A new study using NASA's Kepler space telescope just discovered 1,284 new exoplanets, meaning the number of known alien planets has increased by more than 60 percent. Included in these new findings are nine rocky worlds that could support life in the same way as Earth. The discovery marks the largest amount of alien planets ever uncovered at one time.
The total number of exoplanets known is now approximately 3,200, with 2,235 of them discovered by Kepler.
"When NASA decided to build and launch the Kepler space telescope, we did not know if exoplanets - especially small, rocky exoplanets - were common or rare in the galaxy," said Paul Hertz of the NASA Headquarters in Washington, D.C. "We now know that exoplanets are common, most stars in our galaxy have planetary systems and a reasonable fraction of stars in our galaxy have potentially habitable planets. Knowing this [is] the first step toward addressing the question, 'Are we alone in the universe?'"
The data indicated that around 25 percent of the "normal" stars located in the Milky Way contain Earth-size planets in their habitable zones, which means that liquid water could exist on their surfaces. There are approximately 70 billion normal stars in our galaxy, meaning the potential for life on alien planets is certainly there.
"You can see, doing the math, that you're talking about tens of billions of potentially habitable, Earth-sized planets out there in the galaxy," Kepler mission scientist Natalie Batalha said.
Kepler was designed to locate planets by detecting the dimming of starlight that occurs when planets move in front of stars and block their light. However, in order to determine that this dimming is actually caused by a planet, follow-up observations with other telescopes are needed, which takes a lot of effort.
"The process of verifying a candidate as a true planet has traditionally involved detailed, in-depth study on a case-by-case basis," said Timothy Morton, a researcher at Princeton University and co-author of the study.
Morton developed a new automated technique that determined the probability that a Kepler signal is a real planet without the standard follow-up observations, which led to the current results.
"This is the most exoplanets that have ever been announced at one time," Morton said.
The findings were published in the May 10 issue of The Astrophysical Journal.
