Andromeda Collision course

[Shrykull]

I was watching a documentary the other night how our galaxy is on a collision course and will eventually collide with the Andromeda Galaxy, most of the stars will pass through each other, almost, but then the galaxy will join, forming a two huge black holes, then they'll consume everything, then they'll slowly evaporate. I guess if there's no way to go faster than light and travel to another galaxy that everyone in both galaxies is going to die.

[pecker]

I was watching a documentary the other night how our galaxy is on a collision course and will eventually collide with the Andromeda Galaxy, most of the stars will pass through each other, almost, but then the galaxy will join, forming a two huge black holes, then they'll consume everything, then they'll slowly evaporate. I guess if there's no way to go faster than light and travel to another galaxy that everyone in both galaxies is going to die.

Hell, I'll be dead already. And odds are if there's a way to go faster than light, we'll figure it out long before that happens.. Worse to worse, freeze yourself and head to another galaxy

[Shrykull]

Hell, I'll be dead already.

I know that, I meant as a species us (we probably won't look anything like we do now if we're still around then

And odds are if there's a way to go faster than light, we'll figure it out long before that happens.. Worse to worse, freeze yourself and head to another galaxy.

Hibernation would work, but certainly not freezing, and exactly how long could you keep yourself in hibernation alive? I don't think for a 250 million light year trip!

[GrandMasterTerwynn]

I was watching a documentary the other night how our galaxy is on a collision course and will eventually collide with the Andromeda Galaxy, most of the stars will pass through each other, almost, but then the galaxy will join, forming a two huge black holes, then they'll consume everything, then they'll slowly evaporate. I guess if there's no way to go faster than light and travel to another galaxy that everyone in both galaxies is going to die.

Actually, no. The collision of Andromeda and the Milky Way will be similar to two puffs of smoke passing through each other. The distances between stars is orders of magnitude greater than the distances between galaxies. What some will have to worry about is the flurry of new star formation that takes place after the collision, and the increased number of supernovae 10 million years later. Some stars will be thrown clear of the galaxies entirely. And yes, the two black holes will eventually merge, but you'll end up with an irregular galaxy, which will eventually become just another giant elliptical galaxy (like most galaxies in the universe.)

[GrandMasterTerwynn]

Hell, I'll be dead already.

I know that, I meant as a species us (we probably won't look anything like we do now if we're still around then

And odds are if there's a way to go faster than light, we'll figure it out long before that happens.. Worse to worse, freeze yourself and head to another galaxy.

Hibernation would work, but certainly not freezing, and exactly how long could you keep yourself in hibernation alive? I don't think for a 250 million light year trip!

Hell, most likely humans and everything currently alive on Earth will be long extinct come then. When the two galaxies merge, it will be three billion years into the future. Earth will have been uninhabitable for two billion years before that. (Increasing solar luminosity will eventually dry up the planet, creating a Venus-like world, or an arid, mostly airless hulk, and make it impossible for life to exist.) Of course, the Sun may be tossed free of the supergalaxy, but it becomes a moot point two billion years after that when the Sun evolves off the main sequence.

[XaLEv]

The distances between stars is orders of magnitude greater than the distances between galaxies.

LOL!

I think you might mean that the distances between stars in a galaxy are orders of magnitude larger than the sizes of said stars. Else you just said that the stars in a galaxy are separated by hundreds of millions or billions of lightyears.

[GrandMasterTerwynn]

The distances between stars is orders of magnitude greater than the distances between galaxies.

LOL!

I think you might mean that the distances between stars in a galaxy are orders of magnitude larger than the sizes of said stars. Else you just said that the stars in a galaxy are separated by hundreds of millions or billions of lightyears.

Oops. I meant to say the relative distance between stars is greater than the relative distance between galaxies. For example a galaxy may only be less than 20 galaxy-diameters away from it's nearest large neighbor. A typical star on the other hand will be at least 1000 stellar-diameters away from it's neighbor.

[Sea Skimmer]

Hell, I'll be dead already.

I know that, I meant as a species us (we probably won't look anything like we do now if we're still around then

And odds are if there's a way to go faster than light, we'll figure it out long before that happens.. Worse to worse, freeze yourself and head to another galaxy.

