I don't know about Colin Renfew's book (Archaeology and Language; the Puzzle of Indo-European Origin [Jonathan Cape, London, 1987] is Citation #3, from the Science paper) and its acceptance by linguists, but Renfew's a well-accepted researcher in the field. A few years back, he received the Fyssen Foundation's International Prize, which is awarded annually to a scientist who has conducted distinguished research in ethology, human paleontology, anthropology, psychology, epistemology, logic, or the neurosciences. It's a prestigious award, and the list of recipients reads like a Who's Who in those fields.
Maybe it's a problem to the linguists that Renfew's an anthropologist?
(FWIW, I very nearly switched my major from physics to anthropology... if I'd had the inclination, I could have taken a couple more classes and had a double major. It still interests me, and I also subscribe to both Science and Nature so I can follow developments in the field. I definitely don't share your opinion of Renfew.)
A recent issue of Science contained a paper on the famous (or should that be "infamous"?) martian meteorite earlier reported to contain evidence of life. The new paper concluded that the highest internal temperature experienced during entry into Earth's atmosphere was no more than 40 C -- in other words, quite a bit below sterilization temperatures for most microorganisms.
The authors conclude that "these data support the hypothesis that meteorites could transfer life between planets in the solar system." Not just the chemical precursors for life, as Jenniskens et al. are reporting -- they state that "[e]very million years, ~10 rocks larger than 100 g are transferred in just 2 to 3 years", and point out that microorganisms and bacterial spores can survive 5 years in space, as shown by experiments on NASA's Long Duration Exposure Facility (LDEF).
Looks like panspermia's going to make a comeback... the authors of the Science paper even suggest there's no reason to quarantine the rocks from a Mars sample return mission, because whatever's there, we've already got.
Before I finally decided to get a wireless phone, I watched how well my associates' phones worked out in the field, since I'm often in the middle of nowhere testing aerospace stuff (Yuma, White Sands, Edwards AFB, Utah TTR -- places like that).
The folks with AT&T service ended up sharing their phones a lot, since they had the only ones which worked just about everywhere. So I got an AT&T Digital One-Rate plan myself -- with my usage level (close to 800 minutes/month) it works out to a bit over 12 cents a minute, which is not much more than what my landline costs once all the standard monthly costs are added in.
I've never seen anything that can beat it, if getting the call through is your primary concern... and it really doesn't cost that much, either.
I just don't see it: there seems to be a gulf which can't be crossed in little steps, between our present "humans + machines" replicators and the nanoscale devices. Thomas envisions ever-smaller replicators becoming ubiquitous, but doesn't really treat what this would entail -- and basically, it would seem to require nanotechnology to work.
Look at present-day factories: they're getting bigger as they automate, not smaller. While I'll admit there are a few areas where micro-level "replication" might work (things on the order of the highly-modified inkjet printers now being used to manufacture polymer electronics... experimentally), it's hard to see how that scale of device would manufacture other than specialty items; the raw materials don't exist in the right forms to do generalized manufacture, for one -- even if the same general mix of elements can make both food and clothing, micro-scale fabrication relies on very specific compounds, not generic building blocks. And forget about anything at a larger-than-micro scale, since the problems only get worse.
Nanoscale manufacturing, on the other hand, conceptually takes just the raw elements and builds up from there. Anything larger requires increasing numbers of preformed, more highly modified "raw" materials: either the actual machine doing the fab work is small, with a huge (and very task-specific) materials supply (and large factories to produce that), or the machine is very large and does all the preliminary work on the materials itself. There's nothing in between.
As I good example of what I'm talking about, consider books: you can make them in a couple of ways, either with a fairly large printing plant which manufactures all sorts of books at low cost, or by using a laser printer to roll your own. The plant buys materials in bulk and does significant modifications on them in the process of making books -- and the more cost-efficient it is, the "rawer" the materials (right up to vertical businesses which make their own paper and ink, in the end). You, on the other hand, buy precut paper and toner cartridges, and staple the output together -- and still have a significantly different product, which occupies only one tiny corner of the "product space" of the printing plant's possible output. And the more complexity you want to add, the larger the number of specialized toner cartridges and home-office binding machines you have to buy -- each of which is task-specific.
Sure, we've got much more power with individual, cheap machines at our fingertips -- but they don't generalize their capabilities, they only get more task-specific. And this trend won't stop until we hit low-cost nanoscale technology, if even then.
While it's a compelling fantasy, I don't think it's a probable path at all.
There are actually five points you are referring to, known as the Lagrangian points; they're where Earth's gravity and the Moon's gravity are equal, providing what's known as an equilibrium point. Three of them are in a line: one between the Earth and Moon, but much closer to the Moon than to Earth; one on the far side of the Moon from Earth; and one on the far side of Earth from the Moon. All three of these points are "unstable" equilibrium points, however -- the equivalent of balancing a marble on a basketball... there's an equilibrium point there, but the marble's not gonna stay put long.
The other two Lagrangian points are along the Moon's orbital path, but 60 degrees ahead of and 60 degrees behind the Moon's position; these are also knows as "Trojan" points, after the Trojan group of asteroids 60 degrees behind Jupiter in its orbit. These positions are stable: in fact, there's stuff there already, in slow orbits around the Lagrange points. These two points, BTW, are sometimes called "L4" and "L5", and there have been several proposals to put manned colonies there (too long a discussion for here, though).
L4 and L5 are stable, and are the ones you're talking about; but the problem is they're way out at the Moon's orbit, and that's almost as far energetically as putting the EUVE in a solar orbit. It's often been said (and very truthfully) that when you've made it to Lunar orbit, you're halfway to anywhere in the Solar Syatem. The bottom line is, EUVE can't get there.
A further comment: it's not so much that the EUVE needs to be reboosted to keep it going -- the $1M/year is for operational funding, just to support the people and hardware to track EUVE, keep it aimed at the desired targets, receive the data it transmits and suchlike. I remember when NASA decided to do the same with one of the Viking Mars landers after it'd worked for years past its funded lifetime: it upset enough people that some group (the Planetary Society, IIRC) collected the funding to keep it going privately, even though NASA gave up...
EUVE just doesn't have the same publicity pull, though -- too bad for UV astronomy.
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Re:praise jebus, the rich are wonderful crowd...
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Sub-Orbital Skydiving
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· Score: 1
Well...
a) The percentage of women in the sport is not nearly what it is in the general population -- perhaps 15% or so, and that's the best it's been in the quarter-century I've been skydiving.
b) The above statistic (which is just ballpark, BTW -- it was around 11% the last firm stats I saw, and it seems to have gone up since then). I think there's nothing inherently gender-biased there, just the history of the sport: it began with a bunch of ex-military paratroopers, back when there weren't any women in that group. It's been trying to catch up to the population ever since.
