Are you the same kind of person that would use nuclear power everywhere, simply because we've only ever had 1 (recorded) nuclear meltdown in history, and "well, it seems safe now!" Nuclear power is about the analog of DDT: it's extremely powerful, and extremely dangerous. Actually, it's about the analog of nuclear power in the 1970s, when we DIDN'T know that much about how to control nuclear plants. Today, we still don't know how to deal with ecosystems well. Honestly, we suck - we're awful. The world is full of examples of how bad we are at managing ecosystems (Look at the outbreak of the aquarium decorative plant in the Mediterranean Sea for a recent example. Aw, it's just a pretty aquarium plant - that is rapidly turning the once-healthy Mediterranean into a single-species lawn, just ripe for a virus to come and wipe out a huge amount of oxygen producers).
There is a single, peer-reviewed, study showing adverse effects of use of DDT. Borneo, when the WHO decided to spray DDT to kill the mosquitos there. It made their lives MUCH worse than when the mosquitos - and malaria - were there. Careful - you didn't say "direct" effect, because ecology
Not using DDT now is like when people fought against using nuclear power everywhere when we weren't really that good at controlling it. It's intelligent. It's admitting "damn, this is powerful, and we really have no freaking clue how to make it not dangerous as hell."
Widespread use of DDT could cause a lot more damage than 300 million dead. A lot. Like, massive ecosystem destruction.
Borneo is not bad science. Nor is it hype. Nor is it something that someone can claim "ooh, the big bad environmentalists did it to us!"
It's an ecology lesson, that's what it is.
For those who don't know the story, here's the short:
Yah, DDT killed mosquitos. It also raised DDT levels in caterpillars. Which raised DDT levels in geckos, making them slow and easy to catch. Which raised DDT levels in cats, which killed them. Which brought in the rats.
Which brought bubonic plague.
Which kills many more, and much worse, than malaria.
So the WHO, which sprayed DDT in the first place, parachuted cats into Borneo (hence the name of the children's book, "The Day They Parachuted Cats Into Borneo". This isn't a joke - there are about a billion resources on the Web to back this up.
So what, you might say. At least they got rid of malaria. Yah. Sure. Except afterwards, their thatched huts caved in as well, because all the geckos - which ate the caterpillars - were dead. (Plus the fish in the rivers were dead, killing the livelihood of many people there, and much more...)
The WHO made a decision because one exercise of DDT went horribly, horribly wrong. You have no idea what introducing DDT into ecosystems would do. "Ecological engineering" is one thing that we just plain do not know how to do. We're awful at it.
DDT is a very powerful killer, and it can be useful. But we are simply far too bad at ecosystem modeling to use it. We chose to not use DDT because we don't understand ecosystems, and it was a good choice. You can only look back and say "ah, if only we had used DDT, life would be happy, and rainbows would spread over all tropical regions!" Sorry - Murphy's Law would've intervened, so the WHO smartly said "look, this stuff is powerful, and we're not smart enough to use it." Good choice.
The "I have experience that differs" is the point of the article. He's an embedded systems consulting company. It's his job to have experience. If it was in context (rather than simply point, click, read through Slashdot) it might make more sense.
Check here for a more thorough "factual" rebuttal, including my favorite quote from the original report...
For the purposes of runtime royalty comparison, only Windows CE.NET and embedded Linux will be considered.
No reasoning, no nothing, as to why Windows XP Embedded (which a lot of the reasoning of the rest of the report was based on). Why, might one ask, would someone do this? Might it have something to do with the fact that the royalty cost for Linux is $0, the royalty cost for Windows CE (in volume) is $2.60, and the royalty cost for Windows XP Embedded is approximately $100 per system?
Yah. OK. That's a bit like me saying I'm going to compare the reliability of Toyotas and Fords, but for the purpose of the study, only Toyota cars that don't actually run will be used.
I mean, really - the original report is so bad it's laughable. It really didn't even NEED a rebuttal.
When will people relaize that MS is not the only people putting out biased reports. I put the same faith in a "Linux is great" report by a Linux group as I do in a "Windows is great" report by MS.
They'll realize this when other people actually read the article in question.
Go ahead. Read it. Carefully. Note that nowhere in the report does it say "Linux is great" or "Linux is better".
In fact, to quote the article,
Consider that in most embedded software development efforts, only a small portion of time is spent on platform issues. In virtually every project I've been associated with over many years, one engineer has selected the development environment, brought it up on the target hardware, and introduced the other engineers to its use. From that point on, everyone involved is focused on the application rather than the environment. Platform issues constitute only a small proportion of the effort expended on all but the simplest cookie-cutter devices.
Note what's said there - it doesn't really matter what platform you develop on. That's what's said there. Develop on whatever platform suits your needs.
Still think it says Linux is better?
It could be, as John Lettice has pointed out, that developers of larger, more innovative, products tend to choose Linux because of the control and flexibility it offers, while developers of cookie-cutter devices tend to choose Windows because of the help it provides.
What's that? There, they're saying "Windows is better for some things!" Blasphemy? No - they are actually trying to be unbiased.
Granted. They can't be completely unbiased. But they're trying, which is the difference.
I've illustrated that like a oscillating charge which creates electromagnetic waves, an oscillating mass can create gravity waves
Not quite. There is no such thing as conservation of charge motion. There IS such a thing as conservation of MASS motion: it's called "momentum", which implies that an oscillating mass does not create gravity waves.
Now, there's no such thing as "conservation of force", so you can have a quadrupole oscillation cause gravity waves, but you can't just wiggle something back and forth and have propagations throughout the universe. It's harder than that.
(Also, I don't believe Einstein actually figured out the gravity waves bit. That was done by others, I believe.)
Finally...
There is no requirement that gravity waves -> gravitons. None whatsoever. That's assuming that a quantum field theory of gravity exists, which it looks like is not true. There may be another theory which describes a quantum version of gravity, but the quanta inside it will not be gravitons in the sense that we think of photons. They'll be much weirder.
General relativity won't work if gravity doesn't move at the speed of light. It's what the whole basic thing is founded on. If gravity doesn't move at the speed of light (and all indications are that it does - we've just never measured it directly - we HAVE measured it indirectly, though) then general relativity is wrong.
Gravitational waves, for instance, propagate at the speed of light in general relativity.
Moving at the speed of light does not require that it have an associated "particle". In fact, no one really knows what requires you to have a particle and what doesn't. Particles are quanta of a certain field - in this case, a graviton would be the quantum of the distortion of space-time, and while it's theorized that this is the case, no one's really sure.
The problem is that we don't know how to work with theories other than quantum field theory very well, and it very much appears that gravity simply is not a quantum field theory. That probably means that in fact, a "graviton" in the traditional sense of the word does not exist. There may be a quantum of space and time, but it won't be a 'particle' in the same sense that a photon, an electron, quarks, and the gauge bosons are.
The electron does not "reverse" spin. It didn't HAVE a definite spin beforehand. When you gave the other one (electron A) a definite spin, you gave the entangled one (electron B) a definite spin. (*)
Nothing travels faster than the speed of light. Yes, quantum phase information travels faster than the speed of light, but that's because quantum phase information is nothing.
It's not "faster than light communication". It's instantaneous collapse of the quantum state. This isn't communicated. Nothing is being transmitted (see previous bullet on 'nothing').
There is no problem between quantum mechanics and special relativity. The two of them better work together. They're the foundation of quantum field theory, which is the foundation for quantum electrodynamics - one of the most successful theories in all of human history - and quantum chromodynamics. The problem is between quantum field theory and general relativity (which is what you need superstring theory for) which is a totally different ball of wax.
(*) It's more complicated than this. There's no way to tell whether or not an electron is in a spin eigenstate or in a superposition without examining it, and when you examine it, it collapses. So the way this experiment has to work is that electron A's spin is measured, electron B's spin is measured, and then wow, there's a remarkable correlation between the two: electron A is spin up, electron B is spin down. However, note that two measurements took place, so the question of "which one happened first" is a matter of perspective, according to relativity. So one viewer might say "electron A was measured first, so electron B collapsed, and then electron B was measured second" and someone ELSE might say "electron B was measured first, so electron A collapsed, and then electron B was measured second". Note that in ONE case, "quantum phase information" is transmitted from A->B, and in the second, from B->A. That's because quantum phase information isn't information. It's nothing. It's a shadow - nothing more.
If anyone wants to correct me, please do. I havent taken a physics course in my life (yet) and am probably wrong about some (most) of what i just said.
Don't worry. It was pretty good for someone who hasn't had any formal physics. The problem is that quantum mechanics and special relativity require you to stop thinking in terms you understand, and start thinking in their terms, and that takes a lot of effort.
The GC isn't far from a PC? Really? With 24 MB of low-latency DRAM which doesn't exist in the PC market, with a graphics chipset with 3 MB of embedded-DRAM (which also doesn't exist in the PC market, save in Bitboys' dreams)? Chips don't make a platform - interfaces do, and the interfaces on the GC are all extremely proprietary. It'd be like thinking that any ARM7 platform can play GBA games if they only used its graphics chips.
The processor is a modified PowerPC architecture, called "Gekko", i.e. a PowerPC 750, i.e. a G3. This part is correct. However, it has a dedicated bus to the ATI graphics core, and (importantly), the system has 24 MB of MoSys 1T-SRAM, which has extremely low latency and therefore extremely high bandwith utilization efficiency.
So you'd need a heavily modifed PPC970 - one with the same SIMD set (as the SIMD set is unique to the Gekko - it's not AltiVec) and you'd need 1T-SRAM as well, or something with comparable latency/bandwidth, and you'd need the specialized bus to the graphics core.
The ATI graphics core is anything -but- a Radeon, and it's already known that NEC is building the next graphics chip for Nintendo. When's the last time you heard of a Radeon with embedded DRAM? The Flipper chip has 3 MB of eDRAM (that is, DRAM that's right on the chip, so it has 20+ GB/s bandwidth so long as it's on-core). Unless the next graphics chipset also has eDRAM, it simply won't work.
Backwards compatibility in consoles only exists with the PS2 and PS1, and the sole reason there is because the PS2 basically *has* a PS1 inside of it! The only other example is the Game Boy Advance, where Nintendo did (guess what) the exact same thing - the ARM7TDMI has a GBC chipset embedded within it.
You can't upgrade the processor and graphics chipset in a console. It's stupid. The miniscule benefits you get are completely outweighed by the fact that you're tied into a platform whose technology is dated. This is why Microsoft's going to have a problem: any Xbox-2, if it does feature backwards compatibility, is going to be hindered by that, not helped.
The only way backwards compatibility has worked in consoles so far is by basically including a fully functional version of the previous console in the new one, and I doubt it'll change anytime soon.
This is all painfully familiar of the whining I used to hear from TeX users about how Word didn't do such-and-such that TeX did, when in actual fact Word did have the feature in question.
(No karma bonus because it's offtopic anyway...)
You're right - but the last example isn't good. Gimp and Photoshop are examples of tools intended for the same job. TeX and Word are *not* - really not. Word is a typewriter (or word processor or whatever - TeX is a document formatting language. There's a huge difference. TeX is *designed* from the ground up to be formatting agnostic. Word isn't.
This is the same thing that another poster said a few bits up: yah, sure, you can use templates in Word to convert styles, you can have it insert math. You can also use a hex editor to make images instead of Photoshop, but you wouldn't. Just because a program has features doesn't mean that those features are useful.
In this case, Photoshop wins over GIMP because it has more features and those that they share it does better.
In the other case, you can't generically compare TeX and Word, because they don't do the same thing.
We have put one - count it - one rover on Mars, and that is it. For experience of long-term rover operation, you have to look at the Soviet Lunokhod remotely operated vehicles which trundled round the Moon in 1970 and 1973 respectively. Lunokhod 1 operated for 11 months, rolled over 10km and conducted over 500 soil tests. Lunokhod 2 worked for only 4 months but covered over 37km.
Yah, yah, I meant probes + rovers, not rovers alone. They all have the same problem. And don't use lunar rovers to compare with Mars rovers. Luna is heaven compared to Mars: no dust, no atmosphere (so perfect solar coverage!) so no problems. Mars isn't so easy. Don't switch celestial bodies to try to justify the point - the longevity of things on Mars's surface sucks. I could, of course, say that the longevity of planetary probes in general is terrible - just look at Venerean landers - but, Venus is much harsher than Mars. Likewise, the Moon is much more forgiving than Mars is.
Yes, it's true - if we sent down all the support equipment humans need, the rovers MIGHT last longer. The problem is that humans self-repair. Real easily. Rovers/probes do not.
Don't discount the dust so easily. It's not an easy problem - not at all. The dust is really, really fine, and very pervasive. It's not as easy to work around as you think.
As for the radiation exposure, the public allowed dosage is really bloody low (and from the documents I've seen, it's 0.1 rem/week, 0.5 rem/year from natural causes). The medical effects aren't so nasty, though: 60 rem adds about 1% risk of fatal cancer to a 35-year old woman, and 80 rem adds 1% risk of fatal cancer to a 35-year old man. So is 50 rem okay? No. It's not good at all. But it won't immediately kill people, which is what you were making it sound like.
More importantly, it's the trip that causes the highest radiation dosage. Mars itself does provide partial shielding (plus you can always just use rock). Mars during solar max (yes, solar max - the greatest threat is from cosmic rays, which are suppressed during solar max by solar modulation). So Mars isn't threatening - it's the trip (and the fact that the trip is so long).
The radiation dosage isn't fundamental. You can shorten it with shorter trip times (the 50 rem count is for 0.7 year one-way) which we can do with known technology, or reasonably expectable technology in the near future. A space elevator would shorten the trip time to Mars by a factor of two or more (gotta love Earth's rotational speed) - cutting it down to 25 rem or less.
And would I take a 1% additional chance of fatal cancer to go to Mars? In a heartbeat. Estimates have to be conservative, for one, and two, I can always be optimistic. It's much nicer to say there's a 99% chance that you won't get a fatal cancer, after all.
Besides, one other thing to consider is that if a mission to Mars was planned, that would definitely spur treatment for radiation poisoning research, which means that the risk would likely be significantly less by the time the mission was launched.
I'm not saying you don't have a point: what I am saying is that a lot more people made a trip just as dangerous a few hundred years ago (I'd bet more than 1 out of 100 people died crossing the Atlantic in the 1500s and 1600s!), and yet now we're worried about a 1% chance? Jeez. Half of the preservation of food and malnutrition effects we know of we know because of the problems with sailors. Same deal here.
And they could sit there for months or years whilst we make up our minds. Not like the astronauts who would be dependent on their air supply. The lunar explorations were always curtailed by the fragility of the men.
Point to the robots I think.
You're joking, right? The rovers on Mars have always been so incredibly limited in what they could do because they have little power, and very little time to do what they want before dust covers over the solar panels or the batteries just fundamentally bite it from the extreme cold swings.
Yah, humans might not seem as robust as robots, but for some reason, we just can't seem to build a self-perpetuating self-repairing autonomous robot yet, now can we? Granted we wouldn't hold up long natively in Mars's environment, but in order to make a more "hospitable" environment, it's going to be more complex, which means more chances for failure unless a human is there to think quickly.
Our knowledge of the Moon increased so many times over from the Apollo missions it's not even funny - and it's *not* just because of the rock samples. It would've increased more had the Apollo astronauts actually been scientists rather than military personnel.
We've done the easy bit. We haven't done the bit that involves spending months in microgravity, slowly cooking in solar radiation before attempting to live on a planet with a radically different environment.
Oh, please. Name one person who's ever died from space radiation exposure. Oh - wait - you can't. Is it bad? Yes. Would you have to take precautions? Sure, of course. Is it tremendously more dangerous than being on a nuclear submarine? Not really.
Anyway, just because something's hard doesn't mean we shouldn't do it. In fact, we should do it because it's hard.
Why? What is there that we can't have better and cheaper on Earth? Mars is a rock, frozen day and night, baked by solar radiation; its atmosphere, what little there is of it, is poisonous, the soil is just plain weird - why would we want to live there? It would make Antarctica look appealing.
There are two questions here:
1: Why should we, humanity, go? 2: Why should anyone, as a single person, go?
The answer to the second one is easy. Because no one else has. No one else has seen the sky thousands of different shades of pink that we've never dreamed of on Earth, or walked in one-third G, or seen valleys so wide and vast that you can't see the sides because they're under the horizon, or an escarpment as high as Mount Everest. Don't forget, people live in extremely hostile environments all the time, and explorers go just about everywhere for the thrill of it. Earth is just as much of a rock as Mars is.
And hell, it'd kick to see Earth in the sky at night. Now *that'd* be beautiful.
So why would we want to live there? Well, for one, because it's not Earth. It's different. From a purely practical perspective, ignoring the radiation issues (which are not as bad as people think - bad, yes, and you'd have to take precautions, but not impossible), Mars is a healthier place to live, fundamentally, because of the lower gravity. It's just less of a strain on bones and your heart. Yah, you can't return to Earth. So?
The answer to the first one is a little more complex, but it's fundamentally the same as the second. We want to go to Mars because it's not Earth. Let me put it to you this way.
Take a hypothetical teenager, or very young adult. Why would they want to leave their parent's house? They have everything they want there - shelter, a private space to themselves, and it's cheaper: don't pay for rent, utilities, food. It's perfect. Living on your own looks like hell in comparison. But they do it - why? Because 1) they know they have to, just like we have to get off this rock. Have to. Humans have to keep expanding, have to keep moving, have to keep learning. It's what makes us human - what makes us us, and 2) because fundamentally, in the long run, it's better for them. They learn more (how to manage a household, how to fix things), develop more, and grow extremely quickly. Again, likewise - it's better for us to go to another world, like Mars. We'll learn more, really quickly. Like how to survive in heavy radiation. Like ecology engineering, and closed-systems engineering, which we have no need to learn here on Earth, but we could DEFINITELY use the technology! Like automated factories, robotic construction equipment, atmospheric engineering. The list goes on. Yah, we could do it here on Earth - but we don't need to, and so we won't do it. Necessity is the mother of invention, and all that. How many examples in human history do you need to justify that?
Perhaps a tiny fraction of the expenditure you are calling for would be better spent on reducing our addiction to fossil fuels which is going to end up killing us.
This is the beauty of pure science. Go to Mars! Guess what? There are no fossil fuels there, so we'll learn really quickly how to live without fossil fuels real quick, and export that knowledge back to Earth.
Humans are getting lazy and complacent - things are too easy. "Well, we could reduce our dependence on fossil fuels... but why would we? There's no real need..." You have to keep pushing. Have to keep moving. Have to keep learning.
That's completely not true - at least, not for decent quality rechargeable alkalines, which have a much lower internal resistance than normal alkalines due to the use of higher-quality electrodes (reference here), which means they will last longer in high-current draw situations, like digital cameras, but still nowhere near as long as NiMHs, which have a much lower internal resistance. (One manufacturer shows 1950 mAh for 30 mA, 1500 for 125 mA, 1200 mAh for 300 mA, and 750 mAh for 500 mA).
