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Fraser
2005-Apr-06, 07:30 AM
SUMMARY: Astronomers have used the Spitzer and Hubble space telescopes to see some of the first stars that formed in the most distant galaxies ever seen. These stars, located in galaxies in the Fornax cluster, are about 13 billion light-years away - they emitted this light only a few hundred million years after the Big Bang. Even though they didn't have much time to form, these galaxies already look quite old, which means that star formation must have got going very early on.

View full article (http://www.universetoday.com/am/publish/light_earliest_stars.html)

What do you think about this story? Post your comments below.

Spyman
2005-Apr-06, 08:00 AM
Quote: "These stars, located in galaxies in the Fornax cluster, are about 13 billion light-years away - they emitted this light only a few hundred million years after the Big Bang."

Quote: "The Keck spectra showed that the galaxies have redshifts of about 6, which means they are so far away that light from them has taken about 13 billion years to reach us."

This can't be right - Is these stars 13 billion light-years away from Earth now or was they 13 billion light-years away when they emitted this light ?

If the Universe is expanding and the time taken for the light to reach us was 13 billion years then they must have been much closer when the light was emitted and be much farther away now when the light reaches us.

Svemir
2005-Apr-06, 12:19 PM
They are 26 billion years away - now, if you think Universe is expanding, according to Bing Bang theory.
Even more if you believe expansion of Universe is accelerating.

They are coutious, they say "suprising", they say "puzzling".
They don't say, "It does not support Bing Bang theory" (in present state).

More (longer) observations will reveal just more galaxies, no "dark ages" or something. Better resolution of CBR will show the source of radiation: just more galaxies.
These are just my prophecies, because, I belive Universe is if not infinitely, then very very old.

I'm not sure how they come to the conclusion : "The galaxies look old".
Metallicity in spectra, shape (eliptical?) or missing neighbours (other galaxies, Hydrogen clouds). At that time the density of matter was much higher and still no signs of interaction, rapid star formation (wich will make them bluer- they look maybe to red?) etc.
It's to quiet over there.

Len Ward
2005-Apr-06, 01:32 PM
The statment that the galaxy is 26 billion or more light years away now implies that it is traveling at or beyond the speed of light.

Spyman
2005-Apr-06, 01:46 PM
According to Cosmos calculator, http://www.earth.uni.edu/~morgan/ajjar/Cos...ogy/cosmos.html (http://www.earth.uni.edu/~morgan/ajjar/Cosmology/cosmos.html), they are 27.47 Billions light-years away now and was 3.92 Billions light-years away when emitting the light, according to Big Bang theory, not 13 billion light-years away.

Read my first quote again, please, the writer of the article relevates to Big Bang theory, what I personally belive in is irrelevant.

The first and the second quotes contradicts according to BB theory, which the writer relevates to, thus the first quote or statement must be wrong, (=False).

Whatever BB is right or wrong, if the Universe is expanding or not, there is a limit how far we will be able to look depending on the streatching of the lights wavelenght, (redshift).

Quote: "Using the Spitzer images, the team was able to weigh the stars in these galaxies by studying the starlight. It seems that in a couple of cases these early galaxies are nearly as massive as galaxies we see around us today, which is a bit surprising when the theory is that galaxies start small and grow by colliding and merging with other galaxies, said Dr. Mark Lacy (Spitzer Science Center)."

"The galaxies look old" depending of their weight, "nearly as massive as galaxies today".
Which means, if BB is correct, star formation must have started very early and happened very fast and if BB is wrong, it's of no surprise.

Spyman
2005-Apr-06, 02:06 PM
If the Big Bang theory is correct then the galaxy doesn't have to travel at all relative us, it is the Universe which is expanding at greater speeds at greater distances, expansion of the space-time fabric faster than the speed of light doesn't contradict the theory of General Relativity.