All that said, my comment wasn't intended to bash women -- it was intended to bash the previous poster, who characterized a great skydiver and very decent person as "rich" and "insane." I didn't say men "owned skydiving" -- I said Cheryl Stearns would own the poster, were they to compete...
And back when it was looked down upon, I often jumped with the few women there were... it was a welcome relief from the testosterone-soaked young men who were in the majority (one of whom was I, no doubt). And the DZ where I spent my student time had more women, percentage-wise, than most do now -- hell, half of my jumpmasters were women -- so they had a good influence on me.
Forgive me?:)
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Re:praise jebus, the rich are wonderful crowd...
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Sub-Orbital Skydiving
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Cheryl is neither rich, nor insane. She is one hell of a skydiver, though, and able to beat most men at their own game. She'll do just fine on this, as she has on everything else she's tried.
She'd 0wn your ass, d00d... take it from me, I know her.
I wonder if they will post a doctor on ISS. It would be a bummer to get a heartattack 20 miles above the closest hospital...
That's one of the reasons for the development of the Crew Return Vehicle (CRV), AKA "SSI lifeboat" or X-38.
Until the CRV is operationally deployed (2003, last I heard -- but it may have slipped again), they'll use a couple of Soyuz spacecraft as lifeboats (but since they have to be refurbed after six months or so on orbit, it really makes NASA nervous -- that means a lot of Russian launches and operational expenses, and if there aren't functional, in-date lifeboats on station, the crew can't stay...).
It had to be redesigned and sent up with the antenna folded up so they could fit it in the space shuttle cargo bay. The reason it had to go up in the space shuttle even after Challenger was because of political interference where people wanted the shuttle to be used for some high profile missions to revive it a bit from the Challenger blowing up in 1986.
Ummmm... I think you've gotten confused, somehow. Galileo was always intended to be launched by Shuttle. The launch, originally intended for 1982, slipped gradually to May of 1986 through a combination of problems, some of which were Shuttle's own delays (remember how late the first Shuttle actually flew?); the mission was supposed to be orbited with a Shuttle-specific version of the LOX/LH Centaur transstage (the Shuttle-Centaur's funding problems caused some of the delay, too). Of course, in late January 1986 Challenger exploded, so Galileo was temporarily grounded for lack of a launch vehicle.
The only real redesign that happened was when Shuttle-Centaur was finally cancelled, as being too dangerous to launch with Shuttle (liquid oxygen/liquid hydrogen in your payload bay is apparently more dangerous than in your fuel tanks...:p ). The transstage was replaced with the much-smaller Inertial Upper Stage, so the flight plan was changed to a six-year multiple-gravity-whip trajectory through the inner solar system, instead of the orignal two-year direct flight. And during the three-year layoff waiting for Shuttle to fly again, Galileo was shipped from Cape Canaveral to JPL in California and back again, spending some time in storage in the interim. It's believed that the main antenna lost some critical lubricant during this unplanned shipping and storage, and this loss caused etching of the standoff pins and sockets, so the the antenna failed to completely unfurl.
So the mission was always intended to fly on Shuttle -- and Shuttle's problems indirectly precipitated the antenna failure. You're correct in that political interference was the reason the mission was to fly on Shuttle -- but it was NASA who interferred, because they wanted Shuttle to carry all the payloads, instead of using expendable launchers (even when they'd have been more suitable). And once designed and built, it would have been very hard to convert Galileo for a Titan IV launch (for example) -- it was built to interface with the Shuttle payload bay, not a Titan payload fairing.
Unfortunately, it was NASA's fault, pretty much entirely... even though the failure was incidental to everything else which went on. Sad, but true. (I regularly work with some of these guys, and believe me, they feel as bad about it as anyone else -- it's the upper management that's cross-threaded in that org.)
I know what you mean -- but again, I don't think people really have them just to do word processing... even is that's all they do with 'em.;)
It's interesting to point out that my Inspiron (also a 7500, BTW -- love those high-capacity LiIon batteries!) gets good enough battery life that I've never had to change batteries on a flight within the US; I live in the mountain West, and there isn't a national flight that lasts more than 4 hours (well, unless you count Alaska or Hawaii). And 4+ hours is pretty good for a fast notebook -- even without much tuning for endurance. With the second battery replacing the CD/floppy drive, I suspect I'd get around 9 hours, which is plenty long for any use I've had to date.
Huh? It can run any code they write a morphing engine for -- Java byte code included. That's one of the two big points they're trying to make (the other being low power consumption).
I still don't understand this rush for ultra faster processors in notebooks
You mean you don't understand the marketing, or you don't understand the bragging rights?;)
I've never seen a hacker compiling a kernel in a plane.
Getting serious: I don't compile kernels on an airplane, but I do serious scientific and engineering work on 'em -- often with a dozen or so heavy-hitting apps running at once -- and sometimes I even attempt as much CAD as I can manage, without having my tablet available.
Some people need the power: my notebook has to do most of what my desktop (a dual PIII 800) does, while I'm on the road. So I have a Dell Inspiron with a PIII 650 (SpeedStep is usually OFF!), 320MB RAM and a 1400x1050 screen... and it's barely enough to get me by.
All that said, I agree with you that 90% of the notebook users don't need more than a 300 MHz processor for what they do. At least, not this year...
Ummmm... you're just talking about the radiation in Earth's upper atmosphere; the radiation environment near Jupiter is a completely different matter.
Remember the Van Allen radiation belts around Earth? They're composed of energetic charged particles (protons and electrons), excited to high energies by the magnetosphere, and are held in their spiraling paths by the terrestrial magnetic field. Before they were discovered (in the late 50's, by James Van Allen), people like Werner Von Braun had planned to put manned satellites in a two-hour orbit -- about 1075 miles up. This turned out to be in the lower Van Allen belt, and the radiation hazard was far too great for safety, so manned spaceflight now is generally in orbits below 250 or 300 miles.
But it's Jupiter we're talking about, and the jovian magnetic field is much stronger than Earth's; the jovian equivalent of the Van Allen belts are millions of times more energetic than the terrestrial belts. Just to give you an idea of what this means to people, compare the exposure at Jupiter (say, in the neighborhood of Io) to that around Earth.
