1,284 alien planets confirmed in new study of NASA Kepler data
NASA's alien planet-hunting Kepler Space Telescope is pretty good at its job, a new statistical analysis suggests.
In total, the study, published Tuesday in the Astrophysical Journal, validates 1,284 newly discovered worlds as planets.
This more than doubles the number of validated exoplanets discovered by Kepler, said Timothy Morton, co-author of the study, during a press conference Tuesday.
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The statistical study marks a new way to analyze all of the data gathered by Kepler to pick out newly discovered planets from a trove of thousands of possible worlds.
Within the new group of planets there are about 550 that could be rocky worlds, and nine of those orbit within their stars' habitable zone -- the orbit in which a world could sustain liquid water on its surface.
Including this new analysis, Kepler has discovered a total of 2,325 previously unknown alien worlds over the course of its mission.
"We are sampling the galaxy to understand how many planets there are," said Kepler scientist Natalie Batalha during the press conference.
And there appear to be a lot of planets.
According to Batalha, there may be be tens of billions of potentially habitable planets in the Milky Way alone.
Kepler: The planet hunter
Kepler finds planets using the transit method. The telescope can detect tiny dips in a star's light which may be due to a planet passing in front of the star from Earth's perspective.
Once those dips signifying possible planets are found in the data, scientists qualify them as "Kepler objects of interest" (or KOIs for short), which can then be validated as official planets after followup observations confirm what Kepler saw.
The new study potentially solves a major problem with gaining insights from Kepler, since it demonstrates a fully automated way of parsing the signal from the noise in the Kepler data. This will free up valuable time for the limited space telescopes around the world.
Scientists will likely still need to do some follow-up observations with Kepler planets, but the new analysis is a good starting point for figuring out how many worlds the telescope has discovered.
The technique researchers employed for this study relies on two different simulations to statistically verify the planets.
According to Morton, the research team simulated the shape of transits in detail and also simulated how common they expect the false positives to be.
If the "reliability score" combining those two simulations is more than 99 percent, then they were declared planets.
Of the 4,302 possible planets in Kepler's July 2015 catalog, the study found that 1,327 are "more likely planets" while 707 are "more likely imposters" with 1,284 validated and 984 that were previously confirmed, according to NASA.
"They say not to count our chickens before they're hatched, but that's exactly what these results allow us to do based on probabilities that each egg (candidate) will hatch into a chick (bona fide planet)," Batalha, a co-author of the paper, said in a statement.
“This work will help Kepler reach its full potential by yielding a deeper understanding of the number of stars that harbor potentially habitable, Earth-size planets -- a number that's needed to design future missions to search for habitable environments and living worlds.”
The Kepler mission as originally conceived is over. Two of the four devices used to keep the spacecraft pointing in space failed, preventing it from continuing its original mission that was designed to point specifically at one spot in the sky for a long time.
Today, Kepler is on its revised K2 mission, still hunting for exoplanets out in the galaxy.
The newly validated planets were discovered as part of the original Kepler mission, but K2 has found 46 confirmed planets in its own right. And its mission continues.
K2 has enough fuel to last about two more years.
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Miriam Kramer worked as a staff writer for Space.com for about 2.5 years before joining Mashable to cover all things outer space. She took a ride in weightlessness on a zero-gravity flight and watched rockets launch to space from places around the United States. Miriam received her Master's degree in science, health and environmental reporting from New York University in 2012, and she originally hails from Knoxville, Tennessee. Follow Miriam on Twitter at @mirikramer.
