NASA’s Kepler Telescope Discovers First Earth-Size Planet in ‘Habitable Zone’

Using NASA’s Kepler Space Telescope, astronomers have discovered the first Earth-size planet orbiting a star in the “habitable zone” — the range of distance from a star where liquid water might pool on the surface of an orbiting planet. The discovery of Kepler-186f confirms that planets the size of Earth exist in the habitable zone of stars other than our sun.

While planets have previously been found in the habitable zone, they are all at least 40 percent larger in size than Earth, and understanding their makeup is challenging. Kepler-186f is more reminiscent of Earth.

“The discovery of Kepler-186f is a significant step toward finding worlds like our planet Earth,” said Paul Hertz, NASA’s Astrophysics Division director at the agency’s headquarters in Washington. “Future NASA missions, like the Transiting Exoplanet Survey Satellite and the James Webb Space Telescope, will discover the nearest rocky exoplanets and determine their composition and atmospheric conditions, continuing humankind’s quest to find truly Earth-like worlds.”

Although the size of Kepler-186f is known, its mass and composition are not. Previous research, however, suggests that a planet the size of Kepler-186f is likely to be rocky.

“We know of just one planet where life exists — Earth. When we search for life outside our solar system, we focus on finding planets with characteristics that mimic that of Earth,” said Elisa Quintana, research scientist at the SETI Institute at NASA’s Ames Research Center in Moffett Field, Calif., and lead author of the paper published today in the journal Science. “Finding a habitable zone planet comparable to Earth in size is a major step forward.”

Kepler-186f resides in the Kepler-186 system, about 500 light-years from Earth in the constellation Cygnus. The system is also home to four companion planets, which orbit a star half the size and mass of our sun. The star is classified as an M dwarf, or red dwarf, a class of stars that makes up 70 percent of the stars in the Milky Way galaxy.

“M dwarfs are the most numerous stars,” said Quintana. “The first signs of other life in the galaxy may well come from planets orbiting an M dwarf.”

Kepler-186f orbits its star once every 130 days and receives one-third the energy from its star that Earth gets from the sun, placing it nearer the outer edge of the habitable zone. On the surface of Kepler-186f, the brightness of its star at high noon is only as bright as our sun appears to us about an hour before sunset.

“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 co-author 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 four companion planets, Kepler-186b, Kepler-186c, Kepler-186d and Kepler-186e, whiz around their sun every four, seven, 13 and 22 days, respectively, making them too hot for life as we know it. These four inner planets all measure less than 1.5 times the size of Earth.

The next steps in the search for distant life include looking for true Earth-twins — Earth-size planets orbiting within the habitable zone of a sun-like star — and measuring their chemical compositions. The Kepler Space Telescope, which simultaneously and continuously measured the brightness of more than 150,000 stars, is NASA’s first mission capable of detecting Earth-size planets around stars like our sun.

Ames is responsible for Kepler’s ground system development, mission operations, and science data analysis. NASA’s Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA’s 10th Discovery Mission and was funded by the agency’s Science Mission Directorate.

The SETI Institute is a private, nonprofit organization dedicated to scientific research, education and public outreach. The mission of the SETI Institute is to explore, understand and explain the origin, nature and prevalence of life in the universe.

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6 thoughts on “NASA’s Kepler Telescope Discovers First Earth-Size Planet in ‘Habitable Zone’”

  1. This discovery is a very important step into the finding of a Earth-like planet because it means that humanity is closer to finding that planet that maybe has the same chemical and physical composition of Earth. This planet can only be referred to as a cousin of Earth but it still means that NASA is closer with their technology to finding an actual habitable planet. NASA thus plays a very big role in the survival of human kind, but this cousin planet is about 500 light years away, and how would that help humanity in its quest to finding Earth-like planets, because we will not be able to travel to that planet with our current technology. Although this is an important step into the discovery of an Earth-like planet, we cannot say fro sure that this discovery means that there is definitely another planet identical to planet Earth. Planet Earth is unique in its composition and is exactly the perfect distance away from the sun to sustain life and with its chemical composition it can sustain life. Another planet thus has to be identical to this planet in order to sustain life, and this planet has not been found. It then makes one wonder if the search for other Earth-like planet is important, while the planet we are inhabiting is buzy deteriorating because of our actions towards the environment?

