KDE's file manager, kwm, also is a fair web browser. It is missing some functions, like Java and Javascript, but on some sites with intrusive Java, I count that as a feature.;-) --
I find it interesting that this experiment is used as proof of an abiotic origin of life. To bad living organisms use a totally different _enzymatic_ pathway to produce amino acids (building blocks of protiens). Miller's experiment showed absolutely nothing in relation to the origin of life on this planet.
(Yeah, Yeah, flamebait)
Yes, as you say, "flamebait." If you're not trolling, then you've entirely missed the point.
One of the questions in abiogenesis is, "Where did the organic chemicals of life come from before there were bacteria to manufacture them?" This question is elegantly answered by the Urey / Miller experiments. They show that most mixtures of reducing gasses expected to be found on primordial Earth-like planets, combined with an energy source strong enough to rearrange molecular bonds, generally results in many of the "chemicals of life."
The energy source, too, can be varied with good results. Electric sparks and UV light both work fine. I'd imagine ionizing radiation works too. --
More to the point, they get similar results with a variety of reducing gas mixtures, so the exact starting composition isn't as important as some folks would have you believe.
IIRC, they've even found one of the RNA bases in some runs. Interesting, yes? --
Short answer - don't expect an IR sensor to work in the rain or through fog, but they should work ok (probably lose some contrast and range) through dust and smoke.
Thanks for the info.
Too bad about the IR absorption. I might have bought one if it worked well in fog. Dust and smoke just aren't big enough problems here in Oregon to be worth the cash.... --
Titan is interesting. It has an atmosphere > twice Earth's, apparently made mostly of nitrogen but with valuable hydrocarbons present. From a colonization point of view, the thick atmosphere is also a problem -- it will carry heat away fast, and out by Saturn it gets Pretty Dern Cold(TM), since the sunlight is about 1/90th of what we get here at 1 AU.
Anyway, too little is known about Titan right now. Cassini's probe and radar will tell us some more. Questions:
What's the surface like? Ethane oceans? Ice continents covered with brown organic goo? Are all rocks (and thus ore bodies) covered with thick layers of ice and/or photochemical crud?
Why is there a distinct color difference at the Titan Equatorial Band?
What's the orange-brown crud in the atmosphere? Can it be used directly as a chemical feed stock or does it need extensive processing?
Between the dim sunlight and smoggy skies, solar power is not going to work. Can manned bases use fission power, or will the superstitions of neo-Luddites make us wait for fusion?
Etc. I'm sure the Cassini folks have a better list than I can think up off hand.
[ To avoid skewing the sales numbers, release Linux first, then Windows later. ]
I'd vote for this too, if Q3 had released a month ago. As it is, Id has to get the game into production as soon as possible for the Xmas consumer feeding frenzy. 8-)
(Id is trying to make money, and more power to them.)
Good point there. Makes you wonder how the whole financial/political/scientific infra-structure of space exploration works. Meaning: If it's for the benefit of Human-Kind, Why (or more importantly, WHO) do we have to pay?
WHO/WHY: Why, ourselves of course. The fuel and building materials and electronics aren't free. Nor do the engineers and technicians work for nothing. (OK, grad students on university projects excepted.;-)
Contrary to the late (and notorious) US Senator Proxmire's short-sighted harping, we have never launched a rocket full of dollar bills or gold coins into space. Every dollar spent was spent on Earth.
The question is: How much gets spent for space exploration vs. say, paper clip budget overruns amongst the myriad of gov. paper-pushers? (Am I biased? Certainly not! 8-)
...for cold fusion. Hot fusion still a just a pipe dream.
If by this you mean muon-catalyzed fusion, I believe the most optimistic power ratio is about 3:1, with the 3 on the power input side. So close, yet so far.... 8-(
If you're talking about Pons and Fleischman style "cold fusion" then I'm afraid you've got a lot of references to provide. I still keep an eye on sci.physics.fusion and I've never seen anyone cough up a repeatable recipe for cold fusion that really works. I've seen a lot of claims and counter-claims flow through my news reader, but never any hard data on a working model.
How many years has it been since that news conference in Utah? More than I care to remember. Where's the hot water heater that Dr. Pons promised in an article in a Utah newspaper years ago? Nowhere to be seen.
If anyone could have made a repeatable experiment, it should have been those two. But, no one has published the experiment that brings cold fusion back from laughing-stock status.
Why not? Could it be to keep commercial advantage?
Maybe. But, IMNSHO keeping such a thing quiet would be a mistake. Who's going to finance a cold fusion project after all the money that Toyota dumped into Dr. P and Dr. F's lab in south France, with no useful product at all?
And yet, if there really is a "cold fusion" effect (experimental error doesn't count as an effect) and it can be reproduced by anyone who cares to try, then the first person to publish the method will get the Nobel Prize that they deserve.
Consider what happened with high temperature superconductors, which were discovered around the same time. Within weeks, labs around the world were publishing both replications of the original recipe and improved ceramics that had higher transition temperatures. In just two or three years, you could order a Hi-Tc superconductor kit from Edmond's Scientific that would allow any talented youngster to make the stuff in their high school lab. Maybe you still can -- I haven't read Edmond's catalog in a long time.
So, I've got to ask again, "If it's real, where is it?"
Oh well, I'm just bummed that I can't go down to the local Radio Shock and buy a Mr. Fusion. 8-)
No, I'm talking about real, honest-to-Cthulhu radioactive decay, a process mediated by the Weak nuclear force. That means alpha or beta decay. Both Uranium and Thorium have well defined chains of decays they go through until they transmute into stable elements. (Sorry, no URL handy. Try a good physics text or any first year nuclear physics book.)
Real fission breaks up the nucleus into two or more big chunks, often together with several neutrons. And, a big release of energy. (Think strong nuclear force here.)
Admitted, some of the more fissionable isotopes also have a chance of spontaneous fission, but that's a small probability compared the main decay pathways.
Now if you're being pedantic and claiming that any emission of a baryon is "fission" then I suggest you go talk to the Hiroshima survivors. They'll set you straight. 8-(
The Earth is not heated by nuclear fission. It is heated by the natural radioactive decay of various radioisotopes that are part of the mantle (and maybe the core) material. The main elements are U, Th, and K.
Nifty bit of trivia: It's worth noting that there is evidence of an ancient, natural fission reactor that fired up spontaneously in the Oklo area of west Africa. This happened some 3 billion year ago, thanks to a rich bed of Uranium ore and the right combination of ground soil and water. In fact there are some 14 known reactor sites. Here's a link about the last one being mined: http://www.apnet.com/inscight/05131997/graphb.htm General info about Oklo: http://www.nuc.umr.edu/~ans/oklo.html The natural reactors depleted the amount of U235 present in the ore and left behind long lived fission products.
Interestingly, neither the fission products nor the plutonium bred from the ore's U238 had migrated from the original reactor sites, despite having had billions of years in which to travel, plus plenty of ground water during a good part of that time.
Anyway, while the Oklo area would have been slightly hotter locally, it could not have put out enough power to alter the global heat balance to any great extent.
That religious experience is unintelligible proves nothing whatsoever. *All* experience is unintelligible; try explaining 'blue' to a blind man.
Sure, but we can define "blue" as light with a wavelength from XXX to YYY nanometers. Blue light is both repeatable (every time I turn my blue LED, durned if I don't see blue) and measurable (use your favorite color meter). It's no problem for science. We can't directly sense radio waves or X-rays, yet both are well developed technologies.
Xtianity and most other western religions view their god(s) as omnipotient, omnipresent, and other omni- words. Those are properties that aren't repeatable (by us) and may not even be measurable (by us). And in any case, such gods aren't noted for dropping by and taking personality tests or altering the laws of physics on request. So, until a god started showing up and working miracles on a regular basis, scientists aren't going to be able to do much with him/her/it/them.
Speculation: If such a thing did happen, the best, most imaginative and flexible scientists would -- guess what -- start trying to make a science of theology. After all, you can't make supernovas or major earthquakes in the lab, yet we have astrophysics and seismology anyway. See Vernor Vinge's excellent A Fire Upon the Deep for hints of what such an Applied Theology would be like. 8-)
As mentioned above, check with http://www.waldherr.org/junkbuster/ for a slightly improved version of the Internet Junkbuster and filter files updated weekly and monthly.
(I just love to turn on the "tinygif 2" option and see all the banner ads I'm not downloading marked "Junkbuster".;-)
Junkbuster is a boon to anyone still using a 56K or less modem. It's worth it to me just to not have those stupid banner ads blinking at me all the time. (Does anyone remember The Andromeda Strain? 8-)
I think I'll just drop this. We're orders of magnitude apart insofar what we see as good science and engineering. To you good engineering is taking a risky endeavor and decreasing the risk as much as possible (an evolutionary approach.) To me good engineering seeks novel, risk free solutions (a revolutionary approach,) and is willing to be patient until the good solutions come.
Life is a risk. You take your life in your hands every time you drive to work. (If you bike, take the bus, or walk you take even bigger risks.) A gasoline truck drove by your workplace today. It had a small, but non-zero risk of intense fire or explosion. Pesticides, herbicides, and serious industrial chemicals are shipped by truck and rail every day. There are risks associated with all of this.
"The cowards never started and the weaklings died along the way." (Please direct all Politically Correct flames to the nearest propane tank.;-) There's dern little risk-free anything in this life. Get used to it. Work with it. Make it work for you. . . . If you just "wait" for revolutionary advances to come to you, they'll never happen. Somebody has to make them happen. Somebody willing to try something new, and possibly a bit dangerous.
And yes, I'm still going to minimize those risks to the extent possible and practical, even if you don't find that esthetically pleasing.
As an example, rather than using plutonium to power Cassini's instruments, why not a flywheel based generator? There have been great advances in flywheel technology lately. In low-G and free fall environments, friction isn't a worry, so you'd get pretty decent efficiency. You ought to be able to torque the flywheel back up by catching a little angular momentum during a grav assist, if you make the approach just right.
Ingenious, but there are a few problems:
Flywheels don't generate power. They just store energy. On a mission that will last 11 years or more, a reliable, long term source of power is needed.
Cassini's last gravity assist is at Jupiter. It won't reach Saturn until years later. What provides minimal housekeeping power (and heat) for that time?
Off hand, I really doubt you can pick up any significant power without a much steeper gravity gradient than either Jupiter or Saturn has (to say nothing of Earth). I suspect it would take a close approach to a neutron star or a black hole to spin up your flywheel. (And no, I'm not going to pull out MTW's Gravitation and try to remember enough calculus to use it without serious consulting money. 8-)
You'd do better to look into electrodynamic tethers. In the presence of a strong planetary magnetic field, they can turn an orbiter's kinetic energy into electricity and vice versa.
Cool? Yes. Ready to use in the outer Solar System? Definitely not.
We've had trouble making tethers work in the two Space Shuttle missions that tried them. The SEDS folks have had better luck with their regular and electrodynamic tethers, possibly because they started small and built up. Besides, the conditions dictated by the Cassini mission wouldn't be right for an ED tether.
It scares me to death to hear someone as apparently educated as you (and the others like you on this site) have no concept of long term ecological responsibility. It's enough for you that "you and I are alive right now," so therefore airborne dispersal of granulated heavy metals and radioactive material have no effect. DDT didn't get banned because humans started dropping off like flys in its presence. Lots and lots of major ecological damage was done before anyone started to do anything about it.
You're still missing my point: The claims that "Pu is the most toxic substance in the world" are bogus, wrong, and incorrect. If those claims were true, we should have been dead many times over. The DoE admits to something like 4.5 tons of Pu-239 was released by USA nuclear bomb testing. That's only the Pu. How about the radio-activated bomb casings, dirt, and other debris? How about the U-235? How about the vastly more deadly fission products? What about the Soviet and French bomb tests? Even more radio-crap kicked into the stratosphere.
When I say "we're still alive" that's an existence proof that the claims of the anti-Cassini groups are flat out wrong. It is not an invitation to dance about the world scattering PuO2 around. Sheesh!
Tell you what -- let's consider Teller's bet. If you still believe that Plutonium is the most lethal substance on Earth, then I'll swallow 1 milligram of Ir-coated Pu-238 dioxide, if you first swallow 1 milligram of botulism toxin. Then we'll see which is the most poisonous stuff around. You'll die in frothing agony within minutes while I might get cancer 20 years from now. Maybe. (Even that is unlikely thanks to the iridium coating -- but since Cassini is using Ir, so can I. 8-)
Furthermore, Cassini wasn't going to crash and didn't crash. If it had, I was willing to bet that the RTG designers had done their job right. (Didn't you watch the tapes of the RTG testing?) Even if they hadn't, we're back to the "deadly Pu" myth again.
You're "scared" that I and others aren't "ecologically responsible" enough to suit you. Well, sorry. I'm not going to stop thinking about life's risks and start emoting about them (i.e. become a neo-Luddite). And, I can't help your fears, other than to point out where they are unfounded and to hope that you will conquer them.
It's not about being a hippie or a luddite, it's just about acknowledging that the current dominant paradigm (to use a scary soc. word) of technological advancement has brought us some pretty dark returns. It's time to start learning from history. If we, as scientists (believe it or not, I am, in fact, a physicist - granted I'm a theorist) want to improve the reputation of scientific advancement, we have to start opening our eyes to the real world outside of the lab. Any risk is too much risk when it comes to endangering what little remains of the global ecosystem.
Well, hell. If you're a theoretical physicist, then you can break out Misner, Thorne, and Wheeler to find out how feasible your flywheel idea is. Remember that you're limited to, at most, one metric ton. (Even that is generous; the RTGs don't weigh that much.) And, you've got to fit the resulting flywheel and it's housing into the Shuttle's cargo bay. Oh, and make sure that this enormous spinning flywheel doesn't make it impossible to maneuver the probe. C'mon -- I dares ya! I double dares ya!;-)
Also, get off your philosophical high horse. Species have been made extinct with nothing more than sticks and stones. (E.g. the hypothesized extinction of the America's large mammals (mammoth, etc) by human hunting after the last Ice Age, and definitely the Dodo, killed by sailors armed with clubs.) Consider human misery caused by the Khmer Rouge with relatively little technology and a whole lot of savagery.
