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English Researchers Find Extra-Terrestrial Water
Lister of Smeg writes: "Some researchers found water on a meteorite that is about 570 million years older than the oldest terrestrial rocks. The implications are that water isn't as rare as we thought, conditions for life may have existed elsewhere in the solar system before Earth, and from the article ... 'There is this old idea that life on Earth may have been seeded from somewhere else.'"
Iodine has a relatively short half-life of 15.6 Myr, and is generally considered useless for measurement on this time scale (i.e. almost 300x the half-life) After 300 half-lives, you'd expect 1 part in 2x10^90! That's one single atom left from 1.77 x 10^65 kg of I-129 - more than the mass of the universe, much less the mass of the I-29 in the universe (and, I'm willing to wager, more than the mass of the meteorite!)
The WashU Laboratory of Space Sciences has a page on isotope age determination in meteors, geologic formations and other ancient inorganic structures. Here's what they say on this very point:
Iodine-129 is now extinct in nature. Its short half-life, 15.6 million years, means that Iodine-129 has long since decayed away in a solar system that is 4.6 billion years old.
Furthermore, any radioisotope age determination is based on two things: a) a knowledge of the relative prevalence of the isotope; and b) the half-life. [If the original prevalence is not known, you can sometimes make estimates from decay products of multiple unrelated isotopes]
According to the 'standard' half-life, I-129 is not a useful isotope, but to make things worse, this sample was irradiated by the high-energy space environment for a very long time (I'm assuming millions or billions of years). Irradiation can cause accelerated decay, changing the effective half-life.
Bottom line: unknown original prevalence (somewhere in space, at some unknown time), unknown effective half-life, due to unknown but significant irradiation history, and an unsuitable isotope. Ugh. This is Scientology!
You'd get a better estimate by flipping coins for binary bits. Wait! Maybe they did! How else did they get that number at all?
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More like oxygen. It's such a reactive material that to early life it was pure poison. It took a lot of evolution for life to be able to withstand the assault of oxygen, contantly combining with fragile chemicals needed for life processes. There are still a lot of organizms that cannot tolerate oxygen. There's probably places in our cells today that require careful segregation from oxygen or else it spoils the chemistry and the cell dies.
If tits were wings it'd be flying around.
It's still a terrible argument.
I-129 is formed in exploding supernovas (as are all elements heavier than iron) because the iron nucleus is exceptionally stable, and producing heavier elements consumes energy, rather than releasing it. *Trace amounts* may be produced in a 'living star' but not concentrations we could detect, even as Xe-129, billions of years later. The accretion disk of a black hole might have this capacity, too, but it does not affect my argument.
That means that the Iodine 129 was produced in a previous star -- and hence possibly a previous solar system (and almost certainly previous material bodies such as dust clouds and asteroids) I don't think anyone would be surprised to learn that previous solar systems may have contained water.
The age of the metorite is unknown. Even if one accepts the theory advanced in the CNN article (it is plausible, but not much more than that) the meteor is almost certainly much older than 4.6 billion. This meteor probably did not accrete in our solar system. To accrete in our solar system there would have had to have been a supernova in our vicinity within few hundred million years before our solar system accreted
If the nova had been any older, its I-139 would already have decayed before the meteor formed and would not be present in detectable quantities. Such a recent, near nova is inconsistent with the astronomic data (no gas cloud remnants, or visible effect on nearby stars) and is inconsistent with any current model of star formation and planetary accretion -- the supernova would have played hell on the proto-sun and proto-planetary gas disk, and it takes more than a few hundred million years
The English theory is just a goofy hypothesis that would knock many far more established theories out of whack, and offers no basis whatsoever to revise those theories. It is embarrassing.
The meteor is most likely *far older* -- more like 7-10 billion years than 4.6 billion
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timothy needs to head back to chemistry class. Water is by no means rare in the universe. If you're the astronomer type and look in the right stellar structures you can see interstellar water floating about. Take a quick flight through the Kuiper belt or around most comets and you'll see a bunch of water there too. Humans have been looking up and seeing extra terrestrial water for years.
I'm a loner Dottie, a Rebel.
Only a higher being could have given us a rose, a bald eagle, a rainbow, etc.
Yes, but that would then mean that the "higher being" also gave us Pauly Shore. This is direct evidence against the existence of a god that is both omnipotent, omniscient, and all-loving.
