Originally posted by MysterX
Seeing as no other 'tunguska event' fragments have ever been found, and knowing that the Earth has constantly been bombarded with asteroids and comets
since it began, even if there turns out to be some asteroid / meteorite fragment buried at the bottom of the lake, i don't see how it could be proven
to be related to the 1908 event one way or the other?
It's true that Earth has been constantly bombarded, but that bombardment has slowed down significantly since Earth formed, and many of the objects out
there have either coalesced to form planets or been sucked into the gravity wells of the larger solar system bodies like the Sun and Jupiter.
In the mean time, the Earth's crust has been constantly renewing itself, so old falls buried just beneath the surface would have been incorporated
into our planet.
On top of this, since the atmosphere formed, it's been stopping all but the largest of objects from impacting the ground with significant force. Most
of the large (1-50m) objects that enter our atmosphere break up or "airburst" just as the Tunguska object did, but usually at high enough altitudes
that there is very little effect on the ground.
In the case of Tunguska, the airburst was low enough to cause significant damage on the ground, probably due to the low angle of entry. If it had come
in at a much higher angle, the forces acting on the object would have been increased, and the object would probably have disintegrated at a much
higher altitude, therefore causing much less damage (perhaps even none at all).
I should add that the Tunguska object seems to have been large enough that a significant portion of it survived the airburst, and appears to have left
the crater where the lake is. Most objects that frequently enter the atmosphere more or less completely break up at tens of km altitude, and any
surviving pieces are usually too small to maintain their momentum, so they hit the ground with relatively little energy.
The point I'm making here, is that lots of things need to "fall into place" before an object will impact the ground - the angle, speed, composition
all have to be just right, and in many cases it's not, so although quite sizable objects hit our atmosphere relatively frequently, one that's big
enough to make it down to the ground and leave a crater is actually quite a rare thing.
So, if you were to find a meteorite buried just beneath Lake Cheko, that lines up with point where the airburst occurred and with the direction of
travel that witnesses reported at the time of the event, that would be very strong evidence that the meteorite was connected to the event that took
place in 1908.
edit on 18-5-2012 by FireballStorm because: fixed typo/added a little extra to the post