The Near-Sighted Astronomer
2005-Apr-06, 04:44 PM
Another possibility is that we are seeing galaxies "on the Far Side" - (no not Gary Larson) such galaxies would be very mature but show extremely high redshifts that would explain both their age and distance...

lswinford
2005-Apr-06, 06:18 PM
Yeah, I've been wondering if we don't have this thing backwards. If we are witnessing light from an "early" star which is just getting to us some 13 billion years later, and we are sitting on a planet around a star that is some 5 billion years matured and in a galaxy that is considerably older still, how does that connect? An "early" star would be closer to the 'bang' that brung it (pardon my slang but the alliteration sounded fun) and if that happened some 13 byrs ago, wouldn't that make us older still? The relative travel speeds I've heard would have meant that far, far above 13 byrs would be needed for us to have separated this distance and still permit us to catch the light of that "early" star.

<--E<-----------O---&#62;U--&#62;

Even if the "early" star (E) were on the opposite side of the Big Bang location (O) and flying in the opposite direction from us (U) and we developed much later, how could we be getting such an "early" picture so late in the game? :blink:

Considering the 26 byr discussion earlier, whatever we saw, its gone now.

Sorry for the dunder-headed moment, maybe my thinking was dulled by a very good lunch. B)

The Near-Sighted Astronomer
2005-Apr-07, 12:25 AM
Hi Iswinford,

I believe that astronomers in general are very leary (not Timithy) about making proclamations related to distances and epochs when discussing redshift data. All the papers I&#39;ve worked from in writing articles simply give a z=??? value for redshift without making claims as to distances and eras. Those of us who attempt to write for the general public then convert the z value to provide a sense of "when" the light was emitted.

As to the validity of this approach it&#39;s hard to say. All we know is that certain spectral lines in excited gases or stars are shifted significantly toward the red indicating a high rate of mutual recession between us and the study involved. Astronomers have no reason to believe that this shift has any basis in sheer distance. (Light is not known to "tire" over vast distances, and absorption only dims - not shifts the frequency of light.) But we do know that doppler shift occurs in nature so what the heck, let&#39;s assume that doppler motion is the cause and not any other exotic mechanism.

Now i am not privy to the amount of mutually recessionary motion needed to cause light to shift six octaves in frequency but certainly it lies somewhere in the 90% speed of light realm and that&#39;s where relativistic factors such as "mass gain" become significant. But Eisnteinian relativism itself may not apply when space itself is expanding (since the sources actual motion is practically nil and therefore within the galaxy itself there is very little redshift).

But unless expansion was anisotropic in the extreme there are likely to be galaxies "on the far side" of the Universe that are receding away from us at highly redshifted velocities compared to those in the same "hemisphere" and I suspect that before too long this will be made apparent when more and more of these absurdly mature galaxies are seen at redshift values approaching 13.7 BYA (using the "time-shift" equations bandied about in the media by writers such as myself...)

jeff

Svemir
2005-Apr-07, 06:56 AM
Spyman, only my first sentence was response on your post.
Rest was comment on the article.
Sorry for misunderstanding.
I overlooked that they determined mass/maturity of the galaxies
from the starlight. Does anybody know how they do that?


Eisnteinian relativism itself may not apply when space itself is expanding I would translate this as "Speed of light is the highest speed in Nature in Einsteins Special Relativity Theory but not in Einsteins General Relativity Theory."
Accelerating an object towards speed of light, adds kinetic energy to the object, the object becomes more massive. To accelerate an object to the speed of light you need infinite amount of energy, the object becomes infinitely massive hence that is impossible to do.That&#39;s SRT.
In GRT space-time is curved. Some solutions to Einsteins equations lead to the expanding space-time. (These solutions are the place where GRT and BBT meet.)
Gravity(mass) causes space-time to curve,
space-time causes gravity(mass) to move without adding kinetic energy to the mass. So, in GRT it&#39;s possible to move an object at the speed thet exceedes speed of light. So Einsteinian relativism does apply to expanding S(pace)T(ime).

But GRT is mathematical construction, it&#39;s a view of reality and not physical reality itself. Still, the question remains: when something (BB) causes ST to expand, do you add more ST to the Universe or just strech the existing ST?
Do both expanding models cause redshift?

