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Habitable Planets May Be Common

Posted by Hemos on from the maybe-counter-earth-exists dept.

swight1701 writes "New Scientist tells us, "one in four of the planetary systems identified to date outside the Solar System are capable of harbouring other Earths, say astrophysicists, a much higher proportion than anyone expected." Two seperate groups have come up with results that line up with each other, the latest one using simulations of 85 systems. Warm up the warp engines, time to go planet hopping!"

16 of 333 comments (clear)

  1. But... by unterderbrucke · · Score: 5, Insightful

    "one in four of the planetary systems identified to date outside the Solar System are capable of harbouring other Earths"

    The operable word here is capable.
    Half of these planets won't have oxygen, another 49.9% will be too cold.
    This study is referring to the distance of the star to the planet being far enough that the sun doesn't fry the planet.

    1. Re:But... by chill · · Score: 5, Informative

      "This study is referring to the distance of the star to the planet being far enough that the sun doesn't fry the planet."

      Actually, it referrs to a bit more than that...

      It referrs to the ability of an Earth-sized planet to exist in a stable "habitable zone" orbit (not too hot, not too cold).

      Not being torn apart or having a perturbed orbit due to the proximity of gas giants, etc. is another big factor.

      However, it isn't exactly time to start looking for a nice time-share condo on Ceta Alpha V, yet.

      --
      Learning HOW to think is more important than learning WHAT to think.
    2. Re:But... by panurge · · Score: 5, Informative
      Sorry, but the Earth didn't have much oxygen until life started producing it. That's the history of life: it changes the planet to suit itself.

      We do it, but even bacteria do it too. As plants have reduced the amount of carbon dioxide in the atmosphere, different dominant plant families have arisen able to survive in the low-CO2 environment. Insects were big at one time because there was more oxygen in the atmosphere, now the species are smaller because there is less. The idea that life requires 0-35C, 20% oxygen, is based on a static view of the world which, as our genetics lecturer once remarked "Unfortunately for some religious groups does not accord with any of the evidence."

      --
      Panurge has posted for the last time. Thanks for the positive moderations.
  2. They say habitable... by doobie · · Score: 5, Interesting

    They say their are habitable for life...why do we always assume every life form will be exactly like us and need our environment to thirve? For some other form of life they may thrive on Venus or Jupiter.

    1. Re:They say habitable... by th1nk · · Score: 5, Insightful

      They say their are habitable for life...why do we always assume every life form will be exactly like us and need our environment to thirve?

      Up to this point in the history of our world, certain things are required for all life as WE know it. If we're searching for life on other planets, wouldn't that be a good place to start?
    2. Re:They say habitable... by Waffle+Iron · · Score: 5, Funny
      They say their are habitable for life...why do we always assume every life form will be exactly like us and need our environment to thirve?

      Nobody's saying they are exactly like us. In fact, on average they have larger breasts, greener skin, heavier mascera, and wear shorter miniskirts.

  3. Huh? by Quixote · · Score: 5, Interesting
    Quoting the article:
    The researchers found that around a quarter of the systems contained regions where life-friendly planets could in principle exist.

    If the requirement is that there be a "region" around the star where a planet could have water in liquid state all-year-round, wouldn't almost every star satisfy this? Every heat source has a distance at which it feels "nice" (as anyone who's been at a campfire can attest to).
    Maybe I'm missing something here (which has been known to happen :-)

  4. In other news.... by karlm · · Score: 5, Funny

    The Raelians have announced their first colonizing ship full of expectant clone mothers is due to arrive in the nearest system in question sometime next month.

    --
    Copyright Violation:"theft, piracy"::Anti-Trust Violation:"thermonuclear price terrorism"<-Overly dramatic language.
  5. intelligent life in the universe by cschieke · · Score: 5, Interesting

    I took a college course called "Intelligent life in the universe" (god I loved college). Where we learned basically:

    1. What we know it takes to support life
    2. What living objects are typically made of (carbon based compounds)
    3. What percentage of stars have planets around them, what percentage of those planets are the proper distance away from the star the orbit (which changes based on the size of the star)
    4. a bunch of biology, and some other related stuff

    It boiled down to the idea that the universe is soo huge that IF we're the only intelligent life in the universe, that there must some type of "god" and if we're not, well then the evolutionary theories are probably fundamentally correct (doesn't mean there isn't "god", but not in the literal old testament sense).

    see, no real hard conclusiions only questions, cause there is always another level deeper to go.