Rechargeable alkalines also last much longer if they're constantly recharged. Deep-discharge cycles will drain about 50% of the battery's capacity in about 10-15 recharges. Shallow-discharge cycles will extend that number to about 100 or so. It's not NiMH quality, but if you buy one rechargeable alkaline and it lasts you as long as 50 disposable alkalines, well, then it's damned cheaper, isn't it?
Decent rechargeable alkalines have a very good use: low current drain devices, and devices that are not tolerant to low battery voltages. Remote controls, clocks, even Game Boys, are all very good locations for rechargeable alkalines.
I hope they find some ways to make the rechargeable alkalines work better. As it is, they are a niche product good for devices that sit for long times and use little power (smoke alarms, remotes, clocks, etc...).... and devices that want 1.5V from a battery, rather than 1.2V, as was the point of my post above, and for devices that have the "can't use rechargeable batteries in this device" void-your-warranty clause. Granted, you'd be 'slightly' lying, but there's no possible way they could detect rechargeable alkalines as opposed to normal alkalines (in fact, some chargers can recharge normal alkalines) - they COULD, however, in theory, know that you'd used NiMH/NiCad batteries, because the voltage is much lower.
Plus, some of your information is just not correct:
A fresh alkaline, or a fully charged alkaline, will lose its charge over years (not months), and in fact, it will virtually NEVER lose its capacity if placed in a cold environment (refrigerator). A rechargeable alkaline will hold its charge for 3-5 years, in normal environments, much longer in colder. NiCads and NiMHs will be dead within 3-4 months (or at least approaching the "rapid voltage drop" portion of their lives).
Also, the capacity of rechargeable alkalines should be as high as or higher than normal alkalines! You can find rechargeable alkalines with a capacity of up to 2000 mAh for a AA, and 1000 mAh for a AAA. In general they don't handle high current draws as well as NiMH, but better than a normal alkaline.
So, where are rechargeable alkalines good? - Remote controls - Clocks - Flashlights (capacity is good, as noted above) - Any electronics device that has >2 batteries in series - Any electronics device that really wants 1.5V out of each battery - "Emergency batteries" for digital cameras, etc. to replace NiMHs that die while taking pictures.
They're EXTREMELY good for the last application, as you want a battery that will last a while, will definitely be charged, and that you're not going to use that long.
To verify info, do a Google search for "rechargeable alkaline capacity" and "rechargeable alkaline shelf life", and use the first web site that actually gives -numbers-.
Alkaline rechargeables are 1.5V. NiMH rechargeables are 1.2V. They hold their charge better than Alkalines, of course (until they run dead, when their voltage drops to 0 very fast). This is, of course, important, as 2 NiMH rechargeables in series gives 2.4V, and 2 alkalines in series gives 3V (i.e. CMOS 3.3V).
Many people don't know that electronics that says "don't use rechargeable batteries", it's because of the voltage. In those, you're fine using alkaline rechargeables.
In many cases you can use NiMH rechargeables and it'll work fine. Electronics is remarkably tolerant to low voltage levels. However, if you read your warranty on many of those devices, you'll find that you void it if you use rechargeable NiMH batteries. With rechargeable alkalines, you don't need to worry at all. It also makes the "battery meter" on electronics work correctly, say, on a Game Boy Advance, where the LED goes from Green to Red at about 1.35V, and then off completely by 1.2V. Rechargeable alkalines show normal behavior. Palm Pilots as well, though Palms can change their battery meter to read NiMH rechargeables.
And don't get me started that NiMH rechargeables lose charge over time by bleed away, and alkalines don't. So NiMH batteries are useless if you want to just leave them in something for a while.
Short answer: Rechargeable alkalines have several advantages over NiMH, which is why you can still buy alkaline rechargeables. NiMH is almost purely better than NiCad, which is why you can't buy NiCad much anymore (plus I think NiMH is friendlier to dispose of).
Also, objects moving along the sheet require some sort of "gravity" to be assumed in order to be pulled down the pocket in the rubber sheet.
This is completely wrong. Again, the rubber sheet analogy uses gravity to restrict the objects to a 2D surface. They can't move off the 2D surface. Moving across the 2D surface, with the mass distorting the sheet (because that's what mass does, see above comment), if they are restricted to the 2D surface, they will be deflected, distorted, or drawn into the distortion in the sheet simply because they are following the sheet, NOT because of any external gravity! This would NOT be true if the sheet was nondistortable (and the endpoints fixed!).
In this case, gravity is what's causing the object to remain on the sheet. If you had some sort of magnetic force holding the test object onto the sheet, it'd produce the same result. It wouldn't explain why the sheet is pulled down (again, that's just what mass does - in this case, you'd have to do it yourself) but it most definitely, very much so, explains why objects get deflected when they pass near the object.
That's a ramjet, not a ramscoop, which is what I'm proposing. Though it's not really a ramscoop, more just a particle collector. The benefit of space is that, well, there's virtually no drag, and so you can coast when you run out of fuel until you get enough. This means that you have a speed limit for short distances, but there are no short distances in space.
If it's fundamentally impossible to get it to fuse in flight, then it's always possible to contain the material, store it, process it, and fuse it later, and increase your speed. Why not? It hasn't cost you anything, or if it did, very little.
So long as you can pick up any material, your speed isn't limited at all. Drag in the ISM is pretty much nonexistent, except at high Lorentz factors. It's only 1 particle/cubic centimeter, after all, and the specific impulse that you get from every particle you pick up is orders of magnitude larger than the cost of ramming into it, so you can coast for a long time before worrying about slowing down too much between the periodic "bursts" of acceleration.
At that point, all you need to worry about is how you power the craft continuously, but that would most likely be solved by better fusion as well - the same that provides the periodic propulsion.
Disclaimer: I haven't actually worked out specific math on this proposal (I doubt anyone would - it's dumb, from a human point of view. It would probably take a long time to get to relativistic speeds - a very long time. But it would get there) but it was just worth pointing out that while there are of course fundamental limits to crafts that carry fuel along with them, there are always options. Nature wasn't -that- cruel to us.
The other point regarding the cost of antiproton factories and solar collectors is naive. An antiproton factory needs (virtually) only energy (and coolants, etc., but a closed enough system can keep those losses down), and solar collectors provide that energy. After that, the quantity of antiprotons you get is just a function of how long you wait. They're luckily easier to store than positrons, so again, it's just a matter of time. So if you want an "unrealistic amount of antiprotons", you need only pay the initial cost, and wait an unrealistic amount of time. Yes, this is naive as well, assuming maintenance costs are zero. However, for this kind of a setup, I highly doubt that after several years, maintenance costs would be significant, and in addition, there are many real uses of antiprotons in medicine and other fields, and one could easily recoup the maintenance costs by selling off a small fraction of the production.
It does nothing of the kind! The rubber sheet analogy is a mapping of 3D space to a 2D plane, which frees up a dimension to illustrate a "real" 4th dimension. The analogy requires that one assume some sort of "gravity" to pull the mass on the sheet down. Also, objects moving along the sheet require some sort of "gravity" to be assumed in order to be pulled down the pocket in the rubber sheet. The rubber sheet analogy is an illustration of the mechanics of gravitational attraction, but does not offer ANY additional information as to what gravity is.
Read the *rest* of the comment, then, not just the beginning. In it I pointed out that if you were in fact asking this question, then there are two answers.
Why does the mass deform the sheet?
1) Because that's what mass does - that's the whole point of general relativity, saying "mass deforms spacetime", which in turn, looks like an attractive force.
2) Well, if you're asking why "mass" - that is, the "mass" that we're all accustomed to thinking is "mass" - that which provides inertia, the "field-squared" term in the Lagrangian - if you're asking why that pulls the sheet down, that's a lot more complex, and it's a completely different thing than asking what is gravity? The rubber sheet analogy shows that a deformation in spacetime can act like a gravitational force. GR then says "mass causes the deformation in spacetime", which is usually explained, in the rubber sheet case, by someone saying "mass causes space to be deformed, like this rubber sheet."
I don't see how it's unclear, other than the 'fundamental deep question', which, well, no one has a clue about yet.
OK, I'll respond.:) Actually, your comments are pretty much the same questions most people have when they start learning relativity, because it's counterintuitive. It's very difficult to separate out different ideas in physics.
So, addressing this:
First, a small object with an insanely large mass would (of course) cause "antigravity" - if, by antigravity, you mean "yanked away from the Earth's surface and sucked into it" - if its gravitational pull is more than the Earth's. The size of an object isn't important (to first order - to second order, it affects tides) just its mass. So an insanely small object with an insanely large mass would act like, well, a normal-sized object with an insanely large mass, or a large sized object with an insanely large mass. In other words, if you wanted to counteract Earth's pull, you'd have to put something the mass of the Earth roughly the same distance as the center of the Earth away from you. You could get away with something smaller if it was much closer, though (but nothing reasonable-sized, of course. It's never going to get more than about half-a-meter from your center of mass, and so it's always got to be huge). That'd be "antigravity"... so long as you were in the centerline between the two masses, and didn't move in the slightest. (That's the L1 point - the point of equal attraction between two bodies: it's unstable. If you move, the pull from one of them pulls you away from that point) It's probably not the antigravity you're thinking of, but that's what would happen.