When the Apollo astronauts went to the moon, they had to penetrate the Van Allen belts twice, going out and coming back; in doing so, they received about 2 rem radiation dose. This isn't too much: the U.S. limits radiation workers to about 25 times this, each year, based on the cancer risk. When you talk acute doses -- say, you do a pass by Io, which is in the middle of the jovian belts -- the whole-body exposure which is 50% fatal within 30 days (when untreated) is around 250-300 rad (under these circumstances, 1 rad ~ 1 rem).
Jupiter's radiation belts are millions of times stronger than Earth's, so if an astronaut spent the same time in them (about 3 hours total on a lunar mission -- but Jupiter's much larger, and so your speed would have to be hugely greater to make the transit in that time) they'd get an exposure of millions of rem. In other words, they'd be dead almost immediately -- an exposure of mere seconds would probably be lethal.
Galileo is radiation-hardened, since it was intended to survive in this environment; however, it's been there for almost three times its design limit, and it must be getting pretty fried by now. As a matter of fact, last year when it made its first really close flyby of Io, there was concern that the radiation would corrupt the computer memory and cause it to go into safe mode, or blind the camera's CCD. When that didn't happen, everyone was relieved -- and they promptly did it again!
The radiation environment is severe enough that they actually expect the spacecraft to be physically destroyed in a few hundred million years, if they left it in Jupiter orbit.
Does anyone else get the feeling that the more we know the more we know how little we know?
I think this is always the case when one does science with one's eyes open. It's only when confirmation of pet theories is sought (ignoring evetything that doesn't fit the theory) that we appear to gaining on the Universe's complexity. Was it Haldane who said something about the Universe not only being stranger than we imagine, it's stranger than we can imagine?
I am amazed at how much they do with so little in funding.
The thing about "faster, better, cheaper" funding is that there's a threshold beneath which you can't reliably do the job -- as they found out with the Polar Lander and Orbiter last year.
Pathfinder by itself -- the one lander -- cost as much as the Polar Lander and Orbiter together. That's part of why it worked... (another other part was luck, 'cause the airbags are a little marginal).
The rest of why they can do it with so little funding is that they don't even try to do the science that the two Viking landers did -- the experiments are fewer and less sophisticated (in terms of todays technology, anyway) -- and operational budgets are small, because the landers are solar powered and therefore don't last more than a few months. Remember how citizens chipped in money to keep Viking operating, after NASA's ops funding ran dry many years into the mission?
But Viking used RTGs, not solar... and I'm not gonna go there -- at least in this thread.;)
I was interested to see that they're not considering air-bag landings for the robot landers, as they apparently add too much weight to the package.
I think there are a couple of reasons why they want to use active-landing systems instead of the passive airbags -- and I don't think that weight has much to do with it. First, they're interested in landing within a much smaller footprint than is possible with a purely-ballistic system (with the airbags, all the aiming is done prior to entering the martian atmosphere -- they want fine control for return missions). Second, I suspect that most of the people involved with Pathfinder were holding their breath, hoping the airbags would work -- you have no idea how much finagling it took to make them even halfway acceptable, once it was clear there would probably be a large horizontal velocity component on impact (which the system wasn't designed for!). I know I nearly had a heart attack before the beacon stopped moving, but didn't stop broadcasting...
Guess they're going to have to work a lot harder on those thruster-assisted landings then!
Oh, they know how to do those -- they did it twice in 1976, with the Viking& lt;/I> landers. The problem with the Polar Lander was that they didn't use the proven technology, but instead went with something quick and dirty^H^H^H^H^H^H^H^H I mean "cheaper," which turned out to have one of the most predictable failure modes around... but they didn't budget time or money to check for that, it seems.
They don't have to go to the moon to find the flaw in the MPL design: it was clear to the investigators what had happened, once people actually looked at the test results. Besides, it's almost as expensive landing something on the moon as it is on Mars -- the extra velocity needed is actually fairly small. Nah, the better way to design a lander is with your eyes open!
In an age where manned exploration of space seems to have taken a slug to the guts since the Apollo days, there is something quite sad about seeing an actual spacecraft, the product of a once proud space program being sold off as "a nice playhouse for kids".
I'll agree that it's a shame, but it's not new: the Russians already have a Buran (the "Russian Shuttle") in Gorky Park as an amusement-park ride (although I believe this is a static-test article, not one of the flight spacecraft).
And the US's very own NASA took the last two fully-functional Saturn V lunar boosters and laid 'em down as lawn ornaments in Huntsville and Cape Canaveral;a static test item is also on display in Houston (it's been alleged -- accurately, I believe -- that NASA did this to reduce competition with Shuttle).
From my POV, I don't know which is worse: selling the hardware for cash when you're broke, or disabling it for motives less admirable...
You're welcome... it's been a while since I delved into some of that myself, so it was fun to revisit.
I'll admit to having a minor stake in the Mars stuff, too -- it's just that my prejudices are on the other side. I worked on Pathfinder and will work on some stuff for the '01 missions (and I hope for the later ones!), so I know some of the people and know about some of the players on a professional level, not just what I read in the papers or online. It makes a difference to me.
That said, I can't really say I'm a fan of NASA's -- it's just that they're the only game in town.
The nanobacteria subject is fascinating but it's another example of a story that is sometimes associated with extra-terrestrial life - probably to gain publicity.
Hmmmm... interesting take, but I don't follow the logic. Robert Folk ruined his reputation with the original "nannobacteria" proposals, and has only recently been supported somewhat by McKay et al. with the "martian fossils", Kajander and his collegues with nanobacteria as a cause for kidney stones, Miller-Hjelle and her collegues with nanobacteria as a cause for polycystic kidney disease, Uwi ns and her findings on nanobes growing on Triassic and Jurassic sandstones collected from petroleum exploration boreholes offshore Western Australia. The American Society for Microbiology has paid serious attention to the controversy, as might be expected. All in all, it's only been recently that "nanobacteria" findings have provided any good publicity at all; mostly, it's been the ruin of the discoverer (in fact, Folk has been described as "coming out of the closet" with his first papers, some 20 years ago -- strong prejudice exists!).
But now things are changing: there are more findings, and more support for the concept. This might even be a scientific paradigm change... and this was my earlier point, that "common sense" arguments are inherently flawed, because the universe is stranger than we imagine.
When was the tectonic plate theory accepted? They must have been interesting times. Certainly my father thinks it's a lot of nonsense...
