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    Habitable Super Earths? Three Candidates Found
    By News Staff | April 18th 2013 03:15 PM | 16 comments | Print | E-mail | Track Comments
    The Kepler mission revealed the existence of potentially habitable planets slightly bigger than Earth. 

    The spacecraft named for Johannes Kepler was launched in 2009 and now it has found two new planetary systems, Kepler-62 and Kepler-69, about 1,200 light years from Earth that include three super-Earth-size planets in the "habitable zone," the range of distance from a star where the surface temperature of an orbiting planet might be suitable for liquid water. 

    The Kepler-62 system has five planets; 62b, 62c, 62d, 62e and 62f. The Kepler-69 system has two planets; 69b and 69c. Kepler-62e, 62f and 69c are the super-Earth-sized planets.

    Two of the newly discovered planets orbit a star smaller and cooler than the sun. Kepler-62f is only 40 percent larger than Earth, making it the exoplanet closest to the size of our planet known in the habitable zone of another star. Kepler-62f is likely to have a rocky composition. Kepler-62e, orbits on the inner edge of the habitable zone and is roughly 60 percent larger than Earth.

    The third planet, Kepler-69c, is 70 percent larger than the size of Earth, and orbits in the habitable zone of a star similar to our sun. Astronomers are uncertain about the composition of Kepler-69c, but its orbit of 242 days around a sun-like star resembles that of our neighboring planet Venus.

    Don't get too excited about a real life Mass Effect adventure just yet. There is no way to know if potentially habitable means habitable much less inhabited.

    Star Kepler-62 is not Sun-like: it is 2/3rds the size of the Sun, cooler, older, and only 1/5 as bright. Planet Kepler-62f, 40% larger than Earth, the smallest known habitable zone exoplanet, orbits every 267 days. Planet Kepler-62e, about 60% larger than Earth, orbits every 122 days in the the habitable zone's inner edge. Kepler-62b, Kepler-62c and Kepler-62d, orbit every 5, 12, and 18 days, respectively, making them very hot and inhospitable for life as we know it.

    Two are larger than Earth and one is about the size of Mars.


    Left to right: Kepler-22b, Kepler-69c, Kepler-62e, Kepler-62f, and Earth (except for Earth, these are artists' renditions). Image credit: NASA Ames/JPL-Caltech.

    Star Kepler-69 is a sun-like star (G-type, 93% the size of the Sun, 80% as luminous, about 2,700 light-years from Earth). Planet Kepler-69c is 70% larger than Earth, the smallest yet found in the habitable zone of a sun-like star. It orbits in 242 days, resembling the orbit of Venus. Planet Kepler-69b is just over twice the size of Earth and, orbiting every 13 days, is toasty hot, not even close to the habitable zone.

    The Kepler space telescope, which simultaneously and continuously measures the brightness of more than 150,000 stars, is NASA's first mission capable of detecting Earth-size planets around stars like our sun. Orbiting its star every 122 days, Kepler-62e was the first of these habitable zone planets identified. Kepler-62f, with an orbital period of 267 days, was later found by Eric Agol, associate professor of astronomy at the University of Washington and co-author of a paper on the discoveries published in the journal Science.

    The size of Kepler-62f is now measured, but its mass and composition are not. However, based on previous studies of rocky exoplanets similar in size, scientists are able to estimate its mass by association.

    Kepler 62 system
    Kepler-62, a five-planet system about 1,200 light-years from Earth.  Image credit: NASA Ames/JPL-Caltech

    "The detection and confirmation of planets is an enormously collaborative effort of talent and resources, and requires expertise from across the scientific community to produce these tremendous results," said William Borucki, Kepler science principal investigator at NASA's Ames Research Center at Moffett Field, Calif., and lead author of the Kepler-62 system paper in Science. "Kepler has brought a resurgence of astronomical discoveries and we are making excellent progress toward determining if planets like ours are the exception or the rule."

    The two habitable zone worlds orbiting Kepler-62 have three companions in orbits closer to their star, two larger than the size of Earth and one about the size of Mars. Kepler-62b, Kepler-62c and Kepler-62d, orbit every five, 12, and 18 days, respectively, making them very hot and inhospitable for life as we know it.

    The five planets of the Kepler-62 system orbit a star classified as a K2 dwarf, measuring just two-thirds the size of the sun and only one-fifth as bright. At seven billion years old, the star is somewhat older than the sun. It is about 1,200 light-years from Earth in the constellation Lyra.

