What is a cosmic red-out and how does it relate to the collision of galaxies?

  • Thread starter TheAlkemist
  • Start date
In summary: The heat death of the universe is the ultimate fate of the universe, a scenario in which the expansion of the universe will cause the temperature and density of the universe to exceed the critical point, at which point the universe will cease to exist as a physical entity.The heat death of the universe is the ultimate fate of the universe, a scenario in which the expansion of the universe will cause the temperature and density of the universe to exceed the critical point, at which point the universe will cease to exist as a physical entity.The heat death of the universe is the ultimate fate of the universe, a scenario in which the expansion of the universe will cause the temperature and density of the universe to exceed the critical
  • #1
TheAlkemist
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Can someone please give me a succinct definition/description of what this is? I can't seem to find any references to this by a Google search.

I understand it's one of the several predicted scenarios of the fate of the universe dues to continued acceleration.

Does this have any relationship to the collision of our galaxy and Andromeda in the future or the aftermath of this collision??

What's the predicted expected time this is going to happen? I've read conflicting timelines from 6 billion years to 20 billion years.

Thanks for your anticipated answers!

TheAlkemist
 
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  • #2
I've never heard of the term "cosmic red-out" before, and a Google search for it turns up this thread as the first result. Where did you see it?

The scenario where the universe expands so quickly that increasingly smaller structures are dissociated is called "Big Rip": http://en.wikipedia.org/wiki/Big_rip. The authors of the Big Rip hypothesis calculated 50 billion years as the time we have left.

As for our collision with Andromeda, no, the Big Rip has nothing to do with that. Galaxy collisions are common, as evidenced by the fact that we can see colliding galaxies with telescopes, and usually not dramatic. Interstellar space is so empty that collisions between stars is likely never going to happen.
 
  • #3
ideasrule said:
I've never heard of the term "cosmic red-out" before, and a Google search for it turns up this thread as the first result. Where did you see it?

The scenario where the universe expands so quickly that increasingly smaller structures are dissociated is called "Big Rip": http://en.wikipedia.org/wiki/Big_rip. The authors of the Big Rip hypothesis calculated 50 billion years as the time we have left.

As for our collision with Andromeda, no, the Big Rip has nothing to do with that. Galaxy collisions are common, as evidenced by the fact that we can see colliding galaxies with telescopes, and usually not dramatic. Interstellar space is so empty that collisions between stars is likely never going to happen.

No, I'm not referring to the Big Rip although it was one of the scenarios cited as a predicted fate of our universe.

I saw this term "Cosmic Red Out" in [an article by Michael S. Turner of the U. of Chicago] the recent September 2009 issue of Scientific American, the schematic cartoon on p. 42.

Heck I might just e-mail him and ask.
 
  • #4
I haven't read the article, but it sounds like the extrapolation of our current knowledge: in ~100-120 Gy, all matter except our local galaxy cluster will have left us. It will be seen approaching an event horizon, some 25 Gly (real distance) away, getting increasingly redshifted and unltimately invisible.
 
  • #5
ideasrule said:
The scenario where the universe expands so quickly that increasingly smaller structures are dissociated is called "Big Rip": http://en.wikipedia.org/wiki/Big_rip. The authors of the Big Rip hypothesis calculated 50 billion years as the time we have left.

Just a quick comment on this side point on the Big Rip. The calculation is not really "how much time we have left". The "Big Rip" occurs if you have "phantom energy", which means dark energy with an equation of state having ω < -1.

IF this is the case, then the implication is that the time from now until a singularity in which the whole universe is ripped apart is
[tex]t_{rip} - t_0 \approx \frac{3}{2(1+\omega)H_0\sqrt{1-\Omega_m}}[/tex]​
The calculation for ω = -1.5, H0 = 70 km/s/MPsec and Ωm = 0.3, gives about 22 billion years as the time we have left. But that is just a sample, for an arbitrarily chosen value of ω, which the authors acknowledge is way too negative.

Empirical evidence places much stronger constraints on ω, and in fact it is unlikely to less than -1 at all.

