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Earth Space Science

Odds Favor Discovery of Earth-Like Exoplanet in 2013 90

Earth-like exoplanets have gotten a lot of attention in the last few years; it's exciting to think that there's life — or even just life-sustaining conditions — on planets other than Earth, whether near by (on Mars) or much farther away (orbiting Vega). Projects like NASA's Kepler, and the ground-based HARPS, attempt to spot planets outside our solar system of all kinds. These exoplanet discoveries have been ramping up lately, and so has sorting of the discovered planets by size and other characteristics; the odds are looking good, say astronomers quoted by Space.com, that an Earth-like planet will be found this year. Abel Mendez runs the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo, and UC Berkeley astromer Geoff Marcy looks for planets as part of the Kepler team; they explain in the article why they think 2013 is an auspicious one for planet hunters.
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Odds Favor Discovery of Earth-Like Exoplanet in 2013

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  • since we can see farther and clearer than ever before, it's kinda likely that if there's a habitable world out there, we're more likely than ever to find it.

    Meanwhile, in other news, farmers announce that if it's not to dry, not to wet, and just the right temperatures, they could harvest bumper crops this year.

    Please stand by while we compile a more complete list of inane almost predictions.

    • by IrquiM ( 471313 )
      Everyday, we're one step closer to finding it!
    • by gopla ( 597381 )

      It is not like farmers predictions. The progress we have been making is quite impressive, as there are 800 know exoplanets by now, and more are getting discovered.

      Scientific discoveries come in batches. There is nothing for a long time, then suddenly the lull ends and a breakthrough is achieved. Lot of similar discoveries occur simultaneously. This prediction is from people who know their stuff. Even though they may not come true this year it is still good prediction.

      • by cnettel ( 836611 )
        For Kepler among others, time itself is of the essence. To get a sure signal, they need several occlusion events (in the plane towards us). If a planet has a long orbital period (year-like), it will take a few... years before a really strong signal of several repeated events is recorded.
    • One more inane prediction then: Humanity will die out in the near scale at geological time.

      If malice isn't enough to describe the outcome, revert to stupidity

  • Is the year of linux on the desktop!
    Has a high likelihood of finding earth-like planets!
    We'll be able to 3D print an entire car! ...all predictions that are made every year. What other predictions are we going to repeat?

  • by gr8_phk ( 621180 ) on Sunday December 30, 2012 @10:19AM (#42425871)
    Sure they'll find one. But being the correct distance from a given star doesn't really make it earth-like. Seriously, Mars qualifies as earth-like but it doesn't seem to have life even though the planet next to it does.
    • I think many people don't understand how tilted the odds are against life.
      It's likely that we would need to search billions of "earth like" planets to find one that had any life potential, let alone one where that potential has given rise to complex organisms.

      • by dkleinsc ( 563838 ) on Sunday December 30, 2012 @12:39PM (#42426457) Homepage

        Actually, we have no idea how tilted the odds are against life. What we do know:
        - On the conditions that existed on Earth in its early history, forming organic compounds was more-or-less inevitable.
        - Life exists on Earth under really unusual conditions, like highly acidic underground lakes.
        - There's some evidence (but no conclusive proof) of there once having been microbes on Mars.

        It's quite possible life is rare. It's also quite possible life is common. We simply have no way of knowing one way or the other right now.

    • by Anonymous Coward

      A planet can be Earth-like in many aspects. It can have an Earth-like orbit, an Earth-like mass, an Earth-like atmosphere, an Earth-like composition, an Earth-like biosphere, etc. Right now, we can only "easily" measure the two first, so those are the aspects of Earth-like we usually refer to. We can try to look for closer resemblances after we have some rough resemblances to start from. This is a field of science which is only 17 years old.

      • In fairness having an Earth-like atmosphere is probably a pretty good indicator of life more-or-less as we know it. Free oxygen is highly reactive and unlikely to be present in large quantities in an atmosphere unless something is continuously producing it. And as far as I know photosynthesis is the only known process that would continue producing free oxygen for hundreds of millions of years, any more transient process would be vanishingly unlikely to be happening just as we happen to look.

