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Ingredients of Life Found Around Sun-Like Star
smooth wombat writes "NASAs Spitzer Space Telescope has detected the basic organic building blocks of life in a ring orbiting in the 'habitable zone', that area where Earth orbits the Sun and where water exists on the borderline between gas and liquid, in a nearby stellar nursery. When acetylene and hydrogen cyanide combine with water they form adenine, one of the four bases of DNA. The detection supports the widely held theory that many of the molecular building blocks of life were present in the solar system even before planets formed, thus assisting the initial formation of complex organic molecules and the start of life itself." Though it was a little shakier than this observation, we've discussed the possibility of life elsewhere in the galaxy before.
Woodstock - CSNY
Computers are useless. They can only give you answers.
-- Pablo Picasso
" Shouldn't it be where water exists on the borderline between gas and solid?"
No. Liquid water doesn't exist at the temp and pressure where there is a borderline between gas and solid, you get direct sublimation from solid to gas under those conditions -- unless you happen to be at exactly the triple point.
Conversion between gas and liquid would help in the formation of life precursors, since the phase changes could help concentrate compounds in acqueous solution, resulting in greater rates of reaction. I'm sure there are other reasons why acqueous phase changes would help formation of complex organic molecules.
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
These chemicals were found in a dust cloud orbiting a young star. No planets have yet condensed out of the cloud. As such, the chemicals are there before the planets, like the theory says.
Free MacMini
We're several years away from being able to do spectrographic studies of rocky planets orbiting other stars (or rocky moons), but once we reach that point, it will probably be only time until we detect free oxygen and/or other molecules that disappear rapidly in the absence of life.
Complex organic molecule formation is one of the biggies that you need for development of life.
Too bad we're talking about very simple molecule formation here, or they would really be on to something. Adenine is just a relatively easy-to-form glob of hydrogen and nitrogen.
Wiki has a map of the molecule in question, if you are curious.
Information wants to be anthropomorphized.
Well, radiation is the first problem; there's a hell of a lot of organic-molecule-shattering 'waves of doom' in space, way more than on the surface of a planet that has the shielding of both an atmosphere and a magenetosphere[1].
Second, tidal pools on a planet keep everything nicely together in the same general area, courtesey of Our Friend Gravity. Tidal pools, at least on Earth, also provide a very necessary solvent for the whole organic chemistry process -- water. No water, and pretty much all of the organic processes that we know about stop working; in fact, when you look at the chemistry, it almost seems that an oxygen atmosphere is optional, but that water is a base requiremet for life because of its properties as a solvent.
So, no, it's doubtful that complex molecules like Keith Richards will form outside of a suitable gravity well, and doubly doubtful that complex organic molecules (e.g., DNA) will form without liquid water.
[1] That's a magnetic field around a planet, not a hamster ball for Sir Ian McKellen.
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I Hit the Karma Cap, and All I Got Was This Lousy
They can do the same in water. However, one of the problems with trying to get organic chemicals in microgravity is that the cloud in which they're supposed to originate is very sparse. Thus, spontaneous creation of many of the chemicals we consider important to life simply takes longer than in a gravity well.
Secondly, after having gone through all that trouble you have a big chance of them simply burning up on athmospheric entry.
Error: password can't contain reverse spelling of ancient Chinese emperor
The best argument I've read for both Intelligent Design and Evolution are from Scott Adams the writer of Dilbert.
"In the game of life, someone always has to lose. To me, if life were fair, that someone would always be Oklahoma." -DKR
Carbon dating measures the ratios of various carbon isotopes (C-12 and C-14 I believe), not the age of individual carbon atoms.
Among the "ways of knowing", Science, with DNA as its totem pole, can only tell us so much. In other words, there are limits to what we can know with Science. Beyond those limits lie questions such as these: What was "before" the big bang? Why are we here? Why are Java developers so insufferable?
