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Black hole in the middle of our galaxy





limpands
Did you guys know that there is a gigantic black hole in the middle of our galaxy?
What are your thoughts about this? Do you think it will suck in the earth?

/Limpands
limpands
Oh, it's actually called: Supermassive black hole.
IndieCthulhu
Note to self: don't make posts at 4.30am
kelseymh
IndieCthulhu wrote:
From what I've heard its is actually more of a gravity well than a black hole as the even horizon is actually spewing out enough matter to create thousands of suns and planets... it's kinda like a giant reset button for the milky-way galaxy in my eyes.


Where exactly did you get this information (provide a link)?

The SMBH in Sagittarius A* has a mass of 4.3 x 10^6 solar masses, and an event horizon diameter of ~37 mas. It is not "spewing out matter." There is a relatively small accretion disk surrounding it, and it is orbitied by at least 20 stars in a cluster (the orbits of those stars are how it's mass was determined).
kelseymh
limpands wrote:
Did you guys know that there is a gigantic black hole in the middle of our galaxy? What are your thoughts about this? Do you think it will suck in the earth?

/Limpands


This is extremely well known: http://en.wikipedia.org/wiki/Sagittarius_A*

No, it won't "suck in the earth." Black holes are simply sources of gravity, just like the Sun, the Moon, and the Earth. With most objects, you can't get very close to their center without running into their surface (or burning up, as with the Sun). The only thing whihc makes a black hole special is that it is extremely compact (point like), so you can get much closer to it than you would normally expect. Get close enough, and you can't escape.
playfungames
I read this somewhere as well. It is pretty cool that there is this super massive black hole. But what can we do, except knowing it?
badai
playfungames wrote:
I read this somewhere as well. It is pretty cool that there is this super massive black hole. But what can we do, except knowing it?


well, you can post about it here. get points and coins.
limpands
badai wrote:
playfungames wrote:
I read this somewhere as well. It is pretty cool that there is this super massive black hole. But what can we do, except knowing it?


well, you can post about it here. get points and coins.


And i can reply on this post to get even more points and coins.
LxGoodies
limpands wrote:
Did you guys know that there is a gigantic black hole in the middle of our galaxy?
What are your thoughts about this? Do you think it will suck in the earth?

/Limpands


Some time our atoms will.. But first we're sucked in by the Sun.. becoming part of a red giant star in 6 bln years

http://www.youtube.com/watch?v=Xn8hq8puOCg

Lx Cool
zerokun
I heard (someplace) that our milky way galaxy is absorbing a galaxy called sagittarius something? placing some stars and planets into milky way making our galaxy a bully towards other like astronomical bodies.. that's what i've read though.
kelseymh
zerokun wrote:
I heard (someplace) that our milky way galaxy is absorbing a galaxy called sagittarius something? placing some stars and planets into milky way making our galaxy a bully towards other like astronomical bodies.. that's what i've read though.


The Milky Way is surrounded by a large number of very small (dwarf) galaxies. The two largest are the Large and Small Magellanic Clouds. Some of these dwarf galaxies have gotten too close to the Milky Way, and have been disrupted by tides. This is similar to the way Saturn's rings formed. Some of the disrupted dwarf galaxies are now in the form of long swatches of stars near the Milky Way; the most prominent of these is called the Sagittarius Stream.

All galaxies form and grow by accretion. Applying absurd anthropomorphic descriptions to the process confuses things and impedes understanding.
scifi-real
Devouring our entire galaxy is billions of years in the future. I am sure of it. Smile
it4e
No it will not suck in the earth.
DerIcyferg
I'm very scared now.
spinout
Black holes do get smaller over time I have heard.
Bluedoll
I'm not even sure that it has been proven they exist yet but if they do I think they don't suck but only might affect you if you wonder into their neighbourhood.
Ankhanu
Bluedoll wrote:
... I think they don't suck but only might affect you if you wonder into their neighbourhood.

Right.
At its most basic, a black hole is just a gravity well, just like any other object out in space. The difference is that it's really small and really dense. The effect of gravity is based on objects' mass and the distance between them... exactly what those objects are are irrelevant. So, the Earth and a blackhole with the same mass as the Earth would appear the same, gravitationally. The difference is the distances possible with these two systems, with a blackhole, there's a point at which the distance is short enough that the gravitational pull is immense.

The Earth has a mass of ~6x10^24 kg, and has a diameter of ~13,000 km. An Earth-based black hole would also be ~6x10^24 kg, but have a diameter less than 2 cm. If the Earth suddenly became a black hole (through magic), the moon and all of our satellites would continue orbiting as they are now, and the Earth-hole would continue orbiting the Sun just as it is now.
The gravitational centre is still the centre of the Earth, which, as it is now, you can only get to within 6,500km of... so the acceleration of gravity doesn't get much greater than 9.8 m/s^2 (getting closer to and further from the centre will alter this a bit). With a black hole Earth, you can get to within 2cm, and the acceleration of gravity at that point that it's impossible to produce enough energy to escape the pull of gravity.

