Astronomers
have been aware of the threat from space for a long time, but
scant attention was given to it.
Then Comet Schumaker - Levi was discovered. It was the first time
the world had a "grand stand" view of
the colossal power in these objects. (E= mv2 / 2). The first terrestrial
impacts occurred very long ago,
and is stooped in myths and legends, within superstitions and lore, globally.
Tanguska was quite recent, and regularly we have massive aerial
impacts of quite a couple of nuclear bombs I have had the privilege of seeing three bolides, almost as bright as the sun and two exploding about 50 kM up.
These object concern astronomers and now
a fully fledged search is under way. A small asteroid, 1km X 1km,
is quite capable of obliterating a continent.
On an astronomical scale, that is quite small. It will take only
a 10 km asteroid to wipe out the planet.
Many legends tell of fire and thunder raining down from the sky and a gods's wrath as fire consumed the people/cities and devastation that followed. People struck with blindness and turning into salt pillars. The foul smell of hell and people burning alive.
This is a fairly accurate description of a Tanguska Impact
