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Astronomers Detect the Earliest Galaxies
FiReaNGeL writes "Astronomers, using NASA's Hubble Space Telescope, have uncovered a primordial population of compact and ultra-blue galaxies that have never been seen before. They are from 13 billion years ago, just 600 to 800 million years after the Big Bang. These newly found objects are crucial to understanding the evolutionary link between the birth of the first stars, the formation of the first galaxies, and the sequence of evolutionary events that resulted in the assembly of our Milky Way and the other 'mature' elliptical and majestic spiral galaxies in today's universe."
Old news!
I suspect I have identified such objects from submillimeter observations http://arxiv.org/abs/0802.1666 but it is very good to see a more robust population identified here.
Is 600 million years long enough to develop a complete galaxy? I'd think that might be too short for even a solor system to develop.
Who would win this election: Andrew Weiner vs Andrew Weiner's weiner.
http://media.aftenposten.no/archive/01011/SPACE-CHANDRA-NEBU_1011148x.jpg
You leave my wife out of this!
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My understanding of cosmology is at best limited, but shouldn't these galaxies appear red-shifted to the extreme? They are furthest and hence should be moving the away from us at an extremely fast pace. Is the name Ultra-blue restricted to element analysis based on spectrum? I'm just confused about the blue light.
Looking at this bit:
They are so blue that they must be extremely deficient in heavy elements, thus representing a population that has nearly primordial characteristics."
I assume this means that light, hydrogen-heavy objects will get hotter for a given amount of heat energy because of their lower density. Maybe these galaxies are red shifted, but they are relatively blue in relation to their red shift.
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the characteristics of which coincide perfectly with the big bag theory.
Blah blah blah. Look, I don't want to hear about how observations matched predictions. That's not science.
It's like this: I don't understand Big Bang Theory, therefore I don't like it, therefore it's nonsense, therefore your "evidence" is really just your prejudice, therefore we're obviously going to find galaxies that are ten billion years older than these ones, and therefore my theory of the Giant Cosmic Bunny Orgy Theory, which is obvious if you even think about it rationally, will be proven correct once and for all and I'll be elected the President of Physics.
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I believe the only reason they can see these galaxies is because they were blue to begin with.
They are using Hubble's infra-red telescope to see them, so that should tell you how far they have shifted. Obviously the pretty picture has been adjusted back to the original color. If you'll notice, the older galaxies (from 600 mil years post Big Bang) are a darker blue than the younger (700 mil years post BB).
The next ones they find will probably have to be pushing violet.
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I *think* TFA is implying that they can determine the intrinsic color, even when highly red-shifted, and that this intrinsic color is extremely blue due to the lack of any elements other than hydrogen and helium. This would be expected, because no elements heavier than helium had yet been synthesized.
Generally, bash is superior to python in those environments where python is not installed.
A few basic Astronomy tidbits for you:
Elements emit light at characteristic colors - frequencies of light. Eg, copper emits a bluish green color. By looking at the spectrum of the object, you can tell what the object is made of. If an object is moving, the spectrum will be shifted relative to normal due to the doppler effect. If it is shifted to higher frequencies the object is approaching you. If the spectrum is red shifted, it is moving away. The greater the shift, the greater the velocity.
Certain stars are close enough to Earth that we can triangulate their distance, using the orbit of the earth as the base of the triange. There is a certain class of star called a cepheid variable, some of which are in triangulateable range. Cepheids give off regular bursts of light, and due to the process by which they do that, the amount of light they give off is proportional to the frequency of the bursts. By using the inverse square law you can tell how far away a cepheid is by its brightness.
Thus, you can tell how far away a galaxy is by looking at its cepheid stars. So, by careful observation, you can detect the composition, speed, direction, distance, and age of a star. By looking at many stars, you can detect patterns like: the farther away a star is, the faster it is moving away from us.
When our name is on the back of your car, we're behind you all the way!
Another way to look at it, is that at the instant before the big bang there was no universe, or you could say the universe was infinitely small. After the BB the universe was expanding, but there was still no space outside the universe. Everything we consider "space" is all packed inside the universe, and the universe was a lot smaller then than it is.
The classic analogy is the balloon analogy. Imagine three dimensional space is the two dimensional surface of a balloon with tiny points all over it representing matter. As the balloon expands, all points on the surface move away from each other, and the balloon has gotten larger. However, the center of the balloon is not on the 2d surface, the center of the balloon is in the 3rd dimension. Therefore, relative to the surface there is no center.
Now, bump everything up one dimension and you have our universe. The "surface" is three dimensional space, and it is expanding along the fourth dimension. We have no way of seeing the fourth dimension, just like a 2d creature on the surface of the balloon could do nothing but look forward, backward, left and right we can only do that plus up and down. We would need to add another dimension to our repertoir to view the fourth dimension, but we can't conceptualise beyond the abstract about what that might be. However, we can definitely see that everything in the third dimension is moving away from everything else. Therefore space is expanding, and no matter which way we look everything is moving away. In fact, no matter what vantage point you take in the universe it will always look the same, because the "surface" of the universe is what is expanding.
It's a bit mind numbing to think about, but there is no direction you can look at and figure out "where" the big bang was. There is no "where" in the third dimension, the where is in a dimension that we are not equipped to experience. All we can do is measure its effects in our own dimension.
I like Carl Sagan's explanation of the fourth dimension best, but wikipedia does a good job, if a bit on the technical side.
Security is mostly a superstition... Avoiding danger is no safer in the long run than outright exposure. - Helen Keller