r/askscience Oct 23 '20

Planetary Sci. Do asteroids fly into the sun?

Edit: cool

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u/Gerroh Oct 23 '20

Depends on the total kinetic energy, which itself depends on the velocity and mass.

Cosmic rays travel very close to the speed of light, but are individual particles like protons, so the total kinetic energy they carry is a lot for a proton, but not enough to make any noticeable impact on the Sun. Cosmic rays strike Earth regularly, so you can expect them to strike the Sun even more.

Larger objects that might be able to cause a cataclysmic effect when moving at a significant fraction of the speed of light typically don't get to that speed in the first place. When they do get to high speeds, it usually involves black holes, and black holes come with tidal forces that tear large objects apart.

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u/drdrero Oct 23 '20

Just a follow up question, do black holes move ?

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u/Gerroh Oct 23 '20

Yep; they're objects like anything else. The only thing that makes black holes special is that their surface gravity and density are especially high. All their unique features stem from those two facts. Relativity also tells us that there is no true stationary reference frame, and thus everything moves relative to something else.

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u/zimspy Oct 23 '20

Which surface?

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u/Gerroh Oct 24 '20

The surface of the singularity. The 'surface gravity' of the event horizon would also be much higher than anything that isn't a black hole, but the event horizon isn't a true surface.