Can a galaxy consume itself?

[SporeFreak]

I've heard that there's a super-massive black hole at the center of each galaxy. My question is: Given the fact that the galactic center is so densely populated with stars and other matter, couldn't the black hole at the galactic center consume our galaxy from the inside out?? :?: :?
Just a speculation. Could you please tell me?? Thx!

 

[MeteorWayne]

Nope. Despite the supermassive black hole, almost all of the mass of the galaxy is orbiting around the center of mass far away from the center. For example we are ~ 26,000 light years from the center (about 1/3 of the way out) and are in an orbit that takes 220 million years to complete. It's a relatively stable orbit and will remain so for billions of years, at least until we collide with Andromeda (if we do).

 

[origin]

Nope. Despite the supermassive black hole, almost all of the mass of the galaxy is orbiting around the center of mass far away from the center. For example we are ~ 26,000 light years from the center (about 1/3 of the way out) and are in an orbit that takes 220 million years to complete. It's a relatively stable orbit and will remain so for billions of years, at least until we collide with Andromeda (if we do).

What do you mean if we do? Do you have doubts that our 2 galaxies are going to collide or do you mean that the collision may not effect sols stable orbit?

 

[MeteorWayne]

Both actually. While the case for a future collision between the galaxies is strong, I don't believe it is ironclad yet. While we are gravitationally bound, the precise intergalactic orbit isn't known with sufficient precision to guarantee that they will pass through each other. At least that's the latest information I recall reading. I'm no expert, it's not something I've researched a lot lately. Based on that uncertaintly, and future predictions about Sol's orbit in the Milky Way is even more uncertain.

I guess I need to look at some journal articles (not Wiki )

 

[ZenGalacticore]

From what I've read, and it's hard to remember it all these days, the black hole at the center of our Galaxy is not 'feeding' in the present epoch.

It is also my understanding that when the Milky Way and Andromeda collide, while it may send millions or billions of stars streaming out in protracted arms this way and that, the disrupted configuration will be "temporary" on the galactic scale, and eventually the two will merge into an even larger galaxy and the spiral arms will reform.

And as most everyone is aware, the constituent stars in each galaxy will hardly collide at all.

The trippy part of it to me is, if we were living in the time of the imminent merger, this giant lumbering Andromeda galaxy would loom in our skies for a billion years! You could live a 1,000 years and it wouldn't appear to move. Awesome!!

 

[neilsox]

A few billion years from now when the milkyway and andromeda are starting to merge the distance may be closing at 0.001 c. If that fast is average during the merger, the merger will end in about 200,000 times 1000 years = 200 million years. Since the spacing is very wide between individual stars, I don't expect much slowing unless the hubs of the galaxies collide. Likely the aim is not that good. More likely only one of our spiral arms will be much disrupted by the pass though. Is my arithmetic faulty? There is a fair chance Earth's orbit will be perturbed unfavorably, but advanced humans (if any) have a chance at survival. The galaxy is not consumed, nor do I see any way a galaxy is likely to be consumed in any scenario other than the big crunch, which is likely trillions of years in our future, if not forever. Neil

 

[ramparts]

From what I've read, and it's hard to remember it all these days, the black hole at the center of our Galaxy is not 'feeding' in the present epoch.

It is also my understanding that when the Milky Way and Andromeda collide, while it may send millions or billions of stars streaming out in protracted arms this way and that, the disrupted configuration will be "temporary" on the galactic scale, and eventually the two will merge into an even larger galaxy and the spiral arms will reform.

It is possible, but highly unlikely, that the spiral arms will reform. These types of mergers tend to result in an elliptical galaxy, which is basically a giant sphere. It'll be a pretty big galaxy

And as has been suggested, while the night sky will change a lot, our solar system is likely to remain pretty unaffected. Of course, this is around the same time that the Sun plans to go red giant, which will mess things up around here...

 

[none12345]

From a distance a black hole is no different then any other object. Our galaxy's central black hole will no more eat us then the sun will.

It will eat anything that gets close enough to 'fall' into the gravity well, just like our planet eats any meteoroid that gets close enough to the earth to 'fall in'.

Its no different.

---------

Assuming you had an infinite amount of time, its possible that our solar system moving through the interstellar dust could eventually slow it down enough to eventually fall into the central black hole. But it would basically take an infinite amount of time for it to happen, and there is so many other things that would be likely to change our orbit much more drastically during that time frame.

There is an infinitesimal probability it will happen given infinite time.

