Most Distant Object Yet Detected, Bagged By Galileo Scope 101
An anonymous reader writes "It's fitting, in this 400th anniversary of the astronomical telescope, that the Telescopio Nationale Galileo (TNG) in the Canary Islands would be used to uncover the most distant object ever seen by mankind. The gamma-ray burst from April 23, a powerful explosion from a dying star, was detected by the Swift satellite using on-board gamma-ray and X-ray instruments. A flurry of activity led to the remarkable discovery that the event occurred roughly 630 million years after the Big Bang. This makes GRB 090423 the most distant known event!"
Telescopio Nazionale Galileo (Score:3, Informative)
Re:How far... (Score:1, Informative)
Umm, the current working scientific theory is that there was no "before" the big bang... The big bang created what we know as "timespace."
Re:I agree - very interesting info (Score:3, Informative)
when that early star exploded it would have had heavier elements, iron has been detected from 900 million years after big bang.
http://physicsworld.com/cws/article/news/17403 [physicsworld.com]
Re:It's fitting... (Score:1, Informative)
It's fitting just because 400 years ago Galileo Galilei (same name as the observatory, see?), in 1609 began his astronomical observations, and as a direct result of that came in direct conflict [wikipedia.org] with the religious establishment [wikipedia.org], since he began supporting Copernicus's heliocentric theory.
Try to explain that to the enlightened individuals who still insist nowadays that the universe is 5000-6000 years old, that dinosaur bones were placed there by some humorous deity just in order to make us wonder, or simply that Evolution [wikipedia.org] is 'just a theory'...
Happy round-numbered birthday to both events, I say, or in other words: eppur si muove. [wikipedia.org]
Re:How far... (Score:4, Informative)
At the time of and before last scattering (approx. 400,000 years after the Big Bang, if our cosmological theories are reasonably close to correct), light was constantly being absorbed and reemitted, as in the interior of a star today. If you suddenly removed all the matter from a star (obviously impossible, but bear with me here), then the photons that had last been emitted would travel off in all directions.
The universal last scattering was a vaguely similar event, in that matter became sufficiently dispersed (due to the expansion of the universe) that light could now travel long distances without interacting with matter. Obviously this was not instantaneous, but on cosmological scales, it was pretty quick.
Now, an object that is at a certain temperature will in general radiate a certain amount of light, distributed in a very particular way over a range of frequencies. For instance, the temperature of the Sun's photosphere (which is about as far into the Sun as you can get and still have the gases be reasonably transparent, thus, it is the Sun's surface of outermost scattering, one might say) almost determines the spectrum of light that the Sun emits, and therefore the color that we see (yellow). This is called blackbody radiation [wikipedia.org].
So, the universe at the time of last scattering contained a gas of photons with a certain spectrum determined by the overall temperature of the universe then. When the universe became transparent, this photon gas remained, and remained at the same spectrum. It still permeates the entire universe. However, due to the expansion of the universe, the wavelength of each and every photon has increased since then, and the density of photons has decreased, leading to a photon gas that looks as if it comes from a much cooler object. In fact, now the largest number of the photons in the universe lie in the region of the spectrum designated "micro-waves", thus we refer to this leftover photon gas as the cosmic microwave background [wikipedia.org].
The CMB was a direct prediction of Big Bang cosmological models, and not a prediction of any other cosmological models, and so its observation dealt a death blow to other models such as the steady state universe.
Re:and how distant was it? (Score:3, Informative)
As shown by follow-up observations performed with ground-based telescopes, it was a very distant event, and soon it looked like this was the farthest GRB ever observed. A team of international astronomers led by Swift Italian Team and CIBO, using the AMICI prism with the Italian Telescopio Nazionale Galileo, was able to compute its redshift at about 8.1, corresponding to a distance of more than 80 Gpc, when the universe was only slightly more than 600 million years old (Figure 2).
Re:Not really the oldest event ever seen - CMB (Score:2, Informative)
Yes, it is a picture of the entire universe when it was 400,000 years old taken today from the earth. But in the same way we take pictures with photo cameras, the object which the picture was taken of is 3D but the resulting picture itself is 2D. In the case of the CMB, we can think of the picture as follows: for each latitude and longitude on the earth, you point a camera straight up and record the CMB photons coming from that direction. Then, for each point on the surface of the earth (2D) you have a number - and that's the picture. These photons are coming from a very distant place in the universe and started traveling to us a very long time ago; and the energy of those photons is proportional to the amount of energy there was at that point in the universe when the photon started its trip towards the earth. Then that picture is telling us what the distribution of matter-energy was 400,000 years after the big bang.
You are perfectly right that the picture is like the internal surface of a sphere, and I've seen balloons with the CMB painted on it, which is probably the best representation of the picture. However, we like to have things on flat paper, and for that we need a projection from the surface of the sphere to a flat space. This is equivalent to the projections used to represent world maps on flat surfaces. I'm not sure what the particular projection used for CMB is.
Another interesting fact is that that picture is not the "actual" picture taken: it has been through two processes. In fact, originally it looks like this [nasa.gov]. This is due to the well-known doppler effect. We are moving with respect to the CMB photons, so the photons coming from the direction we're moving into seem to be more energetic than the photons coming from the opposite direction. This fact allows us to measure the speed we're moving through the CMB which happens to be about 600km/s.
After correcting for the doppler effect, what's left is this [lbl.gov]. In fact, the universe was extremely homogeneous 400,000 year after the big bang. However if one looks carefully it is possible to detect inhomogeneities in that picture, as small as 1 in 10^5. Those inhomogeneities is what actually is represented in the pictures as the one I showed in the previous post.