  6. Scientists by CatWrangler · · Score: 5, Interesting

    First they tell us the earth ain't flat, then the Universe doesn't resolve around our planet... then the fake moon landings, now this. Good thing we have fundamentalists around telling us it isn't so. Seriously, unless there is a nature of physical or sound travel that we are unaware of, it really doesn't matter much to us that much if there is a civilization 1000 light years away. In the 2,000 years it would take to get a super amplified light message to them and back, will we still be around to listen?

    --

    ---
    When you come to a fork in the road, take it! --Yogi Berra--

  7. Mathematics by Dexter77 · · Score: 5, Interesting

    A theory I once heard:

    Universe is about 15 000 000 000 years old. If habitable planets are common then there has to be much older races than we are. Let's say that one of those races is capable of space traveling and it takes 1000 years for that race to spread from planet to another. If they were 1 000 000 years older than us then they would've spread around the universe to 2^1000 planets. Even if it took 10 000 years to populate a planet after reaching one, they would have populated 2^100 planets. Now think about a race that would've been around for a 1 000 000 000 years. They should've populated every habitable planet in the universe.

    I can't remember the name of this theory, but please tell me if you do.

    1. Re:Mathematics by sunspot42 · · Score: 5, Interesting

      There are lots of reasons why we might not have detected alien civilizations (yet) - even if they're quite common throughout the universe - let alone seen any evidence of their colonization. I can briefly list a dozen reasons right off the top of my head:

      1) Gamma ray bursts. Until relatively recently in the history of our universe - perhaps up until 500 million years ago - radiation from gamma ray bursts (and supernovae, for that matter) was routinely sterilizing the surfaces of most planets within our galaxy and every other fair-sized galaxy. It took 4.5 billion years for intelligent life capable of interstellar communication and interplanetary travel to evolve here on our planet. Assuming a roughly similar evolutionary pace on other worlds, there might just now be a handful of intelligent species coming into being throughout this galaxy (and others, for that matter).

      2) We're the first civilization to evolve in our galaxy. Unlikely, but someone's gotta be it. Whether or not we could be the first depends in large part on how rare advanced life forms are in our galaxy - a question we may have the answer to within our lifetimes, thanks to advanced space telescopes like the Terrestrial Planet Finder and its successors. If it turns out life on terrestrial planets is exceedingly rare - on the order of only a few dozen planets in our galaxy - then we very well could be the first intelligent species to evolve.

      3) Intelligence is common. Civilization is less common. Technology is vanishingly rare. Remember, in order to colonize the galaxy - or even be detected by a project like SETI - you have to have more than intelligence. You even need more than civilization. SETI is really the search for extraterrestrial *technology*. Space colonization requires technology. For whatever reason, perhaps few intelligent lifeforms make the leap to civilization, and fewer still make the leap to a technological civilization.

      4) Technological civilizations invariably wipe themselves out, or are wiped out by natural processes before they can begin interstellar colonization. A sobering proposition, but certainly one that's supported by our own civilization's close encounters with destruction (the Black Plague, the Tunguska event, WWI, WWII, the Cuban Missile Crisis, Ebola, AIDS, terrorists with bioweapons . . .).

      5) The technology to engage in interstellar travel might be common, and technological civilizations might endure long enough to make such efforts practical. However, that same technology makes such expensive (and risky) undertakings unappealing. Why spend 50 years traveling to the nearest inhabitable planet? You might send out probes - or build larger telescopes - to observe other worlds, but you can simulate their environments and explore them from the comfort of your living room via virtual reality. If you could go on safari in your living room, would you sit in a cramped airplane seat for 20 hours flying to Africa?