In other words, science isn't the problem; it's what you do with it. There's no tool in existence that can't be used for good or for evil. Any increase in power comes with an increase in responsibility. All your talk about "dark returns" and "want to improve the reputation of scientific achievement" strikes me as a bit too Woody Allen-esque for my tastes.
"Any risk is too much risk...." Feldgercarb! If you truly believe that, then you'd better go out and commit suicide, because your very existence is a slight risk to the global ecosystem. (Sure, it's an incredibly slight risk, but you're the one claiming "any risk is too much".) Remember the the Oklo natural nuclear reactor? It fired up in Africa (references not at hand) a long time ago, and operated sporadically for millions of years. No containment dome. No nothing -- just an unusually rich bed of uranium ore moderated by the soil and ground water. The planet survived that. It will survive us.
That's not to say that we can strew our garbage wherever we like. The ancient proverb, "Do not throw rocks in the well you drink from" still applies. But, the whole point about intelligent life is that it makes new resources and new ecological niches possible. If our species has a "purpose," then it may well be to bring life to lifeless planets. It is not to hide in the basement because we're afraid to do anything at all.
You didn't justify the claimed change in cancer rates.
(.... steep climb in the 60's, 70's, it kind of levelled off in the 80's, and kind of declined in the 90's,...)
In fact, if the Pu took 30-40 years to settle out, wouldn't we just be starting to see an increase in cancer?
Most importantly, you didn't comment on the effects of the anti-smoking campaigns, which started bearing fruit around the time that the claimed cancer rates started dropping.
Anyway, the evidence on dust is against you. Remember Mount Pinatubo(sp?), the volcano that blew up violently in the Phillipeans about ten years ago? It injected a large amount of sulfuric acid aerosols into the stratosphere. The aerosols took only 2 to 3 years to settle down into the troposphere, where rain could wash them out. I remember this clearly, because as an amateur astronomer, I complained about the high haze caused by that acid mist, until it finally cleared. 8-)
ummm... i didn't think we were done counting the casualties from nuke testing yet. seems to me that plenty of people are still suffering and dying from it, not that it's being publicly acknowledged. (and, frankly, i just don't get the mentality that it's ok to do a little more of a bad thing we've done a lot of in the past; not exactly what i'd call social evolution.)
You've missed my point. Did you read the other posts on the "Pu is the world's most toxic substance" urban myth? The very fact that you and I are alive refutes that legend. And, since that seems to be the lynch-pin of your argument, it casts doubt on the rest.
Also, along the "didn't think we're done counting casualties from nuke testing yet" line, how do you separate cancers from N tests versus cancers caused by smoking, food-borne carcinogens, radon seeping up from the basement, or whatever, at this late date? Epidemiology is tricky....
In fact, I wouldn't be surprised to learn that it is dern near impossible to trace the genesis of any specific cancer more than a decade or two from the suspected exposure. (At least, not outside of the lab, which you seem to scorn as the home of unrealistic fiends who want to force-feed you Pu-239. 8-)
. . . . Want some specific "truths" ? How about things like real statistics on the amount of debris in orbit over the earth, and the accuracy to which the trajectories of every piece are truly modelled. . . ..
Ah, now you're getting down to brass tacks, instead of throwing around glittering generalities. But, none of the complaints above invalidate anything you'd learn in Physics 101. They're all textbook examples of ballistics. Horrors!;-)
For what its worth, Space Command (or whatever agency lives under Cheyenne Mountain) tracks the trajectories of all that space junk. NASA routinely clears its orbits with them. "To what degree of accuracy?" Beats me; it's a national security secret.
But, it doesn't matter. The big stuff (say 6" across or more) is tracked by the large Schmidt cameras in Hawaii and various other locations around the world. Their orbits are known to within some classified, but small, amount of error. Anything smaller can't shift the probe's path enough to matter. Sure, one little paint chip could destroy a major subsystem, but that won't alter Cassini's orbit by even 1%. (Think conservation of momentum, another of those useless, totally divorced from the Real World, textbook concepts.)
And again, your alarm at even an infinitesimal possibility of a reentry seems to be based on an exaggerated view on the carcinogenic properties of PuO2 dispersed over some remote part of the world. This I dispute because it already happened and we didn't die. That's not a textbook problem; it's Real Life(TM) data.
In 1964, SNAP-??, installed in a military navsat, reentered the atmosphere. The RTG as designed incinerated the metallic Pu within. (This was a stupid design decision. If you want to gripe about any RTG, this is the one.)
As a result, future RTGs were designed to survive reentry. In 1968 and 1970, they did just that, in a weather satellite and Apollo 13's LEM, respectively. The weathersat RTGs were recovered, refurbished, and reused. The Apollo 13 RTGs were targeted at a deep ocean trench off of Fiji. No signs of leakage were ever discovered.
You might say, "They never really looked." Maybe they did, maybe they didn't. Either way, you're the one claiming world-shaking consequences to a RTG reentry. These happened, yet the searing waves of deadly radiation didn't scorch the life from the planet, or even the Pacific, and we're all here to tell the tale.
How many times are we going to have to hear, "Well, uh, in the tests everything SEEMED fine..." Between the government's history of misinformation and the fact that testing doesn't guarantee jack, I'm sorry if I'm a little skeptical about what I'm feed as truth.
Don't apologize, it is good to be skeptical. Doubt the government; doubt everything I write. Check and double check all assumptions and unstated conditions. Go back to the primary sources and check again.
On the other hand, don't go overboard and descend into paranoia. If the engineers really had kludged the heat shielding on the RTGs, or fudged the risk assessment on the chances of a launch explosion, why were so many of them -- and their families -- present at the launch? Wouldn't simple self-preservation send them into their cellars or on long vacations to the Yukon? 8-)
Is it not possible that they really did do a good job of protecting the RTGs and were proud enough of their work to be present at the launch?
Let me ask you this: Do you think it is even possible to build a RTG that will stand up to a launch accident?
If you don't, just say so. Nothing I write will be able to allay your fears, and we might better use the time elsewhere.
Sorry, but them's the breaks. I just can't condone strapping a bunch of highly toxic material to a rocket that has, what, about a 1 in 6 failure rate?
Again, you imply a vastly greater risk to this event that the evidence supports.
Hmmm.... That 1 in 6 claim sounds familiar. Have you been alarmed by one of those anti-Cassini web sites, the ones that can't tell the difference between a space probe and a H-bomb? If so, take every claim they make with an entire shaker of salt. More than that, is there some specific claim they've made that you would like to discuss?
Nonetheless, the chance of a disaster from which our species would not recover exists, and should be addressed. . . . I can wait a few years in order not to risk the lives of the vast majority of people on this planet . . . . What gives people who like technology the right to constantly risk the lives of those who don't?
This is bogus. See the other posts in the thread for reasons why. (I.e. If 72 pounds of plutonium dioxide can do us in, then why are we alive after tons of Pu-238 were blasted into the air by above ground nuke testing.)