Second point: The whole "as something approaches the speed of light, its mass goes way up" is a concept that just plain needs to die. It's far too misleading to most people, and it serves no useful purpose. The "mass" of any object can be basically replaced with its energy, which is the sum total, in quadrature, of its kinetic and its rest energy. Normally an object's kinetic energy is pathetic compared to its rest energy: a proton in a hydrogen atom, at room temperature, has gamma (energy/rest mass) of 4E-35 - a bit small. But at you add energy to the object, that kinetic energy becomes significant at some point, and relativistic effects start to work. Basically at that point, the basic equations of kinematics start to have a factor that was "1" start to become much more than 1. What's really changing is the relationship between a change in momentum and a change in energy. At low energies, if you double the "delta-P", you quadruple the "delta-E": that is, if you give some object a delta-P of 10 kgm/s, then another object of the same mass a delta-P 20 kgm/s, the second object's change in energy will be 4 times higher than the first. At high energies, if you double the "delta-P", you double the "delta-E" - it's linear, not quadratic.
In addition, there's also a change between an object's velocity and its momentum - it's the same factor that appears in all relativistic kinematics equations - gamma, the ratio of energy to rest mass. The real equation is p = mv*gamma, which, if you're smart, you may notice becomes p/gamma = mv, and since gamma = E/m, then p/E = v. Remember that I said the real change is that "delta-E" goes from being quadratic in "delta-P" to being linear? Well, if it's linear, then p/E approaches a constant - that is, at high energies, your velocity approaches a constant, and that constant is the speed of light. (and since E is always greater than p, because it has the rest energy as well, it's always less than the speed of light).
So. Does this affect gravity? Yes, but only because gravity only gives a damn about energy - good old fashioned energy - both the rest energy AND the kinetic type, and it doesn't care in the tiniest bit which you have. Neutrinos, for example, have ridiculously small mass (less than 10^-3 eV, if memory serves, which is about 10^12 times lighter than a proton), but in most places where they're seen, they've got a couple keV of energy - so they've got a gamma of 10^9 or more. So, as far as anyone will ever be able to tell, they're going the speed of light. But as far as gravity's concerned, they have far less than a proton at rest, and it's still the same old "sucking" kind.
No - you're missing the entire point of the rubber-sheet analogy if you think that the point is that the objects are drawn to the hole. It most definitely does explain why gravity works.
The rubber sheet analogy is 2D gravity. That is, objects are constrained to be on the surface of the sheet, and cannot move up, and cannot move down. "Real gravity" - that is, the thing that's holding the ball to the sheet - is just an implementation of the 2D world in a 3D world (by restricting an object's motion in one dimension).
Gravity in the 2D world is the deformation of the sheet itself, rather than an actual external force. A mass presses down on the sheet, causing a deformation in it, and it presses down on the sheet because that's what masses do (not because of "real gravity") - mass (well, stress-energy) = 8*pi*G, where G is some construct that tells you how much the sheet deforms. That's what general relativity says, fundamentally - the whole shebang, right there. Mass deforms spacetime. In the 2D sheet, it deforms it because gravity pulls down on it. In our world, it does it "just because". In short gravity works because mass deforms space and time. Now, if your comment was that it does nothing to explain why mass deforms spacetime, you're right. If you want to explain why a deformation in spacetime equals mass, then you've got to work out quantum gravity, because in general relativity, mass is just a construct which causes a deformation in the sheet.
Now, obviously, you should already realize the answer to the parent's comment: what would "pull the rubber sheet up?" Getting rid of mass. Until you find something else which deforms spacetime (which, well, we haven't, but there are wacky theories: most of the FTL general relativity ideas involve "negative mass" - that is, things that bend spacetime differently than normal mass) the only way you're going to reduce the gravitational effects caused by something is to reduce its mass.
Most other people here point out that gravitons could be "affected, or blocked", and the simple answer to that is "no". That's like saying "maybe we could find a way to make neutrinos interact more, and harness their energy!" (because frankly, if we could, that'd solve all of our energy problems. The Sun puts out a ton of neutrinos) - well, the whole point is that neutrinos interact only weakly. That's virtually their definition. You can't get them to interact more, because there's no way to do it. Same with gravitons. Gravitons will only interact gravitationally, and thus, the only way we can affect them is, well, with gravity. (Amazing Device Causes Antigravity! "Warning, device is approximately the mass of the Earth, and may cause harm to others in your vicinity as well as the rest of the solar system")
With quarks it's difficult to say that there would be a difference between "merged" and "bound" - the strong force is very weird (it's confining, for one: it gets stronger the farther away the particle gets, and weaker the closer in the particles are) and so it's really quite difficult to distinctly say "yes, this is a distinct 5-quark 'merged' particle" or "no, this is a meson-baryon molecule where the quark-antiquark orbit the other three color-singlet quarks".
After all, no matter what, it's NOT a distinct particle! Any baryon (protons, neutrons, whatever) are 3 coorbiting quarks. All deep-inelastic scattering measurements have shown baryons to look like they're made up of three particles basically at rest (parton model), and this model does remarkably well. So no matter what, the pentaquark is NOT a "merged" particle. It's 5 quarks, hanging around each other.
This particle would be very much a mess. Most of the time it's referred to as a molecular meson-baryon state (look in the literature for this - specifically the SPring paper) and, to be honest, I'm not sure how you could tell the difference. The naive "quark-antiquark here, three quarks here" model is so terrible at these energies that it's really difficult to explain to people to just throw away their intuition for most things.
Truth is, it's probably best to think of this as the lowest energy level of a meson-baryon bound state.
(I have no idea what the grandparent poster was saying - "they specifically said the merged version...". That's crap - read the papers. No one's taking a stance between "5 quark bound state" and "meson-baryon bound state". All this showed is that there IS a bound state in an interaction between a neutron and a gamma ray which decays into some baryon and a kaon.)
No. Relativistic contraction happens only in the direction of motion. The stick would "thin", not shrink.
If you shoved it "towards" Europa, for instance, then the stick would shrink slightly, but, if you're jiggling the stick back and forth, the stick would be shrinking, expanding, shrinking, expanding as you stop and start the motion. It's even worse than that as you're attempting to move a massively elongated object, so you get displacement waves rather than motion.
Plus the fraction that we're talking about here is REALLY small. Look it up - just look up Lorentz contraction somewhere, and use a value of, I don't know, v = 1 m/s (which is still fast). It's ungodly small - somewhere in the vicinity of 1 part in 1 billion.
It's not an easy question to answer - there are quite a few complications involved - but it suffices to say that nothing weird happens. The stick would take a long time to move (at least the characteristic period of the object - speed of sound*length) and if you tried to shove it harder, you'd just distort the stick (bend/break, etc.) and send a wave down the stick, thus moving YOUR end, but not moving the entire object!
I mean, let's work it out - let's assume that it's a billion meters long, so moving it at 1 m/s shrinks it by 1 meter. Let's also say that the speed of sound in the material is 1000 m/s, so it takes a million seconds for a "push" from one end to move to the other end. In order for you to actually see any real Lorentz contraction (from the whole stick), the entire thing has to be moving at 1 m/s, not just the end - Lorentz contraction comes from the fact that a reference frame moving with the stick must measure the speed of light the same as you do, and the 'fractional' contraction is due to the fact that the frame at the very far end of the stick is the same frame as the initial end of the stick.
So, in order for you to see the billion-meter long stick shrink by 1 meter, you'd have to wait a million seconds. And by then your end would have moved one million meters, and if you measured the length of the stick while it was moving at 1 m/s, you'd get 999,999,999 meters. It wouldn't be a sudden jump - it'd smoothly decrease in size as more and more of the stick begins moving. Then, when you try to stop it, it'd take a million seconds for the stick to stop, and the stick would smoothly stretch back out to 1 billion meters.
But, in the end, it still would've moved a million meters. It's only during the motion that you see anything weird happen.
So if you grab it before the whole thing starts moving, then the total contraction would only be due to however much of the stick is actually in motion.
... assuming that said craft does actually carry its own fuel (which you limited yourself to, but...)
That's, of course, not the only kind of craft: ramscoop ideas have been around for a while, and while they're not exactly "production quality" ideas, there's nothing fundamentally killing them. We'd just have to figure out how to do fusion much better than we do now - which is not exactly new physics - it's new engineering. We'd also want to get the hell past the heliopause, to interstellar space. Ramscoops can easily build up to relativistic speeds, because, well, their fuel is free.
Especially when you get to decent Lorentz factors things start to work in your favor: space is compressed, so the interstellar density becomes higher (drag isn't exactly an issue, because presumedly your ramscoop is strong enough to drag in material even at a decent spatial compression) and so you get more fuel as you go faster.
It's not an issue of viability (because it is viable), it's simply scale. A ramscoop type ship would probably need to be large, and the "initial speed" required to start up the reaction is probably high as well, though this depends on exactly how good fusion technology becomes.
Also, as a brief comment, antiproton synthesis is very difficult, but antiproton storage is much easier than positron storage, because they're charged and heavy, so once you cool them, you lose very few. So again, production of large quantities of antiprotons is not difficult at all - it just takes time.
Your final conclusion, though, is definitely right. Relativistic travel = huge cost (in 2003 dollars! note that economies of scale and necessity can help here. Automated antiproton factories, etc.: thank god for that tremendously huge fusion generator sitting next door pumping ungodly amounts of energy out all around us.)
So, finally, calling them "practical problems" may be a bit harsh on them. It's just that, as a species, we're not motivated enough to do it.
Maybe, just maybe, if we ever find a planet which we have a good belief that we could live there, that'll be enough of a motivation for some country to do it.
The difference between an embedded system and a modern PC is minor. Right now it's mainly just the difference between someone who builds a simple computer from bare metal, and someone who uses a complex computer that's been designed from bare metal for them.
The point being that *NIX design isn't just implemented in modern PCs. It's implemented just about everywhere (uClinux, RTLinux, etc., and even larger 'embedded machines') and there's no way that you can suggest that coding that's developed for a *NIX kernel on a modern PC is ANY different than coding for a *NIX kernel on an embedded PC.