 

[ramparts]

Well, it won't take infinite time. It will take somewhere on the order of...oh, within 10^100 years :lol: maybe less. I'm not sure. But all orbits decay over time as they lose some energy to gravitational radiation, so eventually everything in our galaxy will fall into the central black hole.

But as I said, this is something like 10^100 years from now. That's a 1, followed by 100 zeroes.

 

[FlatEarth]

I don't think the combination of galaxies will be as benign as it's being made out to be. Star systems that have the misfortune to closely encounter the black hole center of either galaxy would be negatively affected, and that may number in the millions (just a guess). My understanding is that the centers of the Milky Way and Andromeda will eventually merge, and I've never heard of another scenario. I'd be interested to see if MeteorWayne comes up with another conclusion.

As for the massive BH center of our galaxy consuming the rest of the galaxy, definitely that's a no. However, I believe the merging of Andromeda's center could lead to some star systems going down the Singularity Highway.

 

[SpeedFreek]

I had heard that there is a chance that the Milky-Way and Andromeda may not collide too, but it may have been that I just read it on the wiki page. Either that or I was watching the episode of the Sky at Night where they discussed it. This is the the source that wiki cites for that statement.

http://www.nightskyobserver.com/sky-at- ... r-2007.php

The relevant section starts at around 7 minutes in. It seems the galaxies will merge, but they may not initially hit each other. Instead they orbit each other and the orbit gets smaller until they eventually merge into one.

 

[DarwinLied]

Nope. Despite the supermassive black hole, almost all of the mass of the galaxy is orbiting around the center of mass far away from the center. For example we are ~ 26,000 light years from the center (about 1/3 of the way out) and are in an orbit that takes 220 million years to complete. It's a relatively stable orbit and will remain so for billions of years, at least until we collide with Andromeda (if we do).

maybe we would collide if the universe was 2 dimensional, which it isn't. whos to say it wont go under us or even over? on the grand scale of the cosmos, galaxies are flat disks in a vast emptiness. it would be like 2 Frisbee colliding in a space as big as the solar system

 

[Geoduck2]

I've heard that there's a super-massive black hole at the center of each galaxy. My question is: Given the fact that the galactic center is so densely populated with stars and other matter, couldn't the black hole at the galactic center consume our galaxy from the inside out?? :?: :?
Just a speculation. Could you please tell me?? Thx!

I'm going to play contrarian and say absolutely yes,

given enough time that is.

Eventually, 10e100, 10e1000 years or so, everything is going to go down the drain in black holes. The only real question is if protons will decay first.

 

[MeteorWayne]

Sorry, that's just not correct. If the current icrease in the expansion rate of the Universe continues, most matter will be way too far from black holes to be absorbed, no matter how long you wait.

 

[Geoduck2]

I don't agree. The universe is expanding at an accelerating rate. That is the space between the galaxies is increasing at an accelerating rate. The individual galaxies are are gravitationally bound. The stars are orbiting around the centre of mass. Orbits decay and eventually everything will end up in the middle. What might change this is if protons decay, reducing the mass of the galaxy and causing it to disperse. The open question is if whatever is causing the acceleration acts in between galaxies or inside them.

 

[FlatEarth]

I had heard that there is a chance that the Milky-Way and Andromeda may not collide too, but it may have been that I just read it on the wiki page. Either that or I was watching the episode of the Sky at Night where they discussed it. This is the the source that wiki cites for that statement.

http://www.nightskyobserver.com/sky-at- ... r-2007.php

The relevant section starts at around 7 minutes in. It seems the galaxies will merge, but they may not initially hit each other. Instead they orbit each other and the orbit gets smaller until they eventually merge into one.

Hi Speedy

I tried the link, but the video wasn't accessible. I trust they also touched on the latest theory on the accelerating expansion of the universe and how it is related to the accelerating expansion of space-time. :lol:

 

[FlatEarth]

I think you guys are right that over time galaxies lose their rotational velocity and ultimately collapse, assuming the Big Rip doesn't happen before then. So that's my final answer!

 

[ramparts]

Nope. Despite the supermassive black hole, almost all of the mass of the galaxy is orbiting around the center of mass far away from the center. For example we are ~ 26,000 light years from the center (about 1/3 of the way out) and are in an orbit that takes 220 million years to complete. It's a relatively stable orbit and will remain so for billions of years, at least until we collide with Andromeda (if we do).

maybe we would collide if the universe was 2 dimensional, which it isn't. whos to say it wont go under us or even over? on the grand scale of the cosmos, galaxies are flat disks in a vast emptiness. it would be like 2 Frisbee colliding in a space as big as the solar system

Yes, except they'd be two extremely massive Frisbees tugging on each other ever more. Perhaps the first time around they'd miss, but then they'd swing around and come back for more Also, galaxies aren't that thin compared to their widths. 1/10, 1/20, something like that. Not terrible.