If we let ourselves get used to cheap, brute force crutches like plutonium fueled vehicles, we get stuck with them - they become the standard, not the bonus.
Let's clarify this -- the rocket that launched Cassini was a chemically powered vehicle. The probe itself is equipped with chemical rockets, both for the main engine and the thrusters. Pu is not Cassini's "fuel." It is its power and (to a slight extent) heat source.
Better?
Nothing makes people like that feel more secure about themselves then to believe the great machine that they're a happy little cog in runs as well as everybody promised; that real life does work exactly like the sample problems in their textbooks; that there is never any need to step back and wonder what life might look like if a few "truths" were less than true.
Did you have any specific untrue "truths" in mind? Conservation of Mass-Energy? Newtonian mechanics? (Which are being used to calculate Cassini's trajectory.)
Anyway, I take the contrary view. Before Cassini's launch I saw more news airtime given to the anti-Cassini crowd than the pro-C side. I suppose that graying scientists were a lot less dramatic than oddballs with bad haircuts carrying signs and chanting "No Nukes!" IMNSHO the "cogs in the machine" are the ones who bought the media fear-mongering.
I agree that we should have a better propulsion source, but will not halt all exploration until one is devised. After all, how many new propulsion systems have been brought on-line in the past 30 years? Is there even one? (You can't count DS1's ion engine. They've been around since the 60s. The only innovation is political -- to let the engineers finally install an ion drive as the main engine of a probe.)
Sure, upgraded series of rockets come out, but they differ only in detail from the rockets of the 60s. And, the cost to launch a pound of payload into low orbit hasn't dropped below $3000. There's something wrong here.
Assuming you live in the USA, have you written your congresscritter to support NASA's "Future X" program?
. . ..there was a steep climb in the 60's, 70's, it kind of levelled off in the 80's, and kind of declined in the 90's, . ..
Very interesting, if true. References, please. (And especially, references that take into account the anti-smoking campaigns in the USA during the - wait for it - 80s and 90s.)
Please also explain why there should be a plateau in the 80s, if the half-life of the short lived fision products are months, days, or less, and the long lived products have half-lives of thousands or millions of years.
(Bonus points for essays on common mistakes made in epidemiology, and why correlation does not necessarily imply causation.)
Re:But what's the benefit for science and humanity
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Yes, solar power was considered and rejected. It would have taken solar panels with a surface area of about two tennis courts to power Cassini out by Saturn. Imagine trying to control a probe with two big floppy panels on it, each the size of a tennis court, each built as lightweight as possible. Now imagine controlling those panels out in the vacuum of space, with no air to dampen the vibrations that every slight attitude adjustment makes. Will the panels thrash around enough to damage themselves or the probe? It wouldn't surprise me to learn that controlling lightweight solar panels of that size is beyond the tested state of the art, although Skylab's panels were around that size (but were far too heavy to send to Saturn).
Having done that, further stretch your imagination to include the US Congress paying for a much bigger and heavier probe to Saturn. 8-)
Ironically enough, there was an another choice, but it was one that NASA rejected. Imagine the anti-nuke hysteria that would have happened if Cassini had been launched with an honest-to-God nuclear reactor, instead of just RTGs?
A fission reactor would actually be a bit safer than the RTGs, as it wouldn't need to be turned on until after the Earth fly-by. (But, RTGs are already so safe that the difference between 99.9999% and 99.99999% isn't very great.) Of course, outfitting Cassini with derivative of a SNAP reactor would mean that it would need solar cells for the E-V-E leg of the trajectory, and the reactor's emissions would probably blast the various particle instruments with spurious signals.
Probably the biggest turn-off to NASA was the lack of flight tested reactors. They wouldn't risk Cassini on a power source that hadn't been tested to run for decades.
So it comes down to solar power or RTGs, and solar just won't cut it out that far. Someday, maybe, when we have ultra lightweight and yet somehow more rigid concentrator cells. Don't hold your breath waiting for them.
Re:Do you really believe a "safety report" from NA
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Convenient that NASA wrote the safety report. Kind of like the CIA investigating itself.
NASA wrote the report because they did the engineering. Sheesh! Is everyone in the anti-Cassini / anti-RTG / anti-nuke crowd a conspiracy theorist? Or, worse, are they deliberately posturing that way to prime the real conspiracy nutbars?
They're lying, people! I mean, I want to promote space travel too, but don't be a sucker because they can count on all geeks blindly supporting NASA in everything they do. We are being used.
I strongly disagree with this. NASA does not have my uncritical support. I think the glory days are gone and the few good ideas left are mostly suppressed by the bureaucrats. Dan Goldin's much ballyhooed "Cheaper, Faster, Better" program is partly hype. Look at which programs were put on the chopping block when the budget was being cut. My hat is off the the folks at JPL and elsewhere who have to put up with NASA middle management for the chance to build a Mars Surveyor, NEAR, DS1, etc, every few years.
Despite all of this, when the science side of NASA, by some miracle, does manage to fool the PHBs and build a probe, and actually puts some decent engineering into it, I don't reflexively chop off their heads. I applaud them for it.
If you really "want to promote space travel" then you'd better lose your anti-nuclear attitude and instead support advanced propulsion systems. What we have right now isn't going to get humans out of the inner solar system. Some form of advanced propulsion will eventually be needed, be it fission, fusion, or even antimatter. If you build a working system from MagSails, solar sails, or tethers, I will applaud you. But, dang it, we need something that works.
In the meantime, read the other posts in this thread to see why worrying about a simple RTG is silly when the DoE has admitted that tons of Pu was released into the air by nuke testing, and when so many other radioisotope sources spew vastly more Curies of crap into the air unchecked. (Consider the U and Th content of fly-ash from unscrubbed coal power plants for a start.)
Then for an encore, learn enough Failure Analysis to be able to intelligently check NASA's impact report for substansive errors. If you find any, I'll listen to you.
One of the more radical suggestions I've seen is: Don't come back.
Replace the many tons of return fuel with the equipment to create a colony and lab equipment to analyze the samples on Mars. Only later, when increased interplanetary travel has made investment in the necessary infrastructure practical, do the original colonists get to come back for a vacation.
This plan has the advantage of not risking any possible contamination of Earth by returning astronauts. Even long term medical problems would have become visible before the first return trip. (Not that such is a risk is great, as demonstrated by the Martian metorites that have already "contaminated" Earth.) But, every little bit helps convince the PointyHaired Politicians.
Despite this rather extreme level of commitment, I believe NASA would get volunteers if they asked today....
Moving from the ICR to the CSF (Creation Science Foundation), eh? On a wild hunch, (8-) I searched the Talk.Origins archive for this quote, too. Surprise! It was taken out of context from a talk by Dr. Colin Patterson in 1981, and twists the meaning of his presentation to be the opposite of Patterson's "qualified" opinion.
