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Melis launched a company, Melis Energy, in 2001 to try to commercialize a technique that harnesses algae's ability to turn sunlight into hydrogen. In the fall of 2001, the company built a bioreactor containing 500 liters of water and algae that can produce up to 1 liter of hydrogen per hour. A siphoning system extracts the hydrogen, which is stored in its gaseous state.

So, we have the means to make the hydrogen. We also have vehicles (mainly demonstration models) which can run on the hydrogen. Although at this point, I must interject that fuel cells are not the way to go - hydrogen fuel cells use platinum as a catalyst - do the math on how many people in the US have vehicles and how much platinum a fuel cell requires, and how much platinum is available worldwide, then ask yourself if such fuel cells are viable in the long run. Fuel cell vehicles are not the answer, but directly "burning" the hydrogen can be, we just need a way to store it in an easy form to get it in a car. You can't simply put it into a tank made of any material - hydrogen simply migrates through the material (it is one of the reasons why water is such a good solvent) - it turns steel brittle over time. Plus, in order to get a good volume/energy ratio, you have to store it as a liquid - and it is a very, very cold liquid. I can't ever imagine a homeowner having a car carrying liquid hydrogen parked in their garage. Most people aren't even intelligent enough to manage proper handling of gasoline, let alone liquid hydrogen.

So - you need a different storage mechanism. This one mentioned in the article proposes to use sodium, which we already know is an inefficient transfer medium. What else could be used? One company (whose website seems to be down, or they are not in business anymore) proposed to use hydrides to store the hydrogen - their name was Powerball Technologies, and they supposedly had a working product (IIRC, back when they first announced this several years back, GM had a demonstration vehicle running on the system). What wasn't clear was how much energy it took to convert the hydrogen into hydride - