Estonia and meteor hits

According to last night’s Amazing Race, Estonia has the highest number of craters due to meteorite hits (per unit of area) in the world.

Why would they be concentrated in one area like that?

This article attributes it simply to the interest in the subject there and the corresponding number of geological studies:

In other words, the density of impact craters in Estonia is close to what would be expected worldwide. There seem to be a relatively large number because Estonia has been better studied than most places.

So it’s like a geologic confirmation bias. Cool!

Thanks, Colibri.

Because it’s estonia than most other places.

I’m not a geologist or a meteorologist (hah!), but I can guess two reasons. First, the number of craters you see in an area isn’t just a matter of how many meteorites have hit, but also how much erosion & other geological forces have acted in a given area. It’s not that more meteorites have hit the area, it’s just that the craters haven’t eroded away as quickly.

Also, think about the statistics. Some small countries will have more craters than average, and some will have less. For smaller countries like Estonia, an extra crater or two corresponds to a much larger change in the rate of craters per square mile than it would in, say, Canada.

Looks askance at Askance. :stuck_out_tongue:

An interesting co-incidence would be the Tunguska Incident had it happened about 12 hours (give or take) earlier would have occured over St Petersburg, Russia, which isn’t too far from Estonia.

That’s the most bogus “coincidence” ever.
With +/- 12 hours leeway, the Tungusja Incident would have occurred at the same latitude anywhere around the entire globe. :smack:

Well, ***some ***place has to have the most; if it were somewhere else, you’d still be looking for a reason.

Impact map and list for Europe:
http://www.unb.ca/passc/ImpactDatabase/europe.html

Exactly. Even if meteor strikes are completely random (which they should be), there will be concentrations in particular places simply by chance.

It’s not clear to me they should be randomly distributed. Random by longitude yes, but not necessarily by latitude. If there is a larger concentration of potentials along the ecliptic, then there might be more hits at those portions of the earth (approx + or - 23 degrees latitude) that can be on the ecliptic. Of course I suspect it’d the plane of Jupiter’s orbit rather than Earth’s that might matter more, and I’m not sure they are concentrated on the ecliptic in any case.

In addition if you think of the Earth as moving along its orbit in a direction roughly perpendicular to its axis of rotation then the volume of space swept out by one square mile at the equator will be larger than the volume swept out by one square mile near a pole so if the density of potentials is constant, you’d expect more hits near the equator.

While the most asteroids have orbits close to the ecliptic, they are more spread out than most planets, with some having orbits tilted 30 or even 40 degrees. I would think they would be crosssing the Earth’s orbit in a band considerably wider than the Earth’s diameter.

After more thought, I suspect you’re right. I think the sweeping out argument is still valid. It’s true the meteors are moving as well and could come from any angle, but I’d think sine they’re also in orbit around the sun, their velocities would be comparable to the Earth’s velocity so their will be a non-negligible component of the Earth’s velocity still to deal with. And certainly one square mile of the earth at the equator sweeps out more volume than one square mile near the poles as the Earth revolves around the sun.

Why should they be random? Earth is in a predictable orbit, with a well known rotation and precession.

Meteors are mostly asteroids, right? They come from a belt with its own geometry. What causes one to pop free, and to hit the earth just as it crosses its orbit does not strike me as likely a completely random process.

All the more so, because only objects of a certain size and composition will survive the atmosphere.

While I agree that it can appear random, it seems to me that there is one or more non-random processes popping those asteroids or other object out and spinning them towards earth. Once they are on the collision path, their fate is sealed.

But are the locations of landings random on the earth as a globe? Doesn’t seem likely to me OTTOMH that the density of landings would be equal all over earth at a given latitude and longitude because of the complex motions and geometry involved.

And let’s not forget the moon and possibly Mars which seem to have taken their fair shares of hits too - to what extent do their orbital dynamics prevent the landings on earth from being independently distributed?

What has that got to do with anything? That might determine where the Earth is in its orbit when a meteorite strikes, but not where it hits on the surface.

This just indicates a fundamental lack of understanding of the process. Asteroids certainly don’t “pop free” of the belt and enter Earth’s orbit.

You seem to be confusing “random” and “equal.” A random pattern will show clumping in some places and fewer impacts elsewhere, rather than being “equal all over the Earth.”

Why should they?

I think people sometimes don’t realize just how big a meteor stream (which is mostly made up of comet debris, not asteroids) is compared to the Earth.

When we watch meteor showers it looks as though an occasional piece of debris is getting flicked into our atmosphere from a comparatively small region of the sky over a huge expanse of the immense surface of the Earth’s forward-facing hemisphere, so it seems counterintuitive that it should be about equally likely to hit any spot on the hemisphere.

But in fact, as this diagram (first on the right) shows, meteor streams are tens of thousands of kilometers in diameter. The Earth really does get fully immersed in them as it passes through, so no part of its surface is more likely than any other part to take a higher than average number of hits.