Scrutinizing The Habitable Zone

This week the NASA Kepler telescope team announced the discovery of another 715 “exoplanets” outside our solar system — all of which are in their own multi-planet solar systems. The announcement represents another giant leap forward in our understanding of other solar systems, and how commonplace multi-planet systems are.

The Kepler space telescope was focused on finding instances of “transits,” when light from a faraway sun drops slightly in brightness because a planet has crossed in front of the sun. The size of the variation in light allows scientists to calculate the size of the planet moving across the face of the sun. Most of the newly discovered planets — about 95 percent — are smaller than Neptune, which is four times the size of Earth. The size of the planets is of interest to scientists because it is believed that life is more likely on smaller planets than on Jupiter- and Saturn-like gas giants, with their enormous storms and atmospheres that feature crushing pressures.

Four of the newfound planets are less than 2.5 times the radius of Earth and orbit their suns in the so-called “habitable zone,” where water could be free flowing without being boiled away or frozen forever. The term “habitable zone” may be a misnomer, because we just don’t know yet whether life of some kind exists on, say, Jupiter’s moon Europa — and we won’t know for sure without actually exploring there. We do know, however, that life exists in the “habitable zone” in our solar system, and therefore it makes sense to try to determine whether life might exist in a planet in a similar position in its solar system. All of this effort, of course, is ultimately geared toward trying to make a truly game-changing discovery of some other intelligent life form in the universe.

If you grow weary of the tribal mire of domestic and global human affairs, where progress is rare and and halting and the same disputes and controversies will seemingly never end, you would do well to consider the extraordinary advances in science and technology that we have witnessed in the last few decades. The discoveries of the Kepler telescope team say a lot — all of it good — about what humans are capable of achieving.