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About LinkBacksSwift satellite has imaged the oldest object in the universe:
http://www.nasa.gov/mission_pages/sw...ic_record.html
April 28th, 2009, 01:11 PM
Swift satellite has imaged the oldest object in the universe:
http://www.nasa.gov/mission_pages/sw...ic_record.html
is it neigh possible this is the big bang itself?
Not the big bang itself, because to see that you'd have to be able to peek past the surface of last scattering (ie: the cosmic background radiation). Or in other words: the universe was opaque to light for years after the big bang.
It is believed that these are the supernova outbursts of very massive - maybe even primordial - stars that collapse into a Black Hole at the end of their lives.
May 4th, 2009, 01:31 PM
Originally Posted by Arch2008
Not quite as old as this star a mere 7,500 light years away in our own galaxy.
The star's age, as measured by ESO's Very Large Telescope, is 13.2 billion years.
http://en.wikipedia.org/wiki/HE_1523-0901
.
May 4th, 2009, 02:40 PM
Yes, with a considerable error margin of at least 0.7 billion years.
Not quite as old as this star a mere 7,500 light years away in our own galaxy.
The star's age, as measured by ESO's Very Large Telescope, is 13.2 billion years.
http://en.wikipedia.org/wiki/HE_1523-0901
http://arxiv.org/abs/astro-ph/0703414
But also the estimate of the redshift of the gamma ray burst has large error bars. Most people talk about a redshift of "around 8" The original research note of the distance estimate measurement quotes. And how much that is wrt distance and age depends on the cosmological model. For a standard model, this calculates to a lookback time of
billion years.
Like to add on. The universe was opaque for its first three hundred thousand years until it experienced an decoupling process that finally permitted light to pass through.Not the big bang itself, because to see that you'd have to be able to peek past the surface of last scattering (ie: the cosmic background radiation). Or in other words: the universe was opaque to light for years after the big bang.
May 9th, 2009, 12:48 PM
Just finished looking at the photo, of the GRB, from the "Astronomy Picture of the Day" website dated April 29 2009.
The information given states that the GRB took place around 13 billion years ago. I do not know the answer to what must be a basic question. The universe must have been much smaller, in volume at that time, around 700 million years after the BB.
Clearly this means, given the expansion of the universe, that the light from the GRB has taken 13 billion years to "catch up " on us, or have I got that wrong?
Moderator's remark:
I have merged the two threads on the GRB. The second thread starts here.
There is already a thread on that GRB here:
http://www.thescienceforum.com/13-bi...GRB-18224t.php
But you are right. Since the universe was "smaller" at that time, the spatial distance between its location and the point of space at that time that we occupy now can be neglected. So, the age estimate tells us that the radiation we detect from the GRB took 13 billion years to reach us. The expansion of the universe also shifted the radiation to longer wavelengths. With a measured redshift of 8, the wavelength we measure now is 9 times higher than when it was emitted.
Haliday and Dish :
If that is supposed to have caused the BB expasion of space, then it would have had a redshift of 1000.
So this is another problem for the BBT.
Which red shift are we to use? The CMBR or the Einstein formula RS?
Incidentally, I provided an article on the source of the GRB's and that source is the neutron star decays'.
Cosmo
Huh? None has claimed any nonsense like this. Of course, a GRB did not cause the expansion of space. GRBs are thought to be some kind of supernovae of the earliest stars. Nothing can be observed that is beyond the background radiation, because the universe was optically thick at that time.
As to the redshift, it the measured redshift. Look at the formula: it tells you by how much a measured wavelength was shifted since its emission. It is a definition.
Please stop hijacking threads with your views. If you want to discuss alternative theories, you are welcome to do this in dedicated threads or in the "New Hypotheses" section of this forum. Please, don't become another William McCormick!
I am not sure if I am expressing this question correctly, but what exactly does this tell us about the "speed" of the expansion of the universe?Moderator's remark:
I have merged the two threads on the GRB. The second thread starts here.
There is already a thread on that GRB here:
http://www.thescienceforum.com/13-bi...GRB-18224t.php
But you are right. Since the universe was "smaller" at that time, the spatial distance between its location and the point of space at that time that we occupy now can be neglected. So, the age estimate tells us that the radiation we detect from the GRB took 13 billion years to reach us. The expansion of the universe also shifted the radiation to longer wavelengths. With a measured redshift of 8, the wavelength we measure now is 9 times higher than when it was emitted.
GRB's are usually believed to be very distant but like some quasars, it could just be a wrong measurement because their SMBH's contribute with gravitational redshift so making it look like it has a very high recessional redshift. If GRB's were found to be closer, they would not be such incredibly violent events as is now believed.
Wow,
Although it's theoretically impossible for us to ever see the big bang, or much earlier than OP's explosion, for us to see the big bang we would have had to be traveling above light speed away from the point of origin for at least a milisecond
There is no point of origin. The "origin" is everywhere in a big bang universe.for us to see the big bang we would have had to be traveling above light speed away from the point of origin for at least a milisecond
holy we found our god? that created us that oldest object
June 15th, 2009, 02:25 PM
As the article says, the weighted average age comes out to 13.2 billion years old, so maybe even older?
Decoupling at about 3,000.C yet when we look at the CMB at that time, it is -271.C. Strange!
Light travels at 186,282 mps (for convenience sake, we'll say exactly at that speed). If in the space of a second, the distance of 186,282 miles expands by a nanometer, then light still travels at exactly 186,282 miles and not a nanometer further. Expansion just means that it takes light longer to reach Earth.
Lets say you're looking back through the universe to a redshift of z=1100. This is when the scale factor was 1100 times smaller than it is today. At that time decoupling was taking place and the temp was about 3000K. At this temperature the universe would have the color of your standard incandescent light bulb, somewhere in the yellows, there are stars that are this color. So everywhere you look at the sky it would look like the surface of a star.
Decoupling at about 3,000.C yet when we look at the CMB at that time, it is -271.C. Strange!
Of course this is wrong because the wavelength is being stretched by a factor of 1100. Or rather,
wavelength_observed = wavelength_emitted(1+z)
for yellow, lets say 6x10^-7 m,
wavelength_observed = 6x10^-7(1101) = 6.6 mm (microwaves)
That a pretty crude estimate, because I think it actually peaks around 2mm, but I hope that helps.
Oh... I guess your post was more about the temperature. So here you go.
3000K/1100 = 2.727K
It's not just the proper distance between objects that's expanding, it's space itself. You're right about c not changing, although I'm not sure what that has to do with changing wavelenths.
Light travels at 186,282 mps (for convenience sake, we'll say exactly at that speed). If in the space of a second, the distance of 186,282 miles expands by a nanometer, then light still travels at exactly 186,282 miles and not a nanometer further. Expansion just means that it takes light longer to reach Earth.
Feifer. "The CMB is 2.7K" This does not mean that the CMB photons are redshifted so we see photons of 3,000.C as being just 2.7K. No astronomer talks of stars or clusters 13 billion light years away as having temperatures of just 2.7K so being as cold as the medium around them. Allowances are made.
We are told that space is alive with virtual particles, so effectively a material rather than the nothing I claim it is. But then you have something that has expanded from quantum size to over a hundred billion light years across without changing in any way, that is nonsense.
Space can only "expand" as it is no more than the distances between what occupies an area we call "space".
If light is not stretched, then photons do not change, so do not redshift according to recessional velocities we can measure. If an expansion of maybe 15 mps over a million light years stretches photons, imagine what entering the gravity well of a 1G planet would do? It would virtually rip them apart.
Why should stars which formed 400 million years after the last scattering (CMB) have the same temperature as the space around it? These are two different epoch we're talking about. When we look at the CMB, we're looking back to when there were no stars, just a hot soup of light elements. Small perturbations in the soup allowed gravity to run away with them and condense them into stars. This took a long time to happen, all the while the universe was cooling down. So the universe was cooler on average as well as having dense balls of nuclear fusion (hot) and sparse regions of space with not much in them (cold). No astronomer would talk about them having the same temperature, because it's ridiculous.
Could you "expand" (pun intended) on this a little bit? I'm having trouble following you. Are you saying the photons would be ripped apart if they came to earth in an expanding universe? I'm hoping that you have some prior knowledge of the strange properties of light such as being both a particle and a wave. EM waves can be stretched. How exactly do you "break" a photon?
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