Could the universe be older and bigger than we can see?

"Yousuf Khan" wrote:

Translate it for me, what does it mean?


I author of article http://arxiv.org/abs/gr-qc/0508077 is right then:

(Stripped from author's post at sci.astro.research:
Author: Charles Francis
Title: Missing Mass, Galaxy Ageing, Supernova Redshift, MOND, and Pioneer
Date: 2005-08-04)

"
* The rate of expansion of the universe is half that predicted by the
standard model,
* the universe is twice as old as has been thought,
* and critical density for closure is a quarter of the standard value,
dispensing with at least the bulk of missing mass and resolving any ageing
issues...
"

You should read the article.

--Ivica

Sam Wormley wrote:
Yousuf Khan wrote:

Isn't it possible that given only what we can observe, we will always
come up with a finite age for the universe, and it will always be the
same age limit no matter when we do the calculation? For example if
we're calculating the age of the universe to be somewhere around 15-20
billion years old now, then a 100 billion years from now another set of
observers will look at what they can see in the universe at that time,
and they too will come up with 15-20 billion years rather than 115-120
billion?

We estimate the age of the universe to be about 13.7 billion years.
As the universe expands faster and faster, our observable horizon
will begin to shrink and we will no longer be able to "see" the early
universe.

The portion of the early universe (by which I mean the universe at the
time the CMBR was emitted) that we can see must always be expanding (by
which I mean we that in the future, we see things that were further
away). For this region to shrink, light which has already reached us
would have to reach us again. It is possible, however, for the part of
the early universe we can see to asymptotically approach some bound.

Yousuf Khan wrote:
N:dlzc D:aol T:com (dlzc) wrote:
Are there parts of space so far
away from us that it's expanding away from us *faster* than
the speed of light?

We expect so, yes.

Okay great, then assuming by some discovery we find out how much of the
universe is outside of our viewing range, will that affect the
calculations for the age of the universe?

Not for our part of the universe. The portion of the universe outside
the region from which light has or could have travelled to us cannot
have had an effect on the part of the universe we can, in principle,
observe. To do so, some sort of information about the outside region
would have to have travelled faster than the speed of light to
influence us.

Bruce Scott TOK wrote:
Basically, although we see objects at distance we also see them in the
past and it is that which is relevant. We can see that the state of the
universe is different at high redshift than at zero redshift, and due to
the redshift distance relation this is interpreted as a difference
between past and present epoch. Note that this has a frame-independent
definition: proper time since the initial singularity. When we speak of
the age of the cosmos, we are really giving a number to this coordinate
in the Robertson-Walker metric. We can extrapolate from observations
enough to tell that there is a fundamental limit to this epoch of cosmic
time regardless of how much of the spatial extent of the universe we can
see.

I assume you're talking about things like quasars, which we see lot of
in the past and in the distance, but not so much nearby. Is it possible
that these locations are so far off, that we only see the brightest
objects from there?

Yousuf Khan

Yousuf Khan wrote:
Bruce Scott TOK wrote:

Basically, although we see objects at distance we also see them in the
past and it is that which is relevant. We can see that the state of the
universe is different at high redshift than at zero redshift, and due to
the redshift distance relation this is interpreted as a difference
between past and present epoch. Note that this has a frame-independent
definition: proper time since the initial singularity. When we speak of
the age of the cosmos, we are really giving a number to this coordinate
in the Robertson-Walker metric. We can extrapolate from observations
enough to tell that there is a fundamental limit to this epoch of cosmic
time regardless of how much of the spatial extent of the universe we can
see.


I assume you're talking about things like quasars, which we see lot of
in the past and in the distance, but not so much nearby. Is it possible
that these locations are so far off, that we only see the brightest
objects from there?

Yousuf Khan


Quasars where much more prevalent in the earlier universe and have
evolved into much weaker entities today.

Ivica Kolar wrote:
Author: Charles Francis
Title: Missing Mass, Galaxy Ageing, Supernova Redshift, MOND, and Pioneer
Date: 2005-08-04)

"
* The rate of expansion of the universe is half that predicted by the
standard model,
* the universe is twice as old as has been thought,
* and critical density for closure is a quarter of the standard value,
dispensing with at least the bulk of missing mass and resolving any ageing
issues...
"

You should read the article.

Oh, so it's a MOND site. Yeah, I've read about MOND and Moti Milgrom,
there was an article in Discover or SciAm some years back. I do like
the theory, even though some people call it just a curve-fit theory
(i.e. make the equations fit whatever observations you see). But I
think at this point in our understanding of the universe, we better
stick to curve-fitting as we're not sure what's really out there yet.

Yousuf Khan

"Yousuf Khan" wrote:
Oh, so it's a MOND site.

No, that is not MOND site.

Ben Rudiak-Gould wrote:
The "speed" of the CMBR, in units of comoving distance over cosmological
time, is much larger than the speed of light. I think it's about 3.2c. This
means essentially nothing, since the speed of light has no special status
when talking about cosmological recession velocities.

Oh BTW, if the CMBR is "comoving" so fast away from us, how are we able
to detect its microwaves at all?

Yousuf Khan

Jim Black wrote:
Okay great, then assuming by some discovery we find out how much of the
universe is outside of our viewing range, will that affect the
calculations for the age of the universe?

Not for our part of the universe. The portion of the universe outside
the region from which light has or could have travelled to us cannot
have had an effect on the part of the universe we can, in principle,
observe. To do so, some sort of information about the outside region
would have to have travelled faster than the speed of light to
influence us.

So if the age of the universe is always based on only what we can see,
wouldn't that mean that the age of the universe will always be fixed at
the current age (of whatever estimate you want to use)? If the estimate
says the age of the universe is 13.7 billion years old now, then the
universe will forever be 13.7 billion years old, even if we do the
calculation a 100 billion years or a trillion years from now.

Yousuf Khan

Dear Yousuf Khan:

"Yousuf Khan" wrote in message
oups.com...
....
So if the age of the universe is always based on only what we
can see, wouldn't that mean that the age of the universe will
always be fixed at the current age (of whatever estimate you
want to use)? If the estimate says the age of the universe is
13.7 billion years old now, then the universe will forever be
13.7 billion years old, even if we do the calculation a 100
billion years or a trillion years from now.

No, because the information we base our conclusions on is
imbedded in this Universe with us. The determinations of the
temperature of the CMBR about 1 Gy ago, showed the CMBR was
warmer (about 9 K).

David A. Smith