View Full Version : How old is the universe?

2005-Apr-06, 09:17 PM
If a galaxy is located 13 billion light years away from us, does it mean that the stuff has been traveling there outwards from a big bang center for a mighty long time, and then the light from there travels towards us during 13 b.l.y.

relativism: The more fun you have, the greater the speed of time

2005-Apr-06, 11:36 PM
This may provide some interesting what-if's for you...
New Discovery Brings 80 Year Old Expanding Universe to a Halt (http://www.send2press.com/newswire/2005-04...-0405-003.shtml)

Somewhere in one of these forums I suggested this very same ridiculous (or maybe not so) possibility...

One further comment on your understanding of the "big bang." It seems that we all make the same assumption at first that the "big bang" was like a firework exploding from a central point outward... (makes sense, but...) It's actually an event that happened EVERYWHERE at once. The Newsweek-type descriptions of "Inflation" where a singularity grows from a microscopic speck to the size of a grapefruit in less than a microsecond, only helps to confuse the visualization.

2005-Apr-07, 07:00 AM
Like that, but I just want to know what is EVERYWHERE?

2005-Apr-07, 03:49 PM
:) On Earth, we define "everything as Universal". In the Universe, everything is Universe. Everything can be define as "Existence". Do you believe that everything exist in the Universe? :)

2005-Apr-07, 04:37 PM
The universe came into being as a thought comes into existence in the human mind, in a way.

And the location was a "singularity," the event encompassed a bit more than that...theoretically ours is only one of many...you should research the Ekpyrotic Universe Model.

2005-Apr-07, 06:19 PM
Gee, thanks...
Think I got something to think about there. Exiting search on Ekpyrotic Universe Model!
How about this; "atoms" are spheres, planets are spheres, universas are spheres that require an escape "velocity"

Do you believe that everything exist in the Universe?
Yeah, what to believe in? Wish to become smarter, but got no serious answers or suggestions.

2005-Apr-08, 04:34 PM
I am no expert by any stretch nor do I subscribe to the Big Bang hypothosy but I'd like to convey my understanding of what the BB'ers are trying to describe to us "lay people".
This so called pea, grape, orange or grapefruit sized "singularity" was a point in "pre-space/time" that we ignorant mortals will never understand. This small singularity supposedly contained "all" of the precursor physics that evolved into the forces,matter, and energy that we now observe (and don't observe but presume to be there), only "now" it's a bit more organized. All this "stuff" was compressed together into this "fruit" sized area at the Plank distance scale (10^-33 or thereabouts...was that meter or centimeter?).
Suddenly, some kind of instability occured within this otherwise "stable" singularity (I think they call it perturbation(s)) which resulted in a type of chain reaction and OMG, "BANG", "our" space and time was born but, only at its first stage. I presume that this all took place at one unit of Plank time which is 10^-43 seconds. At this point, the once stable "stuff" in the singularity "transitioned" into a new form of matter/energy and forces that science believes they will one day completely understand and unify; the "Theory of Everything".
Now for the next stage; the "BIG BANG". If I understand what they call the "inflation model", this very small neighborhood of newly created "space" (>10^-33?) now containining all the released energy forces (and some form of sub, sub... atomic constituents, strings maybe?) is so extremely hot and energized and under enormous pressure that it "instantaneously" (much less than a second?) "expands" (not expoded) this newly created "space" in order to make room for itself "ALL AT ONCE". So, in this sence "our" visible universe was born "everywhere" all at a single instant in time with no "obvious center".
Was I close? Bill

2005-Apr-08, 04:51 PM
Originally posted by Guest@Apr 8 2005, 04:34 PM
Was I close?
Yes, you were close.

I would like to point out that not everyone who accepts the expanding universe is convinced that it started this way. We do observe things that suggest details of the first moments, but I think we are all expecting that the details cannot be made really clear until there is some better understanding of whether m-theory has any real chance of describing the universe, or whether perhaps, some completely new idea comes along.

2005-Apr-08, 05:02 PM
Yeahh, says Ior, I'm lay..
Center is need not be a grape, eaven though a grape has a center (kind of). We live in an expanding U. What does it expand in to if it was there from null? All this mambo jambo just to make B.B. seem possible? What was before? How big is U? Is there something outside U? How old is U? Can you exand something without diminishing something else? What is that "else"? So many FAsQ, but still, not so many FAnQ...
Do you think there is something called eternity? What is that? Is U. for ever?

I'm (sort of) "pisssed off" cause I miss answers to the Q.

2005-Apr-09, 07:10 AM
Sorry, just to make it clearer than it perhaps came out in my last input; "mambo jambo" goes for my own thoughts around the subject. I'ts frustrating not to understand how things work
Thanks you all for interesting input

John L
2005-Apr-10, 02:52 AM
As far as I'm concerned the universe is 33 years, 6 months, 12 day and about 14 hours old. That's how long ago I was born and everything that was supposed to have occurred before that is just a figment of my imagination.

2005-Apr-13, 10:16 PM
This may have been mentioned before, so apologies if I'm being repetitious ...

Here (http://arxiv.org/abs/gr-qc/0503107) is a good, recent review article on the current 'state of play' of cosmology, as a science. In parts, the math is heavy, and there are references to approaches and techniques that have been very successful in other parts of physics that a reader without a university-level background in physics may miss, but overall I think it a very good read.

In particular, it outlines the challenges anyone who wishes to develop an alternative faces - how to get a similar degree of consistency across so many independent sets of observations? It also illustrates the strengths (and weaknesses) of the 'dark energy' and 'dark matter' views, and the limits to how 'zero point energy' could make all the weirdness 'go away' (at least, within the framework of 21st century physics).

There is also an extensive list of references, for anyone wanting to follow up on any particular aspect.