Slashdot Mirror
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."
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.
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