What's the difference between a dark star and a black hole?

subject says all.

 

Log in or Sign up to hide all adverts.

Dark star was a silly science fiction movie. Black holes are gravitational singularities.

Do you have a reference? As far as I can tell, dark star is not a scientific term.

 

Log in or Sign up to hide all adverts.

http://en.wikipedia.org/wiki/Dark_star_(Newtonian_mechanics)

 

Log in or Sign up to hide all adverts.

The article you linked to didn't answer your question?

Please Register or Log in to view the hidden image!

 

Doesn't this explain how they're related?

 

It exlains a common characteristic, but there is no reason for a dark star in newtonian mechanics to collapse into a singularity. Also, because it is newtonian, you would not see a time dilation effect associated with its event horizon.

 

You should check out the "dark matter" dark star in the disambiguation link for the wiki article too, those things are a gnarly idea imo. I hope they exist, because they're just cool.

 

Disney's 'Black Hole' wasn't a silly sci-fi movie then?

Please Register or Log in to view the hidden image!

 

^

Please Register or Log in to view the hidden image!

No - it was clearly a documentary!!

Please Register or Log in to view the hidden image!

 

Now, I am confused.
The wikipedia article that Science Man linked implied that a Dark Star would be referred to as a Black Hole in modern theory.
The implication is that there is no Dark Star, just an obsolete theory that such existed, currently modified into Black Hole theory.

Is my impression incorrect?
Can anyone, <cough>, shed some light on this?

 

Take a look here. I don't know too much about any of them though...

 

I was under the impression that a Dark Star was a hypothetical object proposed in the late 18th century from which light could not escape because it had an escape velocity greater than c. As far as I know the idea became obselete once the wave theory of light became established as until GR came along it was believed that light would not be affected by gravity.

 

Thanks.

Although, I realize too late that I was thrown for a loop because I had misread Pandaemoni's post.

Way to go, Neverfly...

 

So wait. The theory of the existance of a Dark Star doesn't exist anymore? by the way, who/what are you guys reffering to when you say GR?

 

General Relativity.

 

I get the impression that the argument is more semantics than anything else.

Under Newton' gravity theory it was possible for an object to have a high enough density so that the escape velocity from the surface was greater than the speed of light. Such an object was called a dark star.

Currently using General Relativity a similar object was postulated and was called a black hole. In recent years there has been lots of evidence these objects exist, including supermassive ones at the center of galaxies.

 

Superficially they are similar, i.e. both have gravity strong enough to trap light, but the physical properties of black holes are vastly different to dark stars because the theories of gravity which predict them are vastly different. Suffice it to say Newtonian dark stars have been obsolete for a long time.

 

if gravity can effect light then light must have a mass but it is hard to prove gravity exists.

a dark star is a canundrum, a star emits the light not absorbs it.

a black hole on the other hand is probablys just a high mass of gravity but then again you cant prove graviy exists thus cant prove black holes exist.

 

Gravity is well known to exist. What cannnot be said is exactly why it works.

Light has no mass. It is effected by gravity because space warps around mass, causing a parabolic curve. Light travels in a straight line through to curve.