 

[maliaki]

I really hate it when SUCH IMPORTANT discoveries go completely unnoticed by so many. While we may now be a part of the Milky Way we didn't originate there. We DO NOT travel around the disk of the Milky Way in some "stable orbit" as MeteorWayne has stated. We are from the SAGITTARIUS DWARF galaxy which has been captured by the Milky Way and we actually orbit AROUND THE POLES of the galaxy! I REALLY WISH people would start understanding this! It has not been spoken loud enough to the space community because SO FEW PEOPLE "get it". ALL measurements that assume this falsity NEED TO BE RE-WORKED! :evil:

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The REAL answer to your question SporeFreak is a RESOUNDING YES! The galaxy CAN and IS consuming itself from the inside out. HOWEVER, at the same time it is shooting jets of matter from it's poles akin to a GIANT "magnetic dynamo" which feeds the galaxies disk, creating more stars further out in a continuous loop. So while it IS eating itself, it is also continuously replenishing itself.

 

[maliaki]

Also, the universe isn't "expanding". The redshift that leads to this conclusion was finally "calibrated" properly and there is no expansion as detailed in a previous SPACE.com article.

Try to keep up people!

 

[DW_Wright]

Well I do belive in the expansion of the universe and its widly accepted as well. As all of the galaxies spread out, the only hope for our home galaxy is to merge with others if not just for the simple reason as more gas and dust to keep our galaxy from "drying up" and not producing anymore stars. In the long run this will come into play as our universe ages and matter is "used" up. And for the simple reason that further down the road we will have to leave this galaxy in search of others but at that time we will be REALLY spread out by then. lets put that off for awhile why dont we?

DW

 

[ZenGalacticore]

From what I've read, and it's hard to remember it all these days, the black hole at the center of our Galaxy is not 'feeding' in the present epoch.

It is also my understanding that when the Milky Way and Andromeda collide, while it may send millions or billions of stars streaming out in protracted arms this way and that, the disrupted configuration will be "temporary" on the galactic scale, and eventually the two will merge into an even larger galaxy and the spiral arms will reform.

It is possible, but highly unlikely, that the spiral arms will reform. These types of mergers tend to result in an elliptical galaxy, which is basically a giant sphere. It'll be a pretty big galaxy

And as has been suggested, while the night sky will change a lot, our solar system is likely to remain pretty unaffected. Of course, this is around the same time that the Sun plans to go red giant, which will mess things up around here...

Not necessarily. Most ellipticals are estimated to contain a trillion or more stars. Andromeda is now thought to be only slightly larger than the Milky Way. Thus the two could merge into an eventual super spiral of 500 billion to 600 billion stars. It could go either way.

And if they are indeed heading towards one another, I don't see how two such massive gravity wells could not eventually collide. As another poster pointed out, the first encounter could miss each other or be a glancing blow, but inevitably they would come back for more and do the galactic tango!!

 

[MeteorWayne]

I really hate it when SUCH IMPORTANT discoveries go completely unnoticed by so many. While we may now be a part of the Milky Way we didn't originate there. We DO NOT travel around the disk of the Milky Way in some "stable orbit" as MeteorWayne has stated. We are from the SAGITTARIUS DWARF galaxy which has been captured by the Milky Way and we actually orbit AROUND THE POLES of the galaxy! I REALLY WISH people would start understanding this! It has not been spoken loud enough to the space community because SO FEW PEOPLE "get it". ALL measurements that assume this falsity NEED TO BE RE-WORKED! :evil:

Sorry, that is not correct. It was suggested a few years ago that our origin might have been from the SAG dwarf galaxy based on metallicity and a few other tidbits, but that hypothesis has wound up in the dustbin.

We DO NOT orbit the poles, we are in a slighly inclined, near circular orbit aligned with the plane of the galaxy. Due to the inclination, we do pass above and below the central plane (as most stars do) but we are most certainly not in a polar orbit.

And just some advice...MAKING every OTHER word IN capital LETTERS makes YOU seem LIKE and OUT of CONTROL fool THAT has TO scream IN an ATTEMPT to MAKE a POINT.

 

[MeteorWayne]

Try to keep up people!

Try to not make stuff up maliaki!! ")

 

[FlatEarth]

And just some advice...MAKING every OTHER word IN capital LETTERS makes YOU seem LIKE and OUT of CONTROL fool THAT has TO scream IN an ATTEMPT to MAKE a POINT.

:lol: