The age of the universe

boostbuck

Joined Oct 5, 2017
549
No surprise. Astrophysics has always been a discipline that necessarily lacks empirical validation, and so is largely stuck with hypotheses.
 

MrAl

Joined Jun 17, 2014
11,572
Hi,

Oh hey that's interesting, cause i did a study too and found that the people that came up with both of those estimates were not 10 to 12 years old they were actually 5 to 6 years old :)
Well ok, but they do act like that sometimes.

It puzzles me how they come up with answers for places that are so far away we can barely even comprehend the distance. We only barely know what is going on in our own galaxy. They know from experience that you have to send probes out to measure things in order to know for sure what is going on, but we can't send probes out to places so very far away.
Egyptology is something like this too. Varied opinions on the age of the Sphinx for example.
If they can't be sure what happened 5 to 10 thousand years ago, how are they ever going to figure out what happened 14 to 28 billion years ago (or more) or why something happened then.
 

Alec_t

Joined Sep 17, 2013
14,379
So time t1is a function of time t2. Does that mean that time t2 is itself a function of time t3? ...... and so ad infinitum?
 

MrAl

Joined Jun 17, 2014
11,572
how do you find out the age of the universe ?
Hi,

You look at the calendar, looking for the Universes birthday, then just keep looking back a year at a time for all the birthdays and count as you go.

I think they use the Hubble constant. My question is what if they still can't see something way out there then the estimate is moot. I think we are seeing that now due to the James Webb telescope which can see farther than before.
 

BobTPH

Joined Jun 5, 2013
9,161
how do you find out the age of the universe ?
All the galaxies we can see are moving apart. The speed depends linearly on the distance between them. Plot their tracks backwards, in time, and about 14 billion years and they in they were all in the same place.

If you accept the premise (which is based on empirical data,) you only need high school geometry to calculate it.

We call the time when they were all together the big bang.
 

drjohsmith

Joined Dec 13, 2021
852
All the galaxies we can see are moving apart. The speed depends linearly on the distance between them. Plot their tracks backwards, in time, and about 14 billion years and they in they were all in the same place.

If you accept the premise (which is based on empirical data,) you only need high school geometry to calculate it.

We call the time when they were all together the big bang.
Just wonder, when we say "all" the galaxies ,
how far distance can we see, more then the age of the universe would be impossible to see.
so we can see old galixies are moving away form the big bang, but are they at the moment !
also do we know where in the universe the big bang was, if its all expanding , there must be a point we can identify .
 

Thread Starter

cmartinez

Joined Jan 17, 2007
8,276
Just wonder, when we say "all" the galaxies ,
how far distance can we see, more then the age of the universe would be impossible to see.
so we can see old galixies are moving away form the big bang, but are they at the moment !
also do we know where in the universe the big bang was, if its all expanding , there must be a point we can identify .
Yes there's a point we can identify ... it's called "everywhere". Remember that the Universe was initially a point, which has no dimensions, And also that the Universe is not a three dimensional sphere with a two dimensional boundary.
 

drjohsmith

Joined Dec 13, 2021
852
Yes there's a point we can identify ... it's called "everywhere". Remember that the Universe was initially a point, which has no dimensions, And also that the Universe is not a three dimensional sphere with a two dimensional boundary.
if universe was every where, how can it be expanding every where, expanding from where ?
 

drjohsmith

Joined Dec 13, 2021
852
Space is being created as it expands
Ok, trouble getting head around this
if the universe is now older than we thought, and as far as I have read, we can see back to "within a few million years " / almost the big bang time,
is the universe now bigger than we thought ?
the I read here, that astrominers can see back 46.5 billion light years,
so they can see past the beginning of the universe if its "only" 27 billion light years wide !
confused,
 

BobTPH

Joined Jun 5, 2013
9,161
There is no center from which it is expanding. Wherever you are looks like the center. This is a mathematical consequence of what an explosion from a single point looks like. I know it is counter-intuitive, but I studied it and was convinced it is true. Not capable of explaining it in a forum post, though. Look it it up if you want yo know, you will find a far better explanation than I could give.
 

BobTPH

Joined Jun 5, 2013
9,161
Ok, trouble getting head around this
if the universe is now older than we thought, and as far as I have read, we can see back to "within a few million years " / almost the big bang time,
is the universe now bigger than we thought ?
the I read here, that astrominers can see back 46.5 billion light years,
so they can see past the beginning of the universe if its "only" 27 billion light years wide !
confused,
If you read contradictory information, both cannot be true. In this case, I believe neither is true. The farthest objects we observe are moving at nearly the speed of light.

Then there is the complication that we believe the expansion is accelerating. But then again, another recent result indicates that nay be incorrect.

You could read for years on this and never come to a solid conclusion.
 
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