Kepler-186f : An Earth-Sized Planet In A Habitable Zone
    By News Staff | April 17th 2014 02:48 PM | 5 comments | Print | E-mail | Track Comments

    Astronomers using NASA's Kepler Space Telescope report discovery of 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.

    Notre Dame astrophysicist Justin R. Crepp is among researchers from NASA working with the Kepler space mission and helped detect the Earth-like planet, 1.11 times the size of our planet.  

    Kepler-186f is part of a multi-planet system around the star Kepler-186 which has five planets, one of which is in the center of the habitable zone—the region around a star within which a planet can sustain liquid water on its surface. While there have been other discoveries of Earth-sized and smaller planets, those planets have been found in orbits that are too close to their host stars for water to exist in liquid form. Findings taken from three years of data show that the intensity and spectrum of radiation from Kepler-186f indicate that the planet could have an Earth-like atmosphere and water at its surface which is likely to be in liquid form.

    Credit: NASA Ames/SETI Institute/JPL-Caltech

    The diagram above compares the planets of our inner solar system to Kepler-186, a five-planet star system about 500 light-years from Earth in the constellation Cygnus. The five planets of Kepler-186 orbit an M dwarf, a star that is is half the size and mass of the sun.
    The Kepler-186 system is home to Kepler-186f, the first validated Earth-size planet orbiting a distant star in the habitable zone—a range of distance from a star where liquid water might pool on the planet's surface. The discovery of Kepler-186f confirms that Earth-size planets exist in the habitable zones of other stars and signals a significant step toward finding a world similar to Earth.

    The size of Kepler-186f is known to be less ten percent larger than Earth, but its mass and composition are not known. Kepler-186f orbits its star once every 130 days, receiving one- third the heat energy that Earth does from the sun. This places the planet near the outer edge of the habitable zone.

    The inner four companion planets each measure less than fifty percent the size of Earth. Kepler-186b, Kepler-186c, Kepler-186d and Kepler-186, orbit every 4, 7, 13 and 22 days, respectively, making them very hot and inhospitable for life as we know it.
    The Kepler space telescope infers the existence of a planet by the amount of starlight blocked when it passes in front of its star. From these data, a planet's radius, orbital period and the amount of energy recieved from the host star can be determined.

    "The host star, Kepler 186, is an M1-type dwarf star which means it will burn hydrogen forever, so there is ample opportunity to develop life around this particular star and because it has just the right orbital period water may exist in a liquid phase on this planet," said Crepp who is the Frank M. Freimann Assistant Professor of Physics in the College of Science.

    Crepp is building an instrument at Notre Dame named named "iLocater" that will be the first ultra-precise Doppler spectrometer to be fiber-fed and operated behind an adaptive optics system. His instrument, to be installed at the Large Binocular Telescope in Arizona, will identify terrestrial planets orbiting in the habitable zone of nearby M-dwarf stars, much closer to the Sun than Kepler-186, by achieving unprecedented radial velocity precision at near-infrared wavelengths. He and his research collaborators will also probe nearby terrestrial planets to tell what their atmospheres are made of.

    Credit: NASA Ames/SETI Institute/JPL-Caltech

    Crepp is one of only 11 Kepler Participating Scientists in the country. He and his colleagues are advancing the goals of the Kepler Mission by seeking to find terrestrial planets comparable in size to Earth, especially those in the habitable zone of their stars where liquid water exists and where life may be sustained.

     Article: "An Earth-sized Planet in the Habitable Zone of a Cool Star", Science. Source: University of Notre Dame


    Then, perhaps, is there fossils or life expressions elsewhere? Isn’t the emergence and maintenance of life a process of radical contingency? That is, is a unique and unrepeatable past totally necessary? Or does life emerge through space like mushrooms when some conditions are present? So, how many conditions are necessary: three, four, trillions, infinite? Only one, water or any sort of God? Is God the word that means infinite conditions, absolute necessity? Anyway, how did the life that emerge in a given conditions resist when switching to a different moment? How does life resist time itself, the effects of entropy? But, is it possible for human beings to recognize a simpler life than their own brain only? On the other hand, beyond likeness, is it possible to recognize a complex life than their brain, is this the extra-terrestrial life that some people are searching unsuccessfully? However, is there an origin of life or would it be as finding a cut in the material history of the universe, an infinite void that human language patches now? Along these lines, there is a peculiar book, a short preview in Just another suggestion, far away from dogmas or axioms.

    Hansolo2, as I understand it - nobody knows. But - seems given the vast numbers of stars and galaxies, that life probably evolved somewhere else and not just here.
    But - the problem is- there is a huge gap in our understanding on Earth. The most primitive forms of life we know are far too complex to evolve in one step from amino acids (probably basic building blocks that life started from). Indeed, the archaea, even the most primitive, are so complex that there have probably been as many major steps of evolution between the amino acids and the most primitive cells as there have been between them and us - judging by their DNA complexity of non redundant nucleotides.

    On Earth - we simply can't study this part of our history directly. All that survives are a few traces of the ancient atmosphere in zircons (diamond like stones) in later rocks. That's because of continental drift. If there is life elsewhere in our solar system, we might learn more. Especially, Mars had oceans, almost certainly, at the same time as early Earth - and in its case, the surface has been preserved, no continental drift, and plunged into a deep freeze also. There are major challenges finding undisturbed ancient deposits on Mars even so, but they probably exist and could tell us much about evolution. Either life evolved on Mars independently - or not at all - or it evolved on Mars and on Earth with some shared ancestry - or some mixture of shared and independent evolution. It's far too soon to try to guess what happened.  There's also the chance of finding ancient meteorites from early Earth that hit the Moon, Mars, or asteroids, preserving organics from that time.

    Until then - there's not too much we can do to settle this - because we have such a huge gap in our knowledge of evolution of the first life forms on Earth. Also, not remotely close to being able to evolve life from primitive chemicals in our laboratories. So - the answer can only be, that we don't know.
    This is fascinating news! Kepler Mission finally delivers an astounding discovery!

    While we are scanning the skies for prime real estate to put up another subdivision, the bug-eyed aliens are doing likewise. They may even have Earth in their sights as we speak!

    I find topics like these very interesting because during the seventeen years of my life the search for extra terrestrial life or just even the search of places where life could exist as intensified greatly. One would think that such life would have been found by now considering that there are literally billions of stars out there with a reasonable number of them having their own planets. This leads me to ask the question, Earth is unique in its position and the events that have resulted in what we have today or is there a possibility of finding a planet that has gone through the same events as our Earth?. Is it possible that Kepler-186f also went through the same processes as earth (a little derivation is expected) and if so could it possibly have life that has gone through or is going through evolution like biological being on earth?