      6) Technological civilizations eventually die not with a bang, but with a whimper. We see evidence of this happening already in Europe, where population growth comes only via immigrants. But what happens if the rest of the world reaches the technological and social advancement Europe has attained? Populations may begin to slowly decline worldwide. Without population pressure, there's no reason to colonize new territory here on Earth, let alone other planets. Indeed, you couldn't spare the human capital.

      7) Interstellar travel is impossible, for some currently unknown reason. Perhaps there are giant invisible particles between the stars - they could even be the source of that missing mass we hear so much about - that an unlucky spacecraft could slam into, instantly halting its journey to a nearby star. This is admittedly an unlikely proposition, but we'd be foolish to think we know everything about the feasibility of interstellar travel. Perhaps it's impossible regardless of your level of technological advancement - hence, no alien colonies scattered about the galaxy.

      8) They're already here. This could either take the form of X-Files-style shenanigans, or more benevolent intervention (think Gary Seven from that old Star Trek episode "Assignment: Earth"). Or perhaps only their probes are here, either so microscopic we don't detect them, or somehow disguised as ordinary objects (or creatures - this would go a long way towards explaining the behavior of housecats).

      9) They've all been wiped out by a malevolent alien über-civilization - one that could be on its way to eliminate us. Such villains are a sci-fi staple (War of the Worlds, Independence Day, The Borg), and one we've been foolish to so easily dismiss, especially in light of the silence that greets us from the heavens. There has to be some reason why alien technological civilizations are so rare, and this explanation is as valid as any other in light of the current evidence. Our radio broadcasts already reach out over 100 light-years, starting with the first primitive Morse Code transmissions from over a century ago. We've even deliberately (and foolishly) transmitted high power radio signals directly into space, in various attempts to announce our presence to interstellar listeners ("an open invitation to alien invasion" as the good Doctor on Britain's Doctor Who once wisely pegged it). How long we have before the day of reckoning depends on how close their nearest listening station is, and whether or not they've perfected a means of hyperlight travel. Assuming their nearest detector is 100 light years away, they've just become aware of our presence. Assuming they're limited to sublight travel, we've got another century before they - or some planet-busting weapon - arrives to deal with this latest disease outbreak in their galaxy.

      If you find this scenario unlikely, consider how you'd react to an anthill suddenly springing up in your living room.

      10) They're all hiding from possible über-civilizations (or each other). This certainly wouldn't be a stupid position to adopt, given the consequences of such an encounter. If you don't know what's out in the forest, you'd do well to keep quiet. And once you do know what's out there, you might have an even better reason to keep quiet. Technological civilizations might go completely underground, perhaps relocating themselves to an unspoiled nearby planet and burrowing deep beneath the surface in an effort to completely hide themselves from alien invaders - at least, until they feel they have the technology to resist any such invasion. Perhaps those gamma ray bursts aren't always natural phenomena at all - maybe they're sometimes the visible artifacts of colossal alien wars.

      11) Maybe they're all hiding from us. Perhaps there are no evil overlord über-civilizations. Maybe a federation of benevolent civilizations rules over our galaxy, perhaps after uniting to defeat less enlightened powers. Perhaps these enlightened powers possess the equivalent of Star Trek's Prime Directive, a strictly hands-off policy regarding lesser civilizations. We could dwell in a kind of interstellar game reserve, one that's off limits to alien intrusion. If so, we might never detect our superiors - at least, not for thousands of years, until we possess the technology to go out and meet them face-to-face. It's a comforting thought, but I wouldn't bet my life on it.

      12) Maybe they aren't deliberately hiding from us. Perhaps we're surrounded by interstellar homebodies, but just can't hear them because they don't use radio to communicate. For whatever reason - simulations, interstellar obstacles, declining populations - they don't travel or colonize (much), so we don't physically encounter them or their artifacts, and their communications technology either doesn't involve radio (maybe they use some form of quantum communications), or utilizes radio in a way that sounds like static to our receivers. Of course, you'd think they'd detect our signals and issue some kind of reply, but they'd have to be within about 50 light years in order for that to be possible. Perhaps there's simply nobody that nearby. Entirely possible, if alien civilizations don't travel much.

