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Exoplanet Count Tops 700
astroengine writes "On Friday, the Extrasolar Planets Encyclopedia registered more than 700 confirmed exoplanets. Although this is an amazing milestone, it won't be long until the 'first thousand' are confirmed. Only two months ago, the encyclopedia — administered by astrobiologist Jean Schneider of the Paris-Meudon Observatory — registered 600 confirmed alien worlds. Since then, there has been a slew of announcements including the addition of a batch of 50 exoplanets by the European Southern Observatory's High Accuracy Radial velocity Planet Searcher (or HARPS) in September."
And 1024, and 1337
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
could've sworn it was there a few months ago... anyone know what happened to it?
I just spend the weekend at a family gathering. Many of my relatives are doctors, scientists, and professors. The topic of alien life came up, and almost all of them laughed it off! Now I'm merely a computer programmer so I didn't say much, but when I hear about there being hundreds of exoplants out there in space I can't help but think that there may be life on at least some of them. After all, these are only the planets that we know about so far! There are probably millions upon millions of other similar planets out there that we just haven't discovered yet.
Why do well-educated scientists consider alien life, even if it's very simple or nothing like life here on earth, to be such an absurd idea? Why do they have so much trouble considering it with any seriousness?
Because if what we've found so far is at least a somewhat representative sample, the overwhelming majority of planets tend to be either gas giants, frozen balls of rock and ice, or roasted balls of rock and lava. You have to be terribly imaginative to see life coming up on worlds like that.
Of course, even if we go by 1 in 700, or 1 in a million for that matter, the Milky way ought to be positively teeming with life. We simply don't have enough data to make a meaningful conclusion either way yet.
Why do well-educated scientists consider alien life, even if it's very simple or nothing like life here on earth, to be such an absurd idea? Why do they have so much trouble considering it with any seriousness?
The scientists in your family may not be representative of scientists in general.
I've always assumed that most people who know the numbers involved think that alien life must exist (with a hundred billion stars per galaxy and hundred billion galaxies, it seem like there are pretty good odds).
Whether we'll communicate with, travel to, or be visited by aliens is an entirely different question with a lot more scope for doubt.
The English word fart is one of the oldest words in the English vocabulary.
I've always assumed that most people who know the numbers involved think that alien life must exist (with a hundred billion stars per galaxy and hundred billion galaxies, it seem like there are pretty good odds).
Part of the problem is that some people use 'alien life' to mean anything from microbe-sized upwards while others use it to mean 'little grey men in flying saucers'. The former is almost certain to exist, but there's no evidence for the latter and good reason to believe that they don't exist; technology merely a few thousand years ahead of ours should be visible across much of the galaxy.
But we know that what we've found so far is NOT a representative sample, because the methods are biasied towards finding jupiter-sized planets?
That's not really good reason to believe they don't exist. A galactic spanning civilization, for one, would only be visible, as you say, across the galaxy. Not across the entire universe. And secondly, as of right now it is only a pipe dream that a couple thousand more years of history will spread us across the stars. We might just as easily blow ourselves up, retreat into a cyber-singularity, or just run out of gas, so to speak.
But anyway, I agree that it's likely that microbial life of various sorts is abundant. And on the other end, I've always felt that it is only a kind of cellular chauvinism that prevents us from thinking of stellar objects as life forms. They grow, they mantain homeostasis, they sometimes reproduce in a fashion, they consume, they die.
There are two kinds of people: 1) those who start arrays with one and 1) those who start them with zero.
Not really. Basically, as soon as our methods allow to detect lower-mass planets we immediately detect them.
It's just that now our tools are not yet good enough to detect Earth-sized planets in habitable zone.
The more planets and potentially earth-like planets we discover, the more paradoxical the Fermi paradox becomes: "where are they?"
We can restate the original premise. Our methods are biased towards finding large planets close to stars.
Given the limits of our current techniques, it should be possible to quantify the limits of their resolution. Put this together with some models of solar system formation and we can extrapolate our observations using a model that says X% of all planetary discs tend to evolve into systems with large planets that migrate in toward their sun. So 1-X remain in some other state. perhaps one we can't detect (yet).