Let me put it this way: what if someone had developed RWU for an embedded multiprocessor system (it's an example, don't pick nits) using a *NIX derivative? They're working 'inside' the OS, but on an embedded system, as you've said, it's a whole different game, so can SCO really claim control over that? If there's more issue with it being developed on an embedded system than on a COTS system, how does that make any sense?
The very fact that there is confusion over this sort of thing just proves that SCO really has no chance. You can't claim that you have the rights to anything that was developed with your technology when "your technology" is the basic foundation of all computer science. Thank God the original inventors of the transistor, integrated circuit, etc., never tried to claim that.
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Are you the same kind of person that would use nuclear power everywhere, simply because we've only ever had 1 (recorded) nuclear meltdown in history, and "well, it seems safe now!" Nuclear power is about the analog of DDT: it's extremely powerful, and extremely dangerous. Actually, it's about the analog of nuclear power in the 1970s, when we DIDN'T know that much about how to control nuclear plants. Today, we still don't know how to deal with ecosystems well. Honestly, we suck - we're awful. The world is full of examples of how bad we are at managing ecosystems (Look at the outbreak of the aquarium decorative plant in the Mediterranean Sea for a recent example. Aw, it's just a pretty aquarium plant - that is rapidly turning the once-healthy Mediterranean into a single-species lawn, just ripe for a virus to come and wipe out a huge amount of oxygen producers).
There is a single, peer-reviewed, study showing adverse effects of use of DDT. Borneo, when the WHO decided to spray DDT to kill the mosquitos there. It made their lives MUCH worse than when the mosquitos - and malaria - were there. Careful - you didn't say "direct" effect, because ecology
Not using DDT now is like when people fought against using nuclear power everywhere when we weren't really that good at controlling it. It's intelligent. It's admitting "damn, this is powerful, and we really have no freaking clue how to make it not dangerous as hell."
Widespread use of DDT could cause a lot more damage than 300 million dead. A lot. Like, massive ecosystem destruction.
Borneo is not bad science. Nor is it hype. Nor is it something that someone can claim "ooh, the big bad environmentalists did it to us!"
It's an ecology lesson, that's what it is.
For those who don't know the story, here's the short:
Yah, DDT killed mosquitos. It also raised DDT levels in caterpillars. Which raised DDT levels in geckos, making them slow and easy to catch. Which raised DDT levels in cats, which killed them. Which brought in the rats.
Which brought bubonic plague.
Which kills many more, and much worse, than malaria.
So the WHO, which sprayed DDT in the first place, parachuted cats into Borneo (hence the name of the children's book, "The Day They Parachuted Cats Into Borneo". This isn't a joke - there are about a billion resources on the Web to back this up.
So what, you might say. At least they got rid of malaria. Yah. Sure. Except afterwards, their thatched huts caved in as well, because all the geckos - which ate the caterpillars - were dead. (Plus the fish in the rivers were dead, killing the livelihood of many people there, and much more...)
The WHO made a decision because one exercise of DDT went horribly, horribly wrong. You have no idea what introducing DDT into ecosystems would do. "Ecological engineering" is one thing that we just plain do not know how to do. We're awful at it.
DDT is a very powerful killer, and it can be useful. But we are simply far too bad at ecosystem modeling to use it. We chose to not use DDT because we don't understand ecosystems, and it was a good choice. You can only look back and say "ah, if only we had used DDT, life would be happy, and rainbows would spread over all tropical regions!" Sorry - Murphy's Law would've intervened, so the WHO smartly said "look, this stuff is powerful, and we're not smart enough to use it." Good choice.
Came a bit too late for Borneo, though.
Check here for a more thorough "factual" rebuttal, including my favorite quote from the original report...
No reasoning, no nothing, as to why Windows XP Embedded (which a lot of the reasoning of the rest of the report was based on). Why, might one ask, would someone do this? Might it have something to do with the fact that the royalty cost for Linux is $0, the royalty cost for Windows CE (in volume) is $2.60, and the royalty cost for Windows XP Embedded is approximately $100 per system?
Yah. OK. That's a bit like me saying I'm going to compare the reliability of Toyotas and Fords, but for the purpose of the study, only Toyota cars that don't actually run will be used.
I mean, really - the original report is so bad it's laughable. It really didn't even NEED a rebuttal.
They'll realize this when other people actually read the article in question.
Go ahead. Read it. Carefully. Note that nowhere in the report does it say "Linux is great" or "Linux is better".
In fact, to quote the article,
Note what's said there - it doesn't really matter what platform you develop on. That's what's said there. Develop on whatever platform suits your needs.
Still think it says Linux is better?
What's that? There, they're saying "Windows is better for some things!" Blasphemy? No - they are actually trying to be unbiased.
Granted. They can't be completely unbiased. But they're trying, which is the difference.
I've illustrated that like a oscillating charge which creates electromagnetic waves, an oscillating mass can create gravity waves
Not quite. There is no such thing as conservation of charge motion. There IS such a thing as conservation of MASS motion: it's called "momentum", which implies that an oscillating mass does not create gravity waves.
Now, there's no such thing as "conservation of force", so you can have a quadrupole oscillation cause gravity waves, but you can't just wiggle something back and forth and have propagations throughout the universe. It's harder than that.
(Also, I don't believe Einstein actually figured out the gravity waves bit. That was done by others, I believe.)
Finally...
There is no requirement that gravity waves -> gravitons. None whatsoever. That's assuming that a quantum field theory of gravity exists, which it looks like is not true. There may be another theory which describes a quantum version of gravity, but the quanta inside it will not be gravitons in the sense that we think of photons. They'll be much weirder.
General relativity won't work if gravity doesn't move at the speed of light. It's what the whole basic thing is founded on. If gravity doesn't move at the speed of light (and all indications are that it does - we've just never measured it directly - we HAVE measured it indirectly, though) then general relativity is wrong.
Gravitational waves, for instance, propagate at the speed of light in general relativity.
Moving at the speed of light does not require that it have an associated "particle". In fact, no one really knows what requires you to have a particle and what doesn't. Particles are quanta of a certain field - in this case, a graviton would be the quantum of the distortion of space-time, and while it's theorized that this is the case, no one's really sure.
The problem is that we don't know how to work with theories other than quantum field theory very well, and it very much appears that gravity simply is not a quantum field theory. That probably means that in fact, a "graviton" in the traditional sense of the word does not exist. There may be a quantum of space and time, but it won't be a 'particle' in the same sense that a photon, an electron, quarks, and the gauge bosons are.
(*) It's more complicated than this. There's no way to tell whether or not an electron is in a spin eigenstate or in a superposition without examining it, and when you examine it, it collapses. So the way this experiment has to work is that electron A's spin is measured, electron B's spin is measured, and then wow, there's a remarkable correlation between the two: electron A is spin up, electron B is spin down. However, note that two measurements took place, so the question of "which one happened first" is a matter of perspective, according to relativity. So one viewer might say "electron A was measured first, so electron B collapsed, and then electron B was measured second" and someone ELSE might say "electron B was measured first, so electron A collapsed, and then electron B was measured second". Note that in ONE case, "quantum phase information" is transmitted from A->B, and in the second, from B->A. That's because quantum phase information isn't information. It's nothing. It's a shadow - nothing more.
If anyone wants to correct me, please do. I havent taken a physics course in my life (yet) and am probably wrong about some (most) of what i just said.
Don't worry. It was pretty good for someone who hasn't had any formal physics. The problem is that quantum mechanics and special relativity require you to stop thinking in terms you understand, and start thinking in their terms, and that takes a lot of effort.
The GC isn't far from a PC? Really? With 24 MB of low-latency DRAM which doesn't exist in the PC market, with a graphics chipset with 3 MB of embedded-DRAM (which also doesn't exist in the PC market, save in Bitboys' dreams)? Chips don't make a platform - interfaces do, and the interfaces on the GC are all extremely proprietary. It'd be like thinking that any ARM7 platform can play GBA games if they only used its graphics chips.
The processor is a modified PowerPC architecture, called "Gekko", i.e. a PowerPC 750, i.e. a G3. This part is correct. However, it has a dedicated bus to the ATI graphics core, and (importantly), the system has 24 MB of MoSys 1T-SRAM, which has extremely low latency and therefore extremely high bandwith utilization efficiency.
So you'd need a heavily modifed PPC970 - one with the same SIMD set (as the SIMD set is unique to the Gekko - it's not AltiVec) and you'd need 1T-SRAM as well, or something with comparable latency/bandwidth, and you'd need the specialized bus to the graphics core.
The ATI graphics core is anything -but- a Radeon, and it's already known that NEC is building the next graphics chip for Nintendo. When's the last time you heard of a Radeon with embedded DRAM? The Flipper chip has 3 MB of eDRAM (that is, DRAM that's right on the chip, so it has 20+ GB/s bandwidth so long as it's on-core). Unless the next graphics chipset also has eDRAM, it simply won't work.
Backwards compatibility in consoles only exists with the PS2 and PS1, and the sole reason there is because the PS2 basically *has* a PS1 inside of it! The only other example is the Game Boy Advance, where Nintendo did (guess what) the exact same thing - the ARM7TDMI has a GBC chipset embedded within it.
You can't upgrade the processor and graphics chipset in a console. It's stupid. The miniscule benefits you get are completely outweighed by the fact that you're tied into a platform whose technology is dated. This is why Microsoft's going to have a problem: any Xbox-2, if it does feature backwards compatibility, is going to be hindered by that, not helped.