Reference: Caldwell, R. et. al. (2003) Phantom Energy and Cosmic Doomsday, in Phys.Rev.Lett. 91 (2003) 071301, also arxiv:astro-ph/0302506

I shall correct the wikipedia article on this. Thanks for bringing it too my attention! (Added in edit: wikipedia updated: I'm "Duae Quartunciae" over there.)

Cheers -- sylas
 
Last edited:
  • #6
sylas, can you answer my question(s)?

Thanks
 
  • #7
TheAlkemist said:
sylas, can you answer my question(s)?

No, sorry. I've never heard of "cosmic red-out". Emailing the author of the article you saw is a reasonable approach, if there's an email provided.

Cheers -- sylas
 
  • #8
sylas said:
No, sorry. I've never heard of "cosmic red-out". Emailing the author of the article you saw is a reasonable approach, if there's an email provided.

Cheers -- sylas

OK.
I e-mailed the author already. I'll let you guys know after I hear back from him.
Thanks.
 
  • #10
Alkemist, I believe that you've confabulated the "Big Rip" and red shift. As the Universe expands, things will move so far away from us that the light that makes it to us from them will red shift due to the Doppler Effect; giving everything a reddish hue.
 
  • #11
Chalnoth said:
Sounds like you're probably thinking of what is more commonly referred to as the "heat death" of the universe.
That was my first thought too.
 
  • #12
Moloch11 said:
Alkemist, I believe that you've confabulated the "Big Rip" and red shift. As the Universe expands, things will move so far away from us that the light that makes it to us from them will red shift due to the Doppler Effect; giving everything a reddish hue.

DaveC426913 said:
That was my first thought too.

No.
I am familiar with what the "Big Rip" and heat death and redshift is.
In the Scientific American article by Michael Turner, he describes the "Big Rip" and "cosmic Red-out" as two separate predicted outcomes of the universe.
I'm yet to get a reply to the e-mail I sent the author.
 
  • #13
TheAlkemist said:
No.
I am familiar with what the "Big Rip" and heat death and redshift is.
In the Scientific American article by Michael Turner, he describes the "Big Rip" and "cosmic Red-out" as two separate predicted outcomes of the universe.
Uh... correct. The Big Rip and heat death are two distinct ends to the universe. So I'm not sure why you're ruling heat death out.
 
  • #14
DaveC426913 said:
Uh... correct. The Big Rip and heat death are two distinct ends to the universe. So I'm not sure why you're ruling heat death out.

Oh. OK. So you're saying maybe the article was referring to "heat death" and "cosmic redout"?
 
  • #15
TheAlkemist said:
Oh. OK. So you're saying maybe the article was referring to "heat death" and "cosmic redout"?

I'm saying those are one and the same. But I'm just supposing.
 
  • #16
I just took a look at the article.

Directly to the OP's question:

It seems as if the author (Michael S. Turner) has coined a new term. He is not referring to a 'big rip' which is also noted on that diagram as something distinctly different. Turner is applying this term to the proposed situation in which acceleration continues and eventually the Milky Way/Andromeda/et al fusion galaxy will find itself alone in the observable universe. I am guessing that the use of the term 'red out' is designed to refer to the ever increasing cosmic redshift of extra-galactic bodies that ultimately leaves us as an island in the observable universe. The article and diagram actually seem pretty clear on this.

Hope this was of some minor help

diogenesNY
 
  • #17
diogenesNY said:
I just took a look at the article.

Directly to the OP's question:

It seems as if the author (Michael S. Turner) has coined a new term. He is not referring to a 'big rip' which is also noted on that diagram as something distinctly different. Turner is applying this term to the proposed situation in which acceleration continues and eventually the Milky Way/Andromeda/et al fusion galaxy will find itself alone in the observable universe. I am guessing that the use of the term 'red out' is designed to refer to the ever increasing cosmic redshift of extra-galactic bodies that ultimately leaves us as an island in the observable universe. The article and diagram actually seem pretty clear on this.

