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

Well, it deals with MOND doesn't it?

Yousuf Khan

Kemchan wrote:
yes there are parts of the univ. we can't see...yet...the light hasn't had
time to reach us yet.

And will that light ever reach us? Isn't it a bit like trying to walk
up a down-escalator, or walk down an up-escalator?

Yousuf Khan

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

In the earliest parts of the universe do we only see quasars, or do we
see normal galaxies too?

Yousuf Khan

Yousuf Khan wrote:
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


There is more than one way to estimate the age of the universe.

Ref: http://www.astro.ucla.edu/~wright/cosmolog.htm#News

New Age for the Universe

30 Jun 2005 - This week's Nature has a letter giving a new determination
of the age of the Universe based on the age of the isotopes. 238U and
232Th are both radioactive with half-lives of 4.468 and 14.05 Gyrs but
the uranium is underabundant in the Solar System compared to the expected
production ratio in supernovae. This is not surprising since the 238U has
a shorter half-life, and the magnitude of the difference gives an estimate
for the age of the Universe. But the production ratio is poorly known from
nuclear physics models, so Dauphas (2005, Nature, 435, 1203) combines the
Solar System 238U:232Th ratio with the ratio observed in very old, metal
poor stars to solve simultaneous equations for both the production ratio
and the age of the Universe, obtaining 14.5 +2.8/-2.2 Gyr.

See: http://www.astro.ucla.edu/~wright/cosmolog.htm#News

Yousuf Khan wrote:
Sam Wormley wrote:

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


In the earliest parts of the universe do we only see quasars, or do we
see normal galaxies too?

Yousuf Khan


Quasar brightness and numbers peaks up in the first few billion
years of the universe. The evidence indicates that quasars are
due to infalling matter into super massive black holes residing
in the cores of galaxies.


Ref: http://www.astro.ucla.edu/~wright/cosmolog.htm#News

MAP Data Released!

11 Feb 2003 - The results from the first year of observing by the
Wilkinson Microwave Anisotropy Probe were announced today at a Space
Science Update in the auditorium of NASA HQ. Important results
include:

o The satellite has been renamed in honor of the late David T.
Wilkinson of Princeton University, a key member of the project from
its conception.

o The polarization of the microwave background anisotropy coming
from scattering by electrons 200 million years after the Big Bang
has been detected. This is evidence for an early generation of
stars existing 4 to 5 times earlier than any object yet observed.

o The WMAP data agree with previous work showing the Universe is
flat and in an accelerating expansion.

o The WMAP data give the most precise values for the density of
ordinary [baryonic] matter made of protons and neutrons and for the
dark matter: 0.4 and 2.5 yoctograms per cubic meter. These
correspond to omega_b = 0.0224 +/- 0.0009 and omega_m = 0.135 +/-
0.009.

o The WMAP data give the most precise value for the age of the
Universe: 13.7 +/- 0.2 Gyr. The Hubble constant is Ho = 71 +/- 4
km/sec/Mpc, and the vacuum energy density corresponds to lambda =
0.73 +/- 0.04. 13 papers by the science team and the maps and
power spectra are available by clicking on the image above.

See: http://www.astro.ucla.edu/~wright/cosmolog.htm#News

Sam Wormley wrote:
Quasar brightness and numbers peaks up in the first few billion
years of the universe. The evidence indicates that quasars are
due to infalling matter into super massive black holes residing
in the cores of galaxies.

Is there any estimates about if a quasar were to exist today, how
bright it would be comparatively in our sky?

Yousuf Khan

"Yousuf Khan" wrote in message
oups.com...
Well, it deals with MOND doesn't it?

Yousuf Khan


Last sentence in the abstract of article is:
"Milgrom's phenomenological law (MOND) is obeyed, showing it to be an
optical effect, affecting observation but not dynamics."

By,
--Ivica

Sam Wormley wrote:
There is more than one way to estimate the age of the universe.

Ref: http://www.astro.ucla.edu/~wright/cosmolog.htm#News

New Age for the Universe

30 Jun 2005 - This week's Nature has a letter giving a new determination
of the age of the Universe based on the age of the isotopes. 238U and
232Th are both radioactive with half-lives of 4.468 and 14.05 Gyrs but
the uranium is underabundant in the Solar System compared to the expected
production ratio in supernovae. This is not surprising since the 238U has
a shorter half-life, and the magnitude of the difference gives an estimate
for the age of the Universe. But the production ratio is poorly known from
nuclear physics models, so Dauphas (2005, Nature, 435, 1203) combines the
Solar System 238U:232Th ratio with the ratio observed in very old, metal
poor stars to solve simultaneous equations for both the production ratio
and the age of the Universe, obtaining 14.5 +2.8/-2.2 Gyr.

So this would indicate the very first Type II supernovas to have
occurred. How many years after the Big Bang would they expect the first
supermassive stars to have formed, and how many years later would they
be expected to explode?

Yousuf Khan

Yousuf Khan wrote:
Sam Wormley wrote:

Quasar brightness and numbers peaks up in the first few billion
years of the universe. The evidence indicates that quasars are
due to infalling matter into super massive black holes residing
in the cores of galaxies.


Is there any estimates about if a quasar were to exist today, how
bright it would be comparatively in our sky?

Yousuf Khan


http://www.nrao.edu/pr/1998/quasars/

Sam Wormley wrote:
Is there any estimates about if a quasar were to exist today, how
bright it would be comparatively in our sky?
Yousuf Khan


http://www.nrao.edu/pr/1998/quasars/

This seems to indicate that nearby quasars are pretty normal looking in
visible light, but they're lit up in radio light. But aren't quasars out
in the distance supposed to be very bright in the visible?

Yousuf Khan