Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Jon Francis on 23/08/2010 06:30:00
-
If the universe was created in an explosion and the background microwave radiation was produced when the universe was young. Why did the radiation not overtake us much earlier? and why do we still see it?
-
Hi Jon,
Well, the background radiation is something that we've measured. The odd part about it is that it seems to be coming from everywhere in the universe at once, in roughly the same amounts. This means that when it was generated, it was generated pretty much equally everywhere in the universe. This is one of the strongest pieces of evidence for the big bang: that the universe was once very hot and dense with matter and energy pretty much evenly distributed throughout it. As the universe expanded and cooled, the matter clumped together due to gravity, but the radiation stayed evenly distributed, although it got stretched out to longer and longer wavelengths as space expanded.
-
Basically because the universe is, and always will be, a lot bigger than we can ever see. when it was first emitted as the electrons and protons combined to create hydrogen atoms and the universe became transparent it created an enormous flash of visible light at a temperature similar to the surface of the sun but some parts of the universe were moving away from us so close to the velocity of light that it has taken until now to reach us and has been stretched out by a factor of about one thousand to become microwave radio signals.
-
If the energy that created the CMB travelled at speeds close to the speed of light it would have overtaken us early providing our speed of expansion was slower.
If our speed of expansion was faster it would never catch us? unless our speed of expansion is reducing?
-
Your thinking is fuzzy here. At all times and all distances the expansion of space has gone from zero (near us) to a high value at some distance to the speed of light at the edge of our observable part of the universe (and to even greater values beyond our visibility horizon). At all times there will always be some photons from the CMB era that are just arriving at us.
The CMB is not a tiny weak signal. As others have put it. if we could see the CMB it would appear brighter than the moon!
-
With the still incoming CMB from the deep past still arriving, and the instruments used to detect it, Would the later activities of stellar actions add to this measurement?
If not how can it be filtered if the frequency is within the bandwidth or is it in different modulated phases?
Looking at this Hubble view below, This is a small section of the Universe and it looks like Christmas in Manhattan.
The invisible Microwaves have to be emitting from them too?
.
http://hubblesite.org/gallery/album/nebula/pr2006055a/xlarge_web/
-
If the universe was created in an explosion and the background microwave radiation was produced when the universe was young. Why did the radiation not overtake us much earlier? and why do we still see it?
You are thinking logically and CMB has become part of the science religion suggesting that science can prove the belief 1st expressed in the Secrets Of Enoch that the universe began as the explosion of a black hole. The idea that the universe had a beginning be coming out of something is common with many religions describing the object as an "egg".
The microwave radiation in question has only been detectable for a short period so there is no way to determine if it exists in other regions of space. The fact that "it seems" to be coming from all directions doesn't necessarily mean anything other that it has been reflected by other planets in the solar system or neighboring star systems. On a cloudy day visible light can seem to be coming equally from all directions because of reflections.
-
wow! so a piece of slavonic apocalyptic apocrypha contains a description of the big bang. where? just read through the creation passages and I am afraid I don't spot it.
-
My thinking is certainly fussy. I imagined a universe where the CMB was released that was considerably smaller than it is now. A universe that is expanding at an increasing rate. When the CMB was created I imagined it being in a universe that light could traverse in a period far shorter than the 13 billion years since. The fact that it still remains implies a universe that is infinite where only the visible universe expanded from a singularity.
-
No you are wrong it does not imply that the universe was infinite to start with. Our visible universe was only a few hundred thousand light years across when the background radiation was created and the universe became transparent. The closer radiation say half way out to the limit took a bit longer to get to us because the universe was expanding in the say one hundred thousand light years it had to travel and it was going at half the speed of light away from us to start with the bit right at the edge that was moving at the velocity of light we will never see we are currently seeing the bit a short distance insude this limit where the light has taken around 13 thousand million years to reach us