    A companion to Kepler-69c, known as Kepler-69b, is more than twice the size of Earth and whizzes around its star every 13 days. The Kepler-69 planets' host star belongs to the same class as our sun, called G-type. It is 93 percent the size of the sun and 80 percent as luminous and is located approximately 2,700 light-years from Earth in the constellation Cygnus.



    "We only know of one star that hosts a planet with life, the sun. Finding a planet in the habitable zone around a star like our sun is a significant milestone toward finding truly Earth-like planets," said Thomas Barclay, Kepler scientist at the Bay Area Environmental Research Institute in Sonoma, Calif., and lead author of the Kepler-69 system discovery published in the Astrophysical Journal.

    When a planet candidate transits, or passes in front of the star from the spacecraft's vantage point, a percentage of light from the star is blocked. The resulting dip in the brightness of the starlight reveals the transiting planet's size relative to its star. Using the transit method, Kepler has detected 2,740 candidates. Using various analysis techniques, ground telescopes and other space assets, 122 planets have been confirmed.

    Early in the mission, the Kepler telescope primarily found large, gaseous giants in very close orbits of their stars. Known as "hot Jupiters," these are easier to detect due to their size and very short orbital periods. Earth would take three years to accomplish the three transits required to be accepted as a planet candidate. As Kepler continues to observe, transit signals of habitable zone planets the size of Earth orbiting stars like the sun will begin to emerge.

    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.

    A few months ago, citizen scientists found PH1b (Kepler uses the name Kepler-64b), their first confirmed exoplanet discovery. The arXiv paper showed 6.18 Earth radii planet orbits outside the 20-day orbit of an eclipsing binary consisting of an F dwarf ( 1.734 x the Radius of the Sun) and M dwarf ( 0.378 x the Radius of the Sun). For the planet, they found an upper mass limit of 169 Earth masses (0.531 Jupiter masses) at the 99.7% confidence level.

    Comments

    MikeCrow
    So, let's just presume Gray's exist, what sort of planet would we be looking for?

    Based on physiology, it would probably be a slightly less massive planet, and based on their eyes maybe a cooler star, like a red dwarf where they see well in IR.
    So, we'd be looking for a smallish planet a bit closer to a red dwarf, and probably close by. But iirc, there are a lot of red and brown dwarfs in the local neighborhood.
    Never is a long time.
    Gerhard Adam
    So, let's just presume Gray's exist, what sort of planet would we be looking for?
    Now you're scaring me, Mike.
    Mundus vult decipi
    MikeCrow
    I realize it's not science, but exoplanets weren't science not too long ago.

    I see no good reason to discount complex lifeforms on other planets, with all the trillions of planets we now estimate exist.
    I'm also not convinced we're the be all end all authority on interstellar travel.
    There are some very compelling eye witness UFO reports, I know it's not "science", it's speculation.

    But as speculation, IF Gray's exist, what sort of planet would they come from?
    Never is a long time.
    Gerhard Adam
    Oh I understand.  I just find "compelling eye witness" to be a contradiction in terms.

    I don't mind the speculation.  What I find fascinating is how one can examine people's speculations and observe how readily they integrate all manner of irrational ideas to support their beliefs. 
    Mundus vult decipi
    MikeCrow
    So, if you got on here, and said you saw something, something that just doesn't fit in the bucket we call real (whether a UFO that clearly was beyond what could be defined as in the ability of humanity, or something supernatural), I would call you a credible eye witness.

    Put yourself in that place, you saw something that is beyond science, how would you wrap your mind around that? How would you convince someone like you what you saw that didn't have a scientific explanation, was real?

    I've never been there, and I suspect many of the people who have those claims are wrong for a various reasons, but I'm not ready to put 100% of all such events in that category.
    Never is a long time.
    Gerhard Adam
    The problem is that we already know that eyewitnesses are notoriously unreliable for things that already have a scientific basis.  Things that we already know are "real".

    When something is unidentified, our brains are only too willing to fill in the gaps, especially within the context of our own belief systems, and depending on the circumstances [i.e. how short was the interval] we may actually "invent" some of the things we think we see.

    As a result, I'm still of the mind that unidentified means exactly that.  There is nothing beyond that.

    Speculation attempts to identify [with even less data] what has already been established as being unidentified.

    Hence I find the contradiction regarding "credible eye-witnesses".

    ==========================

    More importantly, when it comes to UFO's the problem is that we already know that our governments work on numerous secret projects involving aircraft.  So, if I were going to speculate on something in the sky that was unidentified, which makes more sense?  Something secretive from our government/military, or some alien species traveling light years distance  ... avoiding contact ... avoiding detection by scientific means, but too incompetent to avoid being seen in a cornfield?
    Mundus vult decipi
    MikeCrow
    You're rationalizing :)
    Jal 1628, a craft that was much larger than a 747, in close proximity, nothing like it humans have ever built, detected on radar.
    Craft over English Channel.
    Astronaut Gordon Cooper.