First, far from being devoid of transitional fossils, Patterson's Evolution is full of them. Here's an example from page 131:
"In several animal and plant groups, enough fossils are known to bridge the wide gaps between existing types. In mammals, for example, the gap between horses, asses and zebras (genus Equus) and their closest living relatives, the rhinoceroses and tapirs, is filled by an extensive series of fossils extending back sixty-million years to a small animal,
Hyracotherium, which can only be distinguished from the rhinoceros-tapir group by one or two horse-like details of the skull. There are many other examples of fossil 'missing links', such as Archaeopteryx, the Jurassic bird which links birds with dinosaurs (Fig. 45), and Ichthyostega, the late Devonian amphibian which links land vertebrates and the extinct choanate (having internal nostrils) fishes. . .."
That sounds to me like Dr. Patterson has not only heard about evolutionary transitions, but did include them in his book, Evolution.
The author of the Talk.Origins essay, Lionel Theunissen, corresponded with the principals in this matter. Dr. Patterson replied with details, apparently his talk on "Systematics Discussion Group" was secretly recorded by a creationist and quote-mined. (This taping and misattribution may not be legal in Australia.) The creationists were evasive and refused to back up their claims, or even reveal their primary sources for the quote, until pressed with information from Patterson's letter. See Patterson Misquoted: A Tale of Two 'Cites' for the whole thing.
Now, I've got to ask you something, slvrsrfr. I hope that you have checked out the references I've entered, and gone further to read the primary sources to make sure that these are fair refutations to your case. Of the two quotes that you've posted, both have been shown to be scraps of text (or words) that have been taken out of context and twisted backwards to mean the exact opposite of their author's positions by a creationist. Indeed, let the record show that both the ICR and CSF have tried to steal their opponent's authority as "qualified people" and to use it to deceive anybody who didn't look up the facts. So, I ask you:
Is stealing other people's authority the way to find the truth?
Is this Xtian integrity or honesty?
What does this do for the cause of truth and justice?
Most importantly, surely even the most devout believer in Creation and Xtianity should cast out those who tell lies about others. Would not such a person want to keep their cause clean of the taint of the dirty dealings mentioned above? After all, who is "The Father of Lies," hmmmm?
Patterson, Colin, "Evolution" 1978, Routledge & Kegan Paul Ltd.
Have you ever considered what scientists would do if confronted with a god, or some entity that could pinch-hit for a god? Maybe some (being human) would retreat into denial but the good ones, the flexible ones, would start trying to understand this new facet of reality.
Fast forward a few decades and you'd end up with Applied Theology as a hard science! 8-)
For this and other mind-stretching concepts, read Vernor Vinge's A Fire Upon the Deep. Good book!
Slashdot Mirror
KDE's file manager, kwm, also is a fair web browser. It is missing some functions, like Java and Javascript, but on some sites with intrusive Java, I count that as a feature. ;-)
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(Yeah, Yeah, flamebait)
Yes, as you say, "flamebait." If you're not trolling, then you've entirely missed the point.
One of the questions in abiogenesis is, "Where did the organic chemicals of life come from before there were bacteria to manufacture them?" This question is elegantly answered by the Urey / Miller experiments. They show that most mixtures of reducing gasses expected to be found on primordial Earth-like planets, combined with an energy source strong enough to rearrange molecular bonds, generally results in many of the "chemicals of life."
The energy source, too, can be varied with good results. Electric sparks and UV light both work fine. I'd imagine ionizing radiation works too.
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IIRC, they've even found one of the RNA bases in some runs. Interesting, yes?
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Thanks for the info.
Too bad about the IR absorption. I might have bought one if it worked well in fog. Dust and smoke just aren't big enough problems here in Oregon to be worth the cash....
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I wonder if this will see hot engines through fog and help prevent chain collisions like the recent one outside of Denver?
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Anyway, too little is known about Titan right now. Cassini's probe and radar will tell us some more. Questions:
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I'd vote for this too, if Q3 had released a month ago. As it is, Id has to get the game into production as soon as possible for the Xmas consumer feeding frenzy. 8-)
(Id is trying to make money, and more power to them.)
WHO/WHY: Why, ourselves of course. The fuel and building materials and electronics aren't free. Nor do the engineers and technicians work for nothing. (OK, grad students on university projects excepted. ;-)
Contrary to the late (and notorious) US Senator Proxmire's short-sighted harping, we have never launched a rocket full of dollar bills or gold coins into space. Every dollar spent was spent on Earth.
The question is: How much gets spent for space exploration vs. say, paper clip budget overruns amongst the myriad of gov. paper-pushers? (Am I biased? Certainly not! 8-)
If by this you mean muon-catalyzed fusion, I believe the most optimistic power ratio is about 3:1, with the 3 on the power input side. So close, yet so far.... 8-(
If you're talking about Pons and Fleischman style "cold fusion" then I'm afraid you've got a lot of references to provide. I still keep an eye on sci.physics.fusion and I've never seen anyone cough up a repeatable recipe for cold fusion that really works. I've seen a lot of claims and counter-claims flow through my news reader, but never any hard data on a working model.
How many years has it been since that news conference in Utah? More than I care to remember. Where's the hot water heater that Dr. Pons promised in an article in a Utah newspaper years ago? Nowhere to be seen.
If anyone could have made a repeatable experiment, it should have been those two. But, no one has published the experiment that brings cold fusion back from laughing-stock status.
Why not? Could it be to keep commercial advantage?
Maybe. But, IMNSHO keeping such a thing quiet would be a mistake. Who's going to finance a cold fusion project after all the money that Toyota dumped into Dr. P and Dr. F's lab in south France, with no useful product at all?
And yet, if there really is a "cold fusion" effect (experimental error doesn't count as an effect) and it can be reproduced by anyone who cares to try, then the first person to publish the method will get the Nobel Prize that they deserve.
Consider what happened with high temperature superconductors, which were discovered around the same time. Within weeks, labs around the world were publishing both replications of the original recipe and improved ceramics that had higher transition temperatures. In just two or three years, you could order a Hi-Tc superconductor kit from Edmond's Scientific that would allow any talented youngster to make the stuff in their high school lab. Maybe you still can -- I haven't read Edmond's catalog in a long time.
So, I've got to ask again, "If it's real, where is it?"
Oh well, I'm just bummed that I can't go down to the local Radio Shock and buy a Mr. Fusion. 8-)
Real fission breaks up the nucleus into two or more big chunks, often together with several neutrons. And, a big release of energy. (Think strong nuclear force here.)
Admitted, some of the more fissionable isotopes also have a chance of spontaneous fission, but that's a small probability compared the main decay pathways.
Now if you're being pedantic and claiming that any emission of a baryon is "fission" then I suggest you go talk to the Hiroshima survivors. They'll set you straight. 8-(
The Earth is not heated by nuclear fission. It is heated by the natural radioactive decay of various radioisotopes that are part of the mantle (and maybe the core) material. The main elements are U, Th, and K.
Nifty bit of trivia: It's worth noting that there is evidence of an ancient, natural fission reactor that fired up spontaneously in the Oklo area of west Africa. This happened some 3 billion year ago, thanks to a rich bed of Uranium ore and the right combination of ground soil and water. In fact there are some 14 known reactor sites. Here's a link about the last one being mined:
http://www.apnet.com/inscight/05131997/graphb.htm
General info about Oklo: http://www.nuc.umr.edu/~ans/oklo.html
The natural reactors depleted the amount of U235 present in the ore and left behind long lived fission products.
