Jump to content

Sun's energy and earth's rotation


ramanan

Recommended Posts

ramanan said in post #1 :

On earth the rate of energy obtained from the sun is c.170000 mega joules.

Now, does earth consume any of these energy for its rotation ?

Or is it rotating due to sun's gravity and rotational speed?

 

The earth rotates because it has angular momentum, and that's a conserved quantity in the absence of an external torque. We are transferring some angular momentum (and energy) to the moon through tides, so I imagine the same is happening with the sun at a smaller scale. (The moon is currently receding at ~ 4 cm/year). It doesn't take any energy to rotate - the energy is already there. It would take energy (and a torque) to increase the rotation, and energy would have to go somewhere if the rotation rate decreased.

Link to comment
Share on other sites

ramanan said in post #3 :

So shall we infer this way Swansont,that any object in the universe has got its own potential energy?

 

Technically potential energy is shared between the objects in the system, but when the masses are so different we usually "assign" the energy to the smaller. But yes, all objects affected by gravity have some amount of gravitational potential energy.

Link to comment
Share on other sites

aman said in post #4 :

If the Earth has a darker face in any direction, there should be a difference in absorbtion and reflection and an actual positive push in one direction over another.

Just aman

 

But to any extent this happens, it does so radially WRT the sun, and thus it doesn't exert a torque.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.