    • by rossdee ( 243626 )

      Mars may have had life once, it seems to have had liquid water, but it wasn't big enough to keep a decent atmosphere, and was on the outer edge of the habitable zone. Venus could have supported life, but it had a runaway greenhouse effect.
      Of the two rocks that orbit between those to edges of the habitable zone, one is way too small to have an atmosphere ever,, so we are down to one habitable planet in this system. (It clearly supports life, though whether there is any intelligence is not certain (a sample o

      • by grumling ( 94709 )

        Isn't the reason Mars doesn't have much of an atmosphere because it doesn't have a magnetic field to deflect solar wind?

        http://science.nasa.gov/science-news/science-at-nasa/2001/ast31jan_1/ [nasa.gov]

        • Re:Poor definitions (Score:5, Interesting)

          by Immerman ( 2627577 ) on Sunday December 30, 2012 @01:12PM (#42426643)

          That is probably the larger contributor, but even without the solar wind it's atmosphere would likely be much thinner - it only has ~1/3 the surface gravity, and it falls off much faster with altitude. It's smaller size probably also contributed significantly to faster cooling and the associated shut-down of its magnetic dynamo subsequent exposure to the solar-wind. Evidence suggests that Mars did in fact once have a substantial magnetic field. Getting a massive chunk of (presumably) cold material embedded in it's mantle probably didn't help things either - Olympus Mons appears to be the result of the shockwave from a truly massive impact on the opposite side of the planet. Lets all thank Mars for taking the bullet for us, it would've made "the dinosaur killer" look like a pea-shooter in comparison.

        • by redmund ( 955596 )
          If I remember rightly, it doesn't have a magnetic field because it was too small to keep its core active, and it has mostly solidified. At least that was the speculation at the time I heard this.
          • Plate tectonics also play a role. Atmosphere gets fixated and precipitated by various geo/biological processes. We wouldn't have much atmosphere either if the Earth's crust weren't getting constantly recycled. Still, the ultimate cause is the same; Mars's core is not active enough.

    • Mars is not earth-like enough to support life. It can't even hang onto an atmosphere; IIRC its atmosphere is about 1/100 as dense as ours. It has no magnetosphere to protect it from solar winds. It's also a bit too small, and only has 1/3 of earth's gravity (which may be another reason it can't hold its atmosphere). Maybe Mars had life at one point, but it's a dead, barren world now.

    • by jonadab ( 583620 )
      I think if I year the phrase "earth-like planet" one more time, I'm probably going to vomit. It's been overused so much that it has lost all meaning. It's like, hey, yeah, this planet is more massive than Jupiter, or it's closer to its primary than Mercury, or the star is eleven times hotter than the sun, or the planet has no atmosphere to speak of, or it rotates on its axis three three times an hour, or maybe several of those things, plus as far as we know it hasn't got a moon or any significant amount o
  • by JustOK ( 667959 )

    What do the evens favor?

  • Human civilization is only a few thousand years old, and we have a few million to sort stuff out (barring any major disasters). We may never need warp drive to explore the universe, developing generation ships or becoming immortal cyborgs so the travel time is not an issue.
    • by Nyder ( 754090 )

      Human civilization is only a few thousand years old, and we have a few million to sort stuff out (barring any major disasters). We may never need warp drive to explore the universe, developing generation ships or becoming immortal cyborgs so the travel time is not an issue.

      Human civilization is over 100 thousand years old, recorded history is only like 4k or so old.

      • by C0R1D4N ( 970153 )
        The human species and what most people refer to as civilization are very different things. This is semantics though.
      • Modern humans have existed for around 50-200 thousand years depending on how specific you wish to get. Human civilization is around 15 thousand years. My personal favourite statistic is the estimated 7% of all humans that have ever existed are alive today!
  • From what I understand of the process, astronomers measure the drop in light as a planet passes between a star and us to determine its size and distance from said star. So what happens in the case of an Earth like planet with an advanced civilization [adafruit.com], or perhaps if there is a lot of volcanic activity? Wouldn't that alter the expected result, and screw up their calculations?

    • Learn some science.

      Neither volcanoes nor streetlights put out .01% as much light as the sun.

      • Learn some science.

        Neither volcanoes nor streetlights put out .01% as much light as the sun.

        Which according to your comment would mean that the light difference is only 20dB down in power from the starlight.
        Additionally, the planet's light spectra would be different than the light spectra of the star.
        Combine these two facts and I believe his question still stands even if he doesn't "know science".
        Would the sensor be able to detect the difference?
        If background noise at the telescope is at -120dBm (or less with cooling), then is it possible to detect a difference at a specific frequency?

      • Re:Earth-like lights (Score:5, Interesting)

        by grumling ( 94709 ) on Sunday December 30, 2012 @02:25PM (#42427133) Homepage

        I'm trying to, asshole. Why do you think I'm asking a question?

        • Re: (Score:3, Insightful)

          by meetpi ( 2776369 )

          There are actually a few ways that planets are detected. The dimming of the star as a planet passes in front of it is one method. This only works if the planet passes exactly between us and the star while we're looking. This can only happen is the planetary system is aligned the right way (more or less side-on) to us. It also tends to favour detecting larger planets with fast orbits (an alien looking at our solar system would have to wait one year to see the Earth pass the sun twice, and decades for som

    • Outdated technique (Score:5, Informative)

      by Immerman ( 2627577 ) on Sunday December 30, 2012 @01:41PM (#42426827)

      Not really - the atmosphere is an incredibly thin skin around a rocky planet and it's composition can only be detected by the use of *extremely* sensitive instruments. Imagine passing a pea in front of a street light several miles away - it'll be *far* easier to detect the shadow of the pea than the condition of its skin.