Hibernation would work, but certainly not freezing, and exactly how long could you keep yourself in hibernation alive? I don't think for a 250 million light year trip!

Freezing bursts every cell in your body. You can't get much more dead then that.

[Durandal]

Terwynn, you forgot the critical detail that both galaxies have ultra-massive black holes at their centers. These black holes are attracted to each other, and they'll combine, letting off a gravitational shockwave of unimaginable magnitude that'll fuck everything up in both galaxies, not to mention the release of gamma rays. The effect will be anything but two puffs of smoke passing through each other.

[data_link]

Terwynn, you forgot the critical detail that both galaxies have ultra-massive black holes at their centers. These black holes are attracted to each other, and they'll combine, letting off a gravitational shockwave of unimaginable magnitude that'll fuck everything up in both galaxies, not to mention the release of gamma rays. The effect will be anything but two puffs of smoke passing through each other.

So you'll get some gravity waves and a gamma-ray burst. While that would certainly put a crimp in developing life in the galaxy, astronomically it won't be a big problem for stars and planets.

[Durandal]

Terwynn, you forgot the critical detail that both galaxies have ultra-massive black holes at their centers. These black holes are attracted to each other, and they'll combine, letting off a gravitational shockwave of unimaginable magnitude that'll fuck everything up in both galaxies, not to mention the release of gamma rays. The effect will be anything but two puffs of smoke passing through each other.

So you'll get some gravity waves and a gamma-ray burst. While that would certainly put a crimp in developing life in the galaxy, astronomically it won't be a big problem for stars and planets.

I hate to say, but yes it will. Two black holes colliding will produce, as I said, gravitational waves of simply unimaginable magnitude that will measurably affect a very large portion of our visible universe.

[data_link]

I hate to say, but yes it will. Two black holes colliding will produce, as I said, gravitational waves of simply unimaginable magnitude that will measurably affect a very large portion of our visible universe.

Okay, now you've gone off the deep end. Gravitational waves that affect the entire visible universe from the mass of two galaxies? What have you been smoking?

Whatever you may hear in sci-fi about gravity waves is simply not true. Gravity is in fact extremely weak. You can demonstrate this to yourself by jumping off the Empire State building. Notice that in the 8.8 seconds that it takes for you to fall to the ground, the gravity of the entire Earth has accelerated you to the incredible velocity of 86.2 m/s. Notice that when you hit the ground, the electromagnetic force between the electrons in the atoms in your head and the electrons in the atoms in the ground stops you in a very short fraction of a second. This is a clear demonstration of how incredibly weak gravity is. Gravity waves are similarly weak... the devices set up so far to detect them are more disturbed by the slight shift in the foundation caused by the weight of the cars on the parking lot above than they are by the waves that they are designed to detect. Remember that these devices are designed to detect gravity waves from black hole collisions - not of the same magnitude as the one you described, but even a wave billions of times more powerful would produce little more than a slight tremor. Simply put, even the most powrful gravity waves are going to do jack shit on the astronomical scale.

[Durandal]

Yes, data_link, I know about gravity.

We had a whole threadabout this subject.

[Darth Wong]

I should also point out that a sufficiently powerful gamma-ray burst would sterilize a galaxy, never mind the gravitational waves.

[Crown]

This is going to sound very ill-informed, but isn't the universe expanding?

[data_link]

Yes, data_link, I know about gravity.

We had a whole threadabout this subject.

Yes, I saw that thread. And what I'm saying is that the effect of the gravity waves would not be large enough to seriously disrupt stars or planets, or to pose any threat to any life that could survive the gamma ray burst (Although, as DW pointed out, that would probably sterilize most of the galaxy, barring technological intervention). Galaxies have collided before - stars kept right on shining.

Gravity waves are overrated.

This is going to sound very ill-informed, but isn't the universe expanding?

