28 New Planets Found Outside Solar System 258
elkcsr writes "The San Jose Mercury news reports on the phenomenal discovery of 28 new extra-solar planets out there in our galaxy. All of them are outside of the band scientists consider necessary for supporting life as we know it, but the solar systems analyzed should still be quite familiar to those of us in this neck of the woods. System layouts feature small rocky planets towards the star and gas giants further out. The biggest difference seen is a preference for elliptical orbits, instead of generally circular orbit we enjoy. ' For example, the team also described new details about one specific exoplanet, discovered two years ago. This planet, which circles the star Gliese 436, is thought to be half rock, half water. Its rocky core is surrounded by an amount of water compressed into a solid form at high pressures and low temperatures. It makes a short, 2.6-day orbit around Gliese 436. Based on its radius and density, scientists calculate that it has the mass of 22 Earths, making it slightly larger than Neptune. "The profound conclusion is, here we've found yet another type of planet that is already represented in our solar system," Marcy said.'"
Cool (Score:4, Interesting)
Strange... (Score:4, Interesting)
So how many are we up to now, in total? (Score:5, Interesting)
And how many systems have we looked at? It seems with the rate we're finding new planets nowadays, we might be able to start narrowing down the possible values of fp [wikipedia.org]
(Side note: I really wish Slashdot would allow <sub> and <sup> tags. I know only a subset of HTML is allowed to prevent abuse, but there's nothing harmful about subscripts and superscripts!)
Exotic ice. (Score:5, Interesting)
Gliese 436 b is supposed to be at a surface temperature of 520 Kelvin. The phase diagram of H2O [lsbu.ac.uk] indicates that for certain "exotic" forms of ice to form at that temperature, you need more than 10^9 Pascals of pressure. It would be interesting to calculate the gravitational force on the surface of the planet, and at what depth pressures of 10^9 Pa can be created by gravity, from the known data about the mass and size [wikipedia.org] of the planet.
Re:here? (Score:5, Interesting)
Re:Are elliptical orbits easier to detect? (Score:3, Interesting)
Re:Are elliptical orbits easier to detect? (Score:3, Interesting)
I think they mean "more elliptical." Or rather, orbits where the foci of the ellipse are much, much further apart.
I guess the assumption is that a very elliptical orbit would produce too much variation in the planet's climate to sustain live and allow it to evolve very far, although I'm not sure what the basis for that is. Seems that, with the right ingredients, you could get all sorts of interesting forms of life that could withstand dramatic freeze/thaw cycles, as long as they weren't dramatic enough to boil the planet's water or atmosphere away. Here on Earth we have ample examples of creatures with very long reproductive cycles (e.g. 17-year cicadas), so I don't think we should rule anything out.
Re:we are not alone (Score:4, Interesting)
Habitable planets mean just that: there's probably life on them, but not life you would ever think twice about. Many of those planets, if habitable, wouldn't look like they're life-bearing at all. Sure, they might have oxygen atmospheres which we could breath, and they might have liquid water, but toss in your fishing pole and you wouldn't catch any fish (or fish-like animals).
I'm really getting tired of all the sensationalist journalism that reports on findings like this. Sure, there's most likely habitable planets out there, and sure, there's probably life on them, but when you explain to a layperson what kinds of life, they say "oh, is that all?". Science fiction has embedded itself into our consciousness so that the only life we think about is animal life. Unless there are little green men running around on those planets, most people simply don't care (which is sad).
I can't wait until we find signs of life on Mars or Europa. Even bacteria would be the most important discovery in the history of humanity, but the mindless masses with simply shrug their shoulders and flip the channel to something a bit more their level.
Re:We ARE alone (Score:5, Interesting)
think about it for a minute:
A whole minute? Might make brain hurt!
And people who do this for a living have thought about it for far longer than a minute, and have arrived at the exact opposite conclusion as you.
A planet needs to be at a precise distance from a star based on its chemical makeup.
How precise? NASA folks think Mars might have once supported microbial life (maybe still does based on the methane readings). That's two planets in one solar system at a precise distance. They even theorize about life under Europa's ice. That's pretty loose precision. And don't get me started on extremophiles.
A planet needs a trigger in order for life to emerge.
The formation of the first protocells is a hotly debated topic. Who knows how often the "trigger" occurs or how amenable our universe's physics are to it's happening?
The Miller experiment in the 1950's showed you can get the basic organic molecules from the fundamental gasses and some lightning bolts. Organics have also been observed, via spectra, in comets and nebula. They're everywhere.
That life needs to be able to somehow sustain itself.
Isn't that one of the definitions of life?
That life has to be able to survive celestial events.
There some that feel that early Earth microbes surivied the massive collision that created the Moon. All subsequent cataclysims resulted in extinctions, but never a complete erasure of life. I think life has been proven empirically to be rather hardy.
