Science > Physics > Article: Mature Galaxies in Young Universe At Odds with Theory
| Topic: |
Science > Physics |
| User: |
"Robert Karl Stonjek" |
| Date: |
13 Jul 2004 05:04:55 PM |
| Object: |
Article: Mature Galaxies in Young Universe At Odds with Theory |
Mature Galaxies in Young Universe At Odds with Theory
Michael Schirber
The discovery in the distant past of massive galaxies containing more than
10 billion stars has astrophysicists scratching their heads over how such
large objects could have formed so early.
Two teams writing today in Nature provide evidence for large, fully
developed galaxies at the farthest reaches of the cosmos. The light from
these objects takes time to reach the earth, thus astronomers are seeing
them as they looked some 10 billion years ago. Because the big bang is
believed to have occurred nearly 14 billion years ago, these giant
galaxies--some as big as the largest present-day galaxies--must have
completed most of their growth before the universe was a quarter of its age.
This early formation challenges the popular hierarchical model of galaxy
evolution, which assumes that the first galaxies to appear were relatively
tiny. According to this hypothesis, only through the merging of these
smaller entities did larger galaxies slowly develop. The model does not
predict the four massive galaxies that Andrea Cimatti of the Italian
National Institute of Astrophysics and his colleagues observed with the Very
Large Telescope in northern Chile. The assumed age of these mature galaxies
(one of which is located at the center of the image above) implies that they
formed when the universe was just two billion years old.
In a separate survey using the Gemini telescope in Mauna Kea, Hawaii, Karl
Glazebrook of Johns Hopkins University and his collaborators discovered even
more evolved galaxies over a broad time period. Although the researchers did
see a decrease in the number of these galaxies as they looked farther back
in time, the observed drop-off was not as rapid as the predicted one.
Because the hierarchical model has been so successful at explaining other
observations, such as how galaxies cluster, scientists are unlikely to
abandon it. Instead, they may rethink their understanding of how gas turns
into stars. "Some new ingredient is required to make more stars form earlier
in the big galaxies," Glazebrook comments. "But what that ingredient is, we
don't yet know."
From Scientific Amercian
http://cl.extm.us/?fe951c707d66067874-fe3016707360067c711779
Comment:
It seems that each time a larger telescope is turned to the observation of
deep space, bigger and older galaxies are seen. Small, young galaxies are
brighter than big old ones, and so the smaller, younger galaxies are seen at
the 'edges' of the universe. But bigger telescopes will simply push the
'edge' further back.
--
Posted by
Robert Karl Stonjek.
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| User: "Shrikantha S. Shastry" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
20 Jul 2004 12:41:50 AM |
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"Robert Karl Stonjek" <stonjek@ozemail.com.au> wrote in message news:<b0ZIc.26$K53.22@news-server.bigpond.net.au>...
Mature Galaxies in Young Universe At Odds with Theory
Michael Schirber
The discovery in the distant past of massive galaxies containing more than
10 billion stars has astrophysicists scratching their heads over how such
large objects could have formed so early.
Two teams writing today in Nature provide evidence for large, fully
developed galaxies at the farthest reaches of the cosmos. The light from
these objects takes time to reach the earth, thus astronomers are seeing
them as they looked some 10 billion years ago. Because the big bang is
believed to have occurred nearly 14 billion years ago, these giant
galaxies--some as big as the largest present-day galaxies--must have
completed most of their growth before the universe was a quarter of its age.
This early formation challenges the popular hierarchical model of galaxy
evolution, which assumes that the first galaxies to appear were relatively
tiny. According to this hypothesis, only through the merging of these
smaller entities did larger galaxies slowly develop. The model does not
predict the four massive galaxies that Andrea Cimatti of the Italian
National Institute of Astrophysics and his colleagues observed with the Very
Large Telescope in northern Chile. The assumed age of these mature galaxies
(one of which is located at the center of the image above) implies that they
formed when the universe was just two billion years old.
In a separate survey using the Gemini telescope in Mauna Kea, Hawaii, Karl
Glazebrook of Johns Hopkins University and his collaborators discovered even
more evolved galaxies over a broad time period. Although the researchers did
see a decrease in the number of these galaxies as they looked farther back
in time, the observed drop-off was not as rapid as the predicted one.
