I think that statement is confusing because of translation difficulties, and that what was actually said was something about Helium-3.
Helium-3 is an isotope of helium, with two protons and one neutron in the nucleus. It's desirable because it can be used in a fusion reactor at reasonable temperatures and pressures, and won't produce as much secondary radioactivity as things like deuterium or tritium (heavy hydrogen isotopes). There's a lot of it on the moon -- it arrives in the solar wind, and sticks to the surface -- but not much on Earth.
It's one of the good reasons to establish a lunar base.
That was the case quite a while ago: Neptune was predicted from Uranus' unresolved orbital anomalies. But its presence didn't quite cover them all, and what's more, Neptune's orbit wasn't quite what it should have been either -- or so the astronomers calculated. But more recently (within the last 30 years or so) reexamination of the data shows that the orbital anomalies were due to poor data and mis-analysis -- considering the planets' distance from us, and their very long orbital times, this isn't hard to understand.
No one expects a massive outer-system planet nowadays -- all the anomalies have dropped below the level of observational noise. This doesn't mean there's not something out there, though... just that we don't have any evidence for it.
I wonder why this was not noted by the computers. They are supposed to be checking for just such an event. It seems the human eye outclasses the machine this time.
That would depend on what the telescope was being used for -- if it was doing spectroscopy, for example, there'd be no reason for software to be checking for new Solar System objects. Astronomers do a lot besides look for that stuff, you know.
Sorta like when I'm running a trajectory simulation -- the software doesn't catch my input spelling errors... but my wordprocessor does.
the atmosphere of Pluto tends to freeze onto the planet's surface as it approaches the perihelion of its very elliptical orbit
Surely you meant to say "aphelion," since Pluto gets colder the farther it gets from the sun?
Pedantry aside, your definition is close to the working definition I've often seen in the astronomy crowd, except most of them don't seem to think the "atmosphere" part is very critical... and your final "think-it-is" isn't that far off, either.
Cronin, John R., Pizzarello, Sandra
Enantiomeric Excesses in Meteoritic Amino Acids Science 1997 275: 951-955
The proposed reason is
Bailey, Jeremy, Chrysostomou, Antonio, Hough, J. H., Gledhill, T. M., McCall, Alan, Clark, Stuart, Ménard, François, Tamura, Motohide
Circular Polarization in Star- Formation Regions: Implications for Biomolecular Homochirality Science 1998 281: 672-674
IIRC, there are several papers on L-amino acid excesses; I saw them in the search results from Google, but didn't write them down. The above paper I stumbled across during another search on Science, though, so I had it handy...
My email link from the previous post should work for a while, although this account is going to expire at the end of the year... just in case this topic gets archived soon.
Is it possible to detect which aa's are present and in which proportions?
Glycine is the only one I remember, for sure... but I just did a search on Google for "interstellar molecular cloud amino acid spectra" and got about a hundred hits, the first several of which were annotated bibliographies on the subject of ET life origin. You might want to check the same?
Also, have nucleic acids been detected in these clouds?
I'm sure they haven't -- the spectra of complex organics is very complex itself, and there are arguments about the spectra of much simpler compounds (remember, there's a complex mix of molecular species, at very low temperatures, and plenty of stuff between us and them to filter and obfuscate the results). AFAIK, nucleic acids haven't been found in meteorites, either -- but plenty of amino acids have been; upwards of 50 the last time I checked. (Some reports of chirality selection, too -- and speculation that it might be from circularly-polarized light in the IMC.)
What do you say, tesserae....want to submit it?
This topic's gonna be dead soon -- email me and I'll be happy to discuss it more.
Because for life to evolve that mebaolises sugars, the sugars have to be there in the first place.
Huh... so for life to use free oxygen, it had to be there in abundance first?;)
I think life modifies its environment and then adapts to the modifications, so much that we can no longer easily tell what the original environment was.
Maybe your opinion is biased by wanting to believe we are all martians, just like mine is biased by wanting to believe life will originate independently just about anywhere, as long as there is carbon, liquid water and an energy source for prolonged periods of time.
Actually, I think you and I agree far more than we disagree -- I just think that life got its start before it got "trapped" on planetary surfaces... like in the interstellar molecular clouds and in protoplanetary bodies. I also suspect it stirs the pot after that, by transferring between the planetary surfaces often enough to keep things interesting, especially within a planetary system.
I don't doubt that we'll find some pretty bizarre independently-derived life elsewhere (assuming we manage to get there -- or at least send sensors); it's just that the solar system is a very small place, and I think the life here has managed to move around a lot in the billions of years it has had.
