[Jet2]

Earth is spinning everyday.
I assume this spinning action would make the planet move even though it may be sooooo slow that it may only move a cm in many billions year.
But, does anybody know...

Are we getting closer to the Sun?
Or getting away from it?

[sanctus]

Is there any logical reason why it should go away?

Eventually it will fall just into the sun, but probably the sun becomes a nova first...
But this has little to do with the spinning, more with the orbit around the sun. I say little because I can imagine well that since earth is not a perfect sphere there may be some little influence of its kinetic moment.

[Overdog]

Well, this link isn't exactly what you are asking, but I think it gives a pretty good answer...at least up to the point where the question becomes moot.

Archive of Astronomy Questions and Answers

[Moontanman]

Originally Posted by Jet2

Earth is spinning everyday.
I assume this spinning action would make the planet move even though it may be sooooo slow that it may only move a cm in many billions year.
But, does anybody know...

Are we getting closer to the Sun?
Or getting away from it?

Always closer, the Earth is very slowly spiraling down toward the sun and the sun is expanding it's surface toward the earth. The motion of the earth toward the sun is not significant but the other is.

[modest]

There are areas in the solar system where orbits are more chaotic and less likely to remain stable for billions of years. Between Venus and the asteroid belt there is greater long term stability over very long time periods. So, earth's orbit is very stable.

The long-term evolution of orbits in the solar system - A mapping approach

Earth's orbit - Wikipedia, the free encyclopedia

It is, however, true that as the sun looses mass (which it does very, very slowly), Earth's orbit will increase or our distance from the sun will increase. Also, as Earth transfers its kinetic energy to the interplanetary medium, its orbit will become smaller. These are very small factors. Earth has maintained stability for over 4 billion years and there is no reason to assume it won't be stable for another 4 billion - outlasting our star .

~modest

[Reaper]

All orbits decay, but as everyone else here has pointed out it takes a very, very long time. Earth will certainly be orbiting the sun for much longer than the age of the universe, unless Andromeda knocks it away (or into the sun) 3 billion years down the road....

[Overdog]

"Earth is like a bus loaded with people, barreling down a mostly empty highway, with no one at the wheel."

Read that somewhere...

[REASON]

Originally Posted by modest

Earth has maintained stability for over 4 billion years and there is no reason to assume it won't be stable for another 4 billion - outlasting our star.

I'm confused about this last statement I bolded. How can the Earth's stability, or orbit around the Sun outlast the Sun?

Current theory suggests that the Earth will be engulfed by the Sun during it's expansion. At the least I would expect the Earth's orbit to be significantly altered during the expansion period, the nova Planetary Nebula period, and the period of retraction to a White Dwarf state.

[Reaper]

Originally Posted by REASON

Current theory suggests that the Earth will be engulfed by the Sun during it's expansion. At the least I would expect the Earth's orbit to be significantly altered during the expansion period, the nova period, and the period of retraction to a White Dwarf state.

Not quite. It is also predicted that the Earth likely will be pushed out further during the time the sun expands into a Red Giant due to increasing solar winds. In any event, the Earth will still orbit the Sun just fine. As to whether or not the biosphere on Earth will still be around is another issue all together.

[modest]

Originally Posted by REASON

I'm confused about this last statement I bolded. How can the Earth's stability, or orbit around the Sun outlast the Sun?

You're right. I meant 'outlast the main sequence lifetime' I don't think it's so easy to say one way or the other if earth will survive the transition past this to a red giant then white dwarf. I was trying to say that the sun would, in all likelihood, loose stability first and I should not have taken that idea further and stated so definitely that earth would survive.

Originally Posted by REASON

Current theory suggests that the Earth will be engulfed by the Sun during it's expansion. At the least I would expect the Earth's orbit to be significantly altered during the expansion period, the nova period, and the period of retraction to a White Dwarf state.

Small matter, but there is no 'nova' phase. When the red giant throws off its outer layers forming a nebula it is still in the red giant phase - right up until the white dwarf phase. A nova is a different stellar process.

As the sun expands it will loose mass (ejecting it). Kepler's laws then necessitate the earth get farther away from the sun. This is not (as Reaper describes above) the result of the ejecta pushing on the earth, but just conservation of angular momentum. If the sun looses something like 20 percent of its mass then the earth will be far enough away to survive the transition to a white dwarf. If the earth does survive to this point, I have no idea what would happen next.

~modest

EDITED - I edited a few sentences above - more than just typos.