Life in the ‘Goldilocks zone’

If it’s clear tonight, go outside and look up. You’ll probably be able to see the Milky Way. Then think about this: Scientists reported earlier this month that they now believe there are some 50 billion planets in the galaxy, and that upward of 500 million of them are in the “Goldilocks zone”: not too hot, not too cold to sustain life.

The data come from the Kepler satellite launched in March 2009 to look for signs of planets. Focusing on a tiny area of the galaxy near the constellation called the Northern Cross, the satellite has discovered 1,235 potential planets, of which 54 are in the Goldilocks zone. Scientists extrapolated the figures for the entire galaxy from the data Kepler found in that small area of space.

There are an estimated 300 billion stars in the Milky Way galaxy, a figure that seems astonishing only until one considers that there are an estimated 100 billion galaxies in the universe.

Human beings have pondered the mysteries of the universe for as long as they’ve lived on Earth, and no mystery has been more alluring than that of extraterrestrial life. We may never know what life forms exist out there on some of those Goldilocks planets, but now we can be certain that life does exist, no doubt in an abundant variety of forms. That’s something to consider as we ponder the fate of our own small Spaceship Earth.