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28 New Planets Found Outside Solar System
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.'"
What confuses me, is why scientist believe that having conditions the same (or very close to) those on Earth is necessary for life. For all we know, life could be able to live at thousands of degrees hot. You just don't know.
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
(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!)
"[Regarding the 'cloud,'] ownership was what made America different than Russia." -- Woz
An orbit in 2.6 days, huh? That's gotta be a record. Barely time to recover from the New Year's hangover before popping the cork again.
Cold water is denser than ice. So compressing H2O near its melting point actually tends to melt it rather than freeze it. Extremely high pressure can turn this back into solid state again.
Gliese 436 b is supposed to be at a surface temperature of 520 Kelvin. The phase diagram of H2O 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 of the planet.
Ice Cream has no bones.
When you're typing away on your computer late at night, do you consider yourself to be alone? Sure, you might be the only human in the room, but you are definitely not alone. There are insects and mites creeping around that room hidden from view. There are bacteria covering every surface of the room. So while a layperson would say "I'm here by myself" a biologist would smirk and keep quiet so they didn't scare you silly with all the bugs you're surrounded with.
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.
Umm it's been ages since I took any astronomy course, but I thought Kepler figured out that *our* orbit was elliptical?
I assume the article meant "elliptical" in the qualitative sense, that their orbits "looked" like ellipses while our orbit "looks" like a circle.
A circular (or near-circular) orbit should be extremely rare. It is the special case of an elliptical orbit where the speed is very very close to the theoretical speed required to orbit at that distance from the sun and the direction of motion is very close to being at right-angles to the sun.
The Earth is an intriguing case - the original third planet collided with a planet the size of Mars, resulting in part of the crust being blasted off into space forming a mass that is now our moon and a debris ring. A collision on that scale - two almost equally massive objects slamming at an angle - must have resulted in a change in velocity. Since Earth is now on a near-circular orbit, it would seem not unreasonable to assume it started off on a much more elliptical path.
Virtually all of the known objects in the Kepler Belt follow extreme orbits - some varying by 300+ AU in distance from the sun. However, these are all very old objects. They have not been subject to many collisions and are almost in their original state.
On the basis of our extrasolar observations to date, plus the Kepler Belt observations, plus the Earth enigma, I would conclude that elliptical orbits are the norm for younger solar systems and that more circular orbits become slightly more common in older systems where there is a chance that collisions will have averaged things out better.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Actually, so far, 241 extrasolar planets have been discovered.
Ben Hocking
Need a professional organizer?
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. Just being in the right band doesn't mean it'll be habitable, or that life developped... at the right time.
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.
A polar bear is a cartesian bear after a coordinate transform.
I have only been to two other countries and has not seen most of the world yet and they are finding new planets.My life is too short and the universe is too big :)
For all we know, life could be able to live at thousands of degrees hot. You just don't know.
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.
the bugs you're surrounded with.
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.
Mass of the star can be calculated from its spectrum and brightness. We have models for star formation, based on studies of the nuclear reactions that happen at the core. These stars are all relatively near, so the distance to several of them can be measured directly from the parallax. Knowing the type of the star and the distance, the mass can be calculated from the brightness.
This book shows in an introductory way how it's done, with examples of all the calculations in BASIC. It's a very interesting book, highly recommended.