Alfre d Wegener proposed the theory in 1912, but it didn't receive much support (in the U.S., at least) until post-WWII. My college geology text has a chapter written in '65, which concludes "Although the subject is now a respectable one in scientific circles of the Northern Hemisphere, the question is still far from settled." (Physical Geology, Leet and Judson, 3rd Edition; Prentice-Hall, NJ, 1965)
Wilson, a Canadian geologist, brought everything together around '65 with his model of seafloor spreading, which happened to explain the Pacific seafloor magnetic anomalies found in '61 by Raff and Mason (these are reversed-magnetic-polarity stripes, which are embedded in the newly-created seafloor by the Earth's magnetic field, which periodically reverses -- creating alternating stripes which aren't explainable except by tectonic plate theory). This all but cinched it, but it took years for general acceptance to happen -- in '67, my geology prof wasn't yet convinced, and spent a lecture period arguing against it (the students, OTOH, tended to see the light right away, based on the evidence presented). In '68, Pinchon worked out the plate positions, and by the mid-70's, plate tectonic theory was accepted as correct by all but a few lingering die-hards. (It's interesting that similar remnant-field reversals have been discovered on Mars, isn't it?)
Yes, they were interesting times. Overthrow of "established scientific fact" is always interesting, yet it happens often... that's how science progresses, after all. Only some of the time do the revolutionaries get burned at the stake; the rest of the time, they are merely ridiculed in print and reviled in person.
I guess it is the weakest point. When weighing up evidence like this I guess we rely on our own experiences and yours are different from mine. Having worked in string theory related stuff for a few years I know what it is like to have a sceptical audience. But I generally tend to make guarded statements like "Assuming string theory is a good model then...". I would never make a statement like the following from the NASA press release:
METEORITE YIELDS EVIDENCE OF PRIMITIVE LIFE ON EARLY MARS
A NASA research team of scientists at the Johnson Space Center and at Stanford University has found evidence that strongly suggests primitive life may have existed on Mars more than 3.6 billion years ago. (My italics)
I guess that's the difference between your opinion and theirs: they figured they had good evidence, and you figure they don't. Dave McKay (of NASA) still sticks pretty much by the findings, and Kathie Thomas-Keprta (Lockheed Martin) very strongly supports them; time will tell who is right. My point is that science never advances without people going out on a limb with their conviction that a new interpretation is correct, rather than the conventional wisdom. This is not the equivalent of perpetrating a hoax! -- even if they are subsequently proven wrong.
Given the doubt over the interpretation of 'nanobacteria' fossils it seems to me that the most reasonable interpretation of part of this 'evidence' is that it is a demonstration that such 'fossils' can be produced by inorganic processes in a sterile environment but of course you don't get big bucks for a finding like this.
On the contrary: some people are getting funding to disprove the "martian fossil" findings. The ASM link quotes some of them. With any discovery, confirmation or refutation of the findings is critical to its acceptance, and the controversy is the process through which the findings on all sides are integrated by the scientific community; Mari on Anderson's lecture is a good summary of this particular controversy, and concludes (correctly, in my opinion) "The main drawback to this story is the media focus on such sensational news. Media hype may increase public awareness of science, but the problem is that the complexities get lost in the glare of the spotlights." Her last couple of sections are well worth reading.
I think the jury's still out, and I think you're prematurely making up your mind. But, hey, it's your mind -- do with it what you will.
What does the Bible Code bit have to do with the martian life papers? Certainly Science was serious in its publication of the research, and despite significant controversy over several points, the original researchers have produced a second martian meteorite's contents in support of their original paper.
As far as I can tell, your argument boils down to:
It doesn't stand up to common sense
You don't happen to believe it
It may have benefited NASA to have other people to believe it
The popular press overenthusiastically pumped it
Therefore it was a hoax.
Hoax: To deceive or take in by inducing to believe an amusing or mischievous fabrication or fiction; to play upon the credibility of.
-- The Oxford English Dictionary, 1971 Edition
There's a thin thread of possibility in the second definition, but it's not clear who was hoaxing whom -- and the intent is certainly in doubt.
I think the major flaw in your argument is the "common sense" argument: I can think of many examples of research dismissed precisely because of this, which later came to be regarded as fact because of the same reason (continental drift and plate tectonics being one I personally witnessed the change on -- the theory was finally accepted while I was in college, because the evidence became overwhelmingly supportive of it... and now it's "obvious").
The biggest argument against the "martian fossils" is the argument against nanobacteria... and that one seems to be falling (at least in the case of nanobacteria). While it's more likely than not that the "fossils" were actually something else, that is far from conclusive.
And as a final note, it's still "meteorite," not "asteroid."
I doubt that many (if any) genuine researchers really thought that there was any chance that the formations found on those meteorites were formed by life. I don't believe the meteorites themselves were faked but I have major doubts about the credibility of the researchers.
Believe what you will. The truth is that the researchers involved are all credible, with decent publishing histories behind them. And the initial paper was published in Science -- not exactly a journal known for accepting hoaxes, although they do like to be the first to publish controversial papers (and this was no doubt a controversial paper). But "controversial" != "hoax"... and the stature of some of the researchers involved is such that they'd be fools to perpetrate a hoax and destroy their careers.
I won't deny that NASA took advantage of the paper, but calling it a hoax is dangerously close to libeling some good researchers (only some of whom work for NASA). You might want to reconsider your statement?
...Nasa's life bearing asteroid hoax a few years back...
Hoax? Life-bearing asteroid? Maybe you'd make more cogent comments if you actually understood what you're talking about. The alleged fossil remains in a meteorite which is thought to have come from Mars (not an asteroid) were not a hoax; there's always the chance the researchers were wrong, but that's far from a hoax.
And for what it's worth, I don't see a problem with science results which get people interested and excited (the vast majority of those results, at least in astronomy/cosmology/planetary science, don't have to do with "finding life," although extraterrestrial life is a fascinating topic most people pick up on easily). The more people who understand and support scientific endeavor, the better, I say!
Of course, you might just be trolling, in which case I need some help with this hook...
From the space.com article, discussing the newfound problem with the Cassini probe's data reception:
"The problem is in the receiver: the bandwidth within it is not as wide as the design called for," said Bob Mitchell, the Cassini program manager at NASA's Jet Propulsion Laboratory.
I don't know if that's JPLese and he's not completely describing the problem, or if space.com didn't understand it, although they hint at the cause on the second page. What happened is this:
When the receiver was designed, the Doppler shift in the probe's signal in the operational mode wasn't accounted for; it worked fine on the bench, with no delta-V, but the Doppler shift at Titan will push the sidebands (where the data is being transmitted) out of the receiver's range. Cassini will be going like the proverbial bat out of hell as it passes Titan and drops the probe, and the Doppler shift will be substantial.
Technically, this is "not as wide as the design called for," I guess, and it's not clear whether it's lack of a proper specification or lack of attention to detail (and I really can't guess which, since I never worked on that project -- I just talked this week to some of those who did).