Why is it difficult to imagine that life would evolve to use sugars? They're simple, easy to make, and even found in interstellar molecular clouds (IMCs). I'd be more surprised if they weren't common to life everywhere, regardless of its origin.
As far as stereo-selectivity goes, there's good evidence that small-scale structure is inherently chiral: look at carbon single-wall nanotubes, or gold nanotubes -- they naturally form stable spiral structures. Almost every nanostructure we make appears to do that. All you need is an imbalance at some point to evolve specificity for one stereoisomer -- and that imbalance can be as simple as the magnetic field from a nearby supernova remnant, biasing the chemistry in an IMC.
As for life surviving in space, common soil bacteria (Bacillus subtilis) survived unprotected in space aboard the Long Duration Exposure Facility (LDEF) for 6 years. That's bacteria, not spores! A recent paper in Science demonstrated that the interior of the martian meteorite recently alleged to contain fossil evidence of life wasn't subjected to temperatures above 40 C during the entire journey from Mars, including atmospheric entry at Earth. And those researchers noted that "every million years, ~10 rocks larger than 100 g are transferred in just 2 to 3 years" from Mars to Earth. It's an energetically-favorable trajectory.
I'm not suggesting so much that terrestrial life contaminated Mars -- it's much more likely that we're originally martians. A common chemistry won't surprise me at all.
from the picture this isn't a one-handed keyboard at all, but a gamepad with an alphabetic keyboard attached for your thumbs.
If you dig through the site a bit more, it's clearly shown to have the keyboard on the underside, with thumb controls for various functions on the top. The keys appear to be rocker switches, with multidirectional activation -- so your fingers never leave the key, they just twitch in different directions.
From what I've read, these moons are much older than Saturn's other satellites. Instead of forming from the planet's accretion disk they were yanked into orbit after Saturn was pretty well formed. Pretty interesting-they could be leftovers from the solar system's origins.
While it's possible that they're older than Saturn's other satellites, I doubt they're that much older. Most of Saturn's other satellites probably did form from the accretion disk, while the outer satellites in irregular orbits (these four plus Phoebe) were captured (a rather gentler process than "yanked") later. However, they're far enough out that their orbits probably aren't stable over the lifetime of the Solar System: perturbations from the other outer planets (Jupiter, most importantly) can "de-orbit" them in much the same way they were originally captured. This has apparently been observed with a moon of Jupiter's, BTW.
This may be somewhat less true for satellites captured into retrograde orbits, since those orbits tend to become smaller with time, as the moons exchange angular momentum with the primary body through tides; moons orbiting in the "normal" direction, of course, tend to slowly spiral outward -- and if these new moons are in normal ("prograde") orbits, it increases the chance that they'll be lost. Phoebe is indeed in a retrograde orbit, opposite the planetary rotation, and capture into a retrograde orbit is apparently much easier than capture into a prograde orbit. The new moons don't have orbital parameters determined yet, as far as I can tell; my money says they're retrograde (most of 'em, anyway). As far out as they are, tidal influences are pretty weak, anyway.
So they may be old, but Saturn itself (plus its regular moons) is pretty old: current thinking is that the outer ("gas giant") planets may have condensed from the protosolar nebula in the first 10 million years or so, while the inner ("terrestrial") planets may have taken ten times that long. I suspect that these new satellites were captured much more recently, on the general timescale of the Solar System.
I hadn't seen a reference to that PNAS paper (I only get Science and Nature:) -- I'll have to check that out.
In reply to your question: my favorite pet speculation is that essentially all of the prebiotic evolution and the fundamentals of the biotic evolution of life (including what you might call the "formal" origin-of-life) occurred somewhere other than on a planet.
There's plenty of evidence that amino acids are created in interstellar molecular clouds (IMCs -- we routinely detect them there with spectrographs, and more complex molecules are being found all the time); the basic reason is that the IMCs are rich in the chemical species necessary, are cold enough and well-enough shielded from UV that the fragile compounds are stable for long enough for the chemistry to develop (and this is accretional chemistry, BTW -- and it takes a long time!), and full of interstellar dust and icy grains which provide excellent surfaces for the chemistry to proceed upon. And after all the prebiotic stuff happens, over billions of years in IMCs, the IMCs condense into new stellar systems, complete with plenty of warmer protoplanetary bodies -- like comets and asteroids -- within which there are great opportunities and lots of substrates for life to develop on, without all of the nasty disadvantages to planetary surfaces. These substrates, BTW, include clay minerals -- the Tagish Lake meteorite is a great example of that -- and plenty of organics, including amino acids in quantity. And the temperatures are still low enough that the fragile molecules survive for long periods.
