Our Solar System: Rare Species In Cosmic Zoo 197
astroengine writes "Pulling from 20 years of research since the first discoveries of planets beyond our solar system, scientists have concluded that Earth and its sibling worlds comprise what appears to be a relatively rare breed in a diverse cosmic zoo that includes a huge variety of planet sizes, orbits and parent stars. The most common systems contain one or more planets one to three times bigger than Earth, all orbiting much closer to their parent stars than Earth circles the sun, says astronomer Andrew Howard, with the University of Hawaii."
Limitation of detection methods (Score:5, Insightful)
That's because the current methods used to detect exoplanets are biased towards large close in planets. As technology progresses we will get more diversity.
Could this maybe be because.... (Score:5, Insightful)
We're still really bad at detecting planets that are NOT bigger than Earth and orbiting much closer to their parent stars? Seriously, whether we use light occlusion or observing the star's wobble, this is the only type of planet we know how to detect.
Turns out if you're color blind, red and green are very rare and special colours.
Re:God made it. (Score:3, Insightful)
The Universe is so large that it cannot possibly be that we are the only life thriving on a planet orbiting a star. There would be countless other lifeforms out in space on countless planets. I wonder if it is possible that a rogue planet could harbour life. Say if it was thrown out of a solar system but volcanism was keeping it warm enough for life to survive. How long would that last? As that was a plot point in Star Trek Enterprise.
Re:God made it. (Score:5, Insightful)
See? We are the only place in the universe that can sustain life.
Great. Now that we've got that established, we can argue over which god made it.
Re:Observation Bias (Score:5, Insightful)
Limitations of Kepler (Score:5, Insightful)
The problem isn't that there are no planets in more distant orbits; it's that the Kepler Space Telescope is designed to detect occultations, when a planet passes between the star and us. I am frankly ASTONISHED that Kepler has discovered SO MANY planets in so close to the parent star, but a civilization in the Tau Ceti or even Alpha Centauri system would never be able to detect the Earth - because none of our planets ever occult the Sun from their viewpoint.
Look up in the night sky, and imagine those distant (and very hypothetical!) civilizations orbiting those many, many stars and trying to find US.. Using a Kepler-type telescope, ONLY civilizations that are pretty darn close to the ecliptic would be able to detect OUR solar system.
For Kepler to have discovered so many planets, there must be planetary systems around virtually every star out there. There may be a trillion stars in the Milky Way. If only one in a million planets host anything even remotely resembling "life", there must be a million planets with some form of life.
Re:Limitation of detection methods (Score:4, Insightful)
Re:God made it. (Score:5, Insightful)
The Universe is so large that it cannot possibly be that we are the only life thriving on a planet orbiting a star.
There is a huge fallacy here.
The reason that we are on this planet is of course the fact that life IS possible here. However, the chances of life occurring somewhere might be 1 in a gazillion.
It might even be that life exists only in a small part of the multiverse (http://en.wikipedia.org/wiki/Multiverse) Let us assume that at the sub-atomic scale, decisions are not taken at random, but that at every (let's say binary) decision the universe splits in two halves (one half taking one outcome of the decision and the other half the other). Then if --in this big tree of universes-- life exists somewhere, then it may appear in one universe as if either there was a God that created this life, or, to the more scientifically oriented life-forms, it may seem that life may occur elsewhere in the same universe. But the reality is that the formation of life may be much less likely than we think, and other life may exist only in parallel universes.
Yes, we have created small DNA-like structures in reaction chambers. However, life on Earth will not function with only some random string of DNA. Complicated machinery (ribosomes etc) is needed to actually make life work. And we know absolutely nothing about the probability of this machinery to come into existence from scratch.
Comment removed (Score:5, Insightful)
Re:The right conditions? (Score:4, Insightful)
> Rare Earth
I assume you're speaking of the book by Peter Ward and Donald Brownlee? I'll have to look at that one. As I've posted here previously in other threads, I recently finished Alone In The Universe by John Gribbin, which reaches the same conclusion. I don't know about Rare Earth, but Gribbin's book is based on tons of new computer simulations.
Gribbin points out that *simple* single-celled life may indeed be common within the Galactical Habitable Zone. That's an extremely important distinction. Making intelligent life is the trick. A number of very unlikely things have to work out for that.
This flies in the face of intuition. (And besides, Geeks have gotten so used to seeing Klingons and Drazi and Wookies in movies and on TV, it's just taken for granted now.) We just *assume* that the natural end course of evolution is some form of intelligence: give evolution a good, robust single cell to work with and a few billion years of time, and you will inevitably end up with some form of intelligence. But that's not necessarily so.
As someone else points out here, those who actually study this stuff are reaching a consensus that intelligent life (again, don't miss that!) may indeed be extremely rare in our universe. Yes, even though the universe is huge and large and unfathomable.
Re:Call me silly (Score:3, Insightful)
You and a whole horde of other slashdotters have had the idea of ease-of-measurement bias - a large fraction of the posts on this article mention it. Thankfully, the researchers who study these planets have also thought of it. They have even measured how large it is, and corrected for it. One result of this is that even though we see a large number of hot jupiters, we know know that planets get more common the smaller they are. That is actually one of the main points of the article. I guess this goes to show how many actually read it.
Observation (Score:4, Insightful)
Well until we actually observe other alien life the scientific assumption should be that most life is like ours, that ours is the path of least resistance, the optimal path that all life takes. I think we should be open to it being radically different, however until we observe anything to the contrary, it is all just so much speculation. It could be that some life is so radically different that we may have a hard time recognizing to even observe it. It could be that we are the life oddballs, and most take another path. Who knows. However at this time the most rational response would be to surmise that at least at this time, life is likely similar to ourselves.