The article also mentions slowing Cassini down for the encounter, but fails to mention that doing such a thing will screw much of the science opportunity: the subsequent gravity-whip maneuvers depend on the initial velocity and positioning, and losing that will prolong the mission, pushing much of the science past the design life of the spacecraft. Not to mention they'll have to completely recalculate the entire circum-Saturn trajectory, a task for which there's no funding.
It's a real bummer: this might be the last of the "big" planetary-science missions for a long time (everything else is "faster-better-cheaper", and we've seen some of the downsides there), and one of the most exciting parts is endangered -- so much that they're considering crippling a major fraction of the rest of the mission just to recover it.
It's already happening, but not in production yet.
From the 2000 IEEE International Solid-State Circuits Conference schedule:
24.7 A
500Mb/s Quadruple-Data-Rate SDRAM Interface using a Skew Cancellation Technique
4:45 PM
J.
Kim, S-H. Wang, J. Lee, H-S. Nam, Y-G. Kim, J-H. Shim, H. Ahn, S. Kang, K-N. Park*, B-H. Jeong*, J-H. Ahn*, B. Kim
Korea
Advanced Institute of Science and Technology, Taejon, Korea
*Hyundai MicroElectronics Co. Ltd, Cheongju, Korea
A
quadruple data rate (QDR) SDRAM I/O interface uses salient skew cancellation.
Cancellation reduces skews between data lines on PCB to 250ps.
While the points you make are valid in that they increase the storage requirements for information, there's truly more information being generated. Or perhaps I should say "information" (explicit quotes...)
For one example I'm painfully aware of, the size of reports in the aerospace industry has been increasing over the years -- and by "size" I mean total number of words, total number of figures, and so on. I suspect what's happening is that the effort which was once used to painstakingly correct (or simply do correctly the first time) the data package has now been diverted to the creation of more volume for the package, since correction on a computer-generated document is so easy.
When I started in the industry back in the early 80's, lots of engineers still wrote out their stuff by hand and gave it to the secretary to type up; they redlined the first draft, and a final copy was made. Now, the engineer types it in in the first place, the software fixes the spelling, and the engineer writes some more (just think how these guys talk... they write the same way! I can say this 'cause I'm one of 'em.).
Note that aerospace isn't the only place where this is happening -- it's pretty common, in my experience. And I haven't mentioned the amount of data (information) being generated by present-day science; just compare the handful of photos that the early Ranger lunar probes took, with the output of NEAR Shoemaker or Galileo. Or consider genome sequncing. Or numerical simulation of flow in aircraft design. Or numerical simulation of damn near anything.
I think there's a lot more information being generated, and it's only going to get worse.
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Maybe it's a problem to the linguists that Renfew's an anthropologist?
(FWIW, I very nearly switched my major from physics to anthropology... if I'd had the inclination, I could have taken a couple more classes and had a double major. It still interests me, and I also subscribe to both Science and Nature so I can follow developments in the field. I definitely don't share your opinion of Renfew.)
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The authors conclude that "these data support the hypothesis that meteorites could transfer life between planets in the solar system." Not just the chemical precursors for life, as Jenniskens et al. are reporting -- they state that "[e]very million years, ~10 rocks larger than 100 g are transferred in just 2 to 3 years", and point out that microorganisms and bacterial spores can survive 5 years in space, as shown by experiments on NASA's Long Duration Exposure Facility (LDEF).
Looks like panspermia's going to make a comeback... the authors of the Science paper even suggest there's no reason to quarantine the rocks from a Mars sample return mission, because whatever's there, we've already got.
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The folks with AT&T service ended up sharing their phones a lot, since they had the only ones which worked just about everywhere. So I got an AT&T Digital One-Rate plan myself -- with my usage level (close to 800 minutes/month) it works out to a bit over 12 cents a minute, which is not much more than what my landline costs once all the standard monthly costs are added in.
I've never seen anything that can beat it, if getting the call through is your primary concern... and it really doesn't cost that much, either.
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Look at present-day factories: they're getting bigger as they automate, not smaller. While I'll admit there are a few areas where micro-level "replication" might work (things on the order of the highly-modified inkjet printers now being used to manufacture polymer electronics... experimentally), it's hard to see how that scale of device would manufacture other than specialty items; the raw materials don't exist in the right forms to do generalized manufacture, for one -- even if the same general mix of elements can make both food and clothing, micro-scale fabrication relies on very specific compounds, not generic building blocks. And forget about anything at a larger-than-micro scale, since the problems only get worse.
Nanoscale manufacturing, on the other hand, conceptually takes just the raw elements and builds up from there. Anything larger requires increasing numbers of preformed, more highly modified "raw" materials: either the actual machine doing the fab work is small, with a huge (and very task-specific) materials supply (and large factories to produce that), or the machine is very large and does all the preliminary work on the materials itself. There's nothing in between.
As I good example of what I'm talking about, consider books: you can make them in a couple of ways, either with a fairly large printing plant which manufactures all sorts of books at low cost, or by using a laser printer to roll your own. The plant buys materials in bulk and does significant modifications on them in the process of making books -- and the more cost-efficient it is, the "rawer" the materials (right up to vertical businesses which make their own paper and ink, in the end). You, on the other hand, buy precut paper and toner cartridges, and staple the output together -- and still have a significantly different product, which occupies only one tiny corner of the "product space" of the printing plant's possible output. And the more complexity you want to add, the larger the number of specialized toner cartridges and home-office binding machines you have to buy -- each of which is task-specific.
Sure, we've got much more power with individual, cheap machines at our fingertips -- but they don't generalize their capabilities, they only get more task-specific. And this trend won't stop until we hit low-cost nanoscale technology, if even then.
While it's a compelling fantasy, I don't think it's a probable path at all.
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There are actually five points you are referring to, known as the Lagrangian points; they're where Earth's gravity and the Moon's gravity are equal, providing what's known as an equilibrium point. Three of them are in a line: one between the Earth and Moon, but much closer to the Moon than to Earth; one on the far side of the Moon from Earth; and one on the far side of Earth from the Moon. All three of these points are "unstable" equilibrium points, however -- the equivalent of balancing a marble on a basketball... there's an equilibrium point there, but the marble's not gonna stay put long.
The other two Lagrangian points are along the Moon's orbital path, but 60 degrees ahead of and 60 degrees behind the Moon's position; these are also knows as "Trojan" points, after the Trojan group of asteroids 60 degrees behind Jupiter in its orbit. These positions are stable: in fact, there's stuff there already, in slow orbits around the Lagrange points. These two points, BTW, are sometimes called "L4" and "L5", and there have been several proposals to put manned colonies there (too long a discussion for here, though).