  2. This discovery is very essential to finally answering the question of whether we are alone in the universe or not. The discovery of this Earth-like planet might mean that there are other living beings similar to us humans somewhere in the universe! Who knows, in the near future, we might even be trading natural resources with other planets!

  3. Reading this article has sparked my interest yet again in life in the universe! This is a fascinating discovery that can only lead to advances in humans understanding our universe better. There is no doubt in my mind that there is life somewhere out there in our universe and that this discovery can only lead us in the right direction towards discovering this extra terrestrial life.

    That is on the assumption that they havent already discovered us. With all the evidence of unexplainable UFO sightings, area 51, famous incidents such as roswell, the proof of ancient aliens and the fact that statistics show that 280 000 American citizens have claimed to have been abducted; I believe that it is safe to say that extra terrestrial life have already discovered us on our planet and we would be extremely advanced if we disvovered life on other planets aswell. If one does not agree with me, one should simply read authors like Wayne Herschel, The Hidden Records or Robert Temple, The Sirius Mystery.

    I agree with Thomas Bates in his comment that life on this planet found does not have to resemble life on ours as we cannot even begin to imagine what other life could consist of in those conditions that we have not experienced on Earth. The truth is that us as humans on earth know very little about our universe but this discovery acts as motivation for scientists to keep trying and keep discovering, as this drive to know and understand, is what makes us human

  4. I believe that this discovery of Kepler-186f is an amazing discovery in astronomy. It provides further information and possibilities to finding possible life outside of Earth, maybe even intelligent life. Astronomers are one step further to finding such planets that could contain such life.

    I need to disagree with u14002338 when he states that “whether life exists there is hard to believe”. This is because for life to exist, it does not have to resemble life on earth exactly. Kepler-186f is on the edge of the Habitable zone also nicknamed the ‘Goldilocks zone’ but does not mean life cannot be found. Life could have possibly evolved to survive on such a planet just like we have evolved to survive on ours. Even if the atmospheric composition would not resemble one like ours life could still exist. For example, suppose that its composition was mainly sulfur, bacteria such as Thermophiles, which require sulfur for growth, could be resembled.

    But what if life was found on Kepler-186f? This planet is 500 light years away! That is 4.73e18 meters away! Current space shuttles travel at roughly 26509.5 m/s out of orbit which would still mean that ONE trip would take a hefty 5654003.8 years. Even if we could create technology to travel at the speed of light, it would still take 500 years. Because of this, we would never be able to closely examine this planet for life.

    So what is the importance of this planet and possible life to the common man or even an astronomer in the big picture?

  5. The topic of finding life on other planets is very fascinating. The Kelper-186f planet might resemble earth in some way but whether life exists there is hard to believe. SETI found there to be a pool of water on Kelper-186. This raises a question: Is there any intelligent life on other planets. How will finding life on planets 500 light years away help to improve our lives on earth? Discovering almost earth like planets is very important to scientists and astronomers but to the common Joe, this discovery provides no purpose and strikes no interest. Scientists need to keep in mind that the universe is extremely big and what they might find, might not be what they are looking for. What they might find, might not be looking for us.

  6. The discovery of Kepler-186f is surely one of the greatest recent universal findings I have heard of. This truly makes me wonder if we as humans are alone in this universe we call home. I mean look at what we have already discovered in the past century, and I am sure this only the beginning of it! With more and more planets that relate to Earth’s composition being found, we can not say earth is the only planet that can maintain life as we know it. I trust that researchers will find a planet, that can maintain life or perhaps already does, before the end of the century. It will be the biggest discovery in human history. u14063329

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