How far back in time can theoretically see?

Question

Its not possible to actually see the light from the big bang as this light would already have passed far beyond us into the immensity of space. In fact as the universe expanded it did so slower than the speed of light so any light emitted in the early universe up until a point would also have passed beyond us, even the light emitted from the 'far side' of the universe. But based on the distance we now are from the big bang centre of origin and the time taken for earliest light to reach our current position from what was essentially the far side of the universe when those particular photons of light were emitted - is it possible to estimate this theoretical threshold point when we can see the earliest ever light from the primevil universe? Hope the question makes sense, it was kind of hard to explain my thinking.

Thanks everyone. Its clear as mud to me now. I did learn something though.

Answer 1

it seems to me that your question is based on some false premises.

the earliest we can observe is some 380 000 years after the big bang, and the only reason we can not observe anything earlier than that is at the age of 380 000 years the universe became transparent. electrons combined with atomic nuclei, which were about 74 percent hydrogen and 26 percent helium, so light could then pass unhindered without being scattered. we observe this light at microwave wavelengths because of the stretching of space-time. it is the cosmic microwave background. we observe the cmb in every direction in which we look.

(we see the universe as it was not as it is. hypothetically, if any beings exist at the same distance as the cosmic microwave background from us they would see us here exactly the same way we see them there. they would see the cosmic microwave background.)

the universe is finite yet has no center and no edge. it is four-dimensional, but if you can imagine a two-dimensional version then it seems to be something like the surface of a sphere. space-time itself seems to have originated in the big bang. nothing, not even space-time, exists "outside" the universe. the big bang was the entire universe, and everywhere in the universe was once the big bang.

the speed of expansion seems to have varied over the history of the universe. there was a super-fast expansion between the ages of about 10e-35 seconds and 10e-34 seconds. (e refers to the word exponent.) this is called inflation. after inflation, the expansion began to slow, but beginning about 5 billion years ago, the expansion began to speed up. the expansion is now accelerating.

http://www.sciam.com/print_version.cfm?articleID=0009F0CA-C523-1213-852383414B7F0147

What did you learn, and what is muddy about your understanding?

Answer 2

I honestly dislike to point it out, but your question is flawed.

"...the big bang centre of origin..."
The universe has no center or center of origin. Before the Big Bang event there was nothing -- no spacetime, energy, or matter. At the instant of the Big Bang ALL the space (universe)that would ever be began. It happened everywhere at once, thus is without a center.

"...Its not possible to actually see the light from the big bang as this light would already have passed far beyond us..."
Actually the entire universe, including Earth, is bathed in the 'light' from the Big Bang. It's in the form of thermal radiation and requires extremely sensitive and specialized equipment to detect, but it's there. Astronomers call it the Cosmic Microwave Background Radiation (CMBR) and has a temperature of - 454 degrees Fahrenheit.

"...as the universe expanded it did so slower than the speed of light..."
Immediately after the Big Bang, the universe went through a brief period of expansion that actually EXCEEDED the speed of light (..this doesn't violate relativity because it was space that expanded faster than the speed of light) This momentary expansion period is called 'inflation' and is consistent with many of the features we observe in the universe of today.

Hope this helps untangle a little bit your musings about the universe.

Answer 3

What you are forgetting is the Doppler phenomenon.

In very simple terms if something is moving away from you the radiation that is emitting (eg. light, radio waves etc.) is shifted in frequency always towards lower frequencies. Thus the light from the big bang in our part of the universe is shifted to become microwave radiation which we can see! This microwave background radiation is like the echo of the big bang and it is all over the place.

Missions and microwave telescopes have been trying to map this radiation. One of the most interesting is NASAs MAP http://map.gsfc.nasa.gov/. On this site you can see graphical representations of the Big Bang echo which proves that an event like the one that the Big Bang theory actually happened.

Answer 4

We can see to about a trillionth of a second before the big bang.


Also, WMAP confirmed inflation recently, meaning, for that trillionth of a second the universe ballooned in size...expanding almost unimaginably rapidly.

To put into understandable context, it went from say the size of a microorganism to the size of our galaxy nearly instantly.

Answer 5

well, we dont really know, in order to find out, you need the age of the universe, the age of the Earth, the speed of light, and the distance we are form the source of the light.

Answer 6

Your talking about radio astronomy. Radio telescopes are used to do exactly what you are talking about, they are in the process of building a power full enough radio telescope to see back to just after the bang at least (I'm foggy on the details it was a colloquium on radio astronomy after a long day...I dosed off)

Answer 7

Time is relative. Try looking into Remote Viewing. Here is just one example of so called time travel. This is just one topic and not necessarily a religious site.




http://www.trvnews.com/tmn/091405/godreligionlife.html