L4 and L5 are stable, and are the ones you're talking about; but the problem is they're way out at the Moon's orbit, and that's almost as far energetically as putting the EUVE in a solar orbit. It's often been said (and very truthfully) that when you've made it to Lunar orbit, you're halfway to anywhere in the Solar Syatem. The bottom line is, EUVE can't get there.
A further comment: it's not so much that the EUVE needs to be reboosted to keep it going -- the $1M/year is for operational funding, just to support the people and hardware to track EUVE, keep it aimed at the desired targets, receive the data it transmits and suchlike. I remember when NASA decided to do the same with one of the Viking Mars landers after it'd worked for years past its funded lifetime: it upset enough people that some group (the Planetary Society, IIRC) collected the funding to keep it going privately, even though NASA gave up...
EUVE just doesn't have the same publicity pull, though -- too bad for UV astronomy.
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a) The percentage of women in the sport is not nearly what it is in the general population -- perhaps 15% or so, and that's the best it's been in the quarter-century I've been skydiving.
b) The above statistic (which is just ballpark, BTW -- it was around 11% the last firm stats I saw, and it seems to have gone up since then). I think there's nothing inherently gender-biased there, just the history of the sport: it began with a bunch of ex-military paratroopers, back when there weren't any women in that group. It's been trying to catch up to the population ever since.
All that said, my comment wasn't intended to bash women -- it was intended to bash the previous poster, who characterized a great skydiver and very decent person as "rich" and "insane." I didn't say men "owned skydiving" -- I said Cheryl Stearns would own the poster, were they to compete...
And back when it was looked down upon, I often jumped with the few women there were... it was a welcome relief from the testosterone-soaked young men who were in the majority (one of whom was I, no doubt). And the DZ where I spent my student time had more women, percentage-wise, than most do now -- hell, half of my jumpmasters were women -- so they had a good influence on me.
Forgive me? :)
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She'd 0wn your ass, d00d... take it from me, I know her.
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That's one of the reasons for the development of the Crew Return Vehicle (CRV), AKA "SSI lifeboat" or X-38. Until the CRV is operationally deployed (2003, last I heard -- but it may have slipped again), they'll use a couple of Soyuz spacecraft as lifeboats (but since they have to be refurbed after six months or so on orbit, it really makes NASA nervous -- that means a lot of Russian launches and operational expenses, and if there aren't functional, in-date lifeboats on station, the crew can't stay...).
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Ummmm... I think you've gotten confused, somehow. Galileo was always intended to be launched by Shuttle. The launch, originally intended for 1982, slipped gradually to May of 1986 through a combination of problems, some of which were Shuttle's own delays (remember how late the first Shuttle actually flew?); the mission was supposed to be orbited with a Shuttle-specific version of the LOX/LH Centaur transstage (the Shuttle-Centaur's funding problems caused some of the delay, too). Of course, in late January 1986 Challenger exploded, so Galileo was temporarily grounded for lack of a launch vehicle.
The only real redesign that happened was when Shuttle-Centaur was finally cancelled, as being too dangerous to launch with Shuttle (liquid oxygen/liquid hydrogen in your payload bay is apparently more dangerous than in your fuel tanks... :p ). The transstage was replaced with the much-smaller Inertial Upper Stage, so the flight plan was changed to a six-year multiple-gravity-whip trajectory through the inner solar system, instead of the orignal two-year direct flight. And during the three-year layoff waiting for Shuttle to fly again, Galileo was shipped from Cape Canaveral to JPL in California and back again, spending some time in storage in the interim. It's believed that the main antenna lost some critical lubricant during this unplanned shipping and storage, and this loss caused etching of the standoff pins and sockets, so the the antenna failed to completely unfurl.
So the mission was always intended to fly on Shuttle -- and Shuttle's problems indirectly precipitated the antenna failure. You're correct in that political interference was the reason the mission was to fly on Shuttle -- but it was NASA who interferred, because they wanted Shuttle to carry all the payloads, instead of using expendable launchers (even when they'd have been more suitable). And once designed and built, it would have been very hard to convert Galileo for a Titan IV launch (for example) -- it was built to interface with the Shuttle payload bay, not a Titan payload fairing.
Unfortunately, it was NASA's fault, pretty much entirely... even though the failure was incidental to everything else which went on. Sad, but true. (I regularly work with some of these guys, and believe me, they feel as bad about it as anyone else -- it's the upper management that's cross-threaded in that org.)
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It's interesting to point out that my Inspiron (also a 7500, BTW -- love those high-capacity LiIon batteries!) gets good enough battery life that I've never had to change batteries on a flight within the US; I live in the mountain West, and there isn't a national flight that lasts more than 4 hours (well, unless you count Alaska or Hawaii). And 4+ hours is pretty good for a fast notebook -- even without much tuning for endurance. With the second battery replacing the CD/floppy drive, I suspect I'd get around 9 hours, which is plenty long for any use I've had to date.
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You mean you don't understand the marketing, or you don't understand the bragging rights? ;)
Getting serious: I don't compile kernels on an airplane, but I do serious scientific and engineering work on 'em -- often with a dozen or so heavy-hitting apps running at once -- and sometimes I even attempt as much CAD as I can manage, without having my tablet available.
Some people need the power: my notebook has to do most of what my desktop (a dual PIII 800) does, while I'm on the road. So I have a Dell Inspiron with a PIII 650 (SpeedStep is usually OFF!), 320MB RAM and a 1400x1050 screen... and it's barely enough to get me by.
All that said, I agree with you that 90% of the notebook users don't need more than a 300 MHz processor for what they do. At least, not this year...
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Remember the Van Allen radiation belts around Earth? They're composed of energetic charged particles (protons and electrons), excited to high energies by the magnetosphere, and are held in their spiraling paths by the terrestrial magnetic field. Before they were discovered (in the late 50's, by James Van Allen), people like Werner Von Braun had planned to put manned satellites in a two-hour orbit -- about 1075 miles up. This turned out to be in the lower Van Allen belt, and the radiation hazard was far too great for safety, so manned spaceflight now is generally in orbits below 250 or 300 miles.
But it's Jupiter we're talking about, and the jovian magnetic field is much stronger than Earth's; the jovian equivalent of the Van Allen belts are millions of times more energetic than the terrestrial belts. Just to give you an idea of what this means to people, compare the exposure at Jupiter (say, in the neighborhood of Io) to that around Earth.