Then the planetary bodies (including appropriate satellites) get seeded by the life-bearing bodies -- which have recently been shown to be gentle enough to avoid killing any life aboard -- and the life promptly takes over the new environment. After the planets have calmed down, the life actually survives, to eventually become us...
Not quite original (props to Fred Hoyle, among others), but the general scheme answers many of the tough questions about life's origin on planetary bodies.
And I think this would be a great topic for a/. story -- just to get more comments. Any ideas there, yardgnome?
I tend to agree with you, very much; however, there's a NASA-associated culture which wants to argue strongly against Viking results' being positive for life. They initially advanced the "hydrogen peroxide" argument (despite the problems with there being that much hydrogen available without water, and the issues with stability of the compound under martian surface conditions) and then later extended it to a generalized "superoxide" analog.
Gil Levin isn't the only one who is persistent, however, because a few months back a NASA-associated group published a paper in Science dealing with this very topic. Quoting from the abstract:
Using electron paramagnetic resonance spectroscopy, we show that superoxide radical ions (O2-) form directly on Mars-analog mineral surfaces exposed to ultraviolet radiation under a simulated martian atmosphere. These oxygen radicals can explain the reactive nature of the soil and the apparent absence of organic material at the martian surface.
It took them almost 25 years to get this far; does this answer those people who claim that Levin is a flake because he won't let go of his ideas?
Personally, I think the surface of Mars isn't the place to look for life; I think we need to look subsurface, because of things just like this latest paper. Which, by the way, really doesn't invalidate Levin's tests, because the soil samples included both surface and subsurface material -- added complexity, isn't it?
If you found organisms like that on mars, you have found proof that bacteria from earth contaminated your experiment.
Or: you'd have found evidence that life on Mars resembled life on Earth in some salient characteristics. There are several possible reasons for this, the first two of which are:
There has been transfer of life between the two plannets in the past, or transfer of life from the same source to each planet. For example, we now know that there are plenty of rocks making their way from Mars to Earth, as has been discussed (by me, among others) numerous times on/.
This sort of chirality may be inherent in any chemistry complex enough for life to develop in. We simply don't understand either chemistry or life well enough to make a decision on that at this point.
Furthermore, the fact that an organism uses dextrose doesn't mean it uses atmospheric oxygen to oxidize it. Do a search on "anerobic."
And finally, your argument also breaks down because the purported martian life might prefer the sinstrose to the dextrose; given the chiral characteristics of terrestrial life, it wouldn't be surprising to find life from an unrelated origin being similarly chiral, but if the particular choice made were accidental, martian life might have a "taste" for the other handedness.
And as a bonus, here's the complete story (a short one) from ScienceNOW:
Whales' Cultural Revolution
Just as the Beatles once revolutionized American music, a small band of whales seems to have introduced a new musical style to whales living off Australia's East coast. In little more than a year, the crooning visitors managed to make their tune the major local hit, according to a study in the 20 November issue of Nature.
In humpback whales, the vocalists are always male, and they apparently sing to impress females. Each population has its own "in" song, which gradually evolves. That happens when one crooner embellishes his tune with an extra trill or groan, and others in the area pick up the riff. Females probably get bored by the same old song, says bioacoustician Michael Noad from the University of Sydney in Australia, so males keep adding new fillips to spice things up. But switching to a completely different song is unheard of, Noad says; deviating so far from the norm might label the singer as weird, rather than irresistibly trendy, he speculates.
So Noad and his colleagues, who have studied whale songs for many years, were surprised when their hydrophones picked up a novel song in 1996, one that became dominant by late 1997 and the only thing on the charts in 1998. (Click here for the old and the new song.) "The main part of the change just happened over a couple of months," he says. "It was extraordinarily rapid." Initially, the team had no idea where the song had come from--until Noad listened to a tape of western Australia humpbacks. "It was an exact match, no doubt about it."
The team figures the western Australian whales must have introduced the song when they accidentally headed to the east during their annual migration from Antarctica. But he has no idea why their song became popular so fast.
"This is very surprising," says whale researcher and bioacoustician Adam Frankel of Marine Acoustics Inc. in Arlington, Virginia. Nobody had ever reported such a cultural revolution among whales before, Frankel says. "It's huge."