Hope this was of some minor help

diogenesNY

Thanks!
I thought all along this was what the author was alluding to but I wasn't sure.

I hope he responds to my e-mail to confirm.

On another note - and once again, I'm a chemist not a physicist so pardon my ignorance - would said collision between the Milky Way and Andromeda increase the acceleration (of the now fused galaxies) leading to the "cosmic red-out"?
 
  • #18
TheAlkemist said:
would said collision between the Milky Way and Andromeda increase the acceleration (of the now fused galaxies) leading to the "cosmic red-out"?
I don't see why it would.

Perhaps the only reason the collision is mentioned is because, after hearing that galaxies are heading out-of-range, the first question to be asked will likely be: "Even Andromeda? I though it was headed toward us?"

To which the answer is: "It is heading towards us, yes, and will collide. But other than that, the rest of the galaxies are going to yadda yadda yadda..."
 
  • #19
DaveC426913 said:
I don't see why it would.

Perhaps the only reason the collision is mentioned is because, after hearing that galaxies are heading out-of-range, the first question to be asked will likely be: "Even Andromeda? I though it was headed toward us?"

To which the answer is: "It is heading towards us, yes, and will collide. But other than that, the rest of the galaxies are going to yadda yadda yadda..."

hmm ... makes sense.
 
  • #20
TheAlkemist said:
hmm ... makes sense.

The Bad Astronomer's book "Death from the Skies" gives a good account of the very long term history of the universe for the dark energy with ω = -1 (cosmological constant). The local group of galaxies is all gravitationally bound, and will not be separated. The merger with Andromeda is coming up soon, but in longer time scales we'll be combining with most of the other local galaxies as well. By 100 billion years (Phil's estimate) the local group will be one giant elliptical galaxy.

As time goes on, we will no longer be able to see other galaxies. For astronomers in those times, the universe will appear to be one giant galaxy a few million light years across... and it is unlikely that they will have the evidence that would even allow them to infer the existence of other galaxies, or the expansion of the universe.

After 100 trillion years or so, the stars run out of fuel. The galaxy will be a collection of white dwarfs, neutron star, black holes and various low mass objects. And this is just the beginning. Read this book. It's fun.

Cheers -- sylas
 
  • #21
TheAlkemist said:
Thanks!
I thought all along this was what the author was alluding to but I wasn't sure.

I hope he responds to my e-mail to confirm.

On another note - and once again, I'm a chemist not a physicist so pardon my ignorance - would said collision between the Milky Way and Andromeda increase the acceleration (of the now fused galaxies) leading to the "cosmic red-out"?

So basically what I said, lol.
 

1. What is a cosmic red-out?

A cosmic red-out is a phenomenon that occurs when a large amount of cosmic rays collide with the Earth's atmosphere, causing a temporary loss of radio communication and navigation systems. It is similar to an electrical blackout, but caused by high-energy particles instead of power outages.

2. How does a cosmic red-out happen?

Cosmic red-outs occur when the Earth passes through regions of space with high concentrations of cosmic rays. These rays, which are high-energy particles originating from outside our solar system, interact with the Earth's magnetic field and atmosphere, causing disruptions in electronic systems.

3. Is a cosmic red-out dangerous?

While cosmic red-outs can cause disruptions in electronic systems, they are not considered dangerous to human health. The Earth's atmosphere and magnetic field provide protection from most cosmic rays, and the effects of red-outs are temporary and do not cause any significant harm.

4. How often do cosmic red-outs occur?

Cosmic red-outs are relatively rare events and are difficult to predict. They can occur sporadically throughout the year, but are more likely to happen during periods of high solar activity, such as during solar flares or coronal mass ejections.

5. Can we protect ourselves from cosmic red-outs?

While there is no way to completely prevent cosmic red-outs, certain electronic systems can be shielded or hardened to reduce their susceptibility to cosmic ray disruptions. Additionally, monitoring and predicting solar activity can help mitigate the effects of red-outs on critical systems.

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