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The 1st Generation of Stars
Andy_Howell writes "Astronomers may have found members of the first generation of stars in the universe. Using the Hubble Space Telescope and the Keck I telescope, they observed a faint red blob that had been magnified into a double image by a gravitational lens. The blob was found to be a cluster of stars 13.6 billion light years away, seen when the age of the universe was less than a billion years old. The clump appears to contain only about a million stars, and is less than a few million years old. It is thought that swarms of these clumps came together over the age of the universe to create the galaxies we see today."
The current best estimate of the universe, mainly from measurements of the Cosmic Microwave Background and Type Ia Supernovae, consistently give results around 14-15 billion years, leaning towards the lower half of that range.
In any case, the number "13.6 billion light years" is relative to the actual age of the universe. What was measured was a redshift of 5.58. You can map that into a lookback time, but it depends on the cosmological parameters you assume. The beginning of the universe is at redshift infinity, which will give you another lookback time (ie. age of the universe) that depends on the cosmological parameters.
I don't know what particular cosmology was used to map z=5.58 to 13.6 billion years lookback time, but the STScI press release mentions that the cosmology they used gives an age of the universe of 14 billion years. It's probably a "concordance model" flat universe with 0.3 of the closure density coming from matter and the rest from the cosmological constant, with a Hubble constant around 65-70 km/s/Mpc.
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Ok, now for the more complex bit, actually saying what these are.
A photon multiplier is a device which takes in a stream of very low energy photons and generates a stream of much higher energy photons, as a result. It's a basic amplifier, for photons.
A very large telescope gives you a huge collection area. The larger your collection area, the more light you gather. By squishing that light into a much smaller area, you essentially generate a much brighter image.
The same is true of a long baseline. The idea, here, is to increase the time over which you collect the light. Double the time, double the light.
The consequence of using all three techniques is that you can easily collect a few photons from a vast distance, and turn them into an actual, visible image. But don't expect it to be easy. I imagine that the Hubble Telescope had to be pointed at that same spot for 24-48 hours, to generate such a view.
(When you recall that the Earth is rotating on its axis, that it's also rotating round the sun, and that the sun is moving round the galaxy, and that the galaxy has its own motion relative to other galaxies, and that ALL of these are complex, N-body problems, the challange of being able to keep the telescope pointing at a tiny cluster, billions of light-years away for more than a few seconds is an achievement. To manage it for maybe 1-2 DAYS is staggering.)
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Most astronomers had previously ignored these stars, which had been modded down heavily for posting annoying "First star!" messages.
When all you have is a hammer, everything looks like a skull.
The problem with "The Big Bang Never Happened" (which I have read) and other alternative cosmologies is that they don't even attempt to go deep enough to prove their points. There's a reason for this. All of modern cosmology is based on General Relativity. If you are going to say that the Big Bang Never Happened, then your alternative cosmology has to not only come up with an alternative explanation for the Universe, but also explain everything that GR does without having a Big Bang. This is a very tall order.
It isn't enough to point out the contradictions in the standard model. It is also necessary to build a new model that explains all observations. To date, no one has been able to do this without having a Big Bang at the start.
A well-crafted lie appears unquestionable - Dama Mahaleo
Looking at the images, they look like they've got pretty good S/N. I haven't seen the spectra, so I can't comment on that, but if they have spectra for the two different images that both give the same redshift, that's not likely noise.
Then it's haze that happens to shift all of the photons redward by a factor of 6.58. In both images independently. And doesn't make them fainter.
That's an interesting topic. All dust that we see in the universe is inside of galaxies, and preferentially blocks red light. So the places that you'd expect dust to make a difference is in the galaxy itself, in the Milky Way, or maybe in the cluster that's lensing the images (if you can come up with a way of expelling the dust out of a galaxy into the intracluster medium without destroying the dust, which isn't easy to do - dust is pretty fragile)
The only possible evidence for gray dust in the voids between large scale structure is as a way out of having the Type Ia Supernova measurements argue for the existence of a positive cosmological constant - some have argued that the reason that the supernovae are fainter isn't that they're farther away, it's that there's some fairly uniform gray dust (it can't be normal dust because then it would preferentially block red light, and we don't see that happening) that is absorbing some of the light. But there is plenty of other evidence pointing towards a positive cosmological constant, so the dust explanation is unlikely.
Hope that helps.
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