 10% probability of impact, you might want to refine the predictions a bit. Would be a shame if your change to the orbit of the asteroid ended up causing the impact rather than preventing it.

It's a serious enough risk that you would want to proceed with the entire program up to and including landing on the asteroid even as you were refining what the burns would need to be.