Questions About the Universe

[garys_2k]

Maybe dumb questions, but with the new findings about the microwave background radiation, here goes:

1) What, exactly, are those pictures of the MBR showing? I know that the granularity is from different microwave frequencies, showing hotter and cooler areas, but WHAT is this? Are we looking back at the "inside of the eggshell" when the universe was ~380K years old?

2) If inflation never happened, would we expect the "outside" of the universe to lie ~380K light years past this "shell?"

3) Is space itself radiating this microwave energy? IOW, if you captured some intergallactic empty space, put it in a very sensitive radio receiver, would you pick up its radiation?

Thanks for your help...

 

[garys_2k]

OK, I realize this isn't the most popular thing, but no takers?

Anyway, from what I understand what we perceive as microwave background radiation is the red-shifted extremely high temperature emissions of the big bang, as soon as atoms and other boson stuff condensed out of the soup. I also understand that, given the red shift, that my question about an "edge" of the universe lying 380K light years past the grainy microwave "surface" (if that's the right concept) is meaningless -- we could never approach it because it would require light-speed travel. So I take back question #2, but reserve the right to pose #2a:

Given that inflation is now the leading theory, just how far back behind that microwave surface CAN we theoretically go?

 

[espritch]

OK. I avoided responding to this before since I am not an expert in the subject. But it is a good question. And since no one else has responded yet, at risk of demonstrating my ignorance, I'll have a go at it (read: take this with a grain of salt, or a whole shaker maybe ).

The CMB represents the earliest point in the history of the universe that we can directly observe and the most distant. Before this, the universe was light impermeable because primeval hydrogen existed as a plasma which doesn't allow transmission of light. The CMB existed everywhere at the point in time represented by the CMB, but since it is electromagnetic radiation, it moves through space just like the light from stars, etc. The CMB we are observing is the heat of the big bang that started out from the most distant points currently observable. An observer at one of these points looking in our direction would also see the CMB but the radiation they observe would be the radiation that started out in our part of the universe. You can't think of the CMB like an egg shell since it looks the same from any view point in the universe (even from points on our observational limit eggshell). You are correct about the CMB being highly red shifted due to the expansion of the universe. The light of the CMB was radiated from every point in the universe and currently every point in the universe is receiving an approximately equal amount of that energy radiated from points at a distance equal to the distance light has traveled in the time since the CMB was released, red shifted to the temperature now observed.

If wouldn't be accurate to say that space is radiating this energy. It would be correct to say that space (or maybe I should say the plasma in space) radiated it at a certain point in the past, from everywhere to everywhere.

The polarization observed in the CMB is due to the fact that the hydrogen didn't cool into a non plasma evenly. Some areas cooled to a non plasma sooner and light bounced around in these areas until the rest had cooled enough to transmit it. This bouncing resulted in the observed different polarization in different regions of the CMB.

The temperature variations are (warning - I'm stepping out on thin ice here) slight variations in matter density resulting from quantum flux. Quantum flux occurs at a small scale but hyperinflation in the first few moments of the big bang expanded the effect of this small variation so as to produce the large scale structure of the universe that we observe today.

The inflationary theory, as I understand it, brings us back to about 1 Planck time unit (a very small unit of time) after the big bang (at least in theory - observationally we are limited to the time of the formation of the CMB). I don't think it is possible, even theoretically, to get closer than that.

I hope this helps. I hope this is correct.

 

[garys_2k]

Ahh, that makes sense! The CMB is just the afterglow, and it is NOT something being newly-generated. DOH! [Insert sound of hand slapping forehead] Space itself isn't "emitting" anything, it just did about 13.4 billion years ago, but the CMB is what's left of that. Thanks.

So, our view of the radiation is "sort of" like a look at the back wall of the big bang, but I do understand that it's not like we could travel to "it," as there isn't an "it" to travel to. We're seeing a fading flash, where variations in the emissions point to long-ago variations in the soup's density and distribution. But this is NOT a picture of the soup itself (or points to locations of that soup).