While I don't disagree about evolution potentially being fast, in this case (assuming the new findings hold) there were still something like 1200 million years between the first known ocean life and the first known land life...
I suspect life was ready for the transition before the environment was.
I have this funny vision of the ocean stuff keeping an eye on the land, saying "Okay, now, it's getting ripe -- get ready to go for it!"
As an interesting aside, last week's Science had a great paper (summary here) about new discoveries possibly related to early life: an RNA-analogue which uses much simpler tetrose backbone sugars, and is still able to not only form stable Watson-Crick helices with itself, but also with complementary RNA and DNA! The RNA backbone monomers (beta-nucleotides) are difficult to form under primordial conditions, while the tetrose sugars are almost trivially easy to form under prebiotic reducing conditions. This is the first of what's anticipated to be a whole family of plausible RNA precursors -- and that's a huge first!
Not to start a flame war, but it's a major chunk of hard scientific evidence (as opposed to speculation and theorizing) supporting a gradualist development of biotic chemistry -- and a very significant blow to those who argue for creationism based on the complexity of RNA and DNA chemistry. The gaps keep getting smaller...
Don't get me wrong. Very old terrestrial life is a big deal. But 2.6-2.7 bya isn't all *that* long ago.
To me, one of the most interesting things associated with this find has to do with the evolution of an oxygen-rich atmosphere: if there were terrestrial microbial communities, there was almost certainly an ozone layer (to protect them from the otherwise-deadly UV radiation), and an ozone layer can only develop if there's a significant amount of free oxygen in the atmosphere.
The thinking used to be that oxygen really didn't start to accumulate in the atmosphere until about 2 billion years ago, and didn't reach life-protecting levels (i.e., formed a good ozone layer) until about 1.4 billion years ago (there was a lot of iron that had to be "rusted" out of the oceans first). This finding is part of a recent trend (sorry, no links) which have pushed this date back quite a bit (leaving some issues with the banded-iron deposits -- the relics of the "rusting" period, but WTF, one of the best characteristics of science is that it changes itself to fit the hard facts, when necessary...).
Some Slashdot followers really need to get the "all journalists are fools" stick out of their asses.
Dunno about the generality, but I do know this: this journalist (Petreley) just made a fool of himself with this article.
The article is patheticly absurd on the face of it, regardless of what the man may have done for Linux in the past, and I can't imagine this latest article will do Linux any good at all.
You're right that Petreley's article was absurd on the face of it. However, based on my experience with it, from NT3.51 through NT4 (with all six Service Packs) to Windows 2000 Pro (with its first SP), I have to say that the OS has gotten more stable with time. What was once weeks of uptime has gone to months (hell, I haven't crashed W2K in the ~2 months I've had it on this box -- not that that's any profound recommendation!).
I think Microsoft's problems with stability come not from failure to care about stability, but their ranking of stability in their goals: it clearly comes far below things like gaming (yeah, even on their "professional" OSes) and backward compatibility with some of their earlier kludges. As a result, they're always patching the OS to try and get back the stability they sacrificed for other capabilities... and as a side effect, they get the bloat the OS is infamous for, which itself does nothing for stability.
I realize that this isn't completely different than what you've said, but I wanted to make this point: they do design stability in from early on... but they do it without much enthusiasm, and they do a relatively poor job of it.
If you really want to see an unstable OS, check one of their "consumer" OSes, like Win98 -- which must be rebooted at least once daily. Even NT3.51 was a paragon of stability in comparison.
The article in Science describes the propellors as being 750 to 1400 nanometers in length, with shafts 150 nm in diameter. In other words, they're microscale, not nanoscale.
The ATP-fueled motors, of course, are just F1-ATPase enzyme, straight from bacteria... and the enzyme is indeed nanoscale, at ~8 nm diameter and 14 nm length. But Montemagno didn't build it, just co-opted it.
(The article linked will probably require a paid subscription... sorry 'bout that)
What's truly interesting is Dr. Montemagno's claim that "this is the first true nano machine" -- considering that what he did was take an enzyme (F1-ATPase, where the "1" is a subscript) which uses adenosine triphosphate (ATP) as an energy source, creating rotary motion as the result. What he did was stick a propellor on the end of the enzyme's shaft... hardly what I'd call creating a nanomachine.
This is especially true since bacteria already use the enzyme to spin their flagella (for example), to move themselves around. Sort of like taking a car, putting paddlewheels on the axles instead of wheels, and proclaiming that you've developed the "first true self-propelled machine."
