It’s an exciting time to be a nerd interested in space.
Since April 2009, the Kepler satellite has been watching a small patch of sky for the telltale signs of stars that wobble or are eclipsed by orbiting planets. To date, it has identified 2,740 planet candidates and 122 confirmed extrasolar planets. The search for planets that could harbor life has picked up pace since the mission started, and they have made another leap forward today. On April 18th, NASA’s Kepler Mission team announced the discovery of several new planets that lie within their sun’s habitable zones and could harbor the conditions favorable for sustaining surface water.
The Kepler-62 system consists of five planets, two of which (Kepler-62e and 62f) are in orbit within the habitable zone. The Kepler-62 system is interesting in that the star is smaller and cooler than our sun, therefore the zone in which liquid water may be present on its planets is closer to the star. Kepler-62’s two habitable zone planets are actually the outer planets in the system, with three inner planets much closer to their star. Kepler-62f, the outermost planet - the closest analog yet found for Earth within a habitable zone - is only 40% larger than our planet. Kepler 62e is slightly larger, at approximately 60% larger than Earth. It might be a little early to start planning a vacation, as the Kepler-62 system is nearly 1,200 light years away from our own. While it's an interesting case that will help answer questions about how common earth-like planets are in our galaxy, it’s unlikely that we will be visiting anytime soon.
The third announced planet, Kepler-69c, is alone in the habitable zone of Kepler-69. However, it compensates for its crippling loneliness by being roughly 70% larger than Earth. Its sun is similar in ours, but the early indications suggest that conditions on its surface might resemble those on Venus. I would recommend SPF-400 and a sturdy spacecraft that won’t buckle under the pressure. Kepler-69 is even further away from Earth than Kepler-62, at approximately 2,700 light-years.
These discoveries are exciting, as they show progress and refinement in the search for extrasolar planets. In only a few years the ability for skywatchers to identify planets has grown in leaps and bounds. The data that Kepler is collecting will continue to feed scientific inquiry and hopefully inspire new generations to find planets that could someday be reachable by mankind.
For more information, visit the Kepler Mission Page.