Odds that such a planet exists anywhere is astronomical. Earth is really one of a kind place.
We have absolutely no idea what the probability is.
That reminds me. When the heck does "Spore" come out? :-)
It's not that simple (Score:5, Interesting)
E.g., look at Venus. It's in the right band too, but it's hell. The slow rotation speed means it has almost no magnetic field, and the solar radiation stripped away all hydrogen. The result is a world without water, and with an atmosphere of almost pure CO2. (Well, ok, and a little nitrogen.)
E.g., look at Mars. We're finding that it used to have water, but the world is so small that it didn't manage to retain an atmosphere. Not only the low gravity means that gas has a hell of an easier time escaping, but the core already froze and it ended up without much of a magnetic field again. So solar winds helped strip it of whatever atmosphere it hadn't already lost.
Earth itself paints an even scarier story.
See, Earth started with an atmosphere of mosthly methane gas. That's a _very_ powerful greenhouse gas, about 200 times more potent than CO2. But that was ok because the sun also was a lot less hot. Without the methane, Earth would have been a deep frozen snowball and life would never have evolved.
But then the sun gradually got warmer, very gradually over billions of years. And Earth would have eventually become a hell worse than Venus.
Luckily some of these new (at the time) bacteria had started doing photosynthesis for a living, and turned the atmosphere into lots of oxygen and nitrogen, which doesn't quite act as greenhouse gasses.
And incidentally that _did_ cause the planet to turn into a deep frozen snowball in the process. Luckily a new batch of carbon got spewed into the atmosphere and thawed it again. It took some tens of millions of years for that to accumulate, though, because we're talking a _lot_ of carbon in the air to defrost as snowball Earth. As in, at least one estimate says 13% carbon dioxide. And that was the first scary skirting with complete extinction.
And from there it's been riding a bit of a thin line between turning into hell and turning into a snowball. E.g., if you look at the massive coal deposits from the Carboniferous era, they had to come from _somewhere_, and that somewhere is almost certainly the air. Without the right conditions for this (e.g., the lower sea levels and the recent event of plants whose wood couldn't be broken because bacteria which can digest lignin didn't yet exist), would Earth have eventually turned into Venus?
So basically if you look at it, 10% of the planets being in the right band still paints an over-optimistic picture. You also have to have the right conditions and the right timing. E.g., if the oxygen production had come a billion years later, Earth would now be pretty much the same as Venus.
Are we alone? Maybe not, but don't get that optimistic based on that 10% figure.
Alien Chemistry (Score:3, Interesting)
Primordial plasma (Score:5, Interesting)
Sure we know. Life won't survive at thousands of degrees because organic molecules fall apart at those temperatures, unless it's based on some element we don't see in the periodic table. A few thousand degrees means a good part of an eV per particle. Most chemical bonds will break in such an environment. Other elements don't behave right for life- they either form little molecules with a dozen or so atoms, or long simple polymers like asbestos. At thousands of degrees you won't even see that. Oxygen and fluorine can produce stable compounds with high bond energies but even those will break, and ceramic-based life has generally been a non-starter. Carbon itself will for the most part only exist in a free state although carbon monoxide (surprisingly stable) appears in stellar spectra.
Of course the definition of "life" is abstract in a general sense and doesn't necessarily involve electron chemistry at all. But if there's life anywhere on the sun, it's the sort of life that college-age geeks imagine existing at some level in the cellular automata programs they write for homework.
Re:we are not alone (Score:3, Interesting)
I don't know about that. Every single planet we've ever found life on so far has also evolved intelligent life. Coincidence, perhaps, but that's a pretty good hit ratio.
The catch is that perhaps 50% of that intelligent life will take billions of years to evolve, and the other 50% of that intelligent life evolved intelligence billions of years before we did.
Given the quantity of habitable planets out there, it's probably a safe bet that the universe has a good quantity of intelligent life that's been around very very much longer than us.
Re:Cool (Score:2, Interesting)
Methodology? (Score:3, Interesting)
Re:we are not alone (Score:5, Interesting)
And covered with and permeated with, too! The healthy bacterial flora of the skin and digestive system; and even more amazingly the mitochondria in each cell. Most scientists now accept them to be specialized bacteria that became symbiant with primitive cells so many millenia ago, which is why they have their own genes and genetic code, distinct from the host, i.e. you. Though they're as much a part of me as my cells, I sometimes like to think of some percentage of my body weight being made of little creatures living literally in every part of me, processing glucose and ketones into ATP or whatever to keep me going. Kind of creepy but kind of cool.
Re:Cool (Score:3, Interesting)
Me too. Unfortunately, I'm also 99% certain that I won't be able to afford them.
This is probably a good thing, because we can't sustain a world in which everyone lives forever.