Is the center of the galaxy a black hole

[Lekgolo555]

Is the center of the galaxy a black hole?

[Klaynos]

I believe that evidence suggests that there is a supermassive black hole at the centre.

 

http://en.wikipedia.org/wiki/Supermassive_black_hole

 

Enjoy

[Lekgolo555]

So does that mean the solar system is spinning around the event horizon of this suppermassive black hole.

 

Come to think of it does that mean everything everywhere is actually in the event horizon of some black hole somewhere

[[Tycho?]]

So does that mean the solar system is spinning around the event horizon of this suppermassive black hole.

 

Come to think of it does that mean everything everywhere is actually in the event horizon of some black hole somewhere

 

Uh, yes it does mean that. But the event horizon is thousands of light years away, and totally undetectable. So for 99% of the galaxy the black hole in the center doesn't make a difference.

[Wearden]

We also have a SuperMassive Black Hole in our Neighbouring Galaxy!

[DZane]

Why is the center of Galaxys so bright then ?

[Lekgolo555]

Why is the center of Galaxys so bright then ?

 

I guess the reason is because gravity does not suck light into the center but rather causes it to curve. And since we are in the event horizon the light is curving into us.

 

I gave it my best shot :confused:

[Edtharan]

Why is the center of Galaxys so bright then ?

Because there are a lot of stars there.

 

The massive black hole at the centre of galaxies is not very large. (iirc: about the size of our solar system).

 

The Earth is around 6,372 km in radius. If it were converted into a black hole then it's radius would be less than 1cm.

 

If the Earth was shrunk down to this size (keeping the same mass), then the moon would continue in it's current orbit unchanged. Being a black hole doe snot effect objects in any different way than an object of that mass existing there without being a black hole.

 

So a black hole about the size of our solar system and with the mass of 1,000 suns would not suck in all the light in the galaxy (or even just near the core). It the light passed within the radius of the black hole, that is different, it would be sucked in.

 

As the centre of our galaxy is thousands of light years across and the diameter that the Black hole would suck in the light would be less than 1 light year across, you can see why the light from those stars are not overly effected by the black hole.

 

So does that mean the solar system is spinning around the event horizon of this suppermassive black hole.

Simple answer: No.

 

Being pedantic: Yes. We are orbiting around the event horizon of a black hole, the only fact is that it is 25,000 light years away from us. And it makes no difference to us if we are orbiting this or a group of thousands of stars (which are not a black hole).

 

People get a bit confused about what a black hole really is. They begin to think of them as fantastical objects that behave in strange ways. But a black hole is not all that much different than the Earth itself (ok I am simplifying here, but bear with me please).

 

Here on Earth if you throw a tennis ball straight up, it will fall back down eventually. The harder you throw it the higher it goes.

 

However, if you could throw it upwards at around 11km/s (39600km/h) then it would never fall back down. This is called the escape velocity.

 

The reason for this is the further out form Earth you are, the weaker the effect of Earth's gravity is on you. If you work out the sums (too complicated for here), then if you can travel fast enough then the pull of gravity is never strong enough to slow you down to 0 and then pull you back. For Earth this is 11km/s

 

A black hole, on the other hand has gravity so strong that you would have to throw that tennis ball faster than 300,000km/s to reach the escape velocity.

 

Now relativity states that as you go faster, you will require more and more energy to push you that bit faster. To push an object to 300,000km/s (when you do the sums) means that you would need an infinite amount of energy to do so. When you do the sums for light, it means that at that point not even light could escape the gravity (if the Escape velocity is higher than the speed of light then light does not even have the velocity to escape).

 

The further you are form a gravitating object, the weaker the effect of gravity. This also means that starting from that further out position, the escape velocity is less.

 

The event horizon of a black hole is where, due to the lower effect of gravity, the escape velocity becomes less than the speed of light (for Earth this is about 1cm).

 

Now the reason this does not result in a black hole at the centre of the earth is that the earth's mass is not all compressed into such a small space. The mass outside that radius pulls away from that point and so the escape velocity from that point is going to be much less than 300,000km/s.

[Klaynos]

I guess the reason is because gravity does not suck light into the center but rather causes it to curve. And since we are in the event horizon the light is curving into us.

 

I gave it my best shot :confused:

 

Well it does cause light to curve, but it also only causes moving mass to curve. So it does infact pull them both towards the centre of mass, it's just that mass is moving slower so the effects are more noticeable.... Just look at curved orbits...

[spikerz66]

Why is the center of Galaxys so bright then ?

 

They are bright because pf the simple fact that there are, I believe the last number I saw was 400 billion stars in our galaxy. The center of Galaxys are bright because of the face that the "celestial real- estate" is so close to another.

 

It couldnt be because of the curvature of light because you wouldnt see the light unless there was some medium for it to pass through. erg. You dont see the beam of light when you turn on a flashlight only what it shines on, unless your shining it through a medium such as dust or fog. Intersteller dust in our case.