Does the earth's spin slow down over time?

[Sorcerer]

How did the earth acquire it's rotation? How fast was it originally spinning and does the suns gravity slow it down.

 

If earth slows down, how does this effect measurements, will GPS need to account for any difference in 100 million years.

 

How does the reduction in speed influence the coriolis effect and how has/will wear the patterns change as a result?

 

Wouldn't a faster spinning earth have a smoother climate/be more uniform or at equilibrium than a slower turning one? Since less rotation would slow the coriolis mixing of the atmosphere, enabling greater areas of variation/ steeper temperature gradients?

 

How does the moons gravity effect the earth's spin? Has the earth's gravity effected the moons spin?

 

What is the Kinetic energy of the spinning earth converted to as it slows?

[Janus]

How did the earth acquire it's rotation?

Left over angular momentum from its formation.

 

How fast was it originally spinning and does the suns gravity slow it down.

Hard to say how fast it was originally turning. The Sun does have a small effect, but the largest slow down is caused by tidal interaction with the Moon.

 

If earth slows down, how does this effect measurements, will GPS need to account for any difference in 100 million years.

At the present slow down of 2.3 milliseconds per century, in 100,000,000 years, the day will be ~38 seconds longer. We already make occasional adjustments to our official time keeping to keep it synced to the Earth's rotation. (the Earth's rotation hasn't served as the basis for the second for over 50 yrs) This is done by occasionally adding a "leap second". since 1972, this has been done 26 times.

 

How does the reduction in speed influence the coriolis effect and how has/will wear the patterns change as a result?

the trade winds would change

 

Wouldn't a faster spinning earth have a smoother climate/be more uniform or at equilibrium than a slower turning one? Since less rotation would slow the coriolis mixing of the atmosphere, enabling greater areas of variation/ steeper temperature gradients?

 

you'd still have convection winds from the Poles to the Equator. Slower rotation means more heating on the Sun side and more cooling on the unlit side strengthening those winds. All in all it is a pretty complex system and it would be hard to predict exactly what the overall effect would be

 

How does the moons gravity effect the earth's spin?

Answered above.

 

Has the earth's gravity effected the moons spin?

It has tidally locked it so that its rotational period and orbital period are equal.

 

What is the Kinetic energy of the spinning earth converted to as it slows?

Most of it is converted to heat(due to tidal friction) and radiated out into space. The rest is transferred to the Moon, pushing it into a higher orbit.

[Sorcerer]

Wouldn't the moon have been spinning out of sync with the earth originally too though? Or do they form in a system already tidally locked?

 

If the moon formed in a collision how would that effect rotation?

 

Is the sun spinning too and will it slow down?

 

Thinking of it as the earth slowing in spin and the moon orbiting higher and gaining orbital speed. Couldn't it be viewed under relativity as the earth losing mass, gravity weakening and the moons orbit increasing?

 

I mean under E=mc^2. The loss of speed would be the same as a loss of mass and the moon gained that energy. The total mass of the system remains the same I guess, but doesn't the relative masses alter gravity's effect and therefore the orbit?

 

So space flattens out as the earth spins slower, does this mean rotating bodies curve space tighter?

 

If the universe were rotating would this account for some or all missing mass/dark matter?

 

What if a super massive black hole rotates near the speed of light at the center of galaxies?

Edited December 12, 2015 by Sorcerer

[Janus]

Wouldn't the moon have been spinning out of sync with the earth originally too though? Or do they form in a system already tidally locked?

The process took time.

If the moon formed in a collision how would that effect rotation?

The original collision likely changed the rotation rate of the system.

Is the sun spinning too and will it slow down?

The Sun is a bit more complicated as it does not rotate as a single piece

Thinking of it as the earth slowing in spin and the moon orbiting higher and gaining orbital speed. Couldn't it be viewed under relativity as the earth losing mass, gravity weakening and the moons orbit increasing?

 

I mean under E=mc^2. The loss of speed would be the same as a loss of mass and the moon gained that energy. The total mass of the system remains the same I guess, but doesn't the relative masses alter gravity's effect and therefore the orbit?

The equivalent mass loss is insignificant. The slowing of the Earth and increasing distance to the Moon is caused by tidal interaction and a transfer of angular momentum from the Earth to the Moon.