We're going down, in a spiral to the ground
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~/ssh slashdot.org ssh: connect to host slashdot.org port 22: too many beers
slashdot researchers, working from a hidden base, have discovered this lost post in the slashdot story submission queue. this discovery overturns slashdotter theories that the staff was simply unaware of natalie portman's 19th birthday.
natalie portman is slashdot's girl. it's her birthday. once again, slashdot "doesn't get it." we cannot rest until our deepest needs, wants and addictions are addressed.
for nearly a year, the natalie portman obsessive sub-culture of slashdot (a quickly growing segment of the slashdot, indeed the entire open-source, community) have suffered ridicule, persecution, and denial of civil liberties on our favorite tech-savvy message board. today we rested in honor of our beloved's day of birth. tomorrow we bring natalie's message of purity and open-source goodness to the slashdot masses.
thank you.
-osm
i took a bitchslapping for natalie portman!!
A meteorite was found in Texas a year or so ago that had water trapped inside a crystal of salt as well. the link to the artice on that can be found here: http://www.abcnews.go.com/sections/science/DailyNe ws/meteorite990826.html What's new here (I guess) is the dating of the meteorite to within 2 million years after the birth of the solar system. I'm rather skeptical of that claim and would be very interested in how they conducted their tests. A quick check at webelements reveals I 129's half life to be 17 Million years which means that the Iodine in that sample MUST have gone through at least 265 or so half lives!! That should leave practically no I 129 at all in a sample so tiny!! And definitly not enough to obtain an accurate measurement to within 2 million years. Am I missing something or is this bad science?
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BTW, Here's the link to CNN's article on the same topic.
To get their number, they added the current best guess of the Solar system's age to a reasonable guess about the crystal's life before that. The important point is that the crystal is very old -- it crystallized from liquid a few hundred million years after the supernova that formed the solar system.
Here's how they figured that out. First of all, it's generally assumed that the solar system was formed from the debris of a supernova. Supernovae are incredibly energetic explosions of huge stars -- by comparison, the core of the sun is an ice cube. The violence and energy creates pretty much every possible atom: iron, zirconium, uranium, and even weirdies like iodine-129.
Second, from laboratory experiments, we know that iodine-129 is radioactive, and that it decays at a certain rate. After a few hundred million years, it will almost all decay into xenon-129. On cosmic time scales, that's fast.
Third, xenon is a "noble gas", in the same family as helium, neon, argon, etc. Noble gases are very chemically stable: except for a few exotic compounds, they don't form molecules with other atoms. Therefore they are very flighty, and diffuse right out of liquids. (Helium is so diffusive that it can be separated from other gases by diffusing it through solid metal!) So if you find xenon atoms inside a crystal, they had to be put there *after* the crystal became solid.
Well, they found xenon-129 inside their meteorite salt crystal. Putting the above theorems together, they deduced that there was *liquid water* present shortly (shortly in a cosmic sense) after the supernova that formed the solar system (the think the crystal formed in water solution).
Further evidence of the great age of the salt crystal is its purple color. It probably started off as a colorless, translucent crystal, just like everyday table salt. But over time, radiation knocks atoms out of the crystal lattice, leaving "defects" that have color. It's also seen here on Earth, in salt crystals that have been buried without recrystallizing for enormous periods of time.
I'm not sure I buy their hypothesis that the crystal was deposited by water. It is possible to melt salt by itself at reasonable temperatures. Of course, IANAG (I am not a geologist). And even if it wasn't water, the crystal is still fabulously old.
Assuming it was deposited by liquid water, it's a wonderful discovery. It means that life could possibly exist between the stars, without need for a stable system of planets, since all known life requires liquid water. And supernovae are fairly common through the universe, so there's a lot of possible life out there. I'm sure the science fiction writers are already thinking up how to work this into a story...
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I wonder why people could ever think water must be rare outside earth. Besides the obvious limitations on temperature, it seems to be logical to find water in other places on the universe. Let us see: water is very stable, and is composed of very simple elements. Hydrogen is abundant - the most common element in the universe, and oxygen must not be so rare, because is such a 'light' atom.
What does matter is the relationship of water and life. Several properties of water are fundamental to the development of life as we know. There is some chance that other forms of life exist elsewhere based on something else. However, we dont know about other molecule as flexible as water.
There's probably some race of silicon-based extraterrestrials out there, looking at all these planets, thinking, "We must be the only life in the Universe... ours is the only planet we've found without an abundance of that horrible, poisonous, life-quenching water!"
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