There is further proof of inhabitable planets in the galaxy. Using data from, NASA announced Wednesday that data from the Kepler space telescope enabled scientists to discover 715 additional planets, an astronomical number to those taught nine planets in school (when Pluto counted).
The space agency also reported finding four newly discovered planets in what NASA calls the “habitable zone,” meaning their makeup could possibly support life. One appears to be twice the size of Earth; it orbits a star in a 30-day cycle that is half the size of the sun. The other three planets in the habitable zones also are roughly twice the size of Earth.
The NASA announcement nearly doubled the number of known planets outside our solar system. Ninety-five percent of the planets are smaller than Neptune, which is four times the size of Earth. They orbit 305 different stars, mostly the size of the sun or smaller.
Since it was launched in 2009, the Kepler spacecraft sought to discover additional planets, like the 715 planets NASA scientists announced, with an emphasis on Earth-sized spheres suitable for habitation. In the past four years, it has revealed 3,601 possible planets (961 have been confirmed) of varying sizes from super-Jupiters to mini-Neptunes. Kepler detects the planets orbiting nearby stars by recording telltale dips in light they cause when they eclipse their stars. These “transits” can only be spotted for planets traveling in orbits viewable edge-on to Earth, which only happens 10 percent of the time.
Kepler received a lot of attention last spring when it became crippled, threatening to end its planet-hunting mission. Two of the four gyroscopic reaction wheels that helped the telescope aim failed. Last summer, NASA announced that it was unable to restore the craft to full working order.
Astronomers mourned Kepler, but later came up with a last-ditch effort to use the sun to steer the craft. The sun’s photons (light particles) were constantly bombarding the crippled spacecraft and pushing it around. Engineers at Ball Aerospace in Colorado came up the idea to use the sun’s photon pressure as a stabilizer or “third wheel” to work with the two remaining wheels like a tripod and keep the telescope balanced. The trick is working for now giving Kepler a new mission, labeled K2.
Scientists admit that the revamped Kepler craft will not be a precise and it originally was. However, the telescope is still significantly better than anything research telescope on Earth.
On its new K2 mission, Kepler is using a novel “validation through multiplicity” technique that uses the logic of probability. The technique uses gravitational planet interactions in multiple-world solar systems to eliminate false observations of other worlds. In layman’s terms, the telescope looks at stars already known to have a planet since they would be likely to have more than one.
Now, the Kepler craft is enabling NASA scientists to discover a trove of planets making the 715 additional ones announced this week just the beginning. Some astronomers suspect that the galaxy is home to billions of planets similar to Earth.
By Dyanne Weiss