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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.
" 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
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
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.
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
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.