When the Apollo astronauts went to the moon, they had to penetrate the Van Allen belts twice, going out and coming back; in doing so, they received about 2 rem radiation dose. This isn't too much: the U.S. limits radiation workers to about 25 times this, each year, based on the cancer risk. When you talk acute doses -- say, you do a pass by Io, which is in the middle of the jovian belts -- the whole-body exposure which is 50% fatal within 30 days (when untreated) is around 250-300 rad (under these circumstances, 1 rad ~ 1 rem).
Jupiter's radiation belts are millions of times stronger than Earth's, so if an astronaut spent the same time in them (about 3 hours total on a lunar mission -- but Jupiter's much larger, and so your speed would have to be hugely greater to make the transit in that time) they'd get an exposure of millions of rem. In other words, they'd be dead almost immediately -- an exposure of mere seconds would probably be lethal.
Galileo is radiation-hardened, since it was intended to survive in this environment; however, it's been there for almost three times its design limit, and it must be getting pretty fried by now. As a matter of fact, last year when it made its first really close flyby of Io, there was concern that the radiation would corrupt the computer memory and cause it to go into safe mode, or blind the camera's CCD. When that didn't happen, everyone was relieved -- and they promptly did it again!
The radiation environment is severe enough that they actually expect the spacecraft to be physically destroyed in a few hundred million years, if they left it in Jupiter orbit.
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I think this is always the case when one does science with one's eyes open. It's only when confirmation of pet theories is sought (ignoring evetything that doesn't fit the theory) that we appear to gaining on the Universe's complexity. Was it Haldane who said something about the Universe not only being stranger than we imagine, it's stranger than we can imagine?
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The thing about "faster, better, cheaper" funding is that there's a threshold beneath which you can't reliably do the job -- as they found out with the Polar Lander and Orbiter last year.
Pathfinder by itself -- the one lander -- cost as much as the Polar Lander and Orbiter together. That's part of why it worked... (another other part was luck, 'cause the airbags are a little marginal).
The rest of why they can do it with so little funding is that they don't even try to do the science that the two Viking landers did -- the experiments are fewer and less sophisticated (in terms of todays technology, anyway) -- and operational budgets are small, because the landers are solar powered and therefore don't last more than a few months. Remember how citizens chipped in money to keep Viking operating, after NASA's ops funding ran dry many years into the mission?
But Viking used RTGs, not solar... and I'm not gonna go there -- at least in this thread. ;)
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I think there are a couple of reasons why they want to use active-landing systems instead of the passive airbags -- and I don't think that weight has much to do with it. First, they're interested in landing within a much smaller footprint than is possible with a purely-ballistic system (with the airbags, all the aiming is done prior to entering the martian atmosphere -- they want fine control for return missions). Second, I suspect that most of the people involved with Pathfinder were holding their breath, hoping the airbags would work -- you have no idea how much finagling it took to make them even halfway acceptable, once it was clear there would probably be a large horizontal velocity component on impact (which the system wasn't designed for!). I know I nearly had a heart attack before the beacon stopped moving, but didn't stop broadcasting...
Oh, they know how to do those -- they did it twice in 1976, with the Viking& lt;/I> landers. The problem with the Polar Lander was that they didn't use the proven technology, but instead went with something quick and dirty^H^H^H^H^H^H^H^H I mean "cheaper," which turned out to have one of the most predictable failure modes around... but they didn't budget time or money to check for that, it seems.
They don't have to go to the moon to find the flaw in the MPL design: it was clear to the investigators what had happened, once people actually looked at the test results. Besides, it's almost as expensive landing something on the moon as it is on Mars -- the extra velocity needed is actually fairly small. Nah, the better way to design a lander is with your eyes open!
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I'll agree that it's a shame, but it's not new: the Russians already have a Buran (the "Russian Shuttle") in Gorky Park as an amusement-park ride (although I believe this is a static-test article, not one of the flight spacecraft).
And the US's very own NASA took the last two fully-functional Saturn V lunar boosters and laid 'em down as lawn ornaments in Huntsville and Cape Canaveral;a static test item is also on display in Houston (it's been alleged -- accurately, I believe -- that NASA did this to reduce competition with Shuttle).
From my POV, I don't know which is worse: selling the hardware for cash when you're broke, or disabling it for motives less admirable...
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I'll admit to having a minor stake in the Mars stuff, too -- it's just that my prejudices are on the other side. I worked on Pathfinder and will work on some stuff for the '01 missions (and I hope for the later ones!), so I know some of the people and know about some of the players on a professional level, not just what I read in the papers or online. It makes a difference to me.
That said, I can't really say I'm a fan of NASA's -- it's just that they're the only game in town.
Thanks for your participation -- it's been fun!
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Hmmmm... interesting take, but I don't follow the logic. Robert Folk ruined his reputation with the original "nannobacteria" proposals, and has only recently been supported somewhat by McKay et al. with the "martian fossils", Kajander and his collegues with nanobacteria as a cause for kidney stones, Miller-Hjelle and her collegues with nanobacteria as a cause for polycystic kidney disease, Uwi ns and her findings on nanobes growing on Triassic and Jurassic sandstones collected from petroleum exploration boreholes offshore Western Australia. The American Society for Microbiology has paid serious attention to the controversy, as might be expected. All in all, it's only been recently that "nanobacteria" findings have provided any good publicity at all; mostly, it's been the ruin of the discoverer (in fact, Folk has been described as "coming out of the closet" with his first papers, some 20 years ago -- strong prejudice exists!).
But now things are changing: there are more findings, and more support for the concept. This might even be a scientific paradigm change... and this was my earlier point, that "common sense" arguments are inherently flawed, because the universe is stranger than we imagine.
Alfre d Wegener proposed the theory in 1912, but it didn't receive much support (in the U.S., at least) until post-WWII. My college geology text has a chapter written in '65, which concludes "Although the subject is now a respectable one in scientific circles of the Northern Hemisphere, the question is still far from settled." (Physical Geology, Leet and Judson, 3rd Edition; Prentice-Hall, NJ, 1965)
Wilson, a Canadian geologist, brought everything together around '65 with his model of seafloor spreading, which happened to explain the Pacific seafloor magnetic anomalies found in '61 by Raff and Mason (these are reversed-magnetic-polarity stripes, which are embedded in the newly-created seafloor by the Earth's magnetic field, which periodically reverses -- creating alternating stripes which aren't explainable except by tectonic plate theory). This all but cinched it, but it took years for general acceptance to happen -- in '67, my geology prof wasn't yet convinced, and spent a lecture period arguing against it (the students, OTOH, tended to see the light right away, based on the evidence presented). In '68, Pinchon worked out the plate positions, and by the mid-70's, plate tectonic theory was accepted as correct by all but a few lingering die-hards. (It's interesting that similar remnant-field reversals have been discovered on Mars, isn't it?)