Because the hierarchical model has been so successful at explaining other
observations, such as how galaxies cluster, scientists are unlikely to
abandon it. Instead, they may rethink their understanding of how gas turns
into stars. "Some new ingredient is required to make more stars form earlier
in the big galaxies," Glazebrook comments. "But what that ingredient is, we
don't yet know."
From Scientific Amercian
http://cl.extm.us/?fe951c707d66067874-fe3016707360067c711779
Comment:
It seems that each time a larger telescope is turned to the observation of
deep space, bigger and older galaxies are seen. Small, young galaxies are
brighter than big old ones, and so the smaller, younger galaxies are seen at
the 'edges' of the universe. But bigger telescopes will simply push the
'edge' further back.
Singularity based illusory universe while needing no creation and
evolution, deludes on observation as to believe in bigbang creation
which is responsible for such a delusion.
S S Shastry
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| User: "Sam Wormley" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
13 Jul 2004 06:03:44 PM |
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Robert Karl Stonjek wrote:
Mature Galaxies in Young Universe At Odds with Theory
Michael Schirber
The discovery in the distant past of massive galaxies containing more than
10 billion stars has astrophysicists scratching their heads over how such
large objects could have formed so early.
Two teams writing today in Nature provide evidence for large, fully
developed galaxies at the farthest reaches of the cosmos. The light from
these objects takes time to reach the earth, thus astronomers are seeing
them as they looked some 10 billion years ago. Because the big bang is
believed to have occurred nearly 14 billion years ago, these giant
galaxies--some as big as the largest present-day galaxies--must have
completed most of their growth before the universe was a quarter of its age.
This early formation challenges the popular hierarchical model of galaxy
evolution, which assumes that the first galaxies to appear were relatively
tiny. According to this hypothesis, only through the merging of these
smaller entities did larger galaxies slowly develop. The model does not
predict the four massive galaxies that Andrea Cimatti of the Italian
National Institute of Astrophysics and his colleagues observed with the Very
Large Telescope in northern Chile. The assumed age of these mature galaxies
(one of which is located at the center of the image above) implies that they
formed when the universe was just two billion years old.
In a separate survey using the Gemini telescope in Mauna Kea, Hawaii, Karl
Glazebrook of Johns Hopkins University and his collaborators discovered even
more evolved galaxies over a broad time period. Although the researchers did
see a decrease in the number of these galaxies as they looked farther back
in time, the observed drop-off was not as rapid as the predicted one.
Because the hierarchical model has been so successful at explaining other
observations, such as how galaxies cluster, scientists are unlikely to
abandon it. Instead, they may rethink their understanding of how gas turns
into stars. "Some new ingredient is required to make more stars form earlier
in the big galaxies," Glazebrook comments. "But what that ingredient is, we
don't yet know."
From Scientific Amercian
http://cl.extm.us/?fe951c707d66067874-fe3016707360067c711779
Comment:
It seems that each time a larger telescope is turned to the observation of
deep space, bigger and older galaxies are seen. Small, young galaxies are
brighter than big old ones, and so the smaller, younger galaxies are seen at
the 'edges' of the universe. But bigger telescopes will simply push the
'edge' further back.
Ref: http://physicsweb.org/article/news/8/7/3
Massive galaxies may have formed much earlier in the history of the
universe than previously thought according to new observations. Two
teams of astrophysicists have detected massive galaxies with
redshifts of more than 1.5, which means that they must have formed
before the universe was a quarter of its present age. The results
are in direct conflict with the currently favoured "hierarchical"
model of galaxy formation.
According to the hierarchical model large galaxies are formed as a
result of smaller galaxies merging. The model predicts that massive
galaxies should appear rather late in the history of the universe,
when it was about half its present age. Astronomers can calculate
how old a galaxy is by measuring its redshift: galaxies with large
redshifts are older and further away than those with small
redshifts.
However, galaxies with high redshifts are difficult to detect
because they are very faint and because the radiation they emit is
shifted to longer wavelengths that are easily absorbed by the
Earth's atmosphere. This means that although astronomers can now
routinely detect bright star-forming galaxies at redshifts up to
6.6, the most distant massive galaxy observed to date is still an
object with a redshift of 1.552 that was discovered 10 years ago.