I guess the reason I'd thought that "space" was radiating this energy was because of the fact that an observer far away, but looking toward us, would see that same radiation. But, of course, he's only seeing that same afterglow that we do, from all of the universe, long ago.

Thanks very much!

 

[scotth]

Maybe dumb questions, but with the new findings about the microwave background radiation, here goes:

1) What, exactly, are those pictures of the MBR showing? I know that the granularity is from different microwave frequencies, showing hotter and cooler areas, but WHAT is this? Are we looking back at the "inside of the eggshell" when the universe was ~380K years old?

2) If inflation never happened, would we expect the "outside" of the universe to lie ~380K light years past this "shell?"

3) Is space itself radiating this microwave energy? IOW, if you captured some intergallactic empty space, put it in a very sensitive radio receiver, would you pick up its radiation?

Thanks for your help...

Something in the way questions number 2 is worded indicates that there is a major disconnect in your understanding somewhere. That isn't really a problem, this is a complicated subject and difficult to grasp.

But, if you could elaborate on what you mean in question 2, we might be able to phrase a response that will be more enlightening for you.


My first thought is that your it is your question implies that we are somehow outside of this inflationary bubble. If the microwave background radiation is a picture of what we think it is, we are completely inside it, have always been inside it, will always be inside it.

 

[garys_2k]

Re: Re: Questions About the Universe

Something in the way questions number 2 is worded indicates that there is a major disconnect in your understanding somewhere. That isn't really a problem, this is a complicated subject and difficult to grasp.

But, if you could elaborate on what you mean in question 2, we might be able to phrase a response that will be more enlightening for you.


My first thought is that your it is your question implies that we are somehow outside of this inflationary bubble. If the microwave background radiation is a picture of what we think it is, we are completely inside it, have always been inside it, will always be inside it.

Oh, you're right about question two, I withdrew and ammended it in my next post. I think I have it now, as:

Yes, we are looking at the "surface" of the big-bang's first incarnation as EM radiation (from the inside), about 380K years after the event. We are seeing that intense, high energy radiation severely red-shifted to microwave, but its structure has preserved the density variations present at that time.

The radiation is the afterglow of the event, and an object suspended in deep space, shielded from local heating by galaxies or other matter, would drop in temperature to 2.7° K because of heating by the CMB.

There is no "wall" or further "end of our universe" beyond it. To contemplate going that far would require light speed travel and is impossible.

Sound about right?

 

[espritch]

Yes, we are looking at the "surface" of the big-bang's first incarnation as EM radiation (from the inside), about 380K years after the event. We are seeing that intense, high energy radiation severely red-shifted to microwave, but its structure has preserved the density variations present at that time.

I’d say "a spherical slice of the big-bang's first visible incarnation", but essentially correct.

The radiation is the afterglow of the event, and an object suspended in deep space, shielded from local heating by galaxies or other matter, would drop in temperature to 2.7° K because of heating by the CMB.

Correct as well. There are, however, places even colder than the CMB. Check out this thread for example: http://www.randi.org/vbulletin/showthread.php?s=&threadid=14473

There is no "wall" or further "end of our universe" beyond it. To contemplate going that far would require light speed travel and is impossible.

It’s even worse than that. Even a light speed ship wouldn’t help. Zoom out in your light speed ship for 380K years and you will find that the CMB is 760K light years away and even more red shifted. The only way you could reach the CMB boundary would be if you could move backward through time. Every time you look out into space you are looking into the past as well: the more distant the object, the farther back in time. And on top of that, since the universe was less expanded in the past, there’s a kind of fish eye effect going on when you look deep into space. The farther out you look, the more crowded together things are. It’s a little mind boggling when you think about it.

 

[Soapy Sam]

And the leading contender for the understatement of the Billennium award is:-
"The farther out you look, the more crowded together things are. It’s a little mind boggling when you think about it. "