NASA Finds Most Earth-Like Planet Yet

It’s only 500 light-years away!

The artist's concept depicts Kepler-186f , the first validated Earth-size planet to orbit a distant star in the habitable zone.
National Journal
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Brian Resnick
April 17, 2014, 10:41 a.m.

In the con­stel­la­tion Cygnus, which ap­pears to us as a great swan in the sky, about 500 light-years away, there is a star about half the size of our sun. And around that star or­bits a plan­et that has a high prob­ab­il­ity of look­ing like our own. It’s called Kepler-186f, de­pic­ted above in an artist’s ren­der­ing. Today, NASA is an­noun­cing that it is the most Earth-like plan­et it has ever found.

That’s be­cause it’s around the size of the Earth, is likely to be rocky, and, most im­port­ant, it lies in the hab­it­able zone of its star sys­tem. That’s the range of dis­tances from the star in which li­quid wa­ter could ex­ist.

The NASA press re­lease reads:

“Be­ing in the hab­it­able zone does not mean we know this plan­et is hab­it­able. The tem­per­at­ure on the plan­et is strongly de­pend­ent on what kind of at­mo­sphere the plan­et has,” said Thomas Barclay, re­search sci­ent­ist at the Bay Area En­vir­on­ment­al Re­search In­sti­tute at Ames, and coau­thor of the pa­per. “Kepler-186f can be thought of as an Earth-cous­in rather than an Earth-twin. It has many prop­er­ties that re­semble Earth.”

The Kepler plan­et circles a star that is much smal­ler than the sun, as can be seen in the com­par­is­on chart be­low. In the com­ing dec­ades, re­search­ers will be look­ing for a true Earth twin, circ­ling a star the size of the sun. Such plan­ets would be the most likely to har­bor life sim­il­ar to ours. Right now, we just don’t have the tech­no­logy to find such a plan­et. Stars like the sun are just too bright. (Put­ting it crudely, NASA finds new plan­ets by meas­ur­ing the change in light from the star as the plan­et crosses it. Kind of like look­ing for sol­ar ec­lipses, just ones light-years away.)

“It’s like look­ing for a fire­fly next to a search light,” Sara Seager, an MIT as­tro­phys­i­cist, said at a lec­ture at the Na­tion­al Academy of Sci­ence last month. NASA re­search­ers are cur­rently work­ing on a new tele­scope sys­tem, equipped with what’s called star shade, that will make it easi­er to see Earth-like plan­ets or­bit­ing around bright, sun-like stars. And that’s our best chance of find­ing life in the uni­verse. 


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