NASA yesterday announced that the Kepler Space Telescope confirmed the existence of its 1000th exoplanet. Among the most recently confirmed exoplanets are an additional three earth-size planets that orbit in the habitable region of their suns. This brings to eight the total number of confirmed earth-sized planets whose orbits make it possible for liquid water to exist on the surface. This makes it possible for life as we know it to evolve. Kepler still has more than 3,000 exoplanet candidates that need to be confirmed, making it likely that the total of earth-like exoplanets will increase. The confirmed discovery of earth-sized exoplanets in the habitability zone has excited the scientific community which now believes the discovery of extraterrestrial life is inevitable.
Two of the newly confirmed exoplanets, Kepler-438b and Kepler 442b, are nearly 1.5 times Earth’s diameter, and are respectively 475 to 1100 light years away. Quite close in astronomical terms but still too far away in terms of conventional space travel technologies.
According to the John Grumsfeld, associate administrator of NASA’s Science Mission Directorate: "Each result from the planet-hunting Kepler mission's treasure trove of data takes us another step closer to answering the question of whether we are alone in the Universe."
Dough Caldwell, co-author of the research paper announcing the Kepler discovery and part of the SETI mission seeking extraterrestrial life, writes: "With each new discovery of these small, possibly rocky worlds, our confidence strengthens in the determination of the true frequency of planets like Earth."
NASA scientists will have to wait for the arrival of more powerful space telescopes to find the tell-tale signatures of life in the atmosphere of exoplanets. The James Webb Space Telescope scheduled for launch in 2018 will be able to scan the atmospheres of exoplanets for oxygen, methane and nitrous oxide, all of which are produced by living organisms. For example, on December 16, 2014, NASA scientists announced that a significant amount of methane was found by the Mars Curiosity Rover thereby raising hopes that microbial life exist under the Martian surface.
NASA is not simply waiting for life to be discovered but is taking a proactive approach. On September 18-19, 2014, NASA and the Library of Congress convened a symposium on “Preparing for Discovery: A Rational Approach to the Impact of Finding Microbial, Complex or Intelligent Life Beyond Earth.” NASA scientists agree that eventually extraterrestrial life will be discovered, and humanity needs to be prepared. The latest discovery of earth-sized exoplanets takes us a step closer to such a discovery.