Earth's Rotational Speed in Relation to Distance to Sun

[Tsunami982]

Ok, I'm wracking my brain on this one and figured it might just be easier to ask. Ok... if you increased the distance of the Earth from the sun, would this increase, decrease, or not affect the rotation of the Earth? Basically, would it make days longer?

Any sources would be greatly appreciated.


Thanks,

D

 

[Snock514]

Years would be longer but I don't think days would be affected significantly because days are based on the earth's rotation around its axis.

 

[Tsunami982]

Years would be longer but I don't think days would be affected significantly because days are based on the earth's rotation around its axis.

Do you have any sources for this? I'm thinking the change in gravity from the sun and angular momentum would somehow affect its rotational speed.


Thanks,

D

 

[Saylick]

Hm... Well, from what I'm reading, the moon's gravity has an effect on how long days last due to tidal acceleration.

I suppose shifting Earth position would have drastic effects on the length of day due to changes in gravity, e.g. if Earth was placed near Jupiter.

 

[Enigmoid]

There is absolutely no relationship between a planet's distance from the sun and its axial rotation period (day). The relationship between the distance from the sun and its orbital period (year) is determined by Kepler's laws of planetary motion.

 

[Paratus]

Off the top of my head, the Earths rotation would stay the same, but the rate of change of rotation due to tidal forces caused by the sun would change.

So immediately after moving a day would still be a day, but after a long while the length if the day would be different if the planet hadn't moved.

 

[Ken g6]

Technically - that's what this forum's about, right? - the sidereal day would remain the same, but Earth would have a longer year. So the day would be slightly shorter even if Earth rotated at the same speed. That's because the Earth orbits as it turns, so it has to turn slightly more than 360 degrees to get the sun to the same point in the sky. A longer, slower orbit would mean it would have to turn slightly less.

Otherwise I generally agree with Paratus. One thing does occur to me, though: Farther from the sun the Earth's oceans would freeze. So the tides wouldn't rise as high - probably only as high as the rock has tides - and the tidal drag effect would be even smaller.

 

[SecurityTheatre]

Off the top of my head, the Earths rotation would stay the same, but the rate of change of rotation due to tidal forces caused by the sun would change.

So immediately after moving a day would still be a day, but after a long while the length if the day would be different if the planet hadn't moved.

Agreed. Minor changes to tidal forces until the oceans freeze or boil, then even MORE minor changes due to tidal forces on rock and air....

No significant effect on rotational velocity.

 

[cytg111]

I cant see why it should .. But it ignites another question in my head .. a hit from an external body at the right angle and right mass could speed up or slow down our day by some amount (anything with that kind of mass would problary be an extinction event) .. We could also turn the earth into a giant gyroscope and seriously f* up night and day.. thatd be awsome..

 

[silverpig]

Technically - that's what this forum's about, right? - the sidereal day would remain the same, but Earth would have a longer year. So the day would be slightly shorter even if Earth rotated at the same speed. That's because the Earth orbits as it turns, so it has to turn slightly more than 360 degrees to get the sun to the same point in the sky. A longer, slower orbit would mean it would have to turn slightly less.

Otherwise I generally agree with Paratus. One thing does occur to me, though: Farther from the sun the Earth's oceans would freeze. So the tides wouldn't rise as high - probably only as high as the rock has tides - and the tidal drag effect would be even smaller.

This is correct.

There is a process where the earth's day is slowing down due to tidal forces from the moon and the sun. The long term (i.e., billions of years from now) steady state is for two bodies in orbit around each other to become tidally locked so the length of a sidereal day equals the length of the year (the same side always faces the sun).

So a longer year would mean a longer day. But, it also means that the tidal locking process would be slower - i.e., it would take billions more years for the earth and sun to become tidally locked if the earth was farther out than it is.

I guess this is another one of those "it's not realistic to just do X, so the answer depends on how technical you want to get and how many other rules of physics you want to ignore" answers.