Slashdot Mirror

← Back to Stories (view on slashdot.org)

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!"

12 of 333 comments (clear)

  1. Gas giants in the wrong orbits... by BattleWolf · · Score: 2, Informative
    As I understood the article, the gravitational pull of the gas giants that can be seen from earth can "pull" smaller (sofar invisible earth-sized) bodies out of this region if they are in the "wrong" area.

    Depending how you look at it (glass half full/empty) it turns out that the giants are in the wrong spot three out of four times...

  2. Re:Huh? by imnoteddy · · Score: 3, Informative

    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?

    From the article:
    The first thing they looked for in each system was whether a small terrestrial planet could exist in a stable orbit. The gravitational tugs exerted by gas giants can force smaller planets into unstable orbits or eject them from a system altogether.

    So the requirement is that there be a stable orbit within the distance range where water would be liquid.

    --
    No electrons were harmed creating this post, though some may have been subjected to electrical and/or magnetic fields.
  3. 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.
  4. Rare Earth by Anonymous Coward · · Score: 1, Informative
    Peter Ward and Donald Brownlee have written a book titled Rare Earth. They cogently argue that while simple, microbial life may be common, complex life is rare. Their argument is based on enumerating myriad physical properties that the Earth enjoys but are probably missing from most of the Universe. They admit in the preface that
    [i]t is very difficult to do statistics with an N of 1. But in our defense, we have staked out a position rarely articulated but increasingly accepted by many astrobiologists.
    However, their argument is convincing and succeeds in going against that old idea of Copernicus. The Earth really is special.
  5. 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.
  6. The Fermi Paradox by dexter+riley · · Score: 3, Informative

    i.e. If there are aliens, why the heck haven't they colonized the earth by now?

    Here's a link.

    But do fleas wonder if there is life on other dogs?

  7. Re:Rolling the dice by cornjchob · · Score: 4, Informative

    Oxygen and water? Again, people are assuming that earth's atmosphere and other conditions need to be recreated to sustain any life--bullshit, honey. remember, oxygen is a corrosive gas. And many organisms even here survive fine without it; even without water. Once and for all, this paradigm of everything having to be like us needs to be blown out of our systems like an explosive kidney stone. Think outside the box, or don't think at all.

    Didn't mean to tear ya up if it came across that way; I just get frustrated very easily.

    --
    We now have confirmed reports from an informed Orange County minister that Ethel is still an active communist.
  8. Link to Original Paper by Alien54 · · Score: 4, Informative
    Here is the link to the Original Paper:

    http://arxiv.org/abs/astro-ph/0210006

    Note that you can download the full original in PDF, Postscript, or other scientific formats. The PDF is about a half meg in size. and is about 38 pages long.

    --
    "It is a greater offense to steal men's labor, than their clothes"
  9. Re:But... by airuck · · Score: 4, Informative

    For an example of a very large prehistoric insect and some discussion of fluctuations in the Earth's oxygen levels see Meganeura monyi and:

    Dudley, R. 1998, Atmospheric oxygen, giant Paleozoic insects and the evolution of aerial locomotor performance. Journal of Experimental Biology. 201: 1043-1050.

    Graham, J.B., Dudley, R., Aguilar, N.M., and Gans, C. 1995, Implications of the late Paleozoic oxygen pulse for physiology and evolution. Nature. 375: 117-120.

    --
    First entomology, then virology, and finally bioinformatics systems. Bugs follow me wherever I go.
  10. Re:But... by Anonymous Coward · · Score: 1, Informative

    "Half of these planets won't have oxygen"...

    Do you realize that you have actually just made an argument for the presence of simple lifeforms?

    The massive quantities of oxygen in the earth's atmosphere are a direct result of early plant life's synthesis of sunlight, water and CO2 into sugars, starches and the byproduct Oxygen. The massive presence of Oxygen in an atmosphere would almost certainly imply the presence of rudementary lifeforms involved in some form of photosynthesis. Oxygen is inherantly reactive, corrosive and rather unstable.

  11. 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.

  12. Too bad there's not more technical details... by shimmin · · Score: 3, Informative
    ... because what constitutes a "stable" orbit is a matter of some debate.

    You only need to play around with an orbital mechanics simulator like the one here a little bit to convince yourself that the long-term stability of an orbital system with more than 2 elements is a rather chaotic matter.

    So I'm curious how long they deemed an orbit had to stay within what boundaries to deem it "stable." For example, for our own system, it appears that most of the planets are likely to remain close to their present orbits until the Sun goes red giant, but Pluto's orbit is difficult to predict past about 3 billion years or so, according to some simulations.