Like in open source, capitalism, and other human endeavours, Choice and the freedom to choose is a good thing. Enter religion: a free open-source alternative to other "ways of knowing." Whereas science can only provide the "how", religion picks up the slack and provides the "why" where other methods for discovering knowledge fall short.
Fundamental theists and atheists would do well to not blindly discredit other epistemological methods. If we can all get along and lay down the weaponry of this culture war going on right now in our courts, schools, and government, we could finally begin to approach real problems, like Man's Greatest Question: Were the dinosaurs killed off on purpose to allow humans to purple monkey dishwasher?
I suggest you look into two of his books, "3:16 Bible Texts Illuminated" and "Things a Computer Scientist Rarely Talks About".
He gave some lectures about how he wrote "3:16", his motivations for doing so, and various thoughts about God. These lectures were the basis for "Things a Computer Scientist Rarely Talks About"
I may twist orthodoxy to partly justify a tyrant. But I can easily make up a German philosophy to justify him entirely.
Carbon dating measures the ratio of C14 to C12. C14 is radioactive and decays over time. When an organism is alive it is constantly ingesting outside sources of carbon and so the C12-C14 ratio is the same as that of the environment. The environment gets C14 when cosmic rays interact with C12 in the upper atmosphere. When the organism dies, it stops ingesting carbon, the C14 decays and the ratio changes. The change in this ratio can tell you how long ago something stopped ingesting C14 (when it died).
You are not really measuring the age of the carbon atoms, just the ratio of a certian short-lived version of Carbon.
Remember, You are unique...just like everyone else.
A human's entire DNA unwound extend 185 billion kilometers
A simple protien must have at least 100 amino acids bonded together in the correct sequence and there are 20 different amino acids that can be used. The amino acids must be left handed and not right handed. They also must be donded on left hand. The probability of the formation of a simple protien comes out to 1 in 1.28x10^175.
The Drake equation never returns a zero answer. The minimum result you can get is 1. The reason is simple enough: the equation calculates the possible number of civilisation capable of interstellar communication, and we are one of them.
Carbon-14 (the radioactive isotope of carbon used in carbon dating) is continuously generated on Earth at a fairly constant rate, by the interaction of neutrons (from cosmic rays) with nitrogen (and occasionally oxygen and carbon) atoms. So, 'new' carbon-14 atoms are being made all the time.
:)
Because it has a relatively constant abundance in nature, living things should also maintain the same ratio of carbon-12 to carbon-14 in their tissues... until they die, at which point they're no longer taking in new carbon from the environment. Then the carbon-14 starts to decay (with a half-life of ~5700 years), but the carbon-12, which is stable, remains. Measuring this ratio can give an approximation of the length of time since the creature died.
The carbon-12 in your body is stable, and could very well pre-date the solar system. Carbon-14 doesn't hang around very long, in astronomical timescales.
Don't just stand there, get that other dog!
"it almost seems that an oxygen atmosphere is optional,"
In fact, Earth's atmostphere originally had no oxygen, until the first anaerobic microbes began producting oxygen as a by-product of their metabolism.
Computers are useless. They can only give you answers.
-- Pablo Picasso
You and your entropy. Entropy only means that chaos increases if no energy is expended to order the system. Think about a messy room (your mother's basement?). It's going to be messy until someone gets fed up with the smell of rotting pizza crusts, at which point they will expend energy and order the system. The entropy of the room decreases because energy was infused into the system. Entropy always increases, but only on a universal scale because no energy can enter or leave the universe. There is no other system of which that is true.
So now, we can move on to molecular biology. The two abstract things you need for life are the ability to get energy from your environment and a way to order yourself. DNA and proteins do this. Lab experiments have shown that ammonia, water, oxygen and methane, in a closed flask, will generate amino acids if they twirl them around enough and give them some energy (your lightning strike). If these amino acids can make an energy gradient by harvesting electrons from something common on a primordial earth, like Hydrogen Sulfide, then you have energy. And if get an amino acids that can store its code on something like DNA...you have life. Now, that's a whole lot of ifs. And, taken together, a very low probability. But, like someone else mentioned, these small molecular reactions would be going on thousands of time a second with a hundreds of moles of materials over a billion years. That's a ludicrous number of chances for something to get it right. And the thing is, once it's right, there is no need for it to happen again. Once you have the system that maintains order and a source of energy, you are good to go. It's the miracle of life.
