So we looked at near-earth asteroids because, well, they are near-earth. Turned out none of them is on a collision course with Earth in the foreseeable future. This is good, of course, but it does not mean that the estimated risk went down—what happened was that it did not go up and that’s a different thing.
I had the impression that the near-earth ones were the ones that, averaged over earth’s history, are the bulk of the problem. So if the current crop of near-earth asteroids aren’t likely to hit us in the historically-near future, doesn’t that mean that our near-future risk of impact is below the long-term average risk?
(I am not an astronomer and do not vouch for “NEAs are the main part of the risk” from personal knowledge.)
Well, IANAAE (I Am Not An Astronomer Either) but I think that with respect to historical record, there are these considerations:
We’re pretty sure that large asteroids (defined as above) have struck Earth before. We are not sure where they came from.
With the passage of time the frequency of collisions should decline as Earth sweeps a path free of other space objects. So the future risk of impact is below the historical risk of impact.
The extinction-scale impact risk seems to be very small. In geologically recent times Earth was not bombarded by asteroids.
I had the impression that the near-earth ones were the ones that, averaged over earth’s history, are the bulk of the problem. So if the current crop of near-earth asteroids aren’t likely to hit us in the historically-near future, doesn’t that mean that our near-future risk of impact is below the long-term average risk?
(I am not an astronomer and do not vouch for “NEAs are the main part of the risk” from personal knowledge.)
Well, IANAAE (I Am Not An Astronomer Either) but I think that with respect to historical record, there are these considerations:
We’re pretty sure that large asteroids (defined as above) have struck Earth before. We are not sure where they came from.
With the passage of time the frequency of collisions should decline as Earth sweeps a path free of other space objects. So the future risk of impact is below the historical risk of impact.
The extinction-scale impact risk seems to be very small. In geologically recent times Earth was not bombarded by asteroids.