More. All I can say is Now if we could only look at water sources within the solar system. Wait... there's always Europa. Why are we not going there but to some boring rocks? I was really excited about the Cassini/Huygens mission but Titan is nothing special. Europa on the other hand could be quite the shocker beneath all the ice.
Good news, not at all surprising. I think there is too much superstition about Europa -- the fear of what we might find.
I'm trying to imagine what 'the news' would cause on this planet. Sudden understanding that we're really small and all and there are better things to do than kill each other? Mass hysteria? Indifference? I'd say indifference. Big news for a few days, then they'll go back to watching reality shows.
Well, the only extrasolar planets we've discovered so far are gas giants, so this discovery would be similar to saying we'd found water vapor in atmo of Jupiter. Even so, it is encouraging. Where there's smoke, there's fire, and water on one extrasolar planet means that water is probably in abundance 'out there'. Can't wait until the TPF arrays finally get launched and we get serious about finding terrestrial sized planets. My money is on 47 Uma, Eta Cassiopeiae 2, Zeta 1 or 2 (particularly Zeta 2 ), and Tau Ceti.
So...the galaxy isn't like it was portrayed in Ice Pirates then, with only 6 planets w/ water, the Earth being one of them? Damn! Just can't trust Hollywood anymore! I blame Actormike!!!!
Yes, ALL. There are currently two methods for finding extrasolar planets. One is by measuring the drop in light levels from the primary if the eccliptic happens to be edge on to us. The other is by measuring the gravitational 'wobble' in the primary caused by the planet. Both methods only work for planets that mass in the gas giant regime- terrestrial sized planets don't block enough light or cause enough wobble. That's the whole reason for the TPF project. When it comes online, not only will we have the means to detect terrestrial sized planets, we'll also be able to analyze their spectographic lines for oxygen, carbon, water, chlorophyll, etc. In other words, if there are terrestrial planets with life that mirrors our biochemistry, we might even be able to find it. But not yet. Right now it's gas giants only, the majority of which have been discovered very close to their primaries and with large (bigger than Jupiter) masses.
Big, but terrestrial. http://en.wikipedia.org/wiki/Mu_Arae_d "Only", 7.5 times the size of earth, composition unknown, presumed terrestrial. http://en.wikipedia.org/wiki/Gliese_876_d Smallest yet at 5.5 times size of earth, also the coldest yet, thought to have a rocky core and thin atmosphere. http://en.wikipedia.org/wiki/OGLE-2005-BLG-390Lb
Okay Dicky, I'll give you three quarters credit here. First, I'd prefer a link other than a wiki article, but okay. But even these articles say that they aren't sure these planets are terrestrial rather than small gas giants, although the third one seems like a likely candidate. Now the cool thing is that with these three in mind, when the TPF arrays are up, they'll be able to take a hard look at them and we'll know for sure, one way or the other. Then they can apply Bode's Law and start looking for other planets in these systems. In about 10 or 15 years we should have the answer, and a whole slew of other new planets as well.
Is there a limit on how big a planet can get before it is classified as a gas giant? Like could there be Jupiter-sized, rocky Earth like planet out there? With continents and oceans but with hundreds of times the available surface? Or is that physically impossible?
Physically possible, but it wouldn't be a gas giant. Gas giants are called that because they're primarily gaseous rather than rocky.
Oh, and unless it's the Pumice Planet, you REALLY wouldn't want to try to live on a rocky world that large.
Hmm. Imagine being able to comfortable fit the entire current human population into only a small fraction of that world's available land area... What is the Pumice Planet?
One of the above wiki articles says that there's an upper limit for terrestrial planetary mass at 14 Earth masses. So no, no Jupiter-sized Earths.
Even if the temperature were amenable, can humans survive on a world that is in effect 5.5 Gs or more?
Not only that, but any planet that big would be almost certain to end up a gas giant anyway as during the planetary formation it would grab onto all the gasses that Earths gravity isn't enough to hold onto.
Gravity is a harsh mistress. A human couldn't hack living on a rocky, Jupiter sized planet. I ain't going to fuck with the math, but a planet massing that much, the surface gravity would be anywhere from 15-30 G's.
Europa is soaked in radiation from Jupiter, I don't see it being a good place for life as we know it.
Yes and no. The water itself will provide something of a radiation shield. Life, if it exists in Europa's oceans, is probably deep where pressure helps with heat. Plus, radiation would results in a higher rate of mutation, pehaps leading to a wide variety of life. Are we going to see terrestrial forms like we have on Earth? Probably not. But there may be something there- something strange.
Water is good at blocking radiation. If there is an ocean on Europa, the few miles of ice above it will offer plenty of protection.
Uranus is 14 Earth masses, and it hardly strikes me as being "barely" a gas giant. I'd figure the threshhold is more likely something under ten.
