Thread: neutron star

What is the proportion of gravity between the surface of neutron star and the event horizon of a Black hole? Or rather how far away from a EH would you need to go to have the same gravity as that of a neutron star.

I assume that if you have the same mass that it would be the same distance right ?

Is this question spawned from a real event? Where is there a neutron star anywhere close to a blackhole? Asking the outcome of a nonexistant event is without purpose, in my opinion. Please don't take offense to my reply.

Originally Posted by Davethetheorist

Is this question spawned from a real event? Where is there a neutron star anywhere close to a blackhole? Asking the outcome of a nonexistant event is without purpose, in my opinion. Please don't take offense to my reply.

No sorry if I worded my question badly. What I am asking is what is the size difference between say a 2 solar mass BH and a 2 solar mass neutron star.

Originally Posted by tom

I assume that if you have the same mass that it would be the same distance right ?

The prediction of Newton's law of gravity is that, if they had the same mass, it would be the same distance from the center, not the surface (or EH).

To improve this statement to account for relativistic effects is beyond by current abilities, and may possibly remain so for some time

Originally Posted by tom

No sorry if I worded my question badly. What I am asking is what is the size difference between say a 2 solar mass BH and a 2 solar mass neutron star.

You won't find a 2 solar mass black hole. A black hole is always going to be more massive than a neutron star, otherwise it wouldn't be a black hole, so the size difference is irrelevant.

Originally Posted by stereobot

You won't find a 2 solar mass black hole. A black hole is always going to be more massive than a neutron star, otherwise it wouldn't be a black hole, so the size difference is irrelevant.

You can have Black Holes of any size ... why would there be a mass limitation? It would just be much more compact than the sun or a similar sized Neutron star.

Originally Posted by tom

You can have Black Holes of any size ... why would there be a mass limitation? It would just be much more compact than the sun or a similar sized Neutron star.

A star has to be something around 5+ solar masses in order to possibly become a black hole following a supernova, if you are referring to naturally occurring black holes. Otherwise, sure, black holes can be created in particle colliders with a couple particles, but it is just going to evaporate almost instantly.

Also, when talking about things being "compact" are you referring to density or volume?

I guess the actual black hole itself - that is infinitely compacted. The Event Horizon may be large, but the actual black hole "core" is infinitely small.

Yeah I was talking theoretically ... any size could be stable.
3.8 SM seems to be the smallest we know of.
SPACE.com -- Smallest Black Hole Found

compact I am talking about high desitiy ( lots of mass in a small volume )

the "core" or singularity is in theory a point so infinitely dense ...

However the EH is the smallest area ( volume? ) that mass can fit into.

Originally Posted by stereobot

A star has to be something around 5+ solar masses in order to possibly become a black hole following a supernova, if you are referring to naturally occurring black holes. Otherwise, sure, black holes can be created in particle colliders with a couple particles, but it is just going to evaporate almost instantly.

Also, when talking about things being "compact" are you referring to density or volume?

I guess the actual black hole itself - that is infinitely compacted. The Event Horizon may be large, but the actual black hole "core" is infinitely small.