The discovery of Kepler 452b, a planet orbiting a star similar to our own sun and just 4 percent larger and 10 percent brighter, hit the news recently. Detected by the Kepler Space Telescope, the planet is a so-called “super Earth” with five times the mass of Earth and a 60 percent larger diameter. Kepler 452b orbits its star every 385 days, again very similar to our own world.
This is not the first earth-like planet found in the habitable zone (where we would expect liquid water to be present on the planet’s surface), but it is the first such exoplanet found that orbits a G2 star like our sun rather than a common M star. The Kepler 452 system is estimated to be 1.5 billion years older than our own solar system.
Just imagine Earth 1.5 billion years in the future. What will it be like? Will it still be habitable? What will have become of the human species in that unimaginably distant future? Will we have destroyed ourselves, or will our technology have become so advanced that it would appear like magic to us in the 21st century?
We don’t expect to know the answers anytime soon. Kepler-452b is 1,400 light years from Earth. At the moment we can’t be sure whether it has a breathable atmosphere or life on its surface. Some scientists speculate that Kepler-452b has a thicker atmosphere, with more cloud cover and active volcanoes, as in the artist’s conception above. But with current technology there is no way to verify even this. Nevertheless, it is an intriguing thought that we may have discovered a planet that resembles what our own world will become in the distant future.
This planet would also make an obvious first target for the $100 million Breakthrough Initiative SETI project announced by Russian billionaire Yuri Milner and Stephen Hawking a couple of days prior to the Kepler announcement. One of the two breakthrough initiatives, Breakthrough Listen, will be the most comprehensive search ever undertaken for signs of intelligent life beyond Earth. The second, Breakthrough Message, is intended to produce messages that might one day be transmitted to civilizations on other worlds. While no one objects to listening for signals, the second initiative is more controversial, as sending out messages to target planets and providing them with our location may invite alien life that might not be benign. In fact, we might be inviting our own destruction, as pointed out by Hawking himself some time ago. First, though, we have to find promising targets for transmitting messages—and Kepler 452b currently would be at the top of the list.