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Author Topic: The whole lot is spinning  (Read 1603 times)

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Offline tony.673

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The whole lot is spinning
« on: 18:18:30, 17 December, 2010 »
Hi all,
Having ruled out the situation where Earth is the center of the universe I would like to know what causes a planetary body (or a star for that matter) to spin on it's axis and what causes it's direction of spin.

We seem to be in a situation where the Moon travels around Earth, Earth travels around the Sun and the solar system travels around the Milkyway. Is the Milkyway traveling around anything else.

Answers not too technical please.

Tony
102mm f6 refractor, HEQ5, AA Gpcam130c, Neximage, SPC900, Celestron 15x70 binos, Canon 550D 70-300mm, 18-250mm, 400mm f6.3 & nifty fifty.

Offline swashy

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Re: The whole lot is spinning
« Reply #1 on: 19:21:40, 17 December, 2010 »
The milkyway, and our solar system is rotating around a black hole in the centre, the galaxy is part of a cluster of galaxies called the local group, which also appear to be rotating around an unknown gravitational source called the 'Great Attractor', what is beyond that though, and if other localized galactic clusters gravitational centers are rotating around another common centre is anyones guess, and the possibility of the entire universe rotating just leaves me dizzy
Ade

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Offline swashy

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Re: The whole lot is spinning
« Reply #2 on: 19:43:45, 17 December, 2010 »
There is a good graphic at the bottom on this wiki page http://en.wikipedia.org/wiki/Local_group_of_galaxies
Ade

Imagine...  above us only sky!

Offline koootzz

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Re: The whole lot is spinning
« Reply #3 on: 19:52:18, 17 December, 2010 »
Hi all,
Having ruled out the situation where Earth is the center of the universe I would like to know what causes a planetary body (or a star for that matter) to spin on it's axis and what causes it's direction of spin.

If I understand correctly, the spinning or rotation of planets stars etc is caused when they form from the collapse of interstellar dust and gas, the relatively small and slow movement of the dust/gas is increased by the conservation of motion, much like an ice skaters spin is increased when they pull in their arms and legs.
Leigh
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Offline astrogaz

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Re: The whole lot is spinning
« Reply #4 on: 22:18:06, 17 December, 2010 »
Kootz, Spot on, the gas from which proto stars form has motion, very slight however and under the influence of gravity the collapsing material conserves angular momentum, so takes on a rotation (Like the spinning ice skater). As it collapses further the gravitational pressure increases naturally from the centre of mass, as this mass increases so does its temperature, until...yep you guessed it E=mc2. The outflowing gas pressure is equalised by the incoming gravitational pressure which causes an equilibrium that will only be lost when energy is added or taken away...( look up jeans limit,!)

The Galaxy will gain its rotation from the way in which it was formed, slightly rotating clouds of gas tug at each other and will cause the rotation, however it will not collapse to form a star..there is a limit to this. The black hole will not effect the rotation of the galaxy as the effects (gravitationally ) of the black hole will decrease the further you are from it, so for it to effect the motion of spiral arms thousands of light years out would be quite a feat...its all about energy. Most of which we cannot see, The dark matter abundances are more likely to effect the motion of galaxies. There is a winding paradox with galaxies you could find out about, it may help you understand, IMO of course and I hope this helps.

Gaz.
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Offline tony.673

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Re: The whole lot is spinning
« Reply #5 on: 16:23:51, 18 December, 2010 »
Hi,
Great replies guys. I now understand a little more about the universe albeit at a very basic level.

More web searching and learning now required.

Tony
102mm f6 refractor, HEQ5, AA Gpcam130c, Neximage, SPC900, Celestron 15x70 binos, Canon 550D 70-300mm, 18-250mm, 400mm f6.3 & nifty fifty.

 

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