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Sat Mar 31, 2012, 05:42 PM

Mysteries of "The Redshift Desert" --Why Do Galaxies in the Early Universe Appear Old?



Some of the faintest spectra in the universe raise a glaring question: Why do Galaxies in the early universe appear old? Until recently, astronomers have been nearly blind when looking back in time to survey an era when most stars in the Universe were expected to have formed. This critical cosmological blind-spot was removed in 2011 by a team using the Frederick C. Gillett Gemini North Telescope located on Mauna Kea, Hawaii, showing that many galaxies in the young Universe are not behaving as they would have expected some 8-11 billion years ago.
The surprise: these galaxies appear to be more fully formed and mature than expected at this early stage in the evolution of the Universe.
"Theory tells us that this epoch should be dominated by little galaxies crashing together," said Dr. Roberto Abraham (University of Toronto) who was a Co-Principal Investigator of the team that conducted the observations at Gemini. "We are seeing that a large fraction of the stars in the Universe are already in place when the Universe was quite young, which should not be the case. This glimpse back in time shows pretty clearly that we need to re-think what happened during this early epoch in galactic evolution. The theoreticians will definitely have something to gnaw on!"
These observations are from a multinational investigation, called the Gemini Deep Deep Survey (GDDS), which used a special technique to capture the faintest galactic light ever dissected into the rainbow of colors called a spectrum. In all, spectra from over 300 galaxies were collected, most of which are within what is called the "Redshift Desert," a relatively unexplored period of the Universe seen by telescopes looking back to an era when the universe was only 3-6 billion years old.

http://www.dailygalaxy.com/my_weblog/2012/03/mystery-of-the-redshift-desert-why-do-galaxies-in-the-early-universe-appear-old.html

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Reply Mysteries of "The Redshift Desert" --Why Do Galaxies in the Early Universe Appear Old? (Original post)
n2doc Mar 2012 OP
Speck Tater Mar 2012 #1
DetlefK Mar 2012 #3
Speck Tater Mar 2012 #7
laconicsax Mar 2012 #9
Speck Tater Apr 2012 #10
laconicsax Apr 2012 #11
Speck Tater Apr 2012 #12
laconicsax Apr 2012 #13
Speck Tater Apr 2012 #14
laconicsax Apr 2012 #15
Speck Tater Apr 2012 #16
tridim Mar 2012 #2
DetlefK Mar 2012 #4
tridim Mar 2012 #5
longship Mar 2012 #6
laconicsax Mar 2012 #8

Response to n2doc (Original post)

Sat Mar 31, 2012, 06:10 PM

1. Although shunned by the herd, there are still viable alternatives to the Big Bang theory.

 

As heretical as it might sound, the problem might be that those distant galaxies look old because they are old because the big bang never happened. (And before you jump all over me, I am not a supporter of of Steady State. I believe that has been thoroughly discredited. But, frankly there's still an awful lot we don't know about the universe and it's history, and we could be end up being very wrong about what we think we do know. That's what makes science so exciting!)

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Response to Speck Tater (Reply #1)

Sat Mar 31, 2012, 06:28 PM

3. ??? There either was a beginning of time or there wasn't. You can't have both.

The problem is the Weak Interaction: The universe can't be infinitely old, because stars turn hydrogen into other elements and we still have a lot of interstellar hydrogen around.

And then there's the finite speed of light which causes regions of separated causality, conserving entropy on a cosmological scale and preventing time from running backwards. If the speed of light were infinite, there were a 1:gazillion chance for the whole universe to accidently become young again, which would cause a neverending cycle of the universe aging and rejuvenating.

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Response to DetlefK (Reply #3)

Sat Mar 31, 2012, 08:35 PM

7. Steady State hypothesized the continuous creation of new hydrogen

 

at the rate of something like 1 hydrogen atom per cubic meter every billion years, which is plenty.

There are other problems with Hoyle's version of steady state, and with the various variations of it, which is why I said I don't support steady state. But I don't rule out the possibility that some incarnation of steady state might come along that addresses the objections.

But consider too that the big bang is based on the observation that the universe is expanding. That the universe appears to be expanding is a conclusion drawn from observed red shift, and the assumption that velocity is the only meaningful contributor to the red shift of distant galaxies. But suppose that there were some other mechanism that contributed to red shift? A discovery like that could (and I grant it's pretty far-fetched, but still possible) result in discovering, over night, that the universe is not expanding after all, and that the lion's share of the red shift is the result of something other than velocity.

So the book is never closed in science. The "ultimate truth" is never known, and the one thing that has been constant throughout the history of science is that yesterday's truths look like foolishness today, and today's truths will look like foolishness tomorrow. That's what makes science so exciting!

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Response to Speck Tater (Reply #1)

Sat Mar 31, 2012, 11:16 PM

9. Explain the CMB.

 

The final nail in the coffin of the Steady State model was the discovery of the cosmic microwave background, which appears exactly as one would expect if the big bang happened.

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Response to laconicsax (Reply #9)

Sun Apr 1, 2012, 12:01 AM

10. Yup. That's why steady state in its current form has been discredited.

 

On the other hand, I could use fairies dancing on gas molecules to explain Brownian motion. But just because Brownian motion can be observed doesn't mean that it my dancing fairies theory is the ONLY explanation for what was observed. Sometime in the future some brilliant young theorist might come up with a non-Big Bang explanation for CMB. Someday. Maybe. To pretend we have all the final answers here and now is to deny the very processes of science. Who knows what tomorrow will bring? Certainly not me.

Every time we turn around science hands us another startling new discovery. There's no way I'm going to close the door prematurely on the future of science. And as a non-scientist with no professional reputation to protect I can afford to make all the idle speculations I like in perfect safety. Being right all the time is not in my job description.