      And actually that's a rather obsolete method for detecting planets - you can only detect those whose orbital plane happens to intersect the Earth - a tiny percentage since the alignment is more or less random. More modern techniques detect planets via the wobble they introduce in the motion of their parent star - for example our sun actually orbits a point lying about 1/2 to 2 solar radii away from its center - the barycenter (center of mass) of our solar system, which constantly changes as the massive outer planets move through their orbits. Our own planet introduces a much smaller (since we're far closer and less massive) but higher frequency (since our year is much, much shorter) wobble as well. By detecting similar wobbles in other stars we can make a good estimate about the masses and distances of its planets, and the planet doesn't have to pass directly between its star and us to be detected, allowing us to detect far more planets.

      Analyzing atmospheric composition is more challenging, and I believe current techniques are limited to planets that pass directly between us and their star - essentially a planet with no atmosphere will dim the light slightly as it blocks a tiny percentage of it, an atmosphere will also introduce a *very* tiny spectral shift since some of the starlight that reaches us will have passed through the planet's atmosphere and been partially absorbed based on it's chemical composition. Theoretically a similar technique could be used for out-of-plane planets by analyzing reflected light, but our current instruments aren't nearly sensitive enough to distinguish between the miniscule amount of light reflected from a planet and the raging inferno of its star. Even if we could, it would likely be extremely difficult to distinguish between the spectrum shift introduced by the atmosphere and the shift introduced from surface reflection.

    • It doesn't make much of a difference to Kepler.

      Kepler measures the light level over time, and uses the amount of obstructed time to make most of it's calculations. It does also use the total light output difference to determine the size of the planet (really the ratio of the size of the planet to the size of the star) - but the error bars are pretty big anyway, way more than the total light output of dark side of the Earth.

      The only way that Kepler would miss the planet all together was if the alien civiliz

    • by Anonymous Coward

      I think the neatest thing to do (if an extrasolar planet can be resolved enough) is to get a spectrograph of that planet's atmosphere if and when it happens to pass in front of it's star.

      If there's lots of free oxygen, you've got plant life or something very much akin to it. Not much in nature produces reactive oxygen like that other than photosynthesis. Otherwise that oxygen would be tied up in carbon dioxide or some other chemicals. Of course the plant life producing all that oxygen could all be microbial

  • by Hazelfield ( 1557317 ) on Sunday December 30, 2012 @05:14PM (#42428039)
    What I think is so cool about these discoveries is, in the words of astronomer Steve Vogt, "the emerging view that virtually every star has planets". Think about this for a while. Look at all the stars in the sky, and imagine every single one of them having a planetary system. Suddenly it doesn't seem to much of a stretch thinking some of them might be habitable, or even harbour some kind of life.

    In my eyes this fact, if it gets confirmed by subsequent studies, is the biggest discovery about the universe since the theory of relativity. When I grew up I was taught there were 9 planets in orbit around the sun, and the existence of (or at least abundance of) exoplanets where largely speculative, with the first observations just being confirmed during the 90's. When my kids grow up they'll be taught there are thousands of exoplanets in our very vicinity and millions in the galaxy. And there are free-floating bodies as well, rouge planets that are not gravitationally bound to a star! How cool isn't that? To top it all, we will soon have instruments sensitive enough to measure the very spectrum of an exoplanet atmosphere and look for biosignatures. If it finds free oxygen and methane, that's a very strong indication of life as we know it. (Since oxygen is highly reactive, it tends to show up in compounds such as carbon or silicon dioxide. Biologic activity is one possible supply of free oxygen.) The search for extra-terrestrial life, long belonging to the realm of science fiction, has turned to a serious and highly active field of research in just a few years.
    • by Anonymous Coward

      I think if a habitable planet is found with strong indications of life and is within 10 or so light years this will capture the public imagination. It should give impetus for projects to develop an interstellar probe in the next century or so. So would a break through in fusion power which might propel the probe.

    • What I think is so cool about these discoveries is, in the words of astronomer Steve Vogt, "the emerging view that virtually every star has planets". Think about this for a while. Look at all the stars in the sky, and imagine every single one of them having a planetary system. Suddenly it doesn't seem to much of a stretch thinking some of them might be habitable, or even harbour some kind of life.

      Odd. Even as a kid, I always thought there were LOTS of other planets out there. If this insignificant star has 9 planets (8 now, classifications change), then surely other star systems must have at _least_ one other planet. I would be pretty surprised to find a star with a thousand planets, but anywhere from one to twenty (roughly) planets should be incredibly common.

  • If really can come true, it will have exciting things. Find the use of the planet, it will reduce the pressure of the earth.

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