The only way backwards compatibility has worked in consoles so far is by basically including a fully functional version of the previous console in the new one, and I doubt it'll change anytime soon.
But... if the application runs perfectly fine, without problems...
what the hell is Windows doing that's so useful then, if it doesn't do anything apparent to the end user, and all it does is slow the machine down?
This is all painfully familiar of the whining I used to hear from TeX users about how Word didn't do such-and-such that TeX did, when in actual fact Word did have the feature in question.
(No karma bonus because it's offtopic anyway...)
You're right - but the last example isn't good. Gimp and Photoshop are examples of tools intended for the same job. TeX and Word are *not* - really not. Word is a typewriter (or word processor or whatever - TeX is a document formatting language. There's a huge difference. TeX is *designed* from the ground up to be formatting agnostic. Word isn't.
This is the same thing that another poster said a few bits up: yah, sure, you can use templates in Word to convert styles, you can have it insert math. You can also use a hex editor to make images instead of Photoshop, but you wouldn't. Just because a program has features doesn't mean that those features are useful.
In this case, Photoshop wins over GIMP because it has more features and those that they share it does better.
In the other case, you can't generically compare TeX and Word, because they don't do the same thing.
We have put one - count it - one rover on Mars, and that is it. For experience of long-term rover operation, you have to look at the Soviet Lunokhod remotely operated vehicles which trundled round the Moon in 1970 and 1973 respectively. Lunokhod 1 operated for 11 months, rolled over 10km and conducted over 500 soil tests. Lunokhod 2 worked for only 4 months but covered over 37km.
Yah, yah, I meant probes + rovers, not rovers alone. They all have the same problem. And don't use lunar rovers to compare with Mars rovers. Luna is heaven compared to Mars: no dust, no atmosphere (so perfect solar coverage!) so no problems. Mars isn't so easy. Don't switch celestial bodies to try to justify the point - the longevity of things on Mars's surface sucks. I could, of course, say that the longevity of planetary probes in general is terrible - just look at Venerean landers - but, Venus is much harsher than Mars. Likewise, the Moon is much more forgiving than Mars is.
Yes, it's true - if we sent down all the support equipment humans need, the rovers MIGHT last longer. The problem is that humans self-repair. Real easily. Rovers/probes do not.
Don't discount the dust so easily. It's not an easy problem - not at all. The dust is really, really fine, and very pervasive. It's not as easy to work around as you think.
As for the radiation exposure, the public allowed dosage is really bloody low (and from the documents I've seen, it's 0.1 rem/week, 0.5 rem/year from natural causes). The medical effects aren't so nasty, though: 60 rem adds about 1% risk of fatal cancer to a 35-year old woman, and 80 rem adds 1% risk of fatal cancer to a 35-year old man. So is 50 rem okay? No. It's not good at all. But it won't immediately kill people, which is what you were making it sound like.
More importantly, it's the trip that causes the highest radiation dosage. Mars itself does provide partial shielding (plus you can always just use rock). Mars during solar max (yes, solar max - the greatest threat is from cosmic rays, which are suppressed during solar max by solar modulation). So Mars isn't threatening - it's the trip (and the fact that the trip is so long).
The radiation dosage isn't fundamental. You can shorten it with shorter trip times (the 50 rem count is for 0.7 year one-way) which we can do with known technology, or reasonably expectable technology in the near future. A space elevator would shorten the trip time to Mars by a factor of two or more (gotta love Earth's rotational speed) - cutting it down to 25 rem or less.
And would I take a 1% additional chance of fatal cancer to go to Mars? In a heartbeat. Estimates have to be conservative, for one, and two, I can always be optimistic. It's much nicer to say there's a 99% chance that you won't get a fatal cancer, after all.
Besides, one other thing to consider is that if a mission to Mars was planned, that would definitely spur treatment for radiation poisoning research, which means that the risk would likely be significantly less by the time the mission was launched.
I'm not saying you don't have a point: what I am saying is that a lot more people made a trip just as dangerous a few hundred years ago (I'd bet more than 1 out of 100 people died crossing the Atlantic in the 1500s and 1600s!), and yet now we're worried about a 1% chance? Jeez. Half of the preservation of food and malnutrition effects we know of we know because of the problems with sailors. Same deal here.
And they could sit there for months or years whilst we make up our minds. Not like the astronauts who would be dependent on their air supply. The lunar explorations were always curtailed by the fragility of the men.
Point to the robots I think.
You're joking, right? The rovers on Mars have always been so incredibly limited in what they could do because they have little power, and very little time to do what they want before dust covers over the solar panels or the batteries just fundamentally bite it from the extreme cold swings.
Yah, humans might not seem as robust as robots, but for some reason, we just can't seem to build a self-perpetuating self-repairing autonomous robot yet, now can we? Granted we wouldn't hold up long natively in Mars's environment, but in order to make a more "hospitable" environment, it's going to be more complex, which means more chances for failure unless a human is there to think quickly.
Our knowledge of the Moon increased so many times over from the Apollo missions it's not even funny - and it's *not* just because of the rock samples. It would've increased more had the Apollo astronauts actually been scientists rather than military personnel.
We've done the easy bit. We haven't done the bit that involves spending months in microgravity, slowly cooking in solar radiation before attempting to live on a planet with a radically different environment.
Oh, please. Name one person who's ever died from space radiation exposure. Oh - wait - you can't. Is it bad? Yes. Would you have to take precautions? Sure, of course. Is it tremendously more dangerous than being on a nuclear submarine? Not really.
Anyway, just because something's hard doesn't mean we shouldn't do it. In fact, we should do it because it's hard.
Why? What is there that we can't have better and cheaper on Earth? Mars is a rock, frozen day and night, baked by solar radiation; its atmosphere, what little there is of it, is poisonous, the soil is just plain weird - why would we want to live there? It would make Antarctica look appealing.
There are two questions here:
1: Why should we, humanity, go?
2: Why should anyone, as a single person, go?
The answer to the second one is easy. Because no one else has. No one else has seen the sky thousands of different shades of pink that we've never dreamed of on Earth, or walked in one-third G, or seen valleys so wide and vast that you can't see the sides because they're under the horizon, or an escarpment as high as Mount Everest. Don't forget, people live in extremely hostile environments all the time, and explorers go just about everywhere for the thrill of it. Earth is just as much of a rock as Mars is.
And hell, it'd kick to see Earth in the sky at night. Now *that'd* be beautiful.
So why would we want to live there? Well, for one, because it's not Earth. It's different. From a purely practical perspective, ignoring the radiation issues (which are not as bad as people think - bad, yes, and you'd have to take precautions, but not impossible), Mars is a healthier place to live, fundamentally, because of the lower gravity. It's just less of a strain on bones and your heart. Yah, you can't return to Earth. So?
The answer to the first one is a little more complex, but it's fundamentally the same as the second. We want to go to Mars because it's not Earth. Let me put it to you this way.
Take a hypothetical teenager, or very young adult.
Why would they want to leave their parent's house? They have everything they want there - shelter, a private space to themselves, and it's cheaper: don't pay for rent, utilities, food. It's perfect. Living on your own looks like hell in comparison. But they do it - why? Because 1) they know they have to, just like we have to get off this rock. Have to. Humans have to keep expanding, have to keep moving, have to keep learning. It's what makes us human - what makes us us, and 2) because fundamentally, in the long run, it's better for them. They learn more (how to manage a household, how to fix things), develop more, and grow extremely quickly. Again, likewise - it's better for us to go to another world, like Mars. We'll learn more, really quickly. Like how to survive in heavy radiation. Like ecology engineering, and closed-systems engineering, which we have no need to learn here on Earth, but we could DEFINITELY use the technology! Like automated factories, robotic construction equipment, atmospheric engineering. The list goes on. Yah, we could do it here on Earth - but we don't need to, and so we won't do it. Necessity is the mother of invention, and all that. How many examples in human history do you need to justify that?
Perhaps a tiny fraction of the expenditure you are calling for would be better spent on reducing our addiction to fossil fuels which is going to end up killing us.
This is the beauty of pure science. Go to Mars! Guess what? There are no fossil fuels there, so we'll learn really quickly how to live without fossil fuels real quick, and export that knowledge back to Earth.
Humans are getting lazy and complacent - things are too easy. "Well, we could reduce our dependence on fossil fuels... but why would we? There's no real need..." You have to keep pushing. Have to keep moving. Have to keep learning.
That's completely not true - at least, not for decent quality rechargeable alkalines, which have a much lower internal resistance than normal alkalines due to the use of higher-quality electrodes (reference here), which means they will last longer in high-current draw situations, like digital cameras, but still nowhere near as long as NiMHs, which have a much lower internal resistance. (One manufacturer shows 1950 mAh for 30 mA, 1500 for 125 mA, 1200 mAh for 300 mA, and 750 mAh for 500 mA).
Rechargeable alkalines also last much longer if they're constantly recharged. Deep-discharge cycles will drain about 50% of the battery's capacity in about 10-15 recharges. Shallow-discharge cycles will extend that number to about 100 or so. It's not NiMH quality, but if you buy one rechargeable alkaline and it lasts you as long as 50 disposable alkalines, well, then it's damned cheaper, isn't it?
Decent rechargeable alkalines have a very good use: low current drain devices, and devices that are not tolerant to low battery voltages. Remote controls, clocks, even Game Boys, are all very good locations for rechargeable alkalines.
