http://fullcoverage.yahoo.com/fc/Science/New_Planet_Discovery/
Two new planets, and they are Saturn-sized. Exciting! There are billions of solar systems, so the question is, how many planets are there in the Universe? And how many, if any, have life?
Our solar system has 9 planets, one with life and intelligent life. If that’s typical, then the universe is teeming with life and intelligent life. What do you think?
Does that mean the Teeming Millions become the Teeming Gazillions? 
Zev Steinhardt
I don’t know how you got from lots of planets = lots of life.
Where’s the planet with intelligent life?
It has to have intelligent life. They’re not talking to us! 
Note that the only planets that we can currently find are the type that can’t support life as we know it - they’re too big and circle far too close to their respective suns. Any earth-sized planets with larger orbits perturb their particular suns far too little for our current instruments to be able to detect.
However, it’s reasonable to assume that the more planets of any type that we can find, the more planets it there must be of the size and orbit type that can support life as we know it.
I remember seeing a Discover article that lists 29 extrasolar planets, all apparently gas giants (and most much closer to the sun than us, or any gas giant in our solar system). Do these two make our total 31?
-Steve
“Banned by the Space Pope”
Oh. “over 30” I see, question answered.
[thought] Moron! I should have followed the link, then posted. They’ll think I’m irretrieveablly stupid… and unable to spell the word irretrievably! Read, then post, read then post![/thought]
-Steve
The article linked to in the OP contains an error.
It claims that these two newly-discovered planets are the first extrasolar planets have masses lower than that of Jupiter. This is incorrect. The very first extrasolar planet to be discovered, orbiting 51 Pegasi, has a mass of about 0.5 times (i.e. half of) Jupiter’s mass.
The exciting aspect of this is that planetary formation seems to be highly probable. We might soon create a good estimate (within an order of magnitude) for yet another term in the Drake Equation
And I’ll add my plug here for SETI@Home!
No matter where you go, there you are.
WillGolfForFood,
That’s not a reasonable assumption at all; if we keep finding planets that contradict the data we were earlier using to predict how many Earth-like planets there are, the reasonable assumption could be fewer Earth-like planets than we previously though. What we’re finding right now is close-in gas giants. Our methods are highly biased towards finding them (a huge planet near it’s star shows up better than a little planet a ways out), but we’re finding significantly more close-in gas giants tha we would have expected.
The current favored hypothesis amongst astronomers to explain this is that if planetary formation produces one gas giant, it tends to spiral in towards the sun, absorbing the matter for any smaller planets to form, and that the situation of Sol where 2 similar-sized gas giants lock each other into farther orbits is relatively rare, thus resulting in fewer Earth-like planets. This means that finding more planets like the ours can reasonably be assumed to be less likely based on the planets we’ve seen so far.
Of course, there’s nowhere near enough data at the present to actually come to any firm conclusions. I’m just pointing out that ‘finding planets’ doesn’t neccesarily mean ‘there are more earth-like planets’.
Kevin Allegood,
“At least one could get something through Trotsky’s skull.”
Singledad,
[QUOTE]
The exciting aspect of this is that planetary formation seems to be highly probable. We might soon create a good estimate (within an order of magnitude) for yet another term in the Drake Equation
And I’ll add my plug here for SETI@Home!/
[QUOTE]
Since you said that we’d have an estimate of within an order of magnitude for ‘yet another’ term in the Drake equation, would you be so kind as to tell us which terms we already have an estimate of within an OOM of? AFAIK, all of the terms in the Drake equation are WAGs, and if you take the estimates from various astronomers, biologists, etc. and plug them together, you get anything from one civilization per 10 galaxies to millions of civilizations per galaxy.
Kevin Allegood,
“At least one could get something through Trotsky’s skull.”
These planets have similar mass to Saturn but do you think they could possibly be the same composition? They are so close to their primary that I would assume all of their hydrogen and helium would have volatized away by now. Assuming that it has the mass of Saturn and the density of Moon (the least dense “terrestrial planet” as I recall), it would be about 34,000 km in diameter, about 3x the size of the earth.
By “3x the size” I mean 3x the diameter.
I think the Drake equation is pretty meaningless. First of all, the terms are arbitrary and may not reflect the real requirements for finding life. We may find that one of the most important factors is having a Jupter-sized planet in the system, or we’ll need a term for density of the debris cloud near a solar system.
Second, some of the terms are close to being theoretically or practically unknowable.
Finally, even if you’re off by only one order of magnitude on each term the results will be wildly divergent after you multiply them all together. The error bars will still swamp the data.
But it makes a useful visualization tool for PR, and perhaps that’s all Drake meant it to be.
mipsman wrote:
The same issue was raised when the planet around 51 Pegasi was first discovered in 1995. 51 Pegasi’s planet, unofficially named “Bellerophon” by Geoff Marcy, has an orbital semimajor axis of only 0.05 AU, which is on par with the 0.041 AU semimajor axis for the newly-discovered sub-Saturn-sized planet orbiting HD 46375.
To date, several of these large, close-orbiting extrasolar planets have been discovered. Collectively, they’re referred to as “epistellar Jovians”.
Someone once published a paper in some astrophysics journal or other, claiming that despite the high temperatures involved in being so close to their parent stars (51 Peg.'s planet would have a substellar tempertaure of about 1200 Kelvins), epistellar Jovians could still be composed primarily of gaseous material.
Oh, and before I forget: (ahem)
Visit the Internet Stellar Database at http://www.stellar-database.com . It’s really great. And I’m not saying that just because I created it. 
tracer
Would you mind going to the Moon Landings thread in the Mailbag section and answering the Hubble question? Thanks very much.
Just a quick plug here for a book I finished reading a short while ago:
Here Be Dragons: The Scientific Quest for Extraterrestrial Life, by David Koerner and Simon LeVay.
It’s a good overview of where the science is in trying to figure out what’s going on, how likely it is for other beings to have evolved elsewhere, etc.