It has been a nervous year, with people beginning to feel like Christian Scientists with appendicitis.
Okay I made that last one up. It was a total non sequitur. I'm a bad person.
I got the idea from someone else using rape metaphors when analyzing Newton's work:
link
Or our detection methods simply slant the results to systems like that.
Our detection methods slant towards larger planets, definitely. But the fact that most of those large planets are in highly eccentric orbits or close to their stars has nothing to do with the detection method. It appears to be the predominate result of solar system formation. Ours appears to be the exception, not the rule.
Our detection methods could find Jupiter like planets in Jupiter like orbits, and they do. They're just few and far between.
I don't totally agree. Definitely, the extrasolar planets found by the radial velocity planet searches are largely close to their stars, but that's another observational bias. Not only do closer-in planets tug on their stars more (v ~ 1/r^1/2), but it takes longer for a large-separation planet to complete an orbit, and radial velocity teams don't report a planet until they've seen one orbit. Which means the time baseline of the surveys becomes important. The longest target stars have been monitered is 15 years or so. This is, not coincidentally, the orbital period of the largest-separation extrasolar planet known to date, 55 Cnc d (14.7 years, 6 AU). Also, the star 55 Cnc was being carefully monitered all this time in large part because it was known to already harbor a planet (55 Cnc b, has just a 15 day period, and was one of the first half-dozen extrasolar planets discovered).
My point is that while the results of the radial velocity surveys are pretty complete within 3 or 4 AU or so, beyond this the results are heavily driven by observational bias. Not only do you need 15 years of data to close an orbit, you need enough data points to see a much fainter radial velocity signature. For comparison, the next furthest-out extrasolar planet is at 4.5 AU, and of the 136 extrasolar planets found by the radial velocity method, only 5 are beyond 4 AU (see the California and Carnegie planet almanac for details).
Jupiter is in an orbit of 5.2 AU, taking 12 years to go around the sun. So I would submit we've found no planets of Jupiter-like mass at Jupiter-like orbits (closest would be 55 Cnc d, 6 AU, but--at least--4 times the mass of Jupier, or HD 50499, 1.84 Jupiter masses at 4.4 AU). And I'd say further that current observational techniques would really need to stretch to hit such a planet, so I don't think we're not finding them because they aren't there. (Plus, it's widely suspected that radial velocity teams know about a lot of these long-period planets, but are waiting to announce them until the orbits have been confirmed. All the rest of us can do is wait and see).
As to the basic question of this thread, whether you can get other stellar systems similar to our solar system (namely, a rocky planet in a stable orbit in the habitable zone), I think that issue is nowhere near solved. Recent papers have shown that of nearby, sun-like stars, about 10-20% have a planet that can be detected with the radial velocity method (the exact percentage depends on the metallicty of the star). What that means is that we know between a tenth and a fifth of stars have a planet more massive than Jupiter within the inner 3 or 4 AU. That says absolutely nothing about the other 80-90% of stars. What fraction of these have a Jupiter-like planet in a Jupiter-like orbit is very much up for grabs. We know that it's unlikely for an earth to form in most of the planetary systems we've been seeing (migrating giant planets, or planets in eccentric orbits, would almost certainly disrupt the earth-wannabe). But again, that's only 10 or 20% of stars. So, it could very well be that 80-90% of stars have a rocky planet in the habitable zone. We don't know how common our solar system is yet, and it'll likely take future missions (Kepler, TPF, next-generation adaptive optics systems on ground based telescopes) to really find out.