I hope they find some ways to make the rechargeable alkalines work better. As it is, they are a niche product good for devices that sit for long times and use little power (smoke alarms, remotes, clocks, etc...). ... and devices that want 1.5V from a battery, rather than 1.2V, as was the point of my post above, and for devices that have the "can't use rechargeable batteries in this device" void-your-warranty clause. Granted, you'd be 'slightly' lying, but there's no possible way they could detect rechargeable alkalines as opposed to normal alkalines (in fact, some chargers can recharge normal alkalines) - they COULD, however, in theory, know that you'd used NiMH/NiCad batteries, because the voltage is much lower.
Plus, some of your information is just not correct:
A fresh alkaline, or a fully charged alkaline, will lose its charge over years (not months), and in fact, it will virtually NEVER lose its capacity if placed in a cold environment (refrigerator). A rechargeable alkaline will hold its charge for 3-5 years, in normal environments, much longer in colder. NiCads and NiMHs will be dead within 3-4 months (or at least approaching the "rapid voltage drop" portion of their lives).
Also, the capacity of rechargeable alkalines should be as high as or higher than normal alkalines! You can find rechargeable alkalines with a capacity of up to 2000 mAh for a AA, and 1000 mAh for a AAA. In general they don't handle high current draws as well as NiMH, but better than a normal alkaline.
So, where are rechargeable alkalines good?
- Remote controls
- Clocks
- Flashlights (capacity is good, as noted above)
- Any electronics device that has >2 batteries in series
- Any electronics device that really wants 1.5V out of each battery
- "Emergency batteries" for digital cameras, etc. to replace NiMHs that die while taking pictures.
They're EXTREMELY good for the last application, as you want a battery that will last a while, will definitely be charged, and that you're not going to use that long.
To verify info, do a Google search for "rechargeable alkaline capacity" and "rechargeable alkaline shelf life", and use the first web site that actually gives -numbers-.
Alkaline rechargeables are 1.5V. NiMH rechargeables are 1.2V. They hold their charge better than Alkalines, of course (until they run dead, when their voltage drops to 0 very fast). This is, of course, important, as 2 NiMH rechargeables in series gives 2.4V, and 2 alkalines in series gives 3V (i.e. CMOS 3.3V).
Many people don't know that electronics that says "don't use rechargeable batteries", it's because of the voltage. In those, you're fine using alkaline rechargeables.
In many cases you can use NiMH rechargeables and it'll work fine. Electronics is remarkably tolerant to low voltage levels. However, if you read your warranty on many of those devices, you'll find that you void it if you use rechargeable NiMH batteries. With rechargeable alkalines, you don't need to worry at all. It also makes the "battery meter" on electronics work correctly, say, on a Game Boy Advance, where the LED goes from Green to Red at about 1.35V, and then off completely by 1.2V. Rechargeable alkalines show normal behavior. Palm Pilots as well, though Palms can change their battery meter to read NiMH rechargeables.
And don't get me started that NiMH rechargeables lose charge over time by bleed away, and alkalines don't. So NiMH batteries are useless if you want to just leave them in something for a while.
Short answer: Rechargeable alkalines have several advantages over NiMH, which is why you can still buy alkaline rechargeables. NiMH is almost purely better than NiCad, which is why you can't buy NiCad much anymore (plus I think NiMH is friendlier to dispose of).
Missed this before...
Also, objects moving along the sheet require some sort of "gravity" to be assumed in order to be pulled down the pocket in the rubber sheet.
This is completely wrong. Again, the rubber sheet analogy uses gravity to restrict the objects to a 2D surface. They can't move off the 2D surface. Moving across the 2D surface, with the mass distorting the sheet (because that's what mass does, see above comment), if they are restricted to the 2D surface, they will be deflected, distorted, or drawn into the distortion in the sheet simply because they are following the sheet, NOT because of any external gravity! This would NOT be true if the sheet was nondistortable (and the endpoints fixed!).
In this case, gravity is what's causing the object to remain on the sheet. If you had some sort of magnetic force holding the test object onto the sheet, it'd produce the same result. It wouldn't explain why the sheet is pulled down (again, that's just what mass does - in this case, you'd have to do it yourself) but it most definitely, very much so, explains why objects get deflected when they pass near the object.
That's a ramjet, not a ramscoop, which is what I'm proposing. Though it's not really a ramscoop, more just a particle collector. The benefit of space is that, well, there's virtually no drag, and so you can coast when you run out of fuel until you get enough. This means that you have a speed limit for short distances, but there are no short distances in space.
If it's fundamentally impossible to get it to fuse in flight, then it's always possible to contain the material, store it, process it, and fuse it later, and increase your speed. Why not? It hasn't cost you anything, or if it did, very little.
So long as you can pick up any material, your speed isn't limited at all. Drag in the ISM is pretty much nonexistent, except at high Lorentz factors. It's only 1 particle/cubic centimeter, after all, and the specific impulse that you get from every particle you pick up is orders of magnitude larger than the cost of ramming into it, so you can coast for a long time before worrying about slowing down too much between the periodic "bursts" of acceleration.
At that point, all you need to worry about is how you power the craft continuously, but that would most likely be solved by better fusion as well - the same that provides the periodic propulsion.
Disclaimer: I haven't actually worked out specific math on this proposal (I doubt anyone would - it's dumb, from a human point of view. It would probably take a long time to get to relativistic speeds - a very long time. But it would get there) but it was just worth pointing out that while there are of course fundamental limits to crafts that carry fuel along with them, there are always options. Nature wasn't -that- cruel to us.
The other point regarding the cost of antiproton factories and solar collectors is naive. An antiproton factory needs (virtually) only energy (and coolants, etc., but a closed enough system can keep those losses down), and solar collectors provide that energy. After that, the quantity of antiprotons you get is just a function of how long you wait. They're luckily easier to store than positrons, so again, it's just a matter of time. So if you want an "unrealistic amount of antiprotons", you need only pay the initial cost, and wait an unrealistic amount of time. Yes, this is naive as well, assuming maintenance costs are zero. However, for this kind of a setup, I highly doubt that after several years, maintenance costs would be significant, and in addition, there are many real uses of antiprotons in medicine and other fields, and one could easily recoup the maintenance costs by selling off a small fraction of the production.
It does nothing of the kind! The rubber sheet analogy is a mapping of 3D space to a 2D plane, which frees up a dimension to illustrate a "real" 4th dimension. The analogy requires that one assume some sort of "gravity" to pull the mass on the sheet down. Also, objects moving along the sheet require some sort of "gravity" to be assumed in order to be pulled down the pocket in the rubber sheet. The rubber sheet analogy is an illustration of the mechanics of gravitational attraction, but does not offer ANY additional information as to what gravity is.
Read the *rest* of the comment, then, not just the beginning. In it I pointed out that if you were in fact asking this question, then there are two answers.
Why does the mass deform the sheet?
1) Because that's what mass does - that's the whole point of general relativity, saying "mass deforms spacetime", which in turn, looks like an attractive force.
2) Well, if you're asking why "mass" - that is, the "mass" that we're all accustomed to thinking is "mass" - that which provides inertia, the "field-squared" term in the Lagrangian - if you're asking why that pulls the sheet down, that's a lot more complex, and it's a completely different thing than asking what is gravity? The rubber sheet analogy shows that a deformation in spacetime can act like a gravitational force. GR then says "mass causes the deformation in spacetime", which is usually explained, in the rubber sheet case, by someone saying "mass causes space to be deformed, like this rubber sheet."
I don't see how it's unclear, other than the 'fundamental deep question', which, well, no one has a clue about yet.
OK, I'll respond. :) Actually, your comments are pretty much the same questions most people have when they start learning relativity, because it's counterintuitive. It's very difficult to separate out different ideas in physics.
So, addressing this:
First, a small object with an insanely large mass would (of course) cause "antigravity" - if, by antigravity, you mean "yanked away from the Earth's surface and sucked into it" - if its gravitational pull is more than the Earth's. The size of an object isn't important (to first order - to second order, it affects tides) just its mass. So an insanely small object with an insanely large mass would act like, well, a normal-sized object with an insanely large mass, or a large sized object with an insanely large mass. In other words, if you wanted to counteract Earth's pull, you'd have to put something the mass of the Earth roughly the same distance as the center of the Earth away from you. You could get away with something smaller if it was much closer, though (but nothing reasonable-sized, of course. It's never going to get more than about half-a-meter from your center of mass, and so it's always got to be huge). That'd be "antigravity"... so long as you were in the centerline between the two masses, and didn't move in the slightest. (That's the L1 point - the point of equal attraction between two bodies: it's unstable. If you move, the pull from one of them pulls you away from that point) It's probably not the antigravity you're thinking of, but that's what would happen.
Second point: The whole "as something approaches the speed of light, its mass goes way up" is a concept that just plain needs to die. It's far too misleading to most people, and it serves no useful purpose. The "mass" of any object can be basically replaced with its energy, which is the sum total, in quadrature, of its kinetic and its rest energy. Normally an object's kinetic energy is pathetic compared to its rest energy: a proton in a hydrogen atom, at room temperature, has gamma (energy/rest mass) of 4E-35 - a bit small. But at you add energy to the object, that kinetic energy becomes significant at some point, and relativistic effects start to work. Basically at that point, the basic equations of kinematics start to have a factor that was "1" start to become much more than 1. What's really changing is the relationship between a change in momentum and a change in energy. At low energies, if you double the "delta-P", you quadruple the "delta-E": that is, if you give some object a delta-P of 10 kgm/s, then another object of the same mass a delta-P 20 kgm/s, the second object's change in energy will be 4 times higher than the first. At high energies, if you double the "delta-P", you double the "delta-E" - it's linear, not quadratic.
