With the nearest habitable planet a cozy 12-light years away, astronomers at UC Berkeley and University of Hawaii, Manoa, estimate that the our galaxy may be home to "billions of potentially habitable, Earth-size planets".
Accounting for missed planets, as well as the fact that only a small fraction of planets are oriented so that they cross in front of their host star as seen from Earth, allowed them to estimate that 22 percent of all sun-like stars in the galaxy have Earth-size planets in their habitable zones.
The primary goal of the Kepler mission was to answer the question, When you look up in the night sky, what fraction of the stars that you see have Earth-size planets at lukewarm temperatures so that water would not be frozen into ice or vaporized into steam, but remain a liquid, because liquid water is now understood to be the prerequisite for life? Marcy said. Until now, no one knew exactly how common potentially habitable planets were around sun-like stars in the galaxy.
All of the potentially habitable planets found in the teams survey are around K stars, which are cooler and slightly smaller than the sun, Petigura said. But the researchers analysis shows that the result for K stars can be extrapolated to G stars like the sun. Had Kepler survived for an extended mission, it would have obtained enough data to directly detect a handful of Earth-size planets in the habitable zones of G-type stars.
|The Human Brain Can Read and Do Math Unconsciously|
|OMG Space: the Solar System Done to Scale, In One Big, Scrollable Website|
|Temporo-Parietal Junction: the Part of the Brain that Decides What Goes Viral on Social Media|
|Visit CERN With Google Street View|
|Evolution of the Universe Recreated in a Lab|
|“The prospects and future of AI.”|
|“The robot age is nothing to be worried about.”|
|Japanese Robot Serves Ice Cream From Inside a Vending Machine|
|CaptchaTweet: Write Tweets in Captcha Form|
|“Long live the instant gratification economy—and the increasingly sophisticated technology that’s enabling it.”|
|How to Avoid Jury Duty|
|Why, Typewriters Are Alive and Well, Thank you|
|The (Very Scary) People of Public Transit|
|“Most have no idea who these companies are and how they got their data on them.”|
|“Authoritarianism depends upon people getting used to hearing the things that they want to hear.”|
|“Rejuvenation is Finally an Industry.”|