See: http://physicsweb.org/article/news/8/7/3
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| User: "G=EMC^2 Glazier" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
14 Jul 2004 07:13:19 AM |
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Robert I don't like "early times of the universe" How early is
early? Don't like astronomers telling me the age,and size of our
universe. About 100 years ago the universe was the Milky Way. See what I
mean? Let astronomers tell me the universe is 15 billion years old(most
do) and I will add another billion to it. Let them tell me it is 30
billion years old and I will add another billion to it etc. Astronomers
try to make the universe finite,and I'm taking that away. Bert
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| User: "Bjoern Feuerbacher" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
14 Jul 2004 07:42:05 AM |
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G=EMC^2 Glazier wrote:
Robert I don't like "early times of the universe" How early is
early?
Read the text again. It says that quite clearly.
Don't like astronomers telling me the age,and size of our
universe.
<http://map.gsfc.nasa.gov/m_mm/mr_age.html>
IIRC, this was in the news about 1.5 years ago. No one is trying
to hide this from you.
About 100 years ago the universe was the Milky Way. See what I
mean?
Knowledge has increased since then?
Let astronomers tell me the universe is 15 billion years old(most
do)
13.7 billion years, plus or minus 0.2 billion years.
and I will add another billion to it.
Why?
Let them tell me it is 30
billion years old and I will add another billion to it etc.
Why?
Astronomers
try to make the universe finite,and I'm taking that away. Bert
Astronomers point to clear evidence that the universe has a finite
age. Care to refute that evidence?
Bye,
Bjoern
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| User: "Robert Karl Stonjek" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
14 Jul 2004 05:27:46 PM |
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"Bjoern Feuerbacher" <feuerbac@thphys.uni-heidelberg.de> wrote in message
news:cd39mt$23p$1@news.urz.uni-heidelberg.de...
G=EMC^2 Glazier wrote:
Robert I don't like "early times of the universe" How early is
early?
Read the text again. It says that quite clearly.
Hi Bjoern,
I have a problem with the age "of the entire universe". This implies that
there is some privileged place in the universe where a clock might be placed
to catalogue events.
At the 'other end' of the universe, objects are being carried along by the
expansion of the universe at such a rate that the recession velocity is near
to the speed of light. Can time dilation be ruled out? And to an observer
at the edge, it is we who are being carried along by the expansion of the
universe at near light speed.
Where is this privileged clock? And when the universe turns 15 billion
exactly, is every point in the universe 15 billion years old? A proton
flung off during early star formation, for instance, might travel at 99.99%
of the speed of light until it strikes Earth. If there were a clock on the
proton then it would read only around 67 million years.
Even an object that is static with respect to the CMBR is no guarantee of
consistency, as objects at 10 billion light years distance from us could
also be static with respect to the CMBR, yet be on the move at a rate near
light speed relative to us.
Though it is difficult to formulate, one can not discount the possibility
that the universe always appears to be about 15 billion years old. That is,
if we were to peer out into the universe in 15 billion years time, it would
appear, by all calculations and observations, to be about 15 billion years
old. At that time, however, Earth will long have since joined the dark
matter, possibly being reabsorbed by some other star formation.
--
Kind Regards,
Robert Karl Stonjek.
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| User: "Bjoern Feuerbacher" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
16 Jul 2004 09:14:43 AM |
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Robert Karl Stonjek wrote:
"Bjoern Feuerbacher" <feuerbac@thphys.uni-heidelberg.de> wrote in message
news:cd39mt$23p$1@news.urz.uni-heidelberg.de...
G=EMC^2 Glazier wrote:
Robert I don't like "early times of the universe" How early is
early?
Read the text again. It says that quite clearly.
Hi Bjoern,
I have a problem with the age "of the entire universe". This implies
that there is some privileged place in the universe where a clock might
be placed to catalogue events.
No. More on that below.
At the 'other end' of the universe, objects are being carried along by
the expansion of the universe at such a rate that the recession
velocity is
near to the speed of light.
I could quibble about "other end" here, but the main point here is
that the (apparent!) recession velocity can easily exceed the speed of
light.
See the last paragraph at
<http://www.astro.ucla.edu/~wright/doppler.htm>
Can time dilation be ruled out?
Since the velocity is only apparent and not real motion, yes.
There *is* a time dilation due to peculiar motions (e.g. the one
seen for the solar system in the WMAP dipole anisotropy), but that
it usually neglible. Also, there is gravitational time dilation
(e.g. for the earth due to it being in the gravitational well for
the sun), but that is usually also negligible.
