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Discovering Galaxies Near and Far
Anonymous Coward writes "Researchers using Japan's Subaru telescope in Hawaii have discovered a galaxy 12.9 billion light-years from Earth -- the most distant found to date. The latest finding extends the distance of the known farthest galaxies from Earth by about 3 million light-years." Toward the other end of the scale, JamesD_UK writes "Astronomers at the 2Mass project appear to have found the closest galaxy to the milky way yet, overtaking the Sagittarius dwarf galaxy. The galaxy is only 25,000 light years away and is being torn appart in a collision with the milky way. More information on the The Two Micron All Sky Survey is available here."
This is interesting, because the standard theory for cosmology predicts that galaxies like the Milky Way are build from merging small galaxies. However, only few remnants of this merger events have been found so far.
scientists currently believe the universe to be around 14 billion years old. Things which are too far away for us to see, even if we had an infinitely powerful telescope, are said to lie beyond the light horizon.
As to your question about relative speed, remember that you will always measure the speed of light as 3 * 10^8 or 3E+8 meters per second no matter what. So, if a galaxy was heading away from me very quickly, and I could measure the speed of photons from stars in that galaxy as they passed by, I would find that they are going the 3E+8 m/s. If you and I are in spaceships traveling away from each other at close to the speed of light I shine a flashlight at you, you will measure the speed of the photos and find they are going 3E8 m/s. C is a constant. It does not depend on relative motion.
Instead of apearing slower, the light would be redshifted.
For what (little) it's worth my point was that two objects could travel away from each other with a relative speed of (2*C)-1 i.e. if they're both traveling near the speed of light, relative to each other they will be moving near twice the speed of light. Therefore if two objects were always moving at that speed (or at least since the begining of the universe) and are 14 billion light years apart, it must have taken slightly over 7 billion years for them to get to that location since the big bang requires that they must have been at least somewhat close together (give or take a few hundred million light years).
Anyway, the point being that if we can dig up two objects in space which are (I'm making up a number) 20 billion light years apart then we can say the universe is no younger than 10 billion years old. We can say it's older if we can figure out how fast those objects are moving relative to each other. So (again I'm making up numbers) if we have our two 20 billion light years separated objects and they are moving at half the speed of light away from each other (seems reasonable) then we would be able to say the universe is no younger than 40 billion years old.