<fundie>No, that's just another evolutionist lie. The universe was created by God in seven days exactly as it is now.</fundie>

[GrandMasterTerwynn]

Terwynn, you forgot the critical detail that both galaxies have ultra-massive black holes at their centers. These black holes are attracted to each other, and they'll combine, letting off a gravitational shockwave of unimaginable magnitude that'll fuck everything up in both galaxies, not to mention the release of gamma rays. The effect will be anything but two puffs of smoke passing through each other.

Yes, they will eventually combine. The gravitational interaction between the two of them, and their host galaxies will set off an orgy of new star formation. When all the massive stars go supernova in 20 million years, that's going to sterilize most of the galaxy. When the irregular Andromeda Way galaxy becomes a radio galaxy from the fresh inflow of material into it's black holes, that will sterilize most of the galaxy. However, this will not affect the vast majority of the actual stars in the galaxy. They'll merrily keep shining on until they run out of things to fuse. And though it will have grave consequences for then-current life in the new galaxy, it won't affect the life that evolves on planets that form after the initial starburst period.

[ClaysGhost]

This is going to sound very ill-informed, but isn't the universe expanding?

It is. However, Andromeda and our Galaxy are gravitationally interacting, which will overcome any relative velocity away from each other that they had initially.

The traditional "Big Bang" thought experiment is to draw galaxies on a balloon and blow it up, but this is inaccurate, because it suggests that galaxies themselves expand. If we follow this argument, we'd expect that humans would eventually end up twelve feet tall by virtue of Cosmological expansion! No. Humans and galaxies are bound systems, as is the Galaxy-Andromeda system, and will not expand. A better thought experiment is to glue pennies (or similar) to the balloon to serve as the galaxies.

[Durandal]

Yes, I saw that thread. And what I'm saying is that the effect of the gravity waves would not be large enough to seriously disrupt stars or planets, or to pose any threat to any life that could survive the gamma ray burst (Although, as DW pointed out, that would probably sterilize most of the galaxy, barring technological intervention). Galaxies have collided before - stars kept right on shining.

Gravity waves are overrated.

You're confusing "measurable effects" with "universal effects." The gravity waves will be powerful enough to fuck up everything within the two galaxies, and they could be measured from another galaxy, but won't have any significant effects on that galaxy.

[data_link]

Yes, I saw that thread. And what I'm saying is that the effect of the gravity waves would not be large enough to seriously disrupt stars or planets, or to pose any threat to any life that could survive the gamma ray burst (Although, as DW pointed out, that would probably sterilize most of the galaxy, barring technological intervention). Galaxies have collided before - stars kept right on shining.

Gravity waves are overrated.

You're confusing "measurable effects" with "universal effects." The gravity waves will be powerful enough to fuck up everything within the two galaxies, and they could be measured from another galaxy, but won't have any significant effects on that galaxy.

Measurable effects? Definately - maybe they would be measurable as far away as the next galaxy. But what I'm saying is, that they will not fuck up stars, even in this galaxy. They're simply too weak! The gamma ray burst will have more of an effect on stars and planets than the gravity waves. Now, stop assuming that I must be misunderstanding your argument because I disagree with you.

PS - In case it wasn't clear, I was referring to the stars in the colliding galaxies in my example.

[Raptor 597]

Then are we screwed? Oh, well we are dead ooner or later.

[data_link]

Don't worry, this isn't happening for a long time, and you'll probably be dead before it happens anyway.

[Durandal]

Speak for yourself. I intend to live forever.

[Alnilam]

I suggest you to visit:

http://hubblesite.org/newscenter/archive/1997/34/

After colliding,the Milky Way and Andromeda will look like that cool pair of galaxies.More on what will happen on the collision is in:

http://hubblesite.org/newscenter/archiv ... /astrofile

I wonder what will happen to the other Local Group galaxies.It's knew the Magellanic Clouds will merge with the Milky Way within roughly 1 billion years.But what about the Triangulum Galaxy and those many dwarf elliptical/irregular galaxies that fill the Local Group?.It would be interesting to know their fate...

[Admiral Valdemar]

Funny thing is that 99.999999% of people couldn't give a shit. I know I couldn't and I often get a bit cheated when I read these new Doomsday theories in papers only to have the scientists say "...well withing the next trillion years or so." And then my brain switches off.