Cute trick, but the hard part -- the nanomotor -- was already built. Nice publicity, though.
maybe they have been improved, but they have been around for a long time.
When I was in college, some 30 years ago, there was a guy who was trying to do precisely this. At the time, it was damn near all he could do to just define the problems he faced, and he didn't get very far. He was a pretty bright man, too.
People have been working on this for a long time; it's gradually gotten better, as the technologies have been developed and imported from other fields. It's actually getting useable now -- and that's a significant advance.
There's a world of difference between conceiving of a solution to a problem, and implementing it -- even if you manage to do both in the same detail.
I thought it was Stand on Zanzibar -- the scene where the young recruit gets beheaded when the ecoterrorists string a monofilament line across the train tracks.
Did you ever wonder why math explains how our universe behaves so well?
Well, for starters, all of mathematics doesn't... only some parts do, and those are usually chosen specifically for the task. And as to why: the most likely reason is that we ultimately derive mathematics from nature -- math (axiomatic systems, specifically) is developed through the application of logic, which is in a sense the refinement of natural language, which has evolved to describe the world around us accurately enough so that we can survive in it. It's not surprising that math explains the universe, it'd be surprising somehow if it didn't.
I think most of the mystical amazement at the fit of math to the universe is much like the amazement which comes when 1 + 2 = 3, and also 1 + 1 + 1 = 3... and it always works like that! (math simplified here, for the general public...) Sort of like the "anthropic principle" arguments regarding the values of the universal constants -- if they varied by even a little, the universe wouldn't support life! But if they varied a little, we wouldn't be here to notice it, either -- Doh!
Just because you can't see the structure underlying both mathematics and physics, doesn't mean that it's mystical... it might only mean that you're nearsighted, and keep being surprised when you run into things you didn't know were there, but were actually there all along.
Excellent post! It's great to see posts based on understanding of the subject, rather than just speculation from afar (problems always look easier when they're in someone else's specialty, don't they?).
I agree that there's not necessarily animosity between linguists and anthropologists, any more than there's necessarily animosity between geneticists and anthropologists. It's just that the methodology and details of subject matter vary enough between the disciplines that each can't easily map their own descriptive language onto the other discipline, or the other's onto theirs. Despite this, they keep trying... often without realizing what the true issues are.
It's sad that the questions you've raised (along with many like them) may never be answered, because the "minority" languages which might provide insight into the problem are fast disappearing: the increasing homogeneity of humanity leads to loss of all the differences (not just linguistic, but also genetic and cultural) which could reveal the solutions. What's not been recorded at this point, might truly be lost forever.
In the end, we might be left with little but the genetic analyses, which can illuminate only a part of our history.
Slashdot Mirror
Helium-3 is an isotope of helium, with two protons and one neutron in the nucleus. It's desirable because it can be used in a fusion reactor at reasonable temperatures and pressures, and won't produce as much secondary radioactivity as things like deuterium or tritium (heavy hydrogen isotopes). There's a lot of it on the moon -- it arrives in the solar wind, and sticks to the surface -- but not much on Earth.
It's one of the good reasons to establish a lunar base.
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No one expects a massive outer-system planet nowadays -- all the anomalies have dropped below the level of observational noise. This doesn't mean there's not something out there, though... just that we don't have any evidence for it.
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That would depend on what the telescope was being used for -- if it was doing spectroscopy, for example, there'd be no reason for software to be checking for new Solar System objects. Astronomers do a lot besides look for that stuff, you know.
Sorta like when I'm running a trajectory simulation -- the software doesn't catch my input spelling errors... but my wordprocessor does.
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Surely you meant to say "aphelion," since Pluto gets colder the farther it gets from the sun?
Pedantry aside, your definition is close to the working definition I've often seen in the astronomy crowd, except most of them don't seem to think the "atmosphere" part is very critical... and your final "think-it-is" isn't that far off, either.
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Cronin, John R., Pizzarello, Sandra
Enantiomeric Excesses in Meteoritic Amino Acids
Science 1997 275: 951-955
The proposed reason is
Bailey, Jeremy, Chrysostomou, Antonio, Hough, J. H., Gledhill, T. M., McCall, Alan, Clark, Stuart, Ménard, François, Tamura, Motohide
Circular Polarization in Star- Formation Regions: Implications for Biomolecular Homochirality
Science 1998 281: 672-674
IIRC, there are several papers on L-amino acid excesses; I saw them in the search results from Google, but didn't write them down. The above paper I stumbled across during another search on Science, though, so I had it handy...
