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Re: Extinction scenarios




James R. Cunningham wrote:

> James R. Cunningham wrote:
>
> > Hey guys, (Dan, George, & Jeff)
> > I've e-mailed Stanley Schmidt for permission to xerox the 1966 Enever 
> > article (and
> > asked him to consider reprinting the article, as being pertinent again).  
> > In the
> > meantime, I've converted a few of Enever's numbers to the size of the 
> > Chixulub
> > meteor, assuming a diameter of 8 miles and a specific gravity of 2.65 
> > (assumed for
> > avg. rock, few voids, no significant metal content ---- Enever assumed 
> > nickel/iron
> > --- I'm assuming a solid rather than loosely bound object.  Should it be 
> > loosely
> > bound, my numbers would reduce by about 25%).
> >
> > The Chixulub meteor would have 92.5 times the mass of the Enever bolide, 
> > and would
> > weigh 10,700 Gigatons. Using an incoming velocity of 50Kps (31 miles/sec), 
> > it
> > would strike with an energy of 881 Teratons (881 million Megatons) of TNT, 
> > or 9
> > million
> > times more powerful than the biggest H-bomb ever exploded. This is the 
> > equivilent
> > (almost) of simultaneously exploding 9,000,000 one hundred Megaton Hydrogen 
> > bombs on a
> world-wide
> > grid with each bomb spaced 4.73 miles apart.  Energies at the plasma core 
> > will be
> > enough to
> > generate free neutrons and X-rays.  Nuclear reactions can be expected to 
> > occur at
> > the core (thank God, they would probably absorb energy rather than generate
> > it).The impact energy would amount to 30,000 calories/gram of impactor mass 
> > and
> > would be capable of boiling away 1325 volumes of ocean per volume of 
> > meteorite, so
> > that 355,208 cubic miles of ocean would be converted to cloud cover.  If 
> > the ocean
> > were a mile deep at the impact site, this would boil away a ring of ocean 
> > 672
> > miles in diameter and one mile deep, providing an equivilent of 1017.5 days 
> > of
> > solar evaporative power. As for dust, assuming that erg for erg, Chixulub 
> > lifted
> > only one percent as much microscopic dust as Krakatoa, then it still lifted 
> > more
> > than 5.5 million times more fine powder into the atmosphere than Krakatoa 
> > did.
> > Krakatoa gave red sunsets for ten years.  Imagine ten years with sunsets 5.5
> > million times redder than the ones following Krakatoa.  A description of the
> > tsunami would be similar in tone.  If the impactor came in at 70 Kps the 
> > energy
> > would have been increased by a factor of 1.96, and the effects similarly
> > increased.  What I've said here is highly derivative of the Enever article.
> > Should it be posted to the list with credit to him? Or do you guys think 
> > anyone
> > would be interested?
> > Jim

P.S. They thought some of you would be interested. As George has pointed out, 
luckily the
blast effects won't be uniform (the 4.73 mile grid is a good visualization tool 
for the
energies involved, but uniform energy distribution would have destroyed most 
all life on
earth), resulting in overkill at the blast site, with effects diminishing with 
distance
and then building up again at the antipodes.  I would also expect the tsunami 
to show some
Bay of Fundy effect at the northern end of the Cretaceous sea.  Also, sunsets 5 
or 6
million times redder than the Krakatoa skys translate to coal-black skies for a
significant period. Jeff Hecht has mentioned that the Enever article came out 
early enough
to have affected Alvarez's thinking.  Enever even mentioned iridium , though he 
focused
more on other probable materials in the K-T boundary layer.  It's also worth 
mentioning
that Heinlein's THE MOON IS A HARSH MISTRESS used multi-megaton falling rocks 
as a plot
device, and it came out early enough to have affected Enever's thinking. Jim