Eli5 Is there any thing stopping a super cool sun from orbiting a elw capable of supporting human life?
In: Physics
First of all, the concept of “orbiting something” only works when one thing is *a lot* heavier than the other. Like the Moon and the Earth. Looking at Pluto and its moon Charon (which is 12% of Pluto’s mass), their orbits are more “around each other” than one orbiting the other. They both move around an empty point in space, which is the center of mass of them both. So if you had a sun and a planet roughly the same size, you’d have them move like 2 planets with nothing in the middle.
Second, stars are stars because they have high gravity. The fusion that makes stars hot only works under immense pressure. So in all likelihood, the heaviest object in a system is also the one most likely to be a star.
And third, stars are made up of mostly hydrogen and helium, while the Earth is mostly iron, silicon and oxygen. Those are a lot rarer overall, so it’s less likely that a large body made of heavy elements forms.
TLDR: Geocentric worlds don’t exist because:
* they wouldn’t be “anything-centrtic”
* they would themselves become a star immediately
* they would likely consist of gas, not rock
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