MadSci Network: Physics

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

Date: Sat Oct 9 18:19:29 1999
Posted By: Sidney Chivers, , Nuclear Engineering, retired
Area of science: Physics
ID: 936892685.Ph

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:


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


Keith Little
Senior Software Engineer
Federated Software Group
Maryland Heights, Missouri.

Current Queue | Current Queue for Physics | Physics archives

Try the links in the MadSci Library for more information on Physics.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-1999. All rights reserved.