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Author Topic: What determines the speed of Earth's orbit/rotation?  (Read 6300 times)

Herman Melville

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What determines the speed of Earth's orbit/rotation?
« on: 23/06/2009 12:19:48 »
What factors determine the speed of Earth's orbit around the sun and its rotation on its own axis? Apologies if this is another dumb question.

RD

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What determines the speed of Earth's orbit/rotation?
« Reply #1 on: 23/06/2009 18:04:19 »
The Earth's rotation about its axis is slowing, from the fossil record there were many more days in a year,
(i.e. Earth used to spin quicker), e.g. there were about 377 days in a year when the dinosaurs were knocking about.
« Last Edit: 23/06/2009 18:12:00 by RD »

lyner

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What determines the speed of Earth's orbit/rotation?
« Reply #2 on: 24/06/2009 21:03:55 »
The determining factors are the speeds of the various bits of stuff that were around when the SS was formed. For a given star mass , there is a strict relationship between orbit time and distance from the star. Keppler discovered this and Newton did the sums , assuming that gravity follows an inverse square law.
Why the orbits are nearly circular and how the planets actually formed- rather than a ring structure like the one around Saturn is complicated but it is a pattern of many other SSs that the dense rocky planets are close in and the gas giants are further out.

Herman Melville

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What determines the speed of Earth's orbit/rotation?
« Reply #3 on: 25/06/2009 11:02:57 »
The Earth's rotation about its axis is slowing, from the fossil record there were many more days in a year,
(i.e. Earth used to spin quicker), e.g. there were about 377 days in a year when the dinosaurs were knocking about.

Is this slowing down a problem? How does it affect the planet?

RD

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What determines the speed of Earth's orbit/rotation?
« Reply #4 on: 25/06/2009 11:15:28 »
Is this slowing down a problem?

Requires the occasional leap second.

Ophiolite

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What determines the speed of Earth's orbit/rotation?
« Reply #5 on: 25/06/2009 20:09:34 »
Why the orbits are nearly circular and how the planets actually formed- rather than a ring structure like the one around Saturn is complicated but it is a pattern of many other SSs that the dense rocky planets are close in and the gas giants are further out.
I would be genuinely fascinated if you could specify some of the many solar systems that follow this pattern.

lyner

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What determines the speed of Earth's orbit/rotation?
« Reply #6 on: 25/06/2009 22:16:41 »
Don't know the names but Google "extra solar planetary systems" you will get several hits.

Ophiolite

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What determines the speed of Earth's orbit/rotation?
« Reply #7 on: 26/06/2009 10:41:18 »
Don't know the names but Google "extra solar planetary systems" you will get several hits.
Sophie, I am well aware of the many sites dealing with exoplanets, in particular the excellent exoplanets encyclopedia. I was being sarcastic and for that I apologise. However, it is not "the pattern of many other solar systems that the dense rocky planets are close in and the gas giants are further out".
1. Only thirty four systems have been discovered in whih there are multiple planets.
2. Most of those contain only giants.
3. Most giants orbit very close in to their parent star.

The rocky/gaseous/icy pattern found in our system may be typical of other systems, but observations so far do not show this. This could well be an artifact of the resolution of our tools for discovering these systems. As these improve the pattern may emerge, but it is certainly not there at present.

(Of course my challenge remains - show me using the data that I am talking crap and I shall retract everything I have said.)

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What determines the speed of Earth's orbit/rotation?
« Reply #7 on: 26/06/2009 10:41:18 »