Celestia Forums

If the Good Doctor Schrempp (or one of you other, knowledgeable geniuses here) could help me out in understanding the
following question, I would be very grateful. As you all know, I am NOT the sharpest tool in the shed. I do continue to
have an abundant curiosity and a great interest in the topics of physics though, so please forgive the apparent stupidity
of the question:

To wit,
When we look into any area of the Universe, we see that the temperatures in any given area are consistent. In other
words, they are pretty much the same temperature at any point in space, as long as you are not close to a star or
some other object. After watching an episode of the "Universe" on the history channel. I learned that this is explained
away using some highly technical terminology which states that gravity separated shortly before any other of the
elemental forces, and that the remaining forces stayed together during the first fraction of the Big Bang explosion
long enough so that temperatures were uniformly distributed during the Big Bang itself.

My question though involves the explanation I heard which stated that 13.7 billion years was not enough time for
the temperature to be uniformly distributed in the Universe we see. Can I ask please, "How is this possible?"

Would seem to me that 13.7 billion years should be long enough for any distribution of temperatures.
Sorry for the question, but I really am just curious here. If this really is a stupid question, please just tell me why.

Thanks, Brain-Dead

Bob,

since throughout this week (until Thursday) I am sitting 9 hours/day in our annual "DESY Theory Workshop" with followup dinners and all that... I am currently too busy for such a demanding pedagogical task.

But let me guess: I suppose what you actually are referring to is the Wilkinson Microwave Anisotropy Probe (WMAP) experiment.

Let me just suggest to browse a bit in their popular pages. Here is a great starter picture about the slightly varying temperature in the Universe (bottom picture), as compared to the temperature variation of our globe (top picture}



(The illustrations are NASA graphics.) Watch the drastically different temperature anisotropy in the Universe as depicted below the color code of the lower image!!!

For reasons of time, let me just copy a few lines of the introduction from their page:
http://hyperphysics.phy-astr.gsu.edu/Hb ... /wmap.html
WMAP Home: http://map.gsfc.nasa.gov/
---------------------------------------------------------------------------------------------------------------------
The WMAP mission has provided the first detailed full-sky map of the microwave background radiation in the universe. The map produced is characterized as a map of the effective temperature of the microwave background radiation as depicted below.

Note in the above images that the temperature variation on the Earth covers about 100°C while those measured by WMAP range only over about 0.0004 °C, a smaller range by a factor of a quarter of a million.

...continue reading on their site!

-------------------------------------------------------------------------------------------------------------------

Fridger

t00fri wrote:...continue reading on their site!

Thanks to you sir...

I DO appreciate the response. I know I'm not very well versed in this stuff, but I do have an absolutely
unending curiosity about such matters. Many thanks for the references. I will probably take a few days to
understand what I am reading, but I will read the referential material.

Many thanks, Bob

Let me see if I can answer this one. Usually when they bring up the phrase "13.7 billion years was not enough time for the temperature to be uniformly distributed in the Universe we see." they are usually referring to the heat death of the universe. This imply that all matter is uniformly distributed, no stars, no planet, nothing larger then subatomic partials. See http://en.wikipedia.org/wiki/Heat_death

In order to get a sense of time that it would require to reach said equilibrium you need to think on a different scale you need to think on the scale of the Cosmological decade
http://en.wikipedia.org/wiki/Cosmological_decade

We are at 13,700,000,000 (13.7 billion) before all fusion mater is exhausted it will be the year 100,000,000,000,000 (100 Trillion)
Then we get into the stage of Degenerate Decades which will last until 10,000,000,000,000,000,000,000,000,000,000,000,000 or 100 Trillion, Trillion, Trillion. During this any of the remaining star mass (white dwarfs) cools down and disintegrates into its subatomic partials. The Back Hole Decades 10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 year. By the end of this time all black holes will have evaporated into nothing, and it after this time that (providing the universe stops expanding) everything will start to equalize. This is what they are referring to by the temperature being uniformly distributed.

MKruer wrote:10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000

I've heard this rumor floating around... something about scientists using scientific notation?

MKruer wrote:Let me see if I can answer this one.

MKruer, thanks to you very much for the less technical explanations.
My main problem here lies in the fact that I would have thought that the heat element would have
been transferred throughout the universe at the same speed as the light. Thus, my confusion.
I will be investigating this question only because I am very much interested in the answer.

Again, many thanks to you all for your help here.
See, I should have been a scientist, but I'm afraid that an Associate's Degree is all I could ever
afford. If I had to do it over again, I might be able to understand the Good Doctor's "pedagogical"
references easier.

Not to worry though doctor, I will review your references, and many thanks to you all here.

Hungry4info wrote:

MKruer wrote:10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000

I've heard this rumor floating around... something about scientists using scientific notation?

It was designated like it is for me, the Brain-Dead Bozo that I am.
I very much appreciated the terminology and the notation. Sorry, but it made a real impression on myself.

Again, Thanks MKruer.

Hungry4info wrote:

MKruer wrote:10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000

I've heard this rumor floating around... something about scientists using scientific notation?

We all know that 10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 is larger then 10^100 But yes I wrote it that way purposefully. just giving the powers of numbers dont have the same impact as writing it long hand.

BobHegwood wrote:My main problem here lies in the fact that I would have thought that the heat element would have
been transferred throughout the universe at the same speed as the light. Thus, my confusion.
I will be investigating this question only because I am very much interested in the answer.

This is where the universe gets "weird" although the universe is estimated at 13.7billion years old, it not 27.4 billion light years in diameter (2 time the radius with earth at the center) If you remember from another conversation that because the universe is still expanding, it is estimated to be at least 93 billion light years across. So there is a lot more volume then you might originally be thinking. ~300 times to be a little bit more precise.

For another point of view here is a simple analogy. Think of a still body of water, nice, smooth and flat. As a reference point, this is the universe with nothing in it. Now we are going throw a rock into the water. We can call this “the big splash” its equivalent to the big bang. In the constrained space of the body of water, the ripples from the rock will expand outwards slowly decreasing in height. Eventually the waves will hit the edges and rebound, can continue to loose energy though wave interference, and give enough time, will equalize and the body of water will become flat again. The same wave might have to bounce off of each shore numerous times before this happens though.

Now think of the same body of water. But this time the shoreline is moving away at the speed of the wave when you though the rock in. The wave never has a chance to rebound off the shore, the wave just continues the expand, but the wave height keeps getting infinitely smaller hence it never has a chance to equalize.

BobHegwood wrote:Again, many thanks to you all for your help here.
See, I should have been a scientist, but I'm afraid that an Associate's Degree is all I could ever
afford. If I had to do it over again, I might be able to understand the Good Doctor's "pedagogical"
references easier.

Not to worry though doctor, I will review your references, and many thanks to you all here.

Not a problem, I enjoy doing these types of problems and I figure if I can explain it then I must know it myself.

MKruer wrote:This is where the universe gets "weird" although the universe is estimated at 13.7billion years old, it not 27.4 billion light years in diameter (2 time the radius with earth at the center) If you remember from another conversation that because the universe is still expanding, it is estimated to be at least 93 billion light years across. So there is a lot more volume then you might originally be thinking. ~300 times to be a little bit more precise.

Ah...
This point I did indeed not understand. Also appreciate your wave explanation.
Makes a bit more sense to me now.

Thanks very much for taking the time to explain for this Bozo.