Why does the Earth spin?
Discussion
As a cloud of stuff clusters together it starts rotating. I don't know why it does that.
It has also been clouted by one or more hefty celestial bodies, at a glancing angle.
It keeps doing it because of momentum/inertia.
The moon does spin on its own axis, just at the same rate as it orbits us, so we only see one side of it.
It has also been clouted by one or more hefty celestial bodies, at a glancing angle.
It keeps doing it because of momentum/inertia.
The moon does spin on its own axis, just at the same rate as it orbits us, so we only see one side of it.
The moon used to spin more quickly, but it became locked into always facing the same way due to influence of earth's gravity. See http://en.wikipedia.org/wiki/Tidal_locking
Simpo Two said:
Interesting to ponder what would happen if Earth stopped spinnning. Half perpetual day and half perpetual night would shake the population (and vegetation) up a bit...
Interesting thought!We would roughly half the amout of food available and those living on the "dark side" would habe to try and move to the sunny side!
Simpo Two said:
Interesting to ponder what would happen if Earth stopped spinnning. Half perpetual day and half perpetual night would shake the population (and vegetation) up a bit...
Wouldn't be perpetual, zero spin, would equal ~6m day, ~6m night.The sun side would be much, much hotter, dark side much colder.
Would probably impact magnetic field generation and probably result in a loss of the atmosphere.
I thought Saturn was the fastest rotating but not googled it 
. As stated, the planets are formed by accretion which is the coalescence of matter due to gravity and some spin is inevitable as the masses collide. Tidal forces tend to slow the rotation of satellites over time, and the Earth's rotation is slowing. Eventually it will show the same side to the sun, not sure if there's enough time for that to happen before the sun dies though.
. As stated, the planets are formed by accretion which is the coalescence of matter due to gravity and some spin is inevitable as the masses collide. Tidal forces tend to slow the rotation of satellites over time, and the Earth's rotation is slowing. Eventually it will show the same side to the sun, not sure if there's enough time for that to happen before the sun dies though.Right, so I get that things just spin? Is there any more reason for this, surely it has been investigated further.
People have said that the rotation is slowing down, by how much. How much longer was a day 100 or 1000 or 10,000 or 100,000 years ago?
Perpetual motion has been mentioned, is the earth or even the solar system the biggest perpetual motion machine perhaps?
People have said that the rotation is slowing down, by how much. How much longer was a day 100 or 1000 or 10,000 or 100,000 years ago?
Perpetual motion has been mentioned, is the earth or even the solar system the biggest perpetual motion machine perhaps?
Eighteeteewhy said:
Right, so I get that things just spin? Is there any more reason for this, surely it has been investigated further.
People have said that the rotation is slowing down, by how much. How much longer was a day 100 or 1000 or 10,000 or 100,000 years ago?
Perpetual motion has been mentioned, is the earth or even the solar system the biggest perpetual motion machine perhaps?
The Earth is slowing down and has been since we were theoretically hit by the moon billions of years ago.People have said that the rotation is slowing down, by how much. How much longer was a day 100 or 1000 or 10,000 or 100,000 years ago?
Perpetual motion has been mentioned, is the earth or even the solar system the biggest perpetual motion machine perhaps?
About 600M years ago a day was about 22 Hrs. You're talking a very small fraction of a second per year.
It's caused by many factors, but mainly the drag caused by the moon.
The heat in the earth is finite, the sun will run out of fuel, perpetual means forever, so no it is not a perpetual motion machine.
The current accepted understanding is that eventually the universe will expand so much that eventually matter will break down and there will only be photons left, possibly less.
All this is very, very interesting....but it's also doing my head in. So, let's say that the Earth gets away with being hit by something, and that Mankind stays as he is for, I dunno...a few million/billion years. The Earth would slow down to an extent that half the world would die...or move?
What about gravity? If the Earth slowed by say 50%, would I become 50% lighter?
What about gravity? If the Earth slowed by say 50%, would I become 50% lighter?
As I understand it.
