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No Shadow From the Big Bang?
ultracool writes "In a finding sure to cause controversy, scientists at The University of Alabama in Huntsville (UAH) found a lack of evidence of shadows from "nearby" clusters of galaxies using new, highly accurate measurements of the cosmic microwave background (WMAP). Other groups have previously reported seeing this type of shadows in the microwave background. Those studies, however, did not use data from WMAP, which was designed and built specifically to study the cosmic microwave background."
Shadows require light, an object and an observer. The 'observer' is us here at the earth. The 'object' is this (from TFA):
Galaxy clusters are the largest organized structures in the universe.[snip] The gravity created at the center of some clusters traps gas that is hot enough to emit X-rays.
This gas is also hot enough to lose its electrons (or ionize), filling millions of cubic light years of space inside the galactic clusters with swarming clouds of free electrons. It is these free electrons which bump into and interact with individual photons of microwave radiation, deflecting them away from their original paths and creating the shadowing effect. This shadowing effect was first predicted in 1969 by the Russian scientists Rashid Sunyaev and Yakov Zel'dovich.
And the 'light' is the background microwave radiation, until now assumed to be from the edges of the universe, beyond these clusters.
I can explain it for you, but I can't understand it for you.
First get this in your head. At this point in history, evolutionary biology is a certainty in the way that gravity is a certainty. We may reconceptualize certain parts of it from time to time, but it is clear and obvious that it is there and happening.
The big bang is NOTHING like this. This is because, unlike in biology, in physics at the moment we have massive unknowns (dark matter, dark energy, no clue what the elementary building material of the universe is, no way to connect quatum mechanics to relativity). At this point the best we can say is all clues seem to hint toward a big bang and that seems the most likely explanation to explain currently observed phenomena.
Big difference!
P.S.: Most Christian fundimentalists don't actually understand the difference between evolution and the big bang. They often see the two in their own heads as linked and think by argueing against one, they are arguing against the other as well. See Kent Hovind and his crazyness, for example.
Big apple, new Yorik, undig it, something's unrotting in Edenmark.
I think the big bang gets attacked more in the sense of attacks on exactly what the initial thingy was. There's no real doubt that the universe is exploding and has been for most of physically evident history. It may not be the initial event, the universe could be eternal, cyclical, or whatever -- but it's certainly exploding now, and seems to have been for at least 12 billion years.
There isn't so much an attacking of the big bang as trying to nail down what exactly the big bang was. In other words, it's the same kind of attacks that people like Stephen Gould and Lynn Margulis make on evolution. They don't doubt that evolution is a real phenomenon for a second; they just want to nail down what exactly evolution is, what makes it tick, how it happens. It's the good kind of attacking, and it's what makes science jump.
Fundies, in turn, seem to assume that the big bang was invented for the sole purpose of trying to support evolution, which is so ridiculous that it defies the belief of real people. In fact, they seem to think that every branch of science exists solely to provide support for an otherwise untenable theory of evolution. This despite the fact that many of these ideas preceded Darwin (in a few cases by millenia).
The theory, if I understand it, is that since the CMB and the energy from the nebula should have taken the same time to reach from where they were then to where we are now, and assuming that the CMB was not somehow generated "in front of or "at" nebula (which we currently deduce from its very red-shifted frequency and distribution), then we should see the nebula's emissions, but not the same strength of CMB that is measured from the "background" at very small angular displacements from the nebula.
I need to read the REAL article, since the "Science Daily" was a joke, but, here are some issues with the research as described:
#1 the universe has no "edge" in any layman's sense of word. We're no more in the middle than some galaxy 8 billion light years away in any direction.
#2 the CMB is NOT "pointed at" the Earth. It's going in every direction at the same time, including very, very small angles to "straight away" in any direction.
#3 the WMAP antenna is very good, but it is NOT 100% unidirectional, so it will pick up energy from a very narrow cone, not a line straight away.
Therefore the WMAP data will rarely show a "shadow" of much change in intensity, since the antenna will pick up significant CMB from off-axis of the line between the Earth and the nebula, even if the nebula is resolved to nearly all of the sample point. For that matter, it could be lensing on- or off-axis causing some of the intensity variation described in the artice.
The variations in CMB are incredibly small in the first place, and we don't have THAT many significant digits of intensity in the measurement range. We only really detected them when we got WMAP up there. Any additional small variation in CMB co-incident with an ionized nebula is going to be difficult to unambiguously assign to "shadowing", and the even smaller variations of variations from nebula to nebula are very close to the statistical noise values of the original samples.
As I said, maybe the "Astrophysical Journal" article is better presented, but so far, this doesn't sound well thought-out.