Have gnu, will travel.
Look, my friends said it is very very likely not that it was 100% sure (they are scientists after all!). I mean that's a very reasonable stance to take considering that there are about a 100 billion stars in our galaxy, and about a trillion stars in the OBSERVABLE universe (the actual universe is likely to be MUCH larger, maybe infinite). Considering the large proportion of stars that seem to have planets and the billions of years they've been around it, doesn't it seem very VERY likely that life would have started more than once?
Flip a coin several trillion times. What's the chance that it won't come up heads more than once?
Of course I've read "Rare Earth" AND his other book "Life, But not as we know it" in which he says life could've arisen not just on earth but on Mars, Europa, Enceladus and maybe THREE TIMES on Titan! So while he is (rightfully) concerned that COMPLEX life is "rare" (but not impossible) he also seems to think that (simple) alien life is present almost everywhere!
Also, my chemist friend is in the geological sciences dept. of his university and works with experts in the fields of extremeophiles. As for the others, please realize that science is not a vacuum, at least not at the level that they practice it and they follow major developments in other fields both directly and indirectly; they, to varying degrees, have an excellent idea as to what's going on. (My computational linguist friend probably knows the details of the transit studies, he's the kind of guy who learned a difficult Asian language on his spare time while raising a couple kids while developing algorithms so sophisticated he has to give the state dept. one month advance notice before leaving the country).
Actually I'm beginning to think that the people who claim that their educated brethren say that we are unique have their own, belief based, agenda to push. Whatever.
It's also possible that numerous civilisations with a similar level of technology to ours exist, but it's simply impossible in practice to "colonise the galazy". Inter-stellar travel may simply require too much energy/resources, or it may turn out to be infeasible to survive in space for long enough for anybody to reach another star.
Not to mention objects with really short orbits, which means much more rapid observations. Any planet will only pass between the star and us once per cycle (assuming it's in the plane) which makes it much easier to find orbits measures in weeks or months instead of years and decades. Like for example our Jupiter has an orbit of almost 12 years. They need two measurements to get a period and want three for confirmation, that's 36 years. How long have we been searching for exoplanets again? Oh right, we wouldn't have found our own solar system yet.
Live today, because you never know what tomorrow brings
Gas giants can't form close to stars, they have to migrate towards them.
That too is in question. To understand why we see so many Jupiter-sized planets you really need to understand the techniques we use to detect them.
http://en.wikipedia.org/wiki/Methods_of_detecting_extrasolar_planets#Established_detection_methods
For some methods fully confirming a planet requires more than one orbit. Their orbit may be measured in years, decades or centuries. For other methods it's a one off event and we can't confirm the existence of the planet. The first confirmed planets were detected around a pulsar (a kind of dead star) only in 1992. And the method used only worked for pulsars. It took until 1995 to detect a planet around a main sequence star.
http://en.wikipedia.org/wiki/Extrasolar_planet
Then it took years to get dedicated space instruments up. Effectively we've been at this only for 17 years. Given the difficulty that's nothing. Give it time! Perhaps your grandkids will grow up with earth sized planets confirmed.
These posts express my own personal views, not those of my employer
If you believe the geological models of the rise of life on Earth, I find it very telling that life came about so rapidly.
3.8 billion years ago, the earth was probably still molten rock.
Sometime after that, water started to condense on the surface.
3.5 billion years ago, we find fossils for single cellular life. The surface temperature was still high, there was still much exposed molten lava, the day was only 15 hours, radiation blasted the surface incessantly... but life existed in only the first 0.5% of the wet Earth's lifespan.
The odds of life being extraordinarily unique on Earth, yet popping up within the first 0.5% of the time that there was water on the surface leads me to believe that life is almost inevitable when given the right circumstances.
That really lends more credence to the idea that it might eventually happen elsewhere.
Now, complex life... no idea. There's no way to know how rare that actually is.