Subject: 
            A 2001 KX76 WI
       Date: 
            27 Aug 2001 12:01:44 -0400
       From: 
            jdnicoll@panix.com (James Nicoll)
Organization: 
            PANIX -- Public Access Networks Corp.
 Newsgroups: 
            soc.history.what-if


        2001 KX76 is rather impressive at up to 1270 km in 
diameter, even larger than Ceres. Its discovery has waited
until this year because it is in the 'burbs of the solar
sysem, out in the Kuiper Belt. How dull.

        Kuiper Belt Objects do get perturbed into the inner
system. Even very large ones do, although on a time scale
which suggest the sun will be a white dwarf long before
a so-called supercomet stir-fries the Earth (Larger planet
are less lucky and a BOTEC suggests that Jupiter should
expect to nailed at least one before the sun goes red
giant). This can have serious effects on Earth even without
a collision: the dust and debris from a large KBO can fill
the inner system for many centuries, kickstarting a temporary 
ice age. I have done that WI, though so here's another.

        2001 KX76 gets perturbed into the inner system in
the recent past (Post-Caesar). It does not hit any other 
world and does not end up closer the sun than Earth at 
any point but it does end up in an eccentric orbit from
about 3 AU to about 1.2 AU, which nicely crosses the orbit
of Mars. Luckily for Mars, no direct impact will happen:
if the object lasted long enough it would hit Jupiter but
it won't, being reduced to dust and gas in millenia.

        Because its orbit crosses the frost line, the life
span of 2001 KX76 is longer than the thousand years a true
inner system might last and it is bloody huge to boot. We will
give it 5,000 years as a WAG. From the POV of hypothetical
Martians its appearance would be a tragedy, reducing the already
frigid Mars' temperature by a few percent. Lucky, there are no
Martians or if there are they are subterranian bacteria who
won't notice the cold spell. Mars does intercept a little dust
and water but nothing major on a planetary scale.

        On Earth, however, 2001 KX76 is rather obvious, visible
to the naked eye when active. Activity is dependent on where the
KBO is in its orbit and what the surface is like as it sublimes 
away but the supercomet will never quite drop down to invisibility.
At its brightest, it is huge, only dimmer than the Moon and the Sun.

        For fun, we'll pick the day Julius Caesar gets knifed as
the day it first becomes visible and the next three centuries as
the period it takes for repeated encounters with Jupiter to settle
it into the orbit it will have for the five millennia it lasts.
Any thoughts on how it affects history? 

        For one thing, the idea that the heavens never change on
a long term basis is dead or at least under serious threat. We might
see people thinking in a few centuries that the KBO had always been
there, though.