My email link from the previous post should work for a while, although this account is going to expire at the end of the year... just in case this topic gets archived soon.
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Glycine is the only one I remember, for sure... but I just did a search on Google for "interstellar molecular cloud amino acid spectra" and got about a hundred hits, the first several of which were annotated bibliographies on the subject of ET life origin. You might want to check the same?
I'm sure they haven't -- the spectra of complex organics is very complex itself, and there are arguments about the spectra of much simpler compounds (remember, there's a complex mix of molecular species, at very low temperatures, and plenty of stuff between us and them to filter and obfuscate the results). AFAIK, nucleic acids haven't been found in meteorites, either -- but plenty of amino acids have been; upwards of 50 the last time I checked. (Some reports of chirality selection, too -- and speculation that it might be from circularly-polarized light in the IMC.)
This topic's gonna be dead soon -- email me and I'll be happy to discuss it more.
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Huh... so for life to use free oxygen, it had to be there in abundance first? ;)
I think life modifies its environment and then adapts to the modifications, so much that we can no longer easily tell what the original environment was.
Actually, I think you and I agree far more than we disagree -- I just think that life got its start before it got "trapped" on planetary surfaces... like in the interstellar molecular clouds and in protoplanetary bodies. I also suspect it stirs the pot after that, by transferring between the planetary surfaces often enough to keep things interesting, especially within a planetary system.
I don't doubt that we'll find some pretty bizarre independently-derived life elsewhere (assuming we manage to get there -- or at least send sensors); it's just that the solar system is a very small place, and I think the life here has managed to move around a lot in the billions of years it has had.
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As far as stereo-selectivity goes, there's good evidence that small-scale structure is inherently chiral: look at carbon single-wall nanotubes, or gold nanotubes -- they naturally form stable spiral structures. Almost every nanostructure we make appears to do that. All you need is an imbalance at some point to evolve specificity for one stereoisomer -- and that imbalance can be as simple as the magnetic field from a nearby supernova remnant, biasing the chemistry in an IMC.
As for life surviving in space, common soil bacteria (Bacillus subtilis) survived unprotected in space aboard the Long Duration Exposure Facility (LDEF) for 6 years. That's bacteria, not spores! A recent paper in Science demonstrated that the interior of the martian meteorite recently alleged to contain fossil evidence of life wasn't subjected to temperatures above 40 C during the entire journey from Mars, including atmospheric entry at Earth. And those researchers noted that "every million years, ~10 rocks larger than 100 g are transferred in just 2 to 3 years" from Mars to Earth. It's an energetically-favorable trajectory.
I'm not suggesting so much that terrestrial life contaminated Mars -- it's much more likely that we're originally martians. A common chemistry won't surprise me at all.
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If you dig through the site a bit more, it's clearly shown to have the keyboard on the underside, with thumb controls for various functions on the top. The keys appear to be rocker switches, with multidirectional activation -- so your fingers never leave the key, they just twitch in different directions.
I'd have to use it to be convinced...
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While it's possible that they're older than Saturn's other satellites, I doubt they're that much older. Most of Saturn's other satellites probably did form from the accretion disk, while the outer satellites in irregular orbits (these four plus Phoebe) were captured (a rather gentler process than "yanked") later. However, they're far enough out that their orbits probably aren't stable over the lifetime of the Solar System: perturbations from the other outer planets (Jupiter, most importantly) can "de-orbit" them in much the same way they were originally captured. This has apparently been observed with a moon of Jupiter's, BTW.
This may be somewhat less true for satellites captured into retrograde orbits, since those orbits tend to become smaller with time, as the moons exchange angular momentum with the primary body through tides; moons orbiting in the "normal" direction, of course, tend to slowly spiral outward -- and if these new moons are in normal ("prograde") orbits, it increases the chance that they'll be lost. Phoebe is indeed in a retrograde orbit, opposite the planetary rotation, and capture into a retrograde orbit is apparently much easier than capture into a prograde orbit. The new moons don't have orbital parameters determined yet, as far as I can tell; my money says they're retrograde (most of 'em, anyway). As far out as they are, tidal influences are pretty weak, anyway.
So they may be old, but Saturn itself (plus its regular moons) is pretty old: current thinking is that the outer ("gas giant") planets may have condensed from the protosolar nebula in the first 10 million years or so, while the inner ("terrestrial") planets may have taken ten times that long. I suspect that these new satellites were captured much more recently, on the general timescale of the Solar System.
