[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: impacts are cool!
> Peter Von Sholly wrote:
> > What if the impact(s) were/was in the ocean? Which the odds would seem to
> > favor.
Augustus T. White wrote:
> It wouldn't make any difference. My calculator is AWOL, but we can do
> some order-of-magnitude math for a really impressive strike. Imagine >a
> large, 10km object with a modest density of 1.5 g/cm3 impacting the >earth
> with a velocity of 10 km/sec. The mass comes to something like >7.5 x 10(17)
> g. v-square is 10(12) cm2/sec2. Kinetic energy is thus >on the order of 4 x
> 10(29). This is enough to vaporize 4 x 10(27) cm3 >of cold seawater <snip>
> In fact, this is roughly enough energy to boil >a volume of water the size of
> Mars. It would vaporize rock well into >the mantle no matter what was in the
The amount of iridium favors a comet strike. So does distribution of
amino acids of apparent ET origin within the KT boundary(Zhoa, M. and
Bada, J.L., 1989. Extra-terrestrial amino acids in Cretaceous/Tertiary
boundary sediments at Stevns Klint, Denmark, Nature,339,463-465).
The size of the crater suggests at the very least 180km and more likely
230-300km in diameter. Energies involved would be on the order of
3x10-8th to 3x10-9th megatonnes (10-8th megatonnes=about 5x10^23j), just
as Mr. White pointed out. The strike was on limestone and would have
likely created large plumes of chlorites and sulfites which would have
caused widespread plankton and coral kills due to acidity. The
earthquake associated with the strike would have been somewhere between
10 and 12.8 on the Richter scale. The Alaskan quake was 8.5 and San
Francisco 8.3. Each increase of one on the scale is an order of
magnitude greater or ten times as powerful. Tsunumis would have been
from 200 to 500 feet high (some people think perhaps even 1000). Nuclear
winter would have been almost a certainty considering global effects of
known volcanic eruptions.
This crater is one of the largest in the solar system and thought to be
one of the largest in the last 4 billion years.
You don't need earth tsunumis, world wide fires, etc to know this was a
However, this thread has been beat to death and we still don't_know_it
killed the dinosaurs.
The above reply-to is a spam trap
Remove the hyphen in net-side to reply