Interestingly, neither the fission products nor the plutonium bred from the ore's U238 had migrated from the original reactor sites, despite having had billions of years in which to travel, plus plenty of ground water during a good part of that time.
Anyway, while the Oklo area would have been slightly hotter locally, it could not have put out enough power to alter the global heat balance to any great extent.
Sure, but we can define "blue" as light with a wavelength from XXX to YYY nanometers. Blue light is both repeatable (every time I turn my blue LED, durned if I don't see blue) and measurable (use your favorite color meter). It's no problem for science. We can't directly sense radio waves or X-rays, yet both are well developed technologies.
Xtianity and most other western religions view their god(s) as omnipotient, omnipresent, and other omni- words. Those are properties that aren't repeatable (by us) and may not even be measurable (by us). And in any case, such gods aren't noted for dropping by and taking personality tests or altering the laws of physics on request. So, until a god started showing up and working miracles on a regular basis, scientists aren't going to be able to do much with him/her/it/them.
Speculation: If such a thing did happen, the best, most imaginative and flexible scientists would -- guess what -- start trying to make a science of theology. After all, you can't make supernovas or major earthquakes in the lab, yet we have astrophysics and seismology anyway. See Vernor Vinge's excellent A Fire Upon the Deep for hints of what such an Applied Theology would be like. 8-)
(I just love to turn on the "tinygif 2" option and see all the banner ads I'm not downloading marked "Junkbuster". ;-)
Junkbuster is a boon to anyone still using a 56K or less modem. It's worth it to me just to not have those stupid banner ads blinking at me all the time. (Does anyone remember The Andromeda Strain? 8-)
There's no excuse for a hanging PCI board, but there's even less excuse for the PCI subsystem to permit one to lock up the system.
Life is a risk. You take your life in your hands every time you drive to work. (If you bike, take the bus, or walk you take even bigger risks.) A gasoline truck drove by your workplace today. It had a small, but non-zero risk of intense fire or explosion. Pesticides, herbicides, and serious industrial chemicals are shipped by truck and rail every day. There are risks associated with all of this.
"The cowards never started and the weaklings died along the way." (Please direct all Politically Correct flames to the nearest propane tank. ;-) There's dern little risk-free anything in this life. Get used to it. Work with it. Make it work for you. . . . If you just "wait" for revolutionary advances to come to you, they'll never happen. Somebody has to make them happen. Somebody willing to try something new, and possibly a bit dangerous.
And yes, I'm still going to minimize those risks to the extent possible and practical, even if you don't find that esthetically pleasing.
As an example, rather than using plutonium to power Cassini's instruments, why not a flywheel based generator? There have been great advances in flywheel technology lately. In low-G and free fall environments, friction isn't a worry, so you'd get pretty decent efficiency. You ought to be able to torque the flywheel back up by catching a little angular momentum during a grav assist, if you make the approach just right.
Ingenious, but there are a few problems:
- Flywheels don't generate power. They just store energy. On a mission that will last 11 years or more, a reliable, long term source of power is needed.
- Cassini's last gravity assist is at Jupiter. It won't reach Saturn until years later. What provides minimal housekeeping power (and heat) for that time?
- Off hand, I really doubt you can pick up any significant power without a much steeper gravity gradient than either Jupiter or Saturn has (to say nothing of Earth). I suspect it would take a close approach to a neutron star or a black hole to spin up your flywheel. (And no, I'm not going to pull out MTW's Gravitation and try to remember enough calculus to use it without serious consulting money. 8-)
You'd do better to look into electrodynamic tethers. In the presence of a strong planetary magnetic field, they can turn an orbiter's kinetic energy into electricity and vice versa.Cool? Yes. Ready to use in the outer Solar System? Definitely not.
We've had trouble making tethers work in the two Space Shuttle missions that tried them. The SEDS folks have had better luck with their regular and electrodynamic tethers, possibly because they started small and built up. Besides, the conditions dictated by the Cassini mission wouldn't be right for an ED tether.
It scares me to death to hear someone as apparently educated as you (and the others like you on this site) have no concept of long term ecological responsibility. It's enough for you that "you and I are alive right now," so therefore airborne dispersal of granulated heavy metals and radioactive material have no effect. DDT didn't get banned because humans started dropping off like flys in its presence. Lots and lots of major ecological damage was done before anyone started to do anything about it.
You're still missing my point: The claims that "Pu is the most toxic substance in the world" are bogus, wrong, and incorrect. If those claims were true, we should have been dead many times over. The DoE admits to something like 4.5 tons of Pu-239 was released by USA nuclear bomb testing. That's only the Pu. How about the radio-activated bomb casings, dirt, and other debris? How about the U-235? How about the vastly more deadly fission products? What about the Soviet and French bomb tests? Even more radio-crap kicked into the stratosphere.
When I say "we're still alive" that's an existence proof that the claims of the anti-Cassini groups are flat out wrong. It is not an invitation to dance about the world scattering PuO2 around. Sheesh!
Tell you what -- let's consider Teller's bet. If you still believe that Plutonium is the most lethal substance on Earth, then I'll swallow 1 milligram of Ir-coated Pu-238 dioxide, if you first swallow 1 milligram of botulism toxin. Then we'll see which is the most poisonous stuff around. You'll die in frothing agony within minutes while I might get cancer 20 years from now. Maybe. (Even that is unlikely thanks to the iridium coating -- but since Cassini is using Ir, so can I. 8-)
Furthermore, Cassini wasn't going to crash and didn't crash. If it had, I was willing to bet that the RTG designers had done their job right. (Didn't you watch the tapes of the RTG testing?) Even if they hadn't, we're back to the "deadly Pu" myth again.
You're "scared" that I and others aren't "ecologically responsible" enough to suit you. Well, sorry. I'm not going to stop thinking about life's risks and start emoting about them (i.e. become a neo-Luddite). And, I can't help your fears, other than to point out where they are unfounded and to hope that you will conquer them.
It's not about being a hippie or a luddite, it's just about acknowledging that the current dominant paradigm (to use a scary soc. word) of technological advancement has brought us some pretty dark returns. It's time to start learning from history. If we, as scientists (believe it or not, I am, in fact, a physicist - granted I'm a theorist) want to improve the reputation of scientific advancement, we have to start opening our eyes to the real world outside of the lab. Any risk is too much risk when it comes to endangering what little remains of the global ecosystem.
Well, hell. If you're a theoretical physicist, then you can break out Misner, Thorne, and Wheeler to find out how feasible your flywheel idea is. Remember that you're limited to, at most, one metric ton. (Even that is generous; the RTGs don't weigh that much.) And, you've got to fit the resulting flywheel and it's housing into the Shuttle's cargo bay. Oh, and make sure that this enormous spinning flywheel doesn't make it impossible to maneuver the probe. C'mon -- I dares ya! I double dares ya! ;-)
Also, get off your philosophical high horse. Species have been made extinct with nothing more than sticks and stones. (E.g. the hypothesized extinction of the America's large mammals (mammoth, etc) by human hunting after the last Ice Age, and definitely the Dodo, killed by sailors armed with clubs.) Consider human misery caused by the Khmer Rouge with relatively little technology and a whole lot of savagery.
