Originally posted by movetovanuatu
It wasn't moving really that fast, slower than I thought meteorites could travel. I was precluded from viewing the impact because I had to take the
sharp bends by the lake .
Meteors can be
very deceptive.
There are some very slow meteors that can be just as slow as the fastest satellites travel (about 11 km/s), but even a fast meteor can
appear
to be slow, or even to stand still!
How can this be? you might say...
The answer is
perspective...
Consider a meteoroid entering our atmosphere, and heading
directly towards you. Although it is moving fast, to you it would not appear to move
at all - it would look like a star appeared, suddenly brightened, then dissipated.
In order to see the
true speed of a meteor you have to be observing it from the side ( high in the sky, and away from the
radiant). Anything else (if it even traveling slightly towards/away from you), and
it's impossible to determine it's true speed by just observing it.
Also, due to Earth's (and our atmosphere's) curvature, and the fact that meteors can be surprisingly bright, a meteor tat is still high up in the
atmosphere, can
appear to be close to the ground, and near by, even if it is high up in the
atmosphere and a long way away. Meteors become visible at around 100 km altitude, and due to their brightness this means they can be seen from many
hundreds of km away.
Consider this diagram It's exaggerated, but demonstrates what is going on.:
[atsimg]http://files.abovetopsecret.com/images/member/95efe8242439.jpg[/atsimg]
If you are the observer (B), it will look to you like the meteor has fallen just behind the mountain, but the observer (A) who is observing the same
meteor from a few hundred miles from your location, and over the horizon will see something completely different.
See how easy it is for a meteor to look like it is doing something that it is not?