Dec 18, 2009
The universe is all matter and energy including the Earth, the galaxies, and the contents of space, regarded as a whole. Recent data collected by the Hubble Space Telescope suggest that the universe may be only 8 billion years old. This contradicts the previous belief the universe is somewhere between 15 billion and 20 billion years old.
The 8-billion-year figure was derived using Hubble's constant, which is the rate of expansion of the universe. Hubble's constant is calculated by dividing the speed at which a galaxy is moving away from Earth by its distance from Earth. The age of the universe can be calculated by working backward from the present—that is, divide the galaxy's distance from Earth by that galaxy's recessional speed. In this way, you can determine a time when all matter existed at a single point.
The velocity (speed of motion) with which galaxies are moving, their distances from...
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