And to an observer at the edge,
Sorry, I don't know what you mean by "edge" here.
it is we who are being carried along by the expansion of the
universe at near light speed.
Yes.
Where is this privileged clock?
Simply use a comoving clock (i.e. a clock which has no peculiar
motion).
And when the universe turns 15 billion
exactly, is every point in the universe 15 billion years old?
No. Only comoving objects.
A proton
flung off during early star formation, for instance, might travel at
99.99% of the speed of light until it strikes Earth.
How could a photon travel at less than the speed of light?
If there were a clock on the
proton then it would read only around 67 million years.
Well, clocks on photons are surely not comoving. ;-)
Even an object that is static with respect to the CMBR
Do you mean not moving wrt to it, i.e. comoving?
is no guarantee of
consistency, as objects at 10 billion light years distance from us could
also be static with respect to the CMBR, yet be on the move at a rate
near light speed relative to us.
Since that is only an apparent speed, there is no SR time dilation.
Clocks which are separated by 10 billion light years and appear to
move at great speeds wrt each other, but which are nevertheless both
comoving, show the same time.
Though it is difficult to formulate, one can not discount the
possibility that the universe always appears to be about 15 billion
years old. That is, if we were to peer out into the universe in 15
billion years time, it would appear, by all calculations and
observations, to be about 15 billion years old.
Well, there are a lot of possibilities which one can't discount,
including Last Thursdayism.
<http://home.eznet.net/~heiny/theories/last_thursday.html>
But why should one assume such a strange idea to be true?
At that time, however, Earth will long have since joined the dark
matter, possibly being reabsorbed by some other star formation.
Right.
Bye,
Bjoern
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| User: "G=EMC^2 Glazier" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
16 Jul 2004 08:46:03 AM |
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Bjoern The universe is getting bigger by 95% of "c" in every direction
each second. Out of that comes my dispute on it being finite. Think
about it Bert
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| User: "Bjoern Feuerbacher" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
16 Jul 2004 09:15:35 AM |
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G=EMC^2 Glazier wrote:
Bjoern The universe is getting bigger by 95% of "c" in every direction
each second.
Where on earth did you get that strange idea from???
Out of that comes my dispute on it being finite.
Err, where did I say that it is finite?
[snip]
Bye,
Bjoern
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| User: "G=EMC^2 Glazier" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
16 Jul 2004 05:58:13 PM |
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Bjoern That the universe is expanding at 95% of "c" is in every book.
That is another reason I can't believe you when you brag you have a PH D
When and where did you get it?. In another news group we had a guy name
Scott(much like you) he also bragged that that he was a professor. When
asked where ? He never posted again,and disappeared. Bjoern If true you
should be proud to give us that information. If you don't we know
you lied. I'm betting you won't an are just a big mouth.bragger Bert
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| User: "Sam Wormley" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
19 Jul 2004 11:10:30 AM |
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G=EMC^2 Glazier wrote:
Bjoern That the universe is expanding at 95% of "c" is in every book.
Try to get it right Herb--The universe is now expanding at 71 km/s/mpc.
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| User: "Robert Karl Stonjek" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
19 Jul 2004 05:19:38 PM |
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"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:40FBF269.9F0F933F@mchsi.com...
G=EMC^2 Glazier wrote:
Bjoern That the universe is expanding at 95% of "c" is in every book.
Try to get it right Herb--The universe is now expanding at 71 km/s/mpc.
He was obviously referring to the recession velocity of the most distant
objects with respect to, say, Earth.
According to Wheeler, Thorn etc there are two ways of looking at space. You
can use GR and curved space or you can use a flat space model. The space
around a massive object can be thought of as curved (GR) or flat and under
the influence of a gravitional force. The calculations where possible, give
the same results in either model.
But when it comes to the universe as a whole, particularly the concept of an
expanding coordinate system (GR) we only apply GR because the alternative
model would have the actual recession speed of the most distant objects at
well over the speed of light (as they must be now, not as the light arriving
from them, which is billions of years out of date by the time it arrives).
--
Kind Regards,
Robert Karl Stonjek.
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| User: "Sam Wormley" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
19 Jul 2004 09:41:51 PM |
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Robert Karl Stonjek wrote:
"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:40FBF269.9F0F933F@mchsi.com...
