Can We Rotate the Earth with a Rocket?

AI Thread Summary
The discussion centers on the energy required to rotate the Earth around its equatorial axis, calculated using the formula for rotational energy. The Earth's rotation speed is approximately 72 micro-radians per second, leading to an estimated energy requirement of 229 joules for a complete rotation. However, the conversation notes that nudging the equator slightly would require significantly less energy. It emphasizes the challenge of overcoming the Earth's angular momentum, suggesting that the energy needed is beyond any practical means. Overall, the feasibility of rotating the Earth with a rocket is deemed implausible.
ibeukema
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Hi,

My roommate and I were wondering how much energy is needed to rotate the Earth about an equitorial axis. Just as a fun experiment to get Holland into the sun.
 
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Energy in a rotating body is 1/2 I w2
w is in rad/s so the Earth is rotating at about 2pi/24*3600 = 72uRad/s
I for a solid sphere is 2mr2/5

The mass of the Earth is 6x1024 kg and the radius is about 6*106m

So total energy is = 6x1024*6*106*6*106 * 72*10-6 *72*10-6 /5 = 229 J

Edit, although if you don't want to stop it, just nudge the equator a little it would be a lot less.
 
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his question was about rotating the Earth about an equatorial axis, not polar axis.

For this, you have to consider that you are going against the force of the Earth's angular momentum vector.

I haven't the desire to calculate it, but suffice to say that it is far more than all the king's horses and all the king's men would ever be able to conjure.
 

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