January 26, 2011: How far is far? And, when do you know when you get there? This is not a Dr. Seuss riddle, but the ultimate "final frontier" confronting astronomers. We are on the cusp of seeing nearly as far as we ever can into the universe of stars and galaxies. The question can be better phrased: How young is young? And how do you know when you've seen the earliest objects that ever existed? That's because the farther we look into space the further back into time we see. We're accustomed to instantaneous communications on Earth, but starlight carries a roaming fee. It takes billions of years for information to reach us from the remote universe.
Now astronomers have pushed the Hubble Space Telescope to its limits by finding what they believe is the most distant object ever seen in the universe. Its light traveled 13.2 billion years to reach Hubble. The dim object is a compact galaxy of blue stars that existed 480 million years after the Big Bang, only four percent of the universe's current age. It is tiny. Astronomers were surprised to discover that these observations offer evidence that the rate at which the universe was forming stars grew precipitously in about a 200-million-year time span. This huge change in the rate of star birth means that if astronomers can probe a little further back in time they are going to see even more dramatic changes. This will require the power of the James Webb Space Telescope, the planned successor to Hubble, which will be launched later this decade.See the rest: