[laks]

i would like to know, has antimatter been found at the centre of milkyway? is it true? if yes, what are its implications?

[Bo]

i'm quite sure this isn't true.
as far as we know, the cosmos is filled only with 'normal matter' (except from dark matter which we just don't have a clue of what it is...).

Bo

[Tormod]

If there was antimatter in the center of our galaxy it would most likely cause a giant explosion as it annihilates when it comes in contact with normal matter.

[Aki]

I think you are talking about a big hole? Many galaxies have a black hole at the centre.

[BlameTheEx]

Originally Posted by Aki

I think you are talking about a big hole? Many galaxies have a black hole at the centre.

Speaking as one who doesn't believe in black holes - show me one.

The assumption has always been that anything small and massive enough just has to be a black hole. However that depends on disputed mathematics. My maths is a bit ropy, but Einstein's was good, and he never believed in them.

If black holes can't exist then the evidence works just as well for small massive objects that ain't black holes. The centres of many galaxies could just as easily contain massive neutron stars.

[C1ay]

Originally Posted by BlameTheEx

Speaking as one who doesn't believe in black holes - show me one.

The assumption has always been that anything small and massive enough just has to be a black hole. However that depends on disputed mathematics. My maths is a bit ropy, but Einstein's was good, and he never believed in them.

If black holes can't exist then the evidence works just as well for small massive objects that ain't black holes. The centres of many galaxies could just as easily contain massive neutron stars.

Put another way we could say that you just don't believe there's anything massive enough that even light is cuaght by it's enormous gravitational field. My math's not as good as Einstein's either but Stephen Hawking's is, and he does believe in them.

[BlameTheEx]

Originally Posted by C1ay

Put another way we could say that you just don't believe there's anything massive enough that even light is cuaght by it's enormous gravitational field. My math's not as good as Einstein's either but Stephen Hawking's is, and he does believe in them.

Fairly put.

I believe that to create a black hole you would need INFINITE mass.

The assumption behind Black Holes is that escape velocity is proportional to mass. If that assumption is correct then given a large enough mass the escape velocity reaches C and a Black Hole is born.

But can escape velocity reach C so easily? Gravity is a force that accelerates objects in free fall. how much acceleration to reach C? An object can be accelerated for any finite time with any finite acceleration without reaching C - just gets closer and closer to C without ever quite reaching it. An object falling into a finite gravitational field will never quite reach C. Put a perfect trampoline on the surface so that it bounces off at the same velocity as it arrived and it will escape the gravitational field.

Where an object can go light can follow - it can escape from any object with an escape velocity less than C - it will just be red shifted. Perhaps it will be red shifted dramatically, but it should still escape.

Why should gravitational acceleration be any different for other accelerations?

Einstein Versus Stephen Hawkins? Perhaps I am right and then again I might be wrong, but who would bet with certainty ether way in that fight?

[maddog]

Blame,

As you follow the evolution of the main sequence stars, you find you only need a bit more than three
solar masses to go to a Black Hole. The implosion after the Sodium Flash to Iron produces so much energy
as to Supernova. The remnent at the center is a Black Hole. There are a lot of X-Ray sources from the
Uhuru and more recent satelites that appear to be Black Holes.

Maddog

[Qfwfq]

Originally Posted by BlameTheEx

The assumption behind Black Holes is that escape velocity is proportional to mass.

That isn't quite the assumption behind them. You can find the Schwarzschild solution in Weinberg's book for example. It is a solution to the equations, based on a few reasonable assumptions about the field. It is all done in relativistic framework and isn't refuted by arguments such as:

Originally Posted by BlameTheEx

But can escape velocity reach C so easily? Gravity is a force that accelerates objects in free fall. how much acceleration to reach C? An object can be accelerated for any finite time with any finite acceleration without reaching C - just gets closer and closer to C without ever quite reaching it. An object falling into a finite gravitational field will never quite reach C. Put a perfect trampoline on the surface so that it bounces off at the same velocity as it arrived and it will escape the gravitational field.

If the trampoline is outside the Schwarzschild radius, OK, nobody denies that, but only if the trampoline is outside the Schwarzschild radius. The SR is a singularity. You just try to figure out exactly what happens to he who falls through it.