In other words, science isn't the problem; it's what you do with it. There's no tool in existence that can't be used for good or for evil. Any increase in power comes with an increase in responsibility. All your talk about "dark returns" and "want to improve the reputation of scientific achievement" strikes me as a bit too Woody Allen-esque for my tastes.
"Any risk is too much risk ...." Feldgercarb! If you truly believe that, then you'd better go out and commit suicide, because your very existence is a slight risk to the global ecosystem. (Sure, it's an incredibly slight risk, but you're the one claiming "any risk is too much".) Remember the the Oklo natural nuclear reactor? It fired up in Africa (references not at hand) a long time ago, and operated sporadically for millions of years. No containment dome. No nothing -- just an unusually rich bed of uranium ore moderated by the soil and ground water. The planet survived that. It will survive us.
That's not to say that we can strew our garbage wherever we like. The ancient proverb, "Do not throw rocks in the well you drink from" still applies. But, the whole point about intelligent life is that it makes new resources and new ecological niches possible. If our species has a "purpose," then it may well be to bring life to lifeless planets. It is not to hide in the basement because we're afraid to do anything at all.
- You didn't provide any references.
- You didn't justify the claimed change in cancer rates. In fact, if the Pu took 30-40 years to settle out, wouldn't we just be starting to see an increase in cancer?
- Most importantly, you didn't comment on the effects of the anti-smoking campaigns, which started bearing fruit around the time that the claimed cancer rates started dropping.
Anyway, the evidence on dust is against you. Remember Mount Pinatubo(sp?), the volcano that blew up violently in the Phillipeans about ten years ago? It injected a large amount of sulfuric acid aerosols into the stratosphere. The aerosols took only 2 to 3 years to settle down into the troposphere, where rain could wash them out. I remember this clearly, because as an amateur astronomer, I complained about the high haze caused by that acid mist, until it finally cleared. 8-)You've missed my point. Did you read the other posts on the "Pu is the world's most toxic substance" urban myth? The very fact that you and I are alive refutes that legend. And, since that seems to be the lynch-pin of your argument, it casts doubt on the rest.
Also, along the "didn't think we're done counting casualties from nuke testing yet" line, how do you separate cancers from N tests versus cancers caused by smoking, food-borne carcinogens, radon seeping up from the basement, or whatever, at this late date? Epidemiology is tricky....
In fact, I wouldn't be surprised to learn that it is dern near impossible to trace the genesis of any specific cancer more than a decade or two from the suspected exposure. (At least, not outside of the lab, which you seem to scorn as the home of unrealistic fiends who want to force-feed you Pu-239. 8-)
. . . . Want some specific "truths" ? How about things like real statistics on the amount of debris in orbit over the earth, and the accuracy to which the trajectories of every piece are truly modelled. . . . .
Ah, now you're getting down to brass tacks, instead of throwing around glittering generalities. But, none of the complaints above invalidate anything you'd learn in Physics 101. They're all textbook examples of ballistics. Horrors! ;-)
For what its worth, Space Command (or whatever agency lives under Cheyenne Mountain) tracks the trajectories of all that space junk. NASA routinely clears its orbits with them. "To what degree of accuracy?" Beats me; it's a national security secret.
But, it doesn't matter. The big stuff (say 6" across or more) is tracked by the large Schmidt cameras in Hawaii and various other locations around the world. Their orbits are known to within some classified, but small, amount of error. Anything smaller can't shift the probe's path enough to matter. Sure, one little paint chip could destroy a major subsystem, but that won't alter Cassini's orbit by even 1%. (Think conservation of momentum, another of those useless, totally divorced from the Real World, textbook concepts.)
And again, your alarm at even an infinitesimal possibility of a reentry seems to be based on an exaggerated view on the carcinogenic properties of PuO2 dispersed over some remote part of the world. This I dispute because it already happened and we didn't die. That's not a textbook problem; it's Real Life(TM) data.
In 1964, SNAP-??, installed in a military navsat, reentered the atmosphere. The RTG as designed incinerated the metallic Pu within. (This was a stupid design decision. If you want to gripe about any RTG, this is the one.)
As a result, future RTGs were designed to survive reentry. In 1968 and 1970, they did just that, in a weather satellite and Apollo 13's LEM, respectively. The weathersat RTGs were recovered, refurbished, and reused. The Apollo 13 RTGs were targeted at a deep ocean trench off of Fiji. No signs of leakage were ever discovered.
You might say, "They never really looked." Maybe they did, maybe they didn't. Either way, you're the one claiming world-shaking consequences to a RTG reentry. These happened, yet the searing waves of deadly radiation didn't scorch the life from the planet, or even the Pacific, and we're all here to tell the tale.
How many times are we going to have to hear, "Well, uh, in the tests everything SEEMED fine..." Between the government's history of misinformation and the fact that testing doesn't guarantee jack, I'm sorry if I'm a little skeptical about what I'm feed as truth.
Don't apologize, it is good to be skeptical. Doubt the government; doubt everything I write. Check and double check all assumptions and unstated conditions. Go back to the primary sources and check again.
On the other hand, don't go overboard and descend into paranoia. If the engineers really had kludged the heat shielding on the RTGs, or fudged the risk assessment on the chances of a launch explosion, why were so many of them -- and their families -- present at the launch? Wouldn't simple self-preservation send them into their cellars or on long vacations to the Yukon? 8-)
Is it not possible that they really did do a good job of protecting the RTGs and were proud enough of their work to be present at the launch?
Let me ask you this: Do you think it is even possible to build a RTG that will stand up to a launch accident?
If you don't, just say so. Nothing I write will be able to allay your fears, and we might better use the time elsewhere.
Sorry, but them's the breaks. I just can't condone strapping a bunch of highly toxic material to a rocket that has, what, about a 1 in 6 failure rate?
Again, you imply a vastly greater risk to this event that the evidence supports.
Hmmm.... That 1 in 6 claim sounds familiar. Have you been alarmed by one of those anti-Cassini web sites, the ones that can't tell the difference between a space probe and a H-bomb? If so, take every claim they make with an entire shaker of salt. More than that, is there some specific claim they've made that you would like to discuss?
This is bogus. See the other posts in the thread for reasons why. (I.e. If 72 pounds of plutonium dioxide can do us in, then why are we alive after tons of Pu-238 were blasted into the air by above ground nuke testing.)
If we let ourselves get used to cheap, brute force crutches like plutonium fueled vehicles, we get stuck with them - they become the standard, not the bonus.
Let's clarify this -- the rocket that launched Cassini was a chemically powered vehicle. The probe itself is equipped with chemical rockets, both for the main engine and the thrusters. Pu is not Cassini's "fuel." It is its power and (to a slight extent) heat source.
Better?