    So, back to my question, what would you do if you saw something what was not explainable as you describe above.
    Never is a long time.
    Gerhard Adam
    Speculation is not identification.  Cite as many incidences as you like, but until "unidentified" becomes "identified" you got nothing.
    Mundus vult decipi
    MikeCrow
    I think you have a credible eye witness. And you keep dodging my question.

    What qualifies as identification? It will likely not pass as "science", I know of no experiment that will get a UFO to show up on demand. I think it was a Major who put his hand on the ship in Rendlesham Forest, there was at minimum another person there, and the description of it's flight was not anything that is know to the public, even now. And I think there were some imprints in the ground.
    Other than putting it on display in public, what more is required to at least be possible?

    Now, I am playing advocate, as I said 4 or 5 posts ago I'm not ready to dismiss all of them, but I personally have no evidence.
    Never is a long time.
    Gerhard Adam
    Well, that's my point.  What evidence?

    So, if we put something on display, then the question is ... what has been ascertained from it?  Descriptions of flight are not the same thing as demonstrating that such is possible.

    Unfortunately, it's like anything else.  Lack of evidence is still lack of evidence.  I don't care if it's UFO's, ESP, or the Higgs.  So, you can claim someone is as credible as you like, but in the absence of evidence, their story is simply unknown or suspect. 

    People love to invoke astronauts or pilots or military, etc.  What supposedly makes them exempt from the same illusions as others?  What makes them any less susceptible to strange beliefs?

    You and I have both seen plenty of whack-a-doodles on this site alone with PhD's.  So, now ... define credible?
    Mundus vult decipi
    MikeCrow
    That's why I keep asking how you'd reach if you saw something that you know really happened, and doesn't fit in the human or natural box :)
    Never is a long time.
    Gerhard Adam
    Well, let's assume that it was something that made a significant impression, since anything less, I would probably tend to ignore.

    If it doesn't fit into the "natural box", then clearly I'm mistaken.  I already know that can happen with regularity.  All you have to do is watch Chris Angel to recognize that we are readily fooled into seeing things that aren't "natural".

    As for it appearing to be something beyond humans ... well, that's a bit more problematic, because again, we tend to make assumptions about what is possible that we clearly don't know.  For example, let's assume that I saw something flying making movements that if true, would be beyond the ability for a pilot to handle [i.e. too many G forces].  Why would I conclude that the object had to be manned?  Again, this is setting an assumption and then marveling at the contradiction.

    The fact remains, that if we don't know what something is, then we don't know what it is.  Speculation is simply trying to rationalize something for which we lack the necessary information to formulate a more reasonable explanation.

    Once speculation starts, then all the justifications and "what if" games begin and then, of course, everything becomes possible.
    Mundus vult decipi
    Thor Russell
    You have a point. Now I don't believe aliens have visited earth, and the point about them having to be pretty silly or screwed up is a good one, however calling alien visits "beyond science" is not justified. There has to be some threshold where if most people see something obviously beyond our tech then it has to be taken into account. Calling the possibility of more advanced lifeforms visiting "anti-science" is nonsense. In principle it certainly isn't, however in practice as I said I find other explanations more likely.
    Thor Russell
    Gerhard Adam
    But who claimed it was "anti-science"?  Science requires evidence, so without it, you can call it what you like, but it isn't science.

    Regardless of how reasonable, or how justifiable, or how much rationalizing anyone does ... lack of evidence is still lack of evidence.  Everything is simply speculative then.

    That doesn't mean that evidence may not be acquired at some point, and if so, then there's no problem in investigating and hypothesizing what may be occurring.  However, we can't get ahead of ourselves.  Being open minded is one thing, but without any evidence, there's nothing to be open minded about.  Speculation is little more than opinion.  It may be fun, but it ain't science.
    Mundus vult decipi
    MikeCrow
    But that was actually my point, we're finding planets now, if we presume gray's do exist, where would we look for them, maybe if we start looking, we'd find evidence of life on plants that fit the sort of planet they if they even exist might live on.
    Never is a long time.
    MikeCrow
    Hell, after reading some of the stuff Sascha has written on reality, I'm not even sure I know how to begin to process it, but I believe it to be scientific. I had my son google wheeler spooky action, and he found Wheelers delayed choice experiment, and he was like, 'no', he got that it alters reality.
    Never is a long time.