In addition, there's also a change between an object's velocity and its momentum - it's the same factor that appears in all relativistic kinematics equations - gamma, the ratio of energy to rest mass. The real equation is p = mv*gamma, which, if you're smart, you may notice becomes p/gamma = mv, and since gamma = E/m, then p/E = v. Remember that I said the real change is that "delta-E" goes from being quadratic in "delta-P" to being linear? Well, if it's linear, then p/E approaches a constant - that is, at high energies, your velocity approaches a constant, and that constant is the speed of light.
(and since E is always greater than p, because it has the rest energy as well, it's always less than the speed of light).
So. Does this affect gravity? Yes, but only because gravity only gives a damn about energy - good old fashioned energy - both the rest energy AND the kinetic type, and it doesn't care in the tiniest bit which you have. Neutrinos, for example, have ridiculously small mass (less than 10^-3 eV, if memory serves, which is about 10^12 times lighter than a proton), but in most places where they're seen, they've got a couple keV of energy - so they've got a gamma of 10^9 or more. So, as far as anyone will ever be able to tell, they're going the speed of light. But as far as gravity's concerned, they have far less than a proton at rest, and it's still the same old "sucking" kind.
Hope that helps.
No - you're missing the entire point of the rubber-sheet analogy if you think that the point is that the objects are drawn to the hole. It most definitely does explain why gravity works.
The rubber sheet analogy is 2D gravity. That is, objects are constrained to be on the surface of the sheet, and cannot move up, and cannot move down. "Real gravity" - that is, the thing that's holding the ball to the sheet - is just an implementation of the 2D world in a 3D world (by restricting an object's motion in one dimension).
Gravity in the 2D world is the deformation of the sheet itself, rather than an actual external force. A mass presses down on the sheet, causing a deformation in it, and it presses down on the sheet because that's what masses do (not because of "real gravity") - mass (well, stress-energy) = 8*pi*G, where G is some construct that tells you how much the sheet deforms. That's what general relativity says, fundamentally - the whole shebang, right there. Mass deforms spacetime. In the 2D sheet, it deforms it because gravity pulls down on it. In our world, it does it "just because". In short gravity works because mass deforms space and time. Now, if your comment was that it does nothing to explain why mass deforms spacetime, you're right. If you want to explain why a deformation in spacetime equals mass, then you've got to work out quantum gravity, because in general relativity, mass is just a construct which causes a deformation in the sheet.
Now, obviously, you should already realize the answer to the parent's comment: what would "pull the rubber sheet up?" Getting rid of mass. Until you find something else which deforms spacetime (which, well, we haven't, but there are wacky theories: most of the FTL general relativity ideas involve "negative mass" - that is, things that bend spacetime differently than normal mass) the only way you're going to reduce the gravitational effects caused by something is to reduce its mass.
Most other people here point out that gravitons could be "affected, or blocked", and the simple answer to that is "no". That's like saying "maybe we could find a way to make neutrinos interact more, and harness their energy!" (because frankly, if we could, that'd solve all of our energy problems. The Sun puts out a ton of neutrinos) - well, the whole point is that neutrinos interact only weakly. That's virtually their definition. You can't get them to interact more, because there's no way to do it. Same with gravitons. Gravitons will only interact gravitationally, and thus, the only way we can affect them is, well, with gravity. (Amazing Device Causes Antigravity! "Warning, device is approximately the mass of the Earth, and may cause harm to others in your vicinity as well as the rest of the solar system")
With quarks it's difficult to say that there would be a difference between "merged" and "bound" - the strong force is very weird (it's confining, for one: it gets stronger the farther away the particle gets, and weaker the closer in the particles are) and so it's really quite difficult to distinctly say "yes, this is a distinct 5-quark 'merged' particle" or "no, this is a meson-baryon molecule where the quark-antiquark orbit the other three color-singlet quarks".
After all, no matter what, it's NOT a distinct particle! Any baryon (protons, neutrons, whatever) are 3 coorbiting quarks. All deep-inelastic scattering measurements have shown baryons to look like they're made up of three particles basically at rest (parton model), and this model does remarkably well. So no matter what, the pentaquark is NOT a "merged" particle. It's 5 quarks, hanging around each other.
This particle would be very much a mess. Most of the time it's referred to as a molecular meson-baryon state (look in the literature for this - specifically the SPring paper) and, to be honest, I'm not sure how you could tell the difference. The naive "quark-antiquark here, three quarks here" model is so terrible at these energies that it's really difficult to explain to people to just throw away their intuition for most things.
Truth is, it's probably best to think of this as the lowest energy level of a meson-baryon bound state.
(I have no idea what the grandparent poster was saying - "they specifically said the merged version...". That's crap - read the papers. No one's taking a stance between "5 quark bound state" and "meson-baryon bound state". All this showed is that there IS a bound state in an interaction between a neutron and a gamma ray which decays into some baryon and a kaon.)
No. Relativistic contraction happens only in the direction of motion. The stick would "thin", not shrink.
If you shoved it "towards" Europa, for instance, then the stick would shrink slightly, but, if you're jiggling the stick back and forth, the stick would be shrinking, expanding, shrinking, expanding as you stop and start the motion. It's even worse than that as you're attempting to move a massively elongated object, so you get displacement waves rather than motion.
Plus the fraction that we're talking about here is REALLY small. Look it up - just look up Lorentz contraction somewhere, and use a value of, I don't know, v = 1 m/s (which is still fast). It's ungodly small - somewhere in the vicinity of 1 part in 1 billion.
It's not an easy question to answer - there are quite a few complications involved - but it suffices to say that nothing weird happens. The stick would take a long time to move (at least the characteristic period of the object - speed of sound*length) and if you tried to shove it harder, you'd just distort the stick (bend/break, etc.) and send a wave down the stick, thus moving YOUR end, but not moving the entire object!
I mean, let's work it out - let's assume that it's a billion meters long, so moving it at 1 m/s shrinks it by 1 meter. Let's also say that the speed of sound in the material is 1000 m/s, so it takes a million seconds for a "push" from one end to move to the other end. In order for you to actually see any real Lorentz contraction (from the whole stick), the entire thing has to be moving at 1 m/s, not just the end - Lorentz contraction comes from the fact that a reference frame moving with the stick must measure the speed of light the same as you do, and the 'fractional' contraction is due to the fact that the frame at the very far end of the stick is the same frame as the initial end of the stick.
So, in order for you to see the billion-meter long stick shrink by 1 meter, you'd have to wait a million seconds. And by then your end would have moved one million meters, and if you measured the length of the stick while it was moving at 1 m/s, you'd get 999,999,999 meters. It wouldn't be a sudden jump - it'd smoothly decrease in size as more and more of the stick begins moving. Then, when you try to stop it, it'd take a million seconds for the stick to stop, and the stick would smoothly stretch back out to 1 billion meters.
But, in the end, it still would've moved a million meters. It's only during the motion that you see anything weird happen.
So if you grab it before the whole thing starts moving, then the total contraction would only be due to however much of the stick is actually in motion.
... assuming that said craft does actually carry its own fuel (which you limited yourself to, but...)
That's, of course, not the only kind of craft: ramscoop ideas have been around for a while, and while they're not exactly "production quality" ideas, there's nothing fundamentally killing them. We'd just have to figure out how to do fusion much better than we do now - which is not exactly new physics - it's new engineering. We'd also want to get the hell past the heliopause, to interstellar space. Ramscoops can easily build up to relativistic speeds, because, well, their fuel is free.
Especially when you get to decent Lorentz factors things start to work in your favor: space is compressed, so the interstellar density becomes higher (drag isn't exactly an issue, because presumedly your ramscoop is strong enough to drag in material even at a decent spatial compression) and so you get more fuel as you go faster.
It's not an issue of viability (because it is viable), it's simply scale. A ramscoop type ship would probably need to be large, and the "initial speed" required to start up the reaction is probably high as well, though this depends on exactly how good fusion technology becomes.
Also, as a brief comment, antiproton synthesis is very difficult, but antiproton storage is much easier than positron storage, because they're charged and heavy, so once you cool them, you lose very few. So again, production of large quantities of antiprotons is not difficult at all - it just takes time.
Your final conclusion, though, is definitely right. Relativistic travel = huge cost (in 2003 dollars! note that economies of scale and necessity can help here. Automated antiproton factories, etc.: thank god for that tremendously huge fusion generator sitting next door pumping ungodly amounts of energy out all around us.)
So, finally, calling them "practical problems" may be a bit harsh on them. It's just that, as a species, we're not motivated enough to do it.
Maybe, just maybe, if we ever find a planet which we have a good belief that we could live there, that'll be enough of a motivation for some country to do it.
The difference between an embedded system and a modern PC is minor. Right now it's mainly just the difference between someone who builds a simple computer from bare metal, and someone who uses a complex computer that's been designed from bare metal for them.
The point being that *NIX design isn't just implemented in modern PCs. It's implemented just about everywhere (uClinux, RTLinux, etc., and even larger 'embedded machines') and there's no way that you can suggest that coding that's developed for a *NIX kernel on a modern PC is ANY different than coding for a *NIX kernel on an embedded PC.
Let me put it this way: what if someone had developed RWU for an embedded multiprocessor system (it's an example, don't pick nits) using a *NIX derivative? They're working 'inside' the OS, but on an embedded system, as you've said, it's a whole different game, so can SCO really claim control over that? If there's more issue with it being developed on an embedded system than on a COTS system, how does that make any sense?
The very fact that there is confusion over this sort of thing just proves that SCO really has no chance. You can't claim that you have the rights to anything that was developed with your technology when "your technology" is the basic foundation of all computer science. Thank God the original inventors of the transistor, integrated circuit, etc., never tried to claim that.
Yeesh.