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In reply to your question: my favorite pet speculation is that essentially all of the prebiotic evolution and the fundamentals of the biotic evolution of life (including what you might call the "formal" origin-of-life) occurred somewhere other than on a planet.
There's plenty of evidence that amino acids are created in interstellar molecular clouds (IMCs -- we routinely detect them there with spectrographs, and more complex molecules are being found all the time); the basic reason is that the IMCs are rich in the chemical species necessary, are cold enough and well-enough shielded from UV that the fragile compounds are stable for long enough for the chemistry to develop (and this is accretional chemistry, BTW -- and it takes a long time!), and full of interstellar dust and icy grains which provide excellent surfaces for the chemistry to proceed upon. And after all the prebiotic stuff happens, over billions of years in IMCs, the IMCs condense into new stellar systems, complete with plenty of warmer protoplanetary bodies -- like comets and asteroids -- within which there are great opportunities and lots of substrates for life to develop on, without all of the nasty disadvantages to planetary surfaces. These substrates, BTW, include clay minerals -- the Tagish Lake meteorite is a great example of that -- and plenty of organics, including amino acids in quantity. And the temperatures are still low enough that the fragile molecules survive for long periods.
Then the planetary bodies (including appropriate satellites) get seeded by the life-bearing bodies -- which have recently been shown to be gentle enough to avoid killing any life aboard -- and the life promptly takes over the new environment. After the planets have calmed down, the life actually survives, to eventually become us...
Not quite original (props to Fred Hoyle, among others), but the general scheme answers many of the tough questions about life's origin on planetary bodies.
And I think this would be a great topic for a /. story -- just to get more comments. Any ideas there, yardgnome?
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Gil Levin isn't the only one who is persistent, however, because a few months back a NASA-associated group published a paper in Science dealing with this very topic. Quoting from the abstract:
It took them almost 25 years to get this far; does this answer those people who claim that Levin is a flake because he won't let go of his ideas?
Personally, I think the surface of Mars isn't the place to look for life; I think we need to look subsurface, because of things just like this latest paper. Which, by the way, really doesn't invalidate Levin's tests, because the soil samples included both surface and subsurface material -- added complexity, isn't it?
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Or: you'd have found evidence that life on Mars resembled life on Earth in some salient characteristics. There are several possible reasons for this, the first two of which are:
There has been transfer of life between the two plannets in the past, or transfer of life from the same source to each planet. For example, we now know that there are plenty of rocks making their way from Mars to Earth, as has been discussed (by me, among others) numerous times on /.
This sort of chirality may be inherent in any chemistry complex enough for life to develop in. We simply don't understand either chemistry or life well enough to make a decision on that at this point.
Furthermore, the fact that an organism uses dextrose doesn't mean it uses atmospheric oxygen to oxidize it. Do a search on "anerobic."
And finally, your argument also breaks down because the purported martian life might prefer the sinstrose to the dextrose; given the chiral characteristics of terrestrial life, it wouldn't be surprising to find life from an unrelated origin being similarly chiral, but if the particular choice made were accidental, martian life might have a "taste" for the other handedness.
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I'll make it up to you: the same other account lets me past the screening to the WAV files -- the song the humpbacks sang last year, and the one they picked up from those westcoast punks this year.
And as a bonus, here's the complete story (a short one) from ScienceNOW:
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Plus links to more cetacean and other sea mammal sites, too.
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I suspect life was ready for the transition before the environment was. I have this funny vision of the ocean stuff keeping an eye on the land, saying "Okay, now, it's getting ripe -- get ready to go for it!"
As an interesting aside, last week's Science had a great paper (summary here) about new discoveries possibly related to early life: an RNA-analogue which uses much simpler tetrose backbone sugars, and is still able to not only form stable Watson-Crick helices with itself, but also with complementary RNA and DNA! The RNA backbone monomers (beta-nucleotides) are difficult to form under primordial conditions, while the tetrose sugars are almost trivially easy to form under prebiotic reducing conditions. This is the first of what's anticipated to be a whole family of plausible RNA precursors -- and that's a huge first!
Not to start a flame war, but it's a major chunk of hard scientific evidence (as opposed to speculation and theorizing) supporting a gradualist development of biotic chemistry -- and a very significant blow to those who argue for creationism based on the complexity of RNA and DNA chemistry. The gaps keep getting smaller...
