Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Mattklein on 16/06/2019 05:05:27
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I am just curios as a complete novice to the field, so I welcome any answers, but would an object in space have any gravitational pull if it is stationary? or is gravity purely the result of a body of mass spinning?
secondary question, why does everything spin in space?
I really wish I had paid more attention in science class as now all this stuff fascinates me so much now and I have so many questions. Thanks for any help. :)
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Everything with mass has gravity, spin has nothing to do with it.
As to why objects in space such as planets, asteroids and moons spin, it would be pretty unusual for a object to have zero spin.
To put it simply, they were all formed by stuff falling together and collecting. All this stuff is going to be moving at different speeds and directions. It would take all these various collisions between objects to exactly sum up to zero for the final object formed to end up with no net spin at all.
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With an irregular asteroid in space with no spin initially, light from a nearby star will cause uneven heating of the surface.
- The uneven thermal radiation will give them an increasing spin.
- This could cause small asteroids to break apart, when the centrifugal force exceeds their surface gravity.
See: https://en.wikipedia.org/wiki/Yarkovsky%E2%80%93O%27Keefe%E2%80%93Radzievskii%E2%80%93Paddack_effect
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Cavendish measured the gravitational attraction of some objects which were not spinning.
https://en.wikipedia.org/wiki/Cavendish_experiment
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So it's the other way around. Coalescence by gravitational attraction will generally result in spin, as angular momentum is conserved.