G=EMC^2 Glazier wrote:
Bjoern That the universe is expanding at 95% of "c" is in every book.
Try to get it right Herb--The universe is now expanding at 71 km/s/mpc.
He was obviously referring to the recession velocity of the most distant
objects with respect to, say, Earth.
According to Wheeler, Thorn etc there are two ways of looking at space. You
can use GR and curved space or you can use a flat space model. The space
around a massive object can be thought of as curved (GR) or flat and under
the influence of a gravitional force. The calculations where possible, give
the same results in either model.
But when it comes to the universe as a whole, particularly the concept of an
expanding coordinate system (GR) we only apply GR because the alternative
model would have the actual recession speed of the most distant objects at
well over the speed of light (as they must be now, not as the light arriving
from them, which is billions of years out of date by the time it arrives).
--
Kind Regards,
Robert Karl Stonjek.
Yes--for a very distant object, with a redshift of, say z=10, the "current"
velocity with respect to the earth is approximately cz. And as you point out
the light reaching us now is "very out of date".
Using Ned Wright's Javascript Cosmology Calculator at
http://www.astro.ucla.edu/~wright/CosmoCalc.html
and redshift of Z=10, flat universe and default cosmological
parameters, such an object formed pretty early on.
BTW thanks for posting physics news articles to news:sci.physics
Regards,
-Sam
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| User: "Sam Wormley" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
20 Jul 2004 12:36:19 AM |
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Sam Wormley wrote:
Robert Karl Stonjek wrote:
"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:40FBF269.9F0F933F@mchsi.com...
G=EMC^2 Glazier wrote:
Bjoern That the universe is expanding at 95% of "c" is in every book.
Try to get it right Herb--The universe is now expanding at 71 km/s/mpc.
He was obviously referring to the recession velocity of the most distant
objects with respect to, say, Earth.
According to Wheeler, Thorn etc there are two ways of looking at space. You
can use GR and curved space or you can use a flat space model. The space
around a massive object can be thought of as curved (GR) or flat and under
the influence of a gravitional force. The calculations where possible, give
the same results in either model.
But when it comes to the universe as a whole, particularly the concept of an
expanding coordinate system (GR) we only apply GR because the alternative
model would have the actual recession speed of the most distant objects at
well over the speed of light (as they must be now, not as the light arriving
from them, which is billions of years out of date by the time it arrives).
--
Kind Regards,
Robert Karl Stonjek.
Yes--for a very distant object, with a redshift of, say z=10, the "current"
velocity with respect to the earth is approximately cz. And as you point out
the light reaching us now is "very out of date".
Using Ned Wright's Javascript Cosmology Calculator at
http://www.astro.ucla.edu/~wright/CosmoCalc.html
and redshift of Z=10, flat universe and default cosmological
parameters, such an object formed pretty early on.
BTW thanks for posting physics news articles to news:sci.physics
Regards,
-Sam
Ref: http://www.astro.ucla.edu/~wright/cosmology_faq.html#FTL
Can objects move away from us faster than the speed of light?
Again, this is a question that depends on which of the many distance
definitions one uses. However, if we assume that the distance of an
object at time t is the distance from our position at time t to the
object's position at time t measured by a set of observers moving
with the expansion of the Universe, and all making their observations
when they see the Universe as having age t, then the velocity (change
in D per change in t) can definitely be larger than the speed of
light. This is not a contradiction of special relativity because this
distance is not the same as the spatial distance used in SR, and the
age of the Universe is not the same as the time used in SR. In the
special case of the empty Universe, where one can show the model in
both special relativistic and cosmological coordinates, the velocity
defined by change in cosmological distance per unit cosmic time is
given by v = c ln(1+z) which clearly goes to infinity as the redshift
goes to infinity, and is larger than c for z > 1.718. For the
critical density Universe, this velocity is given by v = 2c[1-(1+z)-0.5]
which is larger than c for z > 3 .
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| User: "Bjoern Feuerbacher" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
20 Jul 2004 03:17:57 AM |
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Robert Karl Stonjek wrote:
"Sam Wormley" <swormley1@mchsi.com> wrote in message
news:40FBF269.9F0F933F@mchsi.com...
G=EMC^2 Glazier wrote:
Bjoern That the universe is expanding at 95% of "c" is in every book.
