Now I wish to introduce the following idea
In 1998, two teams of astronomers independently reported amazing and bizarre news: the Universal expansion known for decades was not slowing down as expected, but was speeding up. Something was accelerating the Universe.
Since then, the existence of this something was fiercely debated, but time after time it fought with and overcame objections. Almost all professional astronomers now accept it’s real, but we still don’t know what the heck is causing it. So scientists keep going back to the telescopes and try to figure it out. (…)
We see galaxies rushing away from us. Moreover, the farther away they are, the faster they appear to be moving. The rate of that expansion is what was measured. If you find a galaxy 1 megaparsec away (about 3.26 million light years), the expansion of space would carry it along at 73.8 km/sec (fast enough to cross the United States in about one minute!). A galaxy 2 megaparsecs away would be traveling away at 147.6 km/sec, and so on*.
The last time this was measured accurately, the speed was seen to be 74.2 +/- 3.6 km/sec/mpc. (…)
By knowing this number so well, it allows better understanding of how the Universe is behaving. It also means astronomers can study just how much the Universe deviates from this constant rate at large distances due to the acceleration. And that in turn allows us to throw out some ideas for what dark energy is, and entertain notions of what it might be.
related { Evidence of Big Bang May Disappear in 1 Trillion Years }
