Re: Comet impact in the Eastern United States - Feasibility of Evacuation

On Sun, 9 Mar 2008 16:45:10 -0500, "Joel Olson"
<joel_olson@[EMAIL PROTECTED]
> wrote:

>"Joetheone" <joetheone@[EMAIL PROTECTED]
> wrote:
>> "Matt Browne SFW" <matt.h.browne@[EMAIL PROTECTED]
> wrote:
>>> On Mar 9, 6:37 pm, jdnic...@[EMAIL PROTECTED]
 (James Nicoll) wrote:
>>>> Matt Browne SFW  <matt.h.bro...@[EMAIL PROTECTED]
> wrote:
>>>>
>>>> It is very unlikely that the Earth will be struck by a large enough
>>>> object in the next five billion years.
>>>>
>>>>         In fact, even if we move the goal posts to mere mass 
>>>> extinctions, there's only one mass extinction that is thought to have

>>>> been caused by an impact and lots of large craters that are not
associated 
>>>> with extinctions at all. Your garden variety flood basalt seems to be

>>>> worse for the environment and any cooling event that leads to a
snowball 
>>>> or slushball Earth would also be very bad.
>>>>
>>> I'm actually not talking about mass extinctions here. Our species will
>>> survive. Most species will suvive this. I'm talking about a comet
>>> which is larger than the meteorite that hit Tunguska in 1908, but a
>>> lot smaller than Chicxulub. An impact that is far less dangerous than
>>> the flood basalt events you mentioned. I'm talking about impacts which
>>> are quite possible in a timeframe of several thousand years. How would
>>> we deal with this? How can we prepare for this? Is evacuation an
>>> option? Should FEMA have a plan ready when needed?

>> If you do any map and compass work, you find that 1 degree=100 feet in
a 
>> mile. What's that work out to, say, from the Moon? They couldn't plot
the 
>> impact zone even to "Greater Pittsburg Area" with any real confidence,
at 
>> best, hours before impact. You'd have just as good a chance of
evacuating 
>> people into, rather than out of the impact zone.And ther's still just
as 
>> good a chance of it hitting in the ocean or the desert, or the Canadian

>> tundra.
>> The only thing to do would be to hope it hit someone else.
>> Like the quote in your sig.
>> Disaster movies, whether SciFi, Discovery or History channel are all
bull.
>> There are more variables working on a body falling from space than
there 
>> are on a 30-06 bullet trying to hit a pie plate at 1000 yards. Not many

>> can predict how that will end up, either. And there's generally
somebody 
>> that cares about that outcome.
>
>I disagree. Given a reasonable time interval, the trajectory and mass
>can be observed to almost total accuracy. 

Because, since it is a comet, there will be no randomly situated
outgassings which will not produce random jinks and jukes in the
motion of the incoming comet...

Right.

>Slowing/deflection as it enters
>the atmosphere would also be quickly simulated, a little less accurately.
>The result will be a calculated impact zone that will most likely be a
long
>elipse, smaller if the angle of descent is steep. The approach trajectory
>may make a difference.
>
>Six months sounds like a reasonable lead time for evacuation.
-- 
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