Try to get it right Herb--The universe is now expanding at 71 km/s/mpc.
He was obviously referring to the recession velocity of the most distant
objects with respect to, say, Earth.
1) He said "the universe is expanding st 95% of c". How do you get from
that to "the recession velocity of the most distant object"?
2) We don't know so far if something like a "most distant object" even
*exists* - if the universe is infinitely large, there *is* no most
distant object.
3) Even if he meant the most distant object *observed* so far, his claim
*still* would be wrong. The recession velocity of the most distant
object observed so far is greater than 95% of c.
According to Wheeler, Thorn etc there are two ways of looking at space.
You can use GR and curved space or you can use a flat space model.
The space around a massive object can be thought of as curved (GR) or
flat and under the influence of a gravitional force.
The calculations where possible, give the same results in either model.
Where do MTW say that? Quote, please.
I agree that *some* of the calculation in *some* circumstances will
give the same results - but surely not all of them?
But when it comes to the universe as a whole, particularly the concept of an
expanding coordinate system (GR) we only apply GR because the alternative
model would have the actual recession speed of the most distant objects at
well over the speed of light (as they must be now, not as the light arriving
from them, which is billions of years out of date by the time it arrives).
So, if you agree with me that the recession velocities are greater
than c and therefore obviously also greater than 95% of c, why did
you take Bert's side here?
Bye,
Bjoern
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| User: "Bjoern Feuerbacher" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
19 Jul 2004 04:58:33 AM |
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[posted and e-mailed, so that you can't say that you missed this]
G=EMC^2 Glazier wrote:
Bjoern That the universe is expanding at 95% of "c" is in every book.
Wrong. Totally utterly completely *****WRONG*****. This is in ***NO***
book.
I challenge you to quote even *one* book which says that!!!
That is another reason I can't believe you when you brag you have a PH D
When and where did you get it?.
Heidelberg university, Germany, last year.
Here is my PhD thesis:
<http://cdsweb.cern.ch/search.py?recid=640975&ln=en>
In another news group we had a guy name
Scott(much like you) he also bragged that that he was a professor.
Well, I never claimed to a professor.
When asked where ? He never posted again,and disappeared.
Sorry for you - I am differenrt. My claim was right, and I can prove this.
Bjoern If true you
should be proud to give us that information.
See above.
If you don't we know
you lied. I'm betting you won't an are just a big mouth.bragger Bert
You lost your bet.
Bye,
Bjoern
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| User: "Bjoern Feuerbacher" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
14 Jul 2004 07:56:43 AM |
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Bjoern Feuerbacher wrote:
G=EMC^2 Glazier wrote:
[snip]
Don't like astronomers telling me the age,and size of our
universe.
<http://map.gsfc.nasa.gov/m_mm/mr_age.html>
IIRC, this was in the news about 1.5 years ago. No one is trying
to hide this from you.
<http://www.cbc.ca/stories/2003/02/11/cosmos_age030211>
See? As I said above.
[snip]
Bye,
Bjoern
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| User: "mitch perkins" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
20 Jul 2004 08:08:18 PM |
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Sam Wormley <swormley1@mchsi.com> wrote in message news:<40F46A4B.BC94E423@mchsi.com>...
Ref: http://physicsweb.org/article/news/8/7/3
Massive galaxies may have formed much earlier in the history of the
universe than previously thought according to new observations. Two
teams of astrophysicists have detected massive galaxies with
redshifts of more than 1.5, which means that they must have formed
before the universe was a quarter of its present age. The results
are in direct conflict with the currently favoured "hierarchical"
model of galaxy formation.
According to the hierarchical model large galaxies are formed as a
result of smaller galaxies merging. The model predicts that massive
galaxies should appear rather late in the history of the universe,
when it was about half its present age. Astronomers can calculate
how old a galaxy is by measuring its redshift: galaxies with large
redshifts are older and further away than those with small
redshifts.
However, galaxies with high redshifts are difficult to detect
because they are very faint and because the radiation they emit is
shifted to longer wavelengths that are easily absorbed by the
Earth's atmosphere. This means that although astronomers can now
routinely detect bright star-forming galaxies at redshifts up to
6.6, the most distant massive galaxy observed to date is still an
object with a redshift of 1.552 that was discovered 10 years ago.