Yes, they were interesting times. Overthrow of "established scientific fact" is always interesting, yet it happens often... that's how science progresses, after all. Only some of the time do the revolutionaries get burned at the stake; the rest of the time, they are merely ridiculed in print and reviled in person.
I guess that's the difference between your opinion and theirs: they figured they had good evidence, and you figure they don't. Dave McKay (of NASA) still sticks pretty much by the findings, and Kathie Thomas-Keprta (Lockheed Martin) very strongly supports them; time will tell who is right. My point is that science never advances without people going out on a limb with their conviction that a new interpretation is correct, rather than the conventional wisdom. This is not the equivalent of perpetrating a hoax! -- even if they are subsequently proven wrong.
On the contrary: some people are getting funding to disprove the "martian fossil" findings. The ASM link quotes some of them. With any discovery, confirmation or refutation of the findings is critical to its acceptance, and the controversy is the process through which the findings on all sides are integrated by the scientific community; Mari on Anderson's lecture is a good summary of this particular controversy, and concludes (correctly, in my opinion) "The main drawback to this story is the media focus on such sensational news. Media hype may increase public awareness of science, but the problem is that the complexities get lost in the glare of the spotlights." Her last couple of sections are well worth reading.
I think the jury's still out, and I think you're prematurely making up your mind. But, hey, it's your mind -- do with it what you will.
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As far as I can tell, your argument boils down to:
There's a thin thread of possibility in the second definition, but it's not clear who was hoaxing whom -- and the intent is certainly in doubt.
I think the major flaw in your argument is the "common sense" argument: I can think of many examples of research dismissed precisely because of this, which later came to be regarded as fact because of the same reason (continental drift and plate tectonics being one I personally witnessed the change on -- the theory was finally accepted while I was in college, because the evidence became overwhelmingly supportive of it... and now it's "obvious").
The biggest argument against the "martian fossils" is the argument against nanobacteria... and that one seems to be falling (at least in the case of nanobacteria). While it's more likely than not that the "fossils" were actually something else, that is far from conclusive.
And as a final note, it's still "meteorite," not "asteroid."
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Believe what you will. The truth is that the researchers involved are all credible, with decent publishing histories behind them. And the initial paper was published in Science -- not exactly a journal known for accepting hoaxes, although they do like to be the first to publish controversial papers (and this was no doubt a controversial paper). But "controversial" != "hoax"... and the stature of some of the researchers involved is such that they'd be fools to perpetrate a hoax and destroy their careers.
I won't deny that NASA took advantage of the paper, but calling it a hoax is dangerously close to libeling some good researchers (only some of whom work for NASA). You might want to reconsider your statement?
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Hoax? Life-bearing asteroid? Maybe you'd make more cogent comments if you actually understood what you're talking about. The alleged fossil remains in a meteorite which is thought to have come from Mars (not an asteroid) were not a hoax; there's always the chance the researchers were wrong, but that's far from a hoax.
And for what it's worth, I don't see a problem with science results which get people interested and excited (the vast majority of those results, at least in astronomy/cosmology/planetary science, don't have to do with "finding life," although extraterrestrial life is a fascinating topic most people pick up on easily). The more people who understand and support scientific endeavor, the better, I say!
Of course, you might just be trolling, in which case I need some help with this hook...
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I don't know if that's JPLese and he's not completely describing the problem, or if space.com didn't understand it, although they hint at the cause on the second page. What happened is this:
When the receiver was designed, the Doppler shift in the probe's signal in the operational mode wasn't accounted for; it worked fine on the bench, with no delta-V, but the Doppler shift at Titan will push the sidebands (where the data is being transmitted) out of the receiver's range. Cassini will be going like the proverbial bat out of hell as it passes Titan and drops the probe, and the Doppler shift will be substantial.
Technically, this is "not as wide as the design called for," I guess, and it's not clear whether it's lack of a proper specification or lack of attention to detail (and I really can't guess which, since I never worked on that project -- I just talked this week to some of those who did).
The article also mentions slowing Cassini down for the encounter, but fails to mention that doing such a thing will screw much of the science opportunity: the subsequent gravity-whip maneuvers depend on the initial velocity and positioning, and losing that will prolong the mission, pushing much of the science past the design life of the spacecraft. Not to mention they'll have to completely recalculate the entire circum-Saturn trajectory, a task for which there's no funding.
It's a real bummer: this might be the last of the "big" planetary-science missions for a long time (everything else is "faster-better-cheaper", and we've seen some of the downsides there), and one of the most exciting parts is endangered -- so much that they're considering crippling a major fraction of the rest of the mission just to recover it.
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It's already happening, but not in production yet.
From the 2000 IEEE International Solid-State Circuits Conference schedule:
24.7 A 500Mb/s Quadruple-Data-Rate SDRAM Interface using a Skew Cancellation Technique 4:45 PM
J. Kim, S-H. Wang, J. Lee, H-S. Nam, Y-G. Kim, J-H. Shim, H. Ahn, S. Kang, K-N. Park*, B-H. Jeong*, J-H. Ahn*, B. Kim
Korea Advanced Institute of Science and Technology, Taejon, Korea
*Hyundai MicroElectronics Co. Ltd, Cheongju, Korea
A quadruple data rate (QDR) SDRAM I/O interface uses salient skew cancellation. Cancellation reduces skews between data lines on PCB to 250ps.
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For one example I'm painfully aware of, the size of reports in the aerospace industry has been increasing over the years -- and by "size" I mean total number of words, total number of figures, and so on. I suspect what's happening is that the effort which was once used to painstakingly correct (or simply do correctly the first time) the data package has now been diverted to the creation of more volume for the package, since correction on a computer-generated document is so easy.
When I started in the industry back in the early 80's, lots of engineers still wrote out their stuff by hand and gave it to the secretary to type up; they redlined the first draft, and a final copy was made. Now, the engineer types it in in the first place, the software fixes the spelling, and the engineer writes some more (just think how these guys talk... they write the same way! I can say this 'cause I'm one of 'em.).
Note that aerospace isn't the only place where this is happening -- it's pretty common, in my experience. And I haven't mentioned the amount of data (information) being generated by present-day science; just compare the handful of photos that the early Ranger lunar probes took, with the output of NEAR Shoemaker or Galileo. Or consider genome sequncing. Or numerical simulation of flow in aircraft design. Or numerical simulation of damn near anything.
I think there's a lot more information being generated, and it's only going to get worse.
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