Somehow the gravity surpress expansion of Universe, there is no sign of expansion in Solar system, Milky Way or higher level structures.
The expansion happens actually in places with no gravity, between structures, in empty voids. Let&#39;s look at Fornax cluster and the light of the very young, yet very old galaxy. Did they take all structures between us and that galaxy in account when calculating redshift? Could it be that the galaxy is further away since there is no expansion (redshift) between us and the galaxy wherever the light travel through places with no expansion?

Spyman
2005-Apr-07, 10:18 AM
Originally posted by The Near-Sighted Astronomer@Apr 7 2005, 12:25 AM
(using the "time-shift" equations bandied about in the media by writers such as myself...)
WHY ???

Big Bang theory is OK to wright about and expansion is OK to wright about.

Then way this censore and printing false statements ?

Spyman
2005-Apr-07, 10:39 AM
Originally posted by Svemir+Apr 7 2005, 06:56 AM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Svemir &#064; Apr 7 2005, 06:56 AM)</td></tr><tr><td id='QUOTE'>Spyman, only my first sentence was response on your post.
Rest was comment on the article.
Sorry for misunderstanding[/b]
Thats OK &#33; :)

<!--QuoteBegin-Svemir@Apr 7 2005, 06:56 AM
Still, the question remains: when something (BB) causes ST to expand, do you add more ST to the Universe or just strech the existing ST?
Do both expanding models cause redshift?[/quote]
The light must be streached if redshifted, (and compressed if blueshifted).
So inserting more ST would cause light to take longer time to reach us but wouldn&#39;t redshift it. Also if new empty ST was inserted inside the lightbeam it would be "chopped" which would cause it to flash on and off.
A more interesting question is how ST during the streaching is able to "grip" matter and bring it away faster than the speed of light and defeating gravity without friction ???

Spyman
2005-Apr-07, 11:23 AM
I will neither defend BB or expansion since I have some trouble accepting them myself.

However I can tell You how I are interpreting the mainstream view:
Originally posted by lswinford+Apr 6 2005, 06:18 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (lswinford &#064; Apr 6 2005, 06:18 PM)</td></tr><tr><td id='QUOTE'>The relative travel speeds I&#39;ve heard would have meant that far, far above 13 byrs would be needed for us to have separated this distance and still permit us to catch the light of that "early" star.[/b]
It is NOT a relative travel speed, it is the space-time fabric itself streaching.
Depending on distance the streaching is several times faster than light.

<!--QuoteBegin-lswinford@Apr 6 2005, 06:18 PM
Even if the "early" star (E) were on the opposite side of the Big Bang location (O) and flying in the opposite direction from us (U) and we developed much later, how could we be getting such an "early" picture so late in the game? :blink: [/quote]
The space-time where we currently are is at least as old as the universe and was closer to the emitting star when the light was emitted, even if the Earth was not created yet. The light from the emitting star should have passed through this place in space-time now even if Earth had not been created or had been created in some other place.
You can throw a ball towards a empty parking slot before the car gets there and still be able to hit the car when it arrives and if no cars arrives the ball still continues in it&#39;s path to the parking slot. It has nothing to do with the age of the car.

lswinford
2005-Apr-07, 08:51 PM
Spyman, its the space-time stretch and the "Depending on distance the streaching is several times faster than light," that is part of my problem. The other part is describing the pitcher of the ball when he threw it into the parking lot before the lot was defined, described, paved, all of which happened before the car that was hit by the ball was built and parked in the lot--to adapt my analogy for use with your analogy.

Sorry, but while I know there are stranger things than this out there in discussion, the potential of space-time stretching, much less stretching "several times faster than light" wasn&#39;t on the boards when I tried to understand the phenomenon reported.

Thanks.

The Near-Sighted Astronomer
2005-Apr-07, 08:55 PM
Hi Spyman,

If i am correct you ask why we writers use temporal notation to explain "distance" and not astronomers - is this correct?

