[amt7565]

After Einstein dashed the Newtonian model of gravity, we now know that, massive objects warp space and the smaller planets follow the slopes of space time caused by more massive objects.

Question:
1- What gives our planets the energy to spin on it's own axis? Since the spin also curls spacetime, wouldn't the spin have to slow down eventually?

2-What gives our planets the energy to go around the Sun at such high speeds? How does it stay in orbit without slowing down? I like to know from a spacetime perspective.

Thanks.
AMT-

[infamous]

Originally Posted by amt7565

After Einstein dashed the Newtonian model of gravity, we now know that, massive objects warp space and the smaller planets follow the slopes of space time caused by more massive objects.

Question:
1- What gives our planets the energy to spin on it's own axis? Since the spin also curls spacetime, wouldn't the spin have to slow down eventually?

2-What gives our planets the energy to go around the Sun at such high speeds? How does it stay in orbit without slowing down? I like to know from a spacetime perspective.

Thanks.
AMT-

I believe science has calculated that the earth is slowing down by the measure of one second every ten years. Some of the angular momemtum of earth is being transfered to the moon.

All orbits are destined to decay. One can understand being in orbit like unto an object falling under the influence of gravity, but because of it's velocity and centrifugal forces a balance is achieved between falling and spinning off into space. Therefore, an orbit will be established, but as I already said, all orbits are destined to decay.

[Qfwfq]

Planets have had their kinetic energy, both in orbiting and in spinning, since the solar system formed from a spinning mass of debris.

Einstein did not exactly dash the Newtonian model of gravity, it's a bit more subtle than that. Curvature of space time doesn't have anything to do with dissipation, it's only a way of seeing gravity.

[bumab]

Originally Posted by amt7565

1- What gives our planets the energy to spin on it's own axis? Since the spin also curls spacetime, wouldn't the spin have to slow down eventually?

It will slow down, but more due to friction. It's just momentum that keeps us spinning from the formation of the earth. We are slowing down due to tidal forces between us and the moon and us and the sun as well.

Originally Posted by amt7565

2-What gives our planets the energy to go around the Sun at such high speeds? How does it stay in orbit without slowing down? I like to know from a spacetime perspective.

Momentum again. The planets formed from a spinning disc of debries, so we still spin. We will slow down eventually from friction with dust and such.

[maddog]

Originally Posted by amt7565

What gives our planets the energy to spin on it's own axis? Since the spin also curls spacetime, wouldn't the spin have to slow down eventually?

As Qfwfq said planets form from coalescing of clouds of material around a proto
version of the Sun. As it comes together it is natural for the material to twist as it
comes together. All according to Newton's Law of Gravitation. Einstein's version does
little effect unless we are speaking of sizeable planets or very small effects (like the
procession of the equinox of Mercury).

Originally Posted by amt7565

What gives our planets the energy to go around the Sun at such high speeds? How does it stay in orbit without slowing down? I like to know from a spacetime perspective.

This is the same effect as the cloud of material come closer to the proto-star.
Natural for material to start to revolve around the star (just forming). As the planet
to be starts to form, it would start rotating as well. Spin is typically inherent.

maddog