      Even if you assume there are thousands of technological alien civilizations in this galaxy, if they only communicated with our form of radio for 100 to 200 years of their existence, it's possible there's nobody using our form of radio at the moment anywhere in the galaxy apart from us. Meanwhile, the galaxy is so vast, even with thousands of civilizations there might not be anybody listening within 500 light years of the Earth.

      Anyhow, it's way too early to say why we haven't been contacted, let alone visited, by alien intelligences. We simply don't have enough evidence. Some of the possible explanations are certainly unsettling, though.

  8. Moon by tsa · · Score: 5, Interesting

    I wonder what life will look like on planets that don't have a moon like ours. The moon is very important in keeping the earth's axis ariented in the same position with regard to the sun. Without the moon, earth's axis could tilt so that one of the poles can be positioned towards the sun, thereby illuminating one side of the earth constantly while keeping the other side in the dark. If life can evolve on such a planet I would very much like to see what it looks like.

    --

    -- Cheers!

  9. Re:more ecosystems to destroy !!! by spike+hay · · Score: 5, Interesting

    Just because it's habitable doesn't mean it has life. Odds are it's just got an atmosphere with oxygen, and liquid water. The land would be bare rock. There's nothing there to destroy. Perhaps we could relocate humans to non-earth planets and preserve earth.

    Yeah, just because it's in the habitable zone doesn't mean it has life or is habitable to humans. Too little atmosphere would make it freeze like Mars (mars is in the goldilox zone) or a dense greenhouse gas rich atmosphere would make it bake like Venus. (Venus is in the habitable zone, also)

    Anyway, I think by the time we have the technology for manned missions to other stars, we won't be at all like today's biological humans. We'll probably be hyperintelligent machines or something more intangible. It's hard to grasp the difficulty of intersteller travel. The stars are so distant. But we'll have the technology someday. If we move fast enough, perhaps the first intersteller colony will be established in this century.

    --
    If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
  10. Re:more ecosystems to destroy !!! by Inexile2002 · · Score: 5, Informative

    The Oxygen in earths atmosphere came from the earliest living organisms. They metabolized CO2 and released waste Oxygen. Oxygen is too reactive to nature naturally in large quantities in an atmosphere. If we find Oxygenated worlds, we found life of some kind, and life that has been established for billions of years no less.

  11. The Catholic Church by dachshund · · Score: 5, Interesting
    Basically, I've never heard anything about the Catholic church disputing the idea of extinction or dinosaurs. Or are you just using that as a type of example?

    There was a great deal of contention prior to 1950, when the Church officially announced that it would tolerate its members believing in the Theory of Evolution. This ocurred when Pope Pius XII produced the papal encyclical entitled "Humani Generis". His statement said, essentially, that it was alright for Catholics to believe whatever scientific theory they wanted... then went on to stress that the Theory of Evolution was still unproven.

    The above poster may be referring to the much more recent (1996) statement by Pope John Paul II entitled "Truth cannot contradict Truth". In this document, the pope not only accepted the ToE as being in line with Catholic beliefs, but he stated that it was "more than a hypothesis". This was the first time that a Pope officially supported the ToE, rather than merely tolerating it.

    So it's more or less correct that the Church only officially got behind Evolution recently, though I don't know if it's accurate to say that they disputed the existence (and extinction) of the Dinosaurs.

    The same applies to fossils. If fossils found far far back didn't belong to deceased animals, then that means (to religious people) that God put them there (the bones). But then that contradicts the watchmaker theory. Why would God create essentially fraudulent records?

    It seems that the existence of fossils could be construed as incompatible with the Watchmaker theory anyway. Why would God, in the process of creating an intricately designed world, feel it necessary to create creatures (actually, entire ecosystems) that would ultimately be unable to survive?

    You could respond that God is ineffable, but that same logic pretty much works for the folks who think God created fake fossils and buried them in the ground. The point is, once you allow for the existence of God, rational arguments are pretty much always vulnerable to the divine wild-card.