Nothing makes people like that feel more secure about themselves then to believe the great machine that they're a happy little cog in runs as well as everybody promised; that real life does work exactly like the sample problems in their textbooks; that there is never any need to step back and wonder what life might look like if a few "truths" were less than true.
Did you have any specific untrue "truths" in mind? Conservation of Mass-Energy? Newtonian mechanics? (Which are being used to calculate Cassini's trajectory.)
Anyway, I take the contrary view. Before Cassini's launch I saw more news airtime given to the anti-Cassini crowd than the pro-C side. I suppose that graying scientists were a lot less dramatic than oddballs with bad haircuts carrying signs and chanting "No Nukes!" IMNSHO the "cogs in the machine" are the ones who bought the media fear-mongering.
I agree that we should have a better propulsion source, but will not halt all exploration until one is devised. After all, how many new propulsion systems have been brought on-line in the past 30 years? Is there even one? (You can't count DS1's ion engine. They've been around since the 60s. The only innovation is political -- to let the engineers finally install an ion drive as the main engine of a probe.)
Sure, upgraded series of rockets come out, but they differ only in detail from the rockets of the 60s. And, the cost to launch a pound of payload into low orbit hasn't dropped below $3000. There's something wrong here.
Assuming you live in the USA, have you written your congresscritter to support NASA's "Future X" program?
Very interesting, if true. References, please. (And especially, references that take into account the anti-smoking campaigns in the USA during the - wait for it - 80s and 90s.)
Please also explain why there should be a plateau in the 80s, if the half-life of the short lived fision products are months, days, or less, and the long lived products have half-lives of thousands or millions of years.
(Bonus points for essays on common mistakes made in epidemiology, and why correlation does not necessarily imply causation.)
Having done that, further stretch your imagination to include the US Congress paying for a much bigger and heavier probe to Saturn. 8-)
Ironically enough, there was an another choice, but it was one that NASA rejected. Imagine the anti-nuke hysteria that would have happened if Cassini had been launched with an honest-to-God nuclear reactor, instead of just RTGs?
A fission reactor would actually be a bit safer than the RTGs, as it wouldn't need to be turned on until after the Earth fly-by. (But, RTGs are already so safe that the difference between 99.9999% and 99.99999% isn't very great.) Of course, outfitting Cassini with derivative of a SNAP reactor would mean that it would need solar cells for the E-V-E leg of the trajectory, and the reactor's emissions would probably blast the various particle instruments with spurious signals.
Probably the biggest turn-off to NASA was the lack of flight tested reactors. They wouldn't risk Cassini on a power source that hadn't been tested to run for decades.
So it comes down to solar power or RTGs, and solar just won't cut it out that far. Someday, maybe, when we have ultra lightweight and yet somehow more rigid concentrator cells. Don't hold your breath waiting for them.
NASA wrote the report because they did the engineering. Sheesh! Is everyone in the anti-Cassini / anti-RTG / anti-nuke crowd a conspiracy theorist? Or, worse, are they deliberately posturing that way to prime the real conspiracy nutbars?
They're lying, people! I mean, I want to promote space travel too, but don't be a sucker because they can count on all geeks blindly supporting NASA in everything they do. We are being used.
I strongly disagree with this. NASA does not have my uncritical support. I think the glory days are gone and the few good ideas left are mostly suppressed by the bureaucrats. Dan Goldin's much ballyhooed "Cheaper, Faster, Better" program is partly hype. Look at which programs were put on the chopping block when the budget was being cut. My hat is off the the folks at JPL and elsewhere who have to put up with NASA middle management for the chance to build a Mars Surveyor, NEAR, DS1, etc, every few years.
Despite all of this, when the science side of NASA, by some miracle, does manage to fool the PHBs and build a probe, and actually puts some decent engineering into it, I don't reflexively chop off their heads. I applaud them for it.
If you really "want to promote space travel" then you'd better lose your anti-nuclear attitude and instead support advanced propulsion systems. What we have right now isn't going to get humans out of the inner solar system. Some form of advanced propulsion will eventually be needed, be it fission, fusion, or even antimatter. If you build a working system from MagSails, solar sails, or tethers, I will applaud you. But, dang it, we need something that works.
In the meantime, read the other posts in this thread to see why worrying about a simple RTG is silly when the DoE has admitted that tons of Pu was released into the air by nuke testing, and when so many other radioisotope sources spew vastly more Curies of crap into the air unchecked. (Consider the U and Th content of fly-ash from unscrubbed coal power plants for a start.)
Then for an encore, learn enough Failure Analysis to be able to intelligently check NASA's impact report for substansive errors. If you find any, I'll listen to you.
Replace the many tons of return fuel with the equipment to create a colony and lab equipment to analyze the samples on Mars. Only later, when increased interplanetary travel has made investment in the necessary infrastructure practical, do the original colonists get to come back for a vacation.
This plan has the advantage of not risking any possible contamination of Earth by returning astronauts. Even long term medical problems would have become visible before the first return trip. (Not that such is a risk is great, as demonstrated by the Martian metorites that have already "contaminated" Earth.) But, every little bit helps convince the PointyHaired Politicians.
Despite this rather extreme level of commitment, I believe NASA would get volunteers if they asked today....
It's being reimplemented with networking built in from the start as King of the Hill. It's still in early development, but already is fun to play.
First, far from being devoid of transitional fossils, Patterson's Evolution is full of them. Here's an example from page 131:
That sounds to me like Dr. Patterson has not only heard about evolutionary transitions, but did include them in his book, Evolution.The author of the Talk.Origins essay, Lionel Theunissen, corresponded with the principals in this matter. Dr. Patterson replied with details, apparently his talk on "Systematics Discussion Group" was secretly recorded by a creationist and quote-mined. (This taping and misattribution may not be legal in Australia.) The creationists were evasive and refused to back up their claims, or even reveal their primary sources for the quote, until pressed with information from Patterson's letter. See Patterson Misquoted: A Tale of Two 'Cites' for the whole thing.
Now, I've got to ask you something, slvrsrfr. I hope that you have checked out the references I've entered, and gone further to read the primary sources to make sure that these are fair refutations to your case. Of the two quotes that you've posted, both have been shown to be scraps of text (or words) that have been taken out of context and twisted backwards to mean the exact opposite of their author's positions by a creationist. Indeed, let the record show that both the ICR and CSF have tried to steal their opponent's authority as "qualified people" and to use it to deceive anybody who didn't look up the facts. So, I ask you:
- Is stealing other people's authority the way to find the truth?
- Is this Xtian integrity or honesty?
- What does this do for the cause of truth and justice?
- Most importantly, surely even the most devout believer in Creation and Xtianity should cast out those who tell lies about others. Would not such a person want to keep their cause clean of the taint of the dirty dealings mentioned above? After all, who is "The Father of Lies," hmmmm?
Patterson, Colin, "Evolution" 1978, Routledge & Kegan Paul Ltd.Fast forward a few decades and you'd end up with Applied Theology as a hard science! 8-)
For this and other mind-stretching concepts, read Vernor Vinge's A Fire Upon the Deep. Good book!