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To me, one of the most interesting things associated with this find has to do with the evolution of an oxygen-rich atmosphere: if there were terrestrial microbial communities, there was almost certainly an ozone layer (to protect them from the otherwise-deadly UV radiation), and an ozone layer can only develop if there's a significant amount of free oxygen in the atmosphere.
The thinking used to be that oxygen really didn't start to accumulate in the atmosphere until about 2 billion years ago, and didn't reach life-protecting levels (i.e., formed a good ozone layer) until about 1.4 billion years ago (there was a lot of iron that had to be "rusted" out of the oceans first). This finding is part of a recent trend (sorry, no links) which have pushed this date back quite a bit (leaving some issues with the banded-iron deposits -- the relics of the "rusting" period, but WTF, one of the best characteristics of science is that it changes itself to fit the hard facts, when necessary...).
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Dunno about the generality, but I do know this: this journalist (Petreley) just made a fool of himself with this article.
The article is patheticly absurd on the face of it, regardless of what the man may have done for Linux in the past, and I can't imagine this latest article will do Linux any good at all.
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I think Microsoft's problems with stability come not from failure to care about stability, but their ranking of stability in their goals: it clearly comes far below things like gaming (yeah, even on their "professional" OSes) and backward compatibility with some of their earlier kludges. As a result, they're always patching the OS to try and get back the stability they sacrificed for other capabilities... and as a side effect, they get the bloat the OS is infamous for, which itself does nothing for stability.
I realize that this isn't completely different than what you've said, but I wanted to make this point: they do design stability in from early on... but they do it without much enthusiasm, and they do a relatively poor job of it.
If you really want to see an unstable OS, check one of their "consumer" OSes, like Win98 -- which must be rebooted at least once daily. Even NT3.51 was a paragon of stability in comparison.
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The ATP-fueled motors, of course, are just F1-ATPase enzyme, straight from bacteria... and the enzyme is indeed nanoscale, at ~8 nm diameter and 14 nm length. But Montemagno didn't build it, just co-opted it.
(The article linked will probably require a paid subscription... sorry 'bout that)
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This is especially true since bacteria already use the enzyme to spin their flagella (for example), to move themselves around. Sort of like taking a car, putting paddlewheels on the axles instead of wheels, and proclaiming that you've developed the "first true self-propelled machine."
Cute trick, but the hard part -- the nanomotor -- was already built. Nice publicity, though.
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When I was in college, some 30 years ago, there was a guy who was trying to do precisely this. At the time, it was damn near all he could do to just define the problems he faced, and he didn't get very far. He was a pretty bright man, too.
People have been working on this for a long time; it's gradually gotten better, as the technologies have been developed and imported from other fields. It's actually getting useable now -- and that's a significant advance.
There's a world of difference between conceiving of a solution to a problem, and implementing it -- even if you manage to do both in the same detail.
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But it's been a while...
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Well, for starters, all of mathematics doesn't... only some parts do, and those are usually chosen specifically for the task. And as to why: the most likely reason is that we ultimately derive mathematics from nature -- math (axiomatic systems, specifically) is developed through the application of logic, which is in a sense the refinement of natural language, which has evolved to describe the world around us accurately enough so that we can survive in it. It's not surprising that math explains the universe, it'd be surprising somehow if it didn't.
I think most of the mystical amazement at the fit of math to the universe is much like the amazement which comes when 1 + 2 = 3, and also 1 + 1 + 1 = 3... and it always works like that! (math simplified here, for the general public...) Sort of like the "anthropic principle" arguments regarding the values of the universal constants -- if they varied by even a little, the universe wouldn't support life! But if they varied a little, we wouldn't be here to notice it, either -- Doh!
Just because you can't see the structure underlying both mathematics and physics, doesn't mean that it's mystical... it might only mean that you're nearsighted, and keep being surprised when you run into things you didn't know were there, but were actually there all along.
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I agree that there's not necessarily animosity between linguists and anthropologists, any more than there's necessarily animosity between geneticists and anthropologists. It's just that the methodology and details of subject matter vary enough between the disciplines that each can't easily map their own descriptive language onto the other discipline, or the other's onto theirs. Despite this, they keep trying... often without realizing what the true issues are.
It's sad that the questions you've raised (along with many like them) may never be answered, because the "minority" languages which might provide insight into the problem are fast disappearing: the increasing homogeneity of humanity leads to loss of all the differences (not just linguistic, but also genetic and cultural) which could reveal the solutions. What's not been recorded at this point, might truly be lost forever.
In the end, we might be left with little but the genetic analyses, which can illuminate only a part of our history.
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