In an article, Peter Kwangjun Suk wrote:

> Another thing that I just thought of while reading the star wars thread:
> Destroying the Earth.  This one tends to reappear as well.  (And the
> calculation for tha amount of energy it would take to raise the biosphere
> to 500 celsius would eb good to have in there.  Anyone remember who did
> that one?)

   No - and please give *that* person credit in the FAQ if you can find
them. But here's a version of that:

   Mass_of_biosphere = 1.148e+17 kg, roughly all water. It takes 4.186 J
to raise 1 g H2O 1 deg-C, (ie- the specific heat of water is 4186
J/deg-C/kg) so to raise entire biosphere 500 deg-C would take 4.806e+20 J,
ignoring the heat required for vaporization. H2O has a heat of
vaporization of 2.26e+6 J/kg, resulting in an additional 2.59e+23 J to
turn the biosphere from liquid to vapor. This later figure more or less
outstrips the former. For comparision, the total solar energy collected by
Earth in 1 year is about 1e+25 J.

   And another calc you might find useful, Underestimating the Death Star
(how much energy to break up the Earth):

   Seperate the Earth into 2 equal masses, and completely remove them from
each other ("Blow the planet apart" in 2 pieces). Mass_of_Earth = 5.98e+24
kg, so each piece would mass about 2.99e+24 kg, and the initial seperation
would be on the order of 1 Earth radius = 6.378e+6 m. The gravitational
potential energy of this system is -G*m1*m2/r, or about 9.35e+31 J, or
about 1/10th of the annual solar output. That death Star must have one
*BIG* capacitor ;-).

                                                -Brian Davis