2 ms·
At 5 AU, gravitational force would be 1/25 or 4% the strength of the sun at 1 AU. If the black hole was four solar masses, it would exert a pull about 16% as s
by kbelder 2mo ago
At 5 AU, gravitational force would be 1/25 or 4% the strength of the sun at 1 AU. If the black hole was four solar masses, it would exert a pull about 16% as strong as the sun. Probably not enough to rip us out of orbit, but enough to seriously perturb it. I think it's at least an end-of-civilization event.
5 AU is the perfect distance to really wreck Jupiter, though.
- bell-cot 2mo agoNot an astrophysicist, but I'm thinking 5 AU could quickly fry the Earth - because it takes very little in the way of solar comets, asteroids, and dust to build a temporary accretion disk around such a black hole. That disk might have a temperature of >1M degrees. Plus the dynamo effects of the disk's interactions with the solar magnetic field? Yeah. 5 ly sounds much safer.
- ben_w 2mo ago> Yeah. 5 ly sounds much safer. Well yeah. I clearly could've phrased this better though: I was aiming for "here is an example distance which *is* bad", not as it appears to have been understood "here is the distance where it is *not* bad".
- kbelder 2mo agoYeah, I'm sure you're right. I was looking purely at orbital mechanics and gravity, but I think a four-stellar-mass black hole would certainly have other harmful environmental effects that would be felt at that range.