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Re: impacts are cool!
Chris Campbell wrote:
> 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 in
> > 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
You have a crater a certain size with reasons to suspect it was a comet.
>From the size of the crater you can calculate energies involved. There
is not much debate that a strike causing a crater 300km in diameter is a
I can't answer why some things lived and others didn't. Maybe some
frogs either burrowed or already were or survived for other reasons. If
you kill 99.9% of all living creatures you still have considerable
biomass hanging around to procreate. And I don't deny that there were
other global changes occuring.
It's a huge crater and look at the energies again. The largest nuclear
weapons are about 200megatonnes or so. This is 3x10^8 or 3x10^9
> > 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.
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