Because the general public doesn&#39;t relate to an object with a z=2.65.

They want to know "How far away is it?" And astronomers prefer to say that a certain emission line has shifted down the em spectrum by 2.65 octaves. All this means is that (as explained above) the wavefront from the object has "spread out" as it moves through space. Based on standard candles - Variables and type1a supernovae - we can see that the spreading occurs more or less evenly across distance in space (allowing for some variability based on epoch and oscillations in the rate of inflation etc.)

But does this really correspond to distance?

The emitting stars are no longer where they were at the time of emission - nor are we where we are at that same time. Both receiver and source have travelled some distance over time and in some cases have undergone complete changes in epoch (decelerative, to expansionary to inflationary). Distances are entangled with epochs etc.
So for an astronomer the best approaches is "Joe Friday" the light has shifted by some number of octaves from what it would appear radiated at rest mass relative speeds...

Spyman
2005-Apr-11, 09:22 AM
Originally posted by lswinford+Apr 7 2005, 08:51 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (lswinford &#064; Apr 7 2005, 08:51 PM)</td></tr><tr><td id='QUOTE'>Spyman, its the space-time stretch and the "Depending on distance the streaching is several times faster than light," that is part of my problem.[/b]
Here I can&#39;t help You, nobody knows ...
Either the fabric is capable of streaching and faster than the speed of light and bringing matter with it due to some cind of friction.
Or matter itself is traveling away from us, in every direction we look, with higher speed than light.
Or it is all an illusion, created by some yet unknown cosmic effect, causing the light to streach, (redshift), sometimes called "tired light".
<!--QuoteBegin-lswinford@Apr 7 2005, 08:51 PM
The other part is describing the pitcher of the ball when he threw it into the parking lot before the lot was defined, described, paved, all of which happened before the car that was hit by the ball was built and parked in the lot--to adapt my analogy for use with your analogy.[/quote]
The parking lot, (fabric of space-time), was either there already before the Big Bang, (inside or outside of the seed), or was created during the Big Bang, so the parking lot was defined a long time before the pitcher throwed the ball, it is only the Sun and the Earth that was created later, (the car), and eventually travelled into this parking lot where we are today.
The pitcher in this case is a star which means he/she throws out photons, (balls), in all possible directions continuously, so every parking lot within reach will get hit by photons from the star all the time. The light bulb in Your room is sending out the photons before they hit Your hand and reflect, the bulb doesn&#39;t know Your hand is there or where it&#39;s going to be, it doesn&#39;t aim at Your hand, it shines in all directions, so every place in the room, the bulb can reach, has a bunch of photons already on their way. You can move Your hand and the light bulb around in the room in different speed and directions and the hand will always reflect light from the bulb, as long as the line of sight between them is open of course.

Spyman
2005-Apr-11, 10:13 AM
Originally posted by The Near-Sighted Astronomer@Apr 7 2005, 08:55 PM
Hi Spyman,

If i am correct you ask why we writers use temporal notation to explain "distance" and not astronomers - is this correct?
I only reacted on that all, not just this article, writers report the distance falsely as a fact despite it certainly seems "unknown" and thus sort of lies for the readers.

The reason of the readers wanting to know "How far away is it?" is no exquise.
Either don&#39;t report the distance, report the fact it&#39;s "unknown" or at least mention the use of temporal notation behind the distance as not Big Bang theory.

According to the Big Bang theory the Universe is expanding thus a fixed distance together with Big Bang theory is a contradiction, (=False).

If the writer referes to a theory he/she should stick to it all the way through the article, if not mention the other theory used.
It is of no good mixing and blending theorys as it suites the writer.

What it all ends up to is "Don&#39;t trust sience writers" which is cind of sad, I know everybody can make errors, like the teaspoon analogy of a neutron star which almost always is calculated totally wrong, but this cind of twisting the truth among the community of sience writers actually caught me of guard.

You don&#39;t have to explain further, Thanks for Your answer.