So space flattens out as the earth spins slower, does this mean rotating bodies curve space tighter?

again, this is insignificant

If the universe were rotating would this account for some or all missing mass/dark matter?

No.

[Sorcerer]

The earth doesn't rotate as one peice either. Hence the geomagnetic field right?

 

But aren't momentum and energy equivalent to mass, couldn't it be explained the other way?

 

What would an observer spinning as the earth moon system see? IE there reference frame view both as stationary?

[Ophiolite]

The earth doesn't rotate as one peice either. Hence the geomagnetic field right?

 

No. The geomagnetic field arises from a geodynamo generated by convection in the outer molten nickel-iron core.

 

I believe research in the last decade or so has revealed that there is a tiny amount of "slippage" of the inner core, so that it rotates very slightly slower than the rest of the planet. This is not, however, related to the geomagnetic field in any fundamental way.

[Sorcerer]

No. The geomagnetic field arises from a geodynamo generated by convection in the outer molten nickel-iron core.

 

I believe research in the last decade or so has revealed that there is a tiny amount of "slippage" of the inner core, so that it rotates very slightly slower than the rest of the planet. This is not, however, related to the geomagnetic field in any fundamental way.

Wouldn't there be a very slight coriolis effect then? Wouldn't that mean a very slightly twisted field? Wouldn't this torsion enable the poles to drift and even flip?

[Ophiolite]

Wouldn't there be a very slight coriolis effect then? Wouldn't that mean a very slightly twisted field? Wouldn't this torsion enable the poles to drift and even flip?

The influence, if any, is many orders of magnitude less than the inter-related effects of convection, current flow and existing field. It has absolutely nothing to do with drift, or field reversal.

[MigL]

The Earth/Moon system doesn't lose energy or mass over time.

Remember these are conserved quantities.

As Janus has pointed out angular momentum is transferred, and this 'disperses' the mass/energy of the system somewhat ( trivial ), but none is lost.

 

As for a frame where Earth and Moon can be considered stationary ?

A universe rotating in the same plane as the Moon's orbit and with the same period ?

[Strange]

The Earth/Moon system doesn't lose energy or mass over time.

Remember these are conserved quantities.

 

Well, the system will lose energy: some of the tidal energy will be lost as heat. And presumably there will be a tiny loss to gravitational waves.

Edited December 12, 2015 by Strange

[MigL]

Unless you consider the heat radiated into deep space ( trivial ) that heat is still part of the system (heats up tidal waters ? ).

So what's lost ?

And we can't even detect gravity waves from energetic events like orbiting BH/pulsars.

How many orders of magnitude less would the waves from the Moon's orbit be ?

Again, trivial.

 

( I'm just being 'nit-picky', but then, so were you )

Edited December 12, 2015 by MigL

[Janus]

Unless you consider the heat radiated into deep space ( trivial ) that heat is still part of the system (heats up tidal waters ? ).

So what's lost ?

The radiated heat loss is not trivial. If you work out the rotational energy lost by the Earth vs the orbital energy gained over by the Moon over the course of a century, you will find that less than 3% of the Earth's lost rotational energy is transferred to the Moon. The rest goes into tidal heating, and that works out to be enough energy to raise the ocean's temperature by ~1 degree C per year. If the Earth held on to that energy and did not radiate it out into space, the oceans and the Earth would just get warmer and warmer and the oceans would have boiled away eons ago.

[studiot]

 

The Earth/Moon system doesn't lose energy or mass over time.

 

The Earth gains material over time, rather than looses it, albeit ever more slowly.

 

Current theory has that the proto Earth swept up much of the hot gas, dust and larger particles local to it.

This process of accretion was reinforced by the fact that as the largest local object was the Earth which therefore attracted local matter and gre at the expense of smaller bodies.

Thus the Earth's locality in space now has been swept relatively clean of such material which has long been incorporated in the Earth.

 

Again current theory has the temperature of the molten out core hotter than the surface of the Sun.

So there is a thermodynamic imperative to radiate vast quantiies of energy, like the Sun.

However, unlike the Sun the core is covered by an insulating blanket called the mantle.

The attempt by the heat to get out is what drives the plate tectonics (whichever version you favour) that takes place on Earth.

[MigL]

Thanks Janus, maybe I should have done some 'back of an envelope' calculations before I shot off my mouth.