The Earth is cooling and slowing and its dance with the moon will tidally lock the two and the pair will rotate around a common point, as they do now, but further apart and the moon will be fixed. Not just facing Earth. The moon is never going to escape the Earth despite its moving away, that is a result from the planetoid that hit us and the debris coalesced into the moon and gravity doing its thing. The mmon will cease to move away in about 15 billion years if it were left alone however there is a tiny issue in the way.
Back to the Earth. As the Earth is cooling it will eventually lose its magnetism as the crust thickens and the core cools and slows and our atmosphere will start to get hammered by the solar winds and eked away as the magnetic field will weaken.
We are doomed.
But the Sun will blow up before that.....
Stands back for someone with more learning to shoot me down.
The Earth is cooling and slowing and its dance with the moon will tidally lock the two and the pair will rotate around a common point, as they do now, but further apart and the moon will be fixed. Not just facing Earth. The moon is never going to escape the Earth despite its moving away, that is a result from the planetoid that hit us and the debris coalesced into the moon and gravity doing its thing. The mmon will cease to move away in about 15 billion years if it were left alone however there is a tiny issue in the way.
Back to the Earth. As the Earth is cooling it will eventually lose its magnetism as the crust thickens and the core cools and slows and our atmosphere will start to get hammered by the solar winds and eked away as the magnetic field will weaken.
We are doomed.
But the Sun will blow up before that.....
Stands back for someone with more learning to shoot me down.
Chilli said:
All this is very, very interesting....but it's also doing my head in. So, let's say that the Earth gets away with being hit by something, and that Mankind stays as he is for, I dunno...a few million/billion years. The Earth would slow down to an extent that half the world would die...or move?
What about gravity? If the Earth slowed by say 50%, would I become 50% lighter?
Gravity is a not based on the spin of a planet - it is based on the mass of the planet. Therefore, a planet or moon that has stopped spinning retains its same basic gravitational pull.What about gravity? If the Earth slowed by say 50%, would I become 50% lighter?
The earth's rate of axial spin is slowing (as has been explained above) but it is slowing at a tiny rate - and even when the earth is destroyed by the sun's death in about 5 billion years time, its spin rate will only be slightly slower than it is today.
annodomini2 said:
The Earth is slowing down and has been since we were theoretically hit by the moon billions of years ago.
I['m not sure the moon existed before the collision. It was more two planets hitting one another. The Moon is made up (at least according to some theories) of a mixture of the two planets.Huh, you learn something every day....thanks gents.
Completely OT, but I was listening to Morgan Freeman the other day....I think he said that there were a billion stars in our galaxy....and hundreds of billions of galaxies. Now, these are just numbers that I am simply unable to compute.
Completely OT, but I was listening to Morgan Freeman the other day....I think he said that there were a billion stars in our galaxy....and hundreds of billions of galaxies. Now, these are just numbers that I am simply unable to compute.
Look up 'Hubble Deep field'. A postage stamp sized are of the sky that to us, had nothing on it. It was black. They pointed the telescope at this area, and kept it there for as long as they could, and this is the image that it produced.
Each of the 'blobs' is a galaxy. All this in an area that was the size of a postage stamp held at arms length, in which we thought there was nothing.
An animation
The numbers are mind boggling. As humans, we can only envisage numbers. Penn and Teller demonstrated this quite well I thought. When we think of 8, we think of 2 groups of 4. 9 as a group of 5 and 4, and so on. We can only visualise, and think of quite small groups. Anything above that and it becomes a lot, quite a few, loads, s
tloads, a fking shipload, and so on.
Each of the 'blobs' is a galaxy. All this in an area that was the size of a postage stamp held at arms length, in which we thought there was nothing.
An animation
The numbers are mind boggling. As humans, we can only envisage numbers. Penn and Teller demonstrated this quite well I thought. When we think of 8, we think of 2 groups of 4. 9 as a group of 5 and 4, and so on. We can only visualise, and think of quite small groups. Anything above that and it becomes a lot, quite a few, loads, s
tloads, a fking shipload, and so on. Gassing Station | Science! | Top of Page | What's New | My Stuff