our galaxy

[lukemcleod]

at the centre of the galaxy there is a super massive black hole I think he called on the tv but anyway if that's so does that mean at some point in time there was a super massive sun at the centre of our galaxy driving it in an orbit similar to a solar system only with all the solar systems and all the stars orbiting the super massive sun whilst the planets orbited the smaller suns like our own sun? if so is it not possible that countless planets possible containing plenty of life or better yet intelligent life could have been lost to this deadly natural disaster?

 

[mathematic]

Super massive black holes do not result from the collapse of a super sun, since suns could never get that big..

 

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

 

In the article the question of origin is discussed (not known).

[Delta1212]

As stuff falls into a black hole, the black hole gets bigger. This black hole is at the center of a whole galaxy where the density of stars and other matter goes up as you move toward the center. That's a lot of stuff that can, and does, fall into the black hole.

[lukemcleod]

Oh so does that still mean there was possibly a sun like our own like maybe the oldest star in our galaxy that collapsed in on itself and over time it's got bigger and bigger and possibly destroyed countless worlds and intelgiant life possibly

[D H]

Oh so does that still mean there was possibly a sun like our own like maybe the oldest star in our galaxy that collapsed in on itself and over time it's got bigger and bigger and possibly destroyed countless worlds and intelgiant life possibly

I'll answer your last question first. It's highly questionable whether intelligent life could arise close to the center of a galaxy. There are just too many chances for disaster: a close encounter with a nearby star that ejects the planet from its solar system, a nearby star going supernova or undergoing a gamma-ray burst and eradicate life on the planet, etc. Intelligent life, at least on Earth, took 4.6 billion years to arise after the Earth first formed. That long a time span mandates some sense of stability, something that doesn't exist near the galactic center.

 

A lot of people have a misconception about black holes, that they act like interstellar vacuum machines that suck up everything and anything that comes even close to them. For the most part that's not true. Suppose that our Sun is magically replaced with a one solar mass black hole. The Earth would not be sucked into this hypothetical sun replacement. It would instead orbit this black hole, exactly as it currently orbits the Sun.

 

That said, black holes can feed. Objects that pass too close are torn apart by the massive tidal forces that exist close to a black hole. The dust that results collides with other stuff, slowing it down a bit. The dust is now orbiting very close to the black hole. Thermodynamic and relativistic effects now come into play. It loses energy through electromagnetic radiation and gravitational waves. The dust spirals in toward the black hole and eventually does fall into it.

 

This is happening right now with the supermassive black hole at the center of our galaxy but it is rather subdued. That black hole is growing very slowly. That's how the black holes at the centers of most galaxies behave nowadays. They aren't currently "active". That's not how things have always been. Our galaxy most likely was actively feeding at a ferocious rate when it was young. It was an "active galactic nucleus" (google that term). Astronomers can still see those active galactic nuclei, but that's because looking at very far away objects is essentially looking back in time.

 

So how did our supermassive black hole first form? That's a good question; nobody knows the right answer. One thing is certain: It did not form from a solar mass sized black hole. One explanation is that these supermassive black holes formed when the first stars died a violent death. Those first stars were very different from the stars we see around us. Some were incredibly massive, 100, maybe even 1000 times as massive as our Sun. The stellar black holes that resulted from these first hypernova (supernova isn't the right term for a 1000 solar mass star) might have formed the seeds from which our galaxy's supermassive black hole eventually formed.

 

Another explanation is that these supermassive black holes formed on their own, no need for stars going supernova or hypernova. Per this explanation, those supermassive black holes preceded the first stars, maybe even the first galaxies. AFIAK, there is no consensus over which of these two leading explanations is the right one.

[lukemcleod]

Awesome very educational post but d h does that mean I was sort of right about the super massive sun just completely wrong about there being planets and smaller stars around when the super massive suns were

[D H]

Awesome very educational post but d h does that mean I was sort of right about the super massive sun just completely wrong about there being planets and smaller stars around when the super massive suns were

Don't know. There is no consensus on which came first of the first stars, the first supermassive black holes, or the first galaxies. One thing is definite: Those first stars had no Earth-like planets. They couldn't have. The only elements that existed back then were hydrogen, helium, and a tiny bit of lithium. The oxygen that (by weight) comprises 88.9% of the oceans' water, the oxygen, silicon, aluminum, etc. that forms our crust, the iron that comprises the bulk of the Earth's core: Not one of those elements existed when the first stars formed. Those elements formed inside stars.

[lukemcleod]

Thank you d h really appreciate the time you took to answer my question very informative

[Airbrush]

It seems to me that supermassive black holes could only have formed soon after the Big Bang. That is the only time so much mass is in such close proximity. After a while, matter is too spread out for them to form.

Edited June 18, 2013 by Airbrush