Re: impacts are cool!

[Chris Campbell <sankarah@ou.edu>]

Michael wrote:
> 
> > 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 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.

But if we had all of these nasty effects, *why* did frogs sail right on
through unscathed?  Sorry to keep bleating on about this, but you need
to explain this.  If you have impact winter, or acid rain, or noxious
fumes, or anything else frogs will be the first to go.  We can see it
today with much milder concentrations of the chemicals and conditions in
question; frogs bite it before anything else, almost unilaterally.  If
the impact was this bad, the froggies *must* have gotten nailed AND THEY
DIDN'T!!!
 
> 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
> serious event.
> 
> However, this thread has been beat to death and we still don't_know_it
> killed the dinosaurs.

And we never will, because the non-geological evidence just doesn't
support extinctions via impact.  It supports extinctions via Deccan
Traps, inland sea regression, and other gradual changes over the course
of 9 million years (or more).  The impact just couldn't have been as bad
as you make out because too much stuff made it through that simply
shouldn't have.

Chris