• Question: Do stars spin around the sun?

    Asked by to Dave on 20 Jun 2014. This question was also asked by .
    • Photo: Dave Jones

      Dave Jones answered on 20 Jun 2014:


      Good question! All of the stars in the sky feel the gravity of the Sun (just the same as they feel the gravity of the Earth and all the other planets) it is just that gravity is very strong close up but gets much weaker the further away you get. That means that even though the other stars feel the pull of the Sun and the Earth, etc. that pull is extremely weak because they are so far away. Because it is so weak they aren’t “bound” to the Sun like the planets are, which is a fancy way of saying that they don’t go in circles around it.

      Instead we have a kind of pyramid of scales of orbit. We have lots of planets orbiting around the Sun, which is like the bottom part of the pyramid because there are so many stars just like the sun who also have planets. After that all those stars are orbiting around the center of our Galaxy, which is much more massive and so has enough gravity to keep everything trapped. After that there are several Galaxies like ours all swirling around one another, because even though they are very far apart the Galaxies are very masssive, so the force of gravity is still strong enough. After that we get to the Virgo Supercluster which is a bunch of gangs of Galaxies all swirling around one another. So, on each scale, the mass of the things spinning around one another has to increase a lot in order to compensate for the massive distances involved, otherwise gravity just isn’t strong enough. Hope that explains it!

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