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."

Comments

Re:Wow, that's astounding

[Red Flayer]

the characteristics of which coincide perfectly with the big bag theory.

You leave my wife out of this!

Re:Ultra-Blue?

[camperdave]

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.

Re:Stupid question

[Bigjeff5]

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.