Astronomers Detect the Earliest Galaxies 127
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."
Really? (Score:3, Interesting)
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.
Re:Ultra-Blue? (Score:4, Interesting)
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.
Re:Ultra-Blue? (Score:4, Interesting)
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.
Re:Really? (Score:3, Interesting)
Since the average temperate of the Universe would have been much greater back then, all that heat could have sped up the process quite a bit compared to the current day.
Re:Stupid question (Score:5, Interesting)
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 [wikipedia.org] does a good job, if a bit on the technical side.
Re:Really? (Score:4, Interesting)