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Response to Speck Tater (Reply #10)

Sun Apr 1, 2012, 01:45 AM

11. Idle speculation isn't how progress is made.

 

While it's possible that some day, every part of the Lambda-CDM model will be replaced by some new revolutionary cosmological model, I sincerely doubt it because of the sheer number of phenomena that new model will have to explain at least as well as the current one.

What's far more likely is a number of refinements. A revolutionary new model would have to not only explain everything that Lambda-CDM explains, but a decent number of things it doesn't. Pretty much everything short of that will merely be a refinement.

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Response to laconicsax (Reply #11)

Sun Apr 1, 2012, 01:20 PM

12. Two things.

 

1. My job is not progress. I'm retired. I'm free to speculate at will, and without consequences.
2. Idle speculation is EXACTLY where progress comes from:

"When I examined myself and my methods of thought, I came to the conclusion that the gift of fantasy has meant more to me than my talent for absorbing positive knowledge." --A. Einstein

"Modern science should indeed arouse in all of us a humility before the immensity of the unexplored and a tolerance for crazy hypotheses." --Martin Gardner

"Almost all really new ideas have a certain aspect of foolishness when they are first produced." --Alfred North Whitehead

"The task is not to see what has never been seen before, but to think what has never been thought before about what you see everyday." --Erwin Schrodinger

"The man who cannot occasionally imagine events and conditions of existence that are contrary to the causal principle as he knows it will never enrich his science by the addition of a new idea." --Max Planck

"Advances are made by answering questions. Discoveries are made by questioning answers." --Bernhard Haisch, astrophysicist


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Response to Speck Tater (Reply #12)

Sun Apr 1, 2012, 04:57 PM

13. All of the advances by those you quote built on the work of others.

 

None of them accomplished what they did by idle speculation.

If you want to see the products of idle speculation, look at theology.

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Response to laconicsax (Reply #13)

Sun Apr 1, 2012, 05:49 PM

14. What was that famous quote?

 

"If I can't see very far it's because giants are standing on my shoulders."

Science is a wonderful, but it needs stuff to work on, and that stuff is all the product of idle speculation. Speculation always comes before systematic evaluation.

People who believe that science is a monotonic march, asymptotic at all times to ultimate truth have only been spectators to the process. The plodders who add the next decimal point to the constants already known create that appearance, but they are a different class of scientist from the creative ones who make the breakthroughs with their imaginative flights of fancy orthogonal to convention. Copernicus was NOT standing on the shoulders of Ptolemy when he kicked geocentrism's ass!

"There are two possible outcomes: If the result confirms the hypothesis, then you've made a measurement. If the result is contrary to the hypothesis, then you've made a discovery." --Enrico Fermi

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Response to Speck Tater (Reply #14)

Sun Apr 1, 2012, 06:59 PM

15. And yet, Copernicus didn't idly speculate.

 

Hypotheses are the product of speculation, but that speculation isn't idle.

Idle speculation is speculation for the purpose of speculation. That's what makes it idle. Meaningful speculation is asking a question as part of trying to figure something out.

Copernicus asked the question, "would a heliocentric model fit the data?" and acted in it.

Newton asked the question, "what if everything was attracted to everything else?" and worked out the consequences.

Einstein asked the question, "what happens if you apply relativity to gravitation?" and worked out the consequences.

The list goes on.

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Response to laconicsax (Reply #15)

Sun Apr 1, 2012, 09:43 PM

16. Ah, so your real quibble is with the word "idle".

 

I'm willing to back down on that point.

"Idle speculation is speculation for the purpose of speculation. That's what makes it idle. Meaningful speculation is asking a question as part of trying to figure something out." So you're saying that it's the motive that makes speculation non-idle. I get it.

So when a meteorologist by the name of Wegener looked at the map and said to himself "Hmmm. Look at that. Africa and South America fit together like pieces in a jigsaw puzzle. I wonder...." That was non-idle speculation. And when Kekulé imagined a molecule of benzene swallowing it's own tail, that was non-idle speculation.

Now, since my speculations about cosmology are for the purpose of possibly figuring something out, then, by your definition, my speculation is not idle. Thank you for clarifying that.

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Response to n2doc (Original post)

Sat Mar 31, 2012, 06:17 PM

2. I'm I the only one who believes redshift can be affected by compressed and/or expanded space?

At least the percieved redshift? The is no guarantee space is flat between Earth and this part of the universe.

Then there is also inflation theory, which would make the early universe appear older than expected.

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Response to tridim (Reply #2)

Sat Mar 31, 2012, 06:39 PM

4. Compressing space won't help

The universe is flat on a cosmological scale. And a local bump, where space is compressed, won't help: Light comes in, gets compressed as it enters and expands again as it leaves.

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Response to DetlefK (Reply #4)

Sat Mar 31, 2012, 07:02 PM

5. Who said the Universe is flat on a cosological scale?

I could easily see the aggrigate compression being slightly greater than the other extreme, espcially considering the Universe has a center.

With sound, air density between the observer and source certainly affects the doppler efffect.

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Response to tridim (Reply #5)

Sat Mar 31, 2012, 08:16 PM

6. Light isn't sound; space isn't air

The Doppler shift of starlight comes from the expanding universe. That's how the Big Bang was discovered. If the expansion is increasing, the extent to which it increases will effect the Doppler Shift of the light, but that happens much slower than we can detect within the timeframe we've been observing it.

There is no media, like air, in the universe. That's what Einstein demonstrated in 1905 in his papers on electrodynamics (aka relativity).

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Response to tridim (Reply #5)

Sat Mar 31, 2012, 11:14 PM

8. The WMAP experiment did.

 

The universe is flat.

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