So, yeah, nothing gets sucked in, but if you get close enough, gravity is so strong that things just fall right in.
infinitude
scifi-real wrote:
Devouring our entire galaxy is billions of years in the future. I am sure of it. Smile

Even I realize this fact rationally, still I feel depression from time to time especially when starring at the night sky...
Vanilla
Well, when our sun becomes a red giant - about 5 billion years from now -, it will engulf the Earth. So why worry about black holes? If we don't destroy our planet first, it will be destroyed by the one thing that is keeping it alive. And that's a cruel irony. Very Happy
Bikerman
This is still an open question..The sun will certainly expand to cover the current earth orbit, but as it does it will be loosing mass rapidly meaning that the earth's orbit will spiral outwards. The question therefore becomes whether the sun will 'catch' the earth or the earth will spiral into a new stable orbit, or even be cast into intergalactic space.
The latest paper suggests that the first of these possibilities is what will happen.
http://www.universetoday.com/12648/will-earth-survive-when-the-sun-becomes-a-red-giant/
spinout
http://www.youtube.com/watch?v=isimsXwilvc

Stephen Hawking... "information paradox"
I find it a bit boring to listen to the speechmachine...
Ankhanu
spinout wrote:
http://www.youtube.com/watch?v=isimsXwilvc

Stephen Hawking... "information paradox"
I find it a bit boring to listen to the speechmachine...

What would you say is the "take home" message of that?
hanjin66
the universe is expanding or contracting?
Ankhanu
hanjin66 wrote:
the universe is expanding or contracting?

Expanding... but that's somewhat off-topic Razz
Pippo90
Well, it's just an hypothesis, but it shouldn't suck the Earth; it simply explains the rotations of the galaxy around a certain point, like the Sun and the solar system. It is not that all the planets are sucked into the Sun despite its gigantic gravitational field. Wink
spinout
Ankhanu wrote:
spinout wrote:
http://www.youtube.com/watch?v=isimsXwilvc

Stephen Hawking... "information paradox"
I find it a bit boring to listen to the speechmachine...

What would you say is the "take home" message of that?


Well I suppose Hawking wants to say that the black hole is not just a "hole" but have more "functionality" than usually is considered. Hm, Haramein-theories are banned here but his name was mentioned in a commentary somewhere to this, he is a frequent guy in the media anyhow, and in a way they do connect here some thinks. I can't personally grasp the black hole functionality, but the "take home" for me is that the black holes are not so "bad" suckers after all Smile .
Bikerman
The debate follows from Hawkings disputed assertion that information is destroyed in a black-hole. If one believes that BHs are the simple devices they seem, with only mass and possibly spin needed to specify them, it follows that the information contained in the mass which falls into a black hole must be lost. This is at odds with basic quantum theory which requires information to be a conserved quantity.
One solution to this apparent paradox is the 'holographic universe' hypothesis. In this scheme all the information from all the mass that crosses the event horizon of a black hole is stored on a 2-D 'skin' at the event horizon - similar to the way in which a 2-D hologram can contain all the information in a 3-D scene.

PS Haramein is banned in the sense that he is full of crap and his assertions are pseudo-scientific gibberish and, therefore, do not belong in a science forum. Haramein is not a special case, the same applies to all crank-theorists.
duytam28
I doubt that it's real. We have no reliable proof so far.
kelseymh
duytam28 wrote:
I doubt that it's real. We have no reliable proof so far.


I'm curious. What are your qualifications to judge "reliable"?

Please, if you would, start with the [url=http://en.wikipedia.org/wiki/Sagittarius_A*]Wikipedia summary on Sgr A*[/url], go down to the published references, and point out to us which ones are wrong. Don't forget to include your own references to published papers showing why. Thanks!
Bikerman
LOL...you beat me to it. I was also wondering who the eminent scientist was that has joined the forum.
Professional scientists are always welcome and I am grateful for any input that they might find time to contribute to the forums.
Given the assertion (or professional opinion?) that Super-massive Black-holes are unproven and unlikely to have ontological rights, I presume Duytam28 is a cosmologist working on a radical new theory of galaxy formation/structure. I will be fascinated to see how this exciting new research explains the orbital characteristics of S2, S14 and other stars close to galactic centre. An orbital period of around 16 years and a pericentral distance of around 17 light hours....that means something is delivering a stonking kick to that star - if not SMBH then what, I wonder?

My amateur jottings give :
T=2pi*sqrt{r^3/u} (where u=Standard Gravitational param [G{m1+m2}], T = orbital period and r = mean orbital radius)
I am, of course, grossly simplifying by assuming a circular orbit....still, should get us somewhere in the ballpark.....Crunching it a couple of times I get something in the order of 10^7 Solar Masses for m1 - the 'gravitational partner' around which S2 is orbiting....That is 10 Million times the mass of our sun.......that makes it many orders of magnitude greater than the mass necessary to push past the Chandrasekhar limit.....

So, kindly sir, please explain, in simple language that an amateur such as myself can understand, how your theory explains:
  • The presence of a mass orders of magnitude greater than that which, if it was a normal star, would guarantee gravitational collapse beyond the electron degeneracy pressure.....
  • If this mass is not as thought then what the hell is propelling S2 and other stars around orbits with velocities that are an appreciable fraction of c (S2 pushes 5000Km/s at peak - that is 1.7% of c to the nearest kilo-tad and using standard gnats todger error bars....).

Best wishes
Bikerman
mshafiq
Well. Im not certain at all. But the way you asked 'Do you know..' is like it is proven ruth or physical law and ask us if we know. Like asking do you know action and reaction are equal and it is law of science or physics.

I do not wan to say the people who believe in it are intelligent or not but i really do not believe it.
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