Re: How much energy would be needed to stop the rotation of earth?

Ok, I guess this could be a serious question.  But,
don't try this at home.



The inertia of the earth, due only to its rotation - neglects any effects
of precession, is about 9.7e37 kg-m2.  The "energy" of the earth's
rotation is about 2.56e29 joules, equivalent to 0.6 quadrillion
10-kiloton nuclear weapon "energy-equivalents" or 1.3 trillion times the
average solar radiation incident on the earth per second, 1.95e17
joules.



Given that neither nuclear weapons or solar radiation are likely
candidates for this task, the earth could be atomized and dispersed with
the appropriate escape velocity by 3.75e32 joules or about 900
quadrillion 10-kiloton nuclear weapon "energy-equivalents".



Sorry, haven't a clue how one would go about tilting the earth 90 degrees
on its axis.  Assuming that it was still rotating though my best
guess is it's less than the energies estimated above.



Disclaimer: Referencing the above numerical estimates without further
research could jeopardize one's meteoric career ascension - significant
assumptions are likely,  the possibility of extraterrestrial sources
cannot be ruled out, orders of magnitude could easily have been lost, and
computations were done manually with disappearing ink.

Keith Little adds:
Peter,
The Kinetic energy required to stop the earths rotation
(denoted below by the letter K) is very large. The formula that must be
considered is ,
where (the
moment of inertia for a solid sphere) and (the
angular velocity of rotation).
Therefore if



and



then

(Joules).

The Hiroshima atomic bomb released about joules
of energy, therefore the number of bomb would be bombs.
This is an enormous amount of energy to dissipate all at one time. It would
certainly destroy all the surface features of the earth. Not too friendly
to human life either!
Some other interesting cosmic facts may be found at http://delcano.mit.edu/.
Cheers,



Keith Little

Senior Software Engineer

Federated Software Group

Maryland Heights, Missouri.