See: http://physicsweb.org/article/news/8/7/3
Hi Sam,
Is there 'list' of 'preferred explanations'?
Also, I can't figure out why the article is news *now*; at the top
it says 1.5 means formation before quarter-age of universe, but 1.552
was observed ten years ago. ?
Mitch
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| User: "Bjoern Feuerbacher" |
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| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
21 Jul 2004 03:22:33 AM |
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mitch perkins wrote:
Sam Wormley <swormley1@mchsi.com> wrote in message news:<40F46A4B.BC94E423@mchsi.com>...
Ref: http://physicsweb.org/article/news/8/7/3
Massive galaxies may have formed much earlier in the history of the
universe than previously thought according to new observations. Two
teams of astrophysicists have detected massive galaxies with
redshifts of more than 1.5, which means that they must have formed
before the universe was a quarter of its present age. The results
are in direct conflict with the currently favoured "hierarchical"
model of galaxy formation.
According to the hierarchical model large galaxies are formed as a
result of smaller galaxies merging. The model predicts that massive
galaxies should appear rather late in the history of the universe,
when it was about half its present age. Astronomers can calculate
how old a galaxy is by measuring its redshift: galaxies with large
redshifts are older and further away than those with small
redshifts.
However, galaxies with high redshifts are difficult to detect
because they are very faint and because the radiation they emit is
shifted to longer wavelengths that are easily absorbed by the
Earth's atmosphere. This means that although astronomers can now
routinely detect bright star-forming galaxies at redshifts up to
6.6, the most distant massive galaxy observed to date is still an
object with a redshift of 1.552 that was discovered 10 years ago.
See: http://physicsweb.org/article/news/8/7/3
Hi Sam,
Is there 'list' of 'preferred explanations'?
Also, I can't figure out why the article is news *now*; at the top
it says 1.5 means formation before quarter-age of universe, but 1.552
was observed ten years ago. ?
I can only guess here - but I would think that the galaxy
observed 10 years ago with z=1.552 was probably not a
"massive" galaxy, as in the sense above.
Bye,
Bjoern
.
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| User: "mitch perkins" |
|
| Title: Re: Article: Mature Galaxies in Young Universe At Odds with Theory |
21 Jul 2004 06:54:57 PM |
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Bjoern Feuerbacher <feuerbac@thphys.uni-heidelberg.de> wrote in message news:<cdl949$d15$1@news.urz.uni-heidelberg.de>...
mitch perkins wrote:
Sam Wormley <swormley1@mchsi.com> wrote in message news:<40F46A4B.BC94E423@mchsi.com>...
Ref: http://physicsweb.org/article/news/8/7/3
Massive galaxies may have formed much earlier in the history of the
universe than previously thought according to new observations. Two
teams of astrophysicists have detected massive galaxies with
redshifts of more than 1.5, which means that they must have formed
before the universe was a quarter of its present age. The results
are in direct conflict with the currently favoured "hierarchical"
model of galaxy formation.
According to the hierarchical model large galaxies are formed as a
result of smaller galaxies merging. The model predicts that massive
galaxies should appear rather late in the history of the universe,
when it was about half its present age. Astronomers can calculate
how old a galaxy is by measuring its redshift: galaxies with large
redshifts are older and further away than those with small
redshifts.
However, galaxies with high redshifts are difficult to detect
because they are very faint and because the radiation they emit is
shifted to longer wavelengths that are easily absorbed by the
Earth's atmosphere. This means that although astronomers can now
routinely detect bright star-forming galaxies at redshifts up to
6.6, the most distant massive galaxy observed to date is still an
object with a redshift of 1.552 that was discovered 10 years ago.
See: http://physicsweb.org/article/news/8/7/3
Hi Sam,
Is there 'list' of 'preferred explanations'?
Also, I can't figure out why the article is news *now*; at the top
it says 1.5 means formation before quarter-age of universe, but 1.552
was observed ten years ago. ?
I can only guess here - but I would think that the galaxy
observed 10 years ago with z=1.552 was probably not a
"massive" galaxy, as in the sense above.
Thanks Bjoern. I see I was confusing distance/age as indicated by
redshift, with size. The last sentence of the article still is a bit
confusing to me, but, barring some major global catastrophe, I still
have 40 years or so to figure it out. ~:?)
Mitch
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