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Q: Meteorite entry speed
Submitted By: troon, 46 days, 1 hour, 40 minutes ago
Whenever objects from space that have a risk of crashing into Earth are discussed, there's always the assumption that they'll be going slowly enough to give us time to detect them and possibly do something about it.
What's stopping something coming in from interstellar space at very high speed, like 1% of c or something like that?
Also, why is there no Science category here?
Please try not to post duplicate answers... if you see an answer that you want to post, just add a vote to it and you can add a note as well. Thank You
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A few thoughts
Submitted By: Agent0100 ( 43 days, 23 hours, 59 minutes ago )
I think one thing to consider is how a large object like that would obtain a speed as high as 1% c. It's probably not very likely. Some phenomenon would have to push a lump of rock or ice with some very significant force to get it to that velocity. That push would almost certainly melt and thus destroy an ice block. The rock lump would likely also be destroyed by such a sudden push. But let's assume for the moment that a rocky lump in space is travelling at a huge velocity. Unless it originated somewhere very near us, it has to travel through a lot of dust and gas clouds on its way here. These will not only slow it down, but in some cases make it smaller. So I think perhaps some of the reason it is assumed that they are relatively slow moving is simple statistics.
As to why there isn't a science category here, I am just as baffled. I think a lot of people would really enjoy not having to scour the web for answers to non-textbook questions.
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on asteroids
Submitted By: AnotherBrian ( 32 days, 9 hours, 59 minutes ago )
The reason we will have time to detect asteroids is not that they are moving slowly, it's that they are not one a straight line course for us. The asteroids that you here about have been orbiting the sun like us for centuries and by tracking them very precisely we can apply some orbital dynamics to run the clock forward to see if it's path will intersect the earth. These are the ones we could maybe do something about it because we can reach it.
If there is an asteroid coming in from deep space at .01c I wouldn't be all that surprised if it went straight through the earth. We would never see it comming because we wouldn't know where to look for it. Even if it was moving at 6 mph, we would be moving and would have no way of knowing where to look. If by some nice alien clued us in, there would be nothing we could do to change it's corse because we couldn't reach it. Actually, we could shine light at it to alter it's course (light might be able to exert a miniscule mechanical force on it probably not be enough force or time). We could move the earth a little bit but probably not enough so that it's gravitational field wouldn't just suck it in any ways.
If there is an asteroid coming in from deep space at .01c I wouldn't be all that surprised if it went straight through the earth. We would never see it comming because we wouldn't know where to look for it. Even if it was moving at 6 mph, we would be moving and would have no way of knowing where to look. If by some nice alien clued us in, there would be nothing we could do to change it's corse because we couldn't reach it. Actually, we could shine light at it to alter it's course (light might be able to exert a miniscule mechanical force on it probably not be enough force or time). We could move the earth a little bit but probably not enough so that it's gravitational field wouldn't just suck it in any ways.