Why does the Earth keep spinning?

[tuggyman]

For 4.5 Billion years our planet has been spinning, that is perpetual motion in my book.
What i cannot understand is yes it's in fictionless space but it has gravitational forces pulling at it in the shape of our moon, causing Trillions of tons of water to be displaced every second. I would of thought this would be a damping effect, where is all this energy to displace all this mass coming from?:-worship
You don't get out for nowt.
Please help me understand!!!!!

 

[TigTex]

This as came from the big explosion: BIG BANG.
In less then a milisecond everything apeared.
Google it: bigbang.

 

[gameboy]

_http://www.mwscomp.com/sounds/mp3/galaxy.mp3

 

[spiney]

tuggyman is correct, the earth's rotation is slowing for exactly those reasons!

http://www.physlink.com/education/askexperts/ae695.cfm .

 

[gameboy]

So, air travel will become quicker...!

 

[Channel Hopper]

So, air travel will become quicker...!

I fear not, as the earth slows down, the gravity attraction will become greater at all points except the poles, progressively more towards the equator.

The atmosphere will also become denser as a result.

More fuel will be required to launch things into space, owing to the higher escape velocities, making satellites a thing of the past.

We do have a few years yet though.

 

[spiney]

So, air travel will become quicker...!

The "life chain" is very tied into day/night, and I'm not sure anything would survive at all (there would be no plants on half the earth!), but assuming the human race still exists:

1) Air travel would be the same (speed is relative to ground!).

2) Gravity will stay the same (this depends on earth's mass!), and there will be no noticable change in weight (just as there isn't now, at either pole!).

4) It's true that we'd lose the "help" of the earth's rotation for equator launching (why rockets are usually launched near the equator), but would still be possible. However, by that time, presumably we'll be using "space elevators".

An interesting sci fi novel about a "still earth" is Aldis' "Hothouse" (one of the few readable novels he's written, despite being a superb sci fi theorist and historian).

I'm not sure the earth will stop before the sun goes nova (like on Dr Who).

 

[tuggyman]

Thanks for replys.
I just thought the Earth should have stopped by now .
Now i know water is fluid but it still has resistance, when you move (effectivly raise the head) of water it requires a lot of energy, especially with the scale of the Earths tides. To do this for 4.5 billion years with only a very small loss seem incredible.
Also the earth is effectivly pulling the moon around in its orbit (another damping effect?)

 

[PaulR]

With regards to the damping effect of the oceans if you imagine that, relatively speaking, the paint on a cricket ball is many times thicker then perhaps you can see why is has such a small effect.

It's not only the oceans which have a damping effect, the atmosphere gets pulled around as well but this is even weaker in its effect.

The Earth and Moon orbit around each other (everything is relative!) but, because the Earth is much more massive, the wobble is is not as noticeable on the Earth.

 

[tuggyman]

ive just had a thought, the gravitational pull from the moon pulls on every atom on earth and is recipricated 6 fold.
we can physically see tides being draged by the moon but do you think this is also true for earths molten core?

 

[PaulR]

Yes, everything on the Earth is affected by gravity, the core is no exception.

 

[Channel Hopper]

Yes, everything on the Earth is affected by gravity, the core is no exception.

The gravitational pull of all the mass of the Earth (in all directions) over the diameter of some 8000 miles, when compared to the pull of a mass some 250,000 miles away, means that there is very little effect on the core.

The water on the surface of the Earth is visible as a result of the periodic harmony of the moons movement over 28 (ish) days and the ability for the seas to ebb and flow water through channels around the planet.
The analogy of the paint thickness on a cricket bat is a good one (though I thought only linseed oil was used on willow);) , and the maximum tide (I think 9m is recorded in Inchon, Korea) is almost as insignificant compared to the overall depth of the oceans.

 

[PaulR]

True but gravity DOES affect it, although as you say it is a very weak effect.

As an aside (no, not going off topic!) gravity affects everything and, although it is the weakest force there is, overall nothing can escape it on a galactic level. Hence the fact that we cannot get "out" of our universe as we live inside a black hole.

 

[spiney]

Yes, gravity is indeed the weakest of the "4 forces", but as PaulR says, the only one acting over (and beyond) galactic distances ......

However, what's this about our being inside a "black hole"? Not true, as far as I know .....

The earth's molten core is indeed highly active, but this is mostly manifested as continental drift (the continents slowly changing their relative positions, as a result of tectonic plates movement), with just the occasional big volcanic explosion .....

 

[Channel Hopper]

However, what's this about our being inside a "black hole"? Not true, as far as I know .....

Maybe Paul had a higher than expected leccy bill this quarter.

 

[PaulR]

Every leccy bill (and gas bill and especially phone bill) is higher than expected. I have 2 teenage daughters - nuff said?

Going back on topic. It depends on how you define a black hole I suppose. Perhaps I was a bit too wide in my license but we defintely live within an event horizon which prevents us from getting outside our universe.

Every blackhole has an event horizon past which anything drawn in cannot escape. Therefore what's the difference?

 

[spiney]

The difference is .....

A black hole has an inside and outside, you can pass one way across the event horizon.

The universe has nothing outside it, that's why it's the universe.

With 2 teenage daughters, presumably you must now use a bookings system for bathroom time?

 

[mouk]

remember guys on the day of judgement the earth will move the other way round.
the sun will rise from the west...

you have been warned...

 

[spiney]

Few things are as much fun as pseudoscience - just so long as nobody takes it seriously ......

http://www.zetatalk.com/poleshft/p00.htm .

 

[Bbigfoot]

Hi Tuggyman..

Never though of the Earth that way (Perpetual Motion).
Next to that in another way is water, its a good thing
it recycles itself naturally.
The glass of water you drank today will have also been drank by the Dinosaurs.
That makes Water Quite old.

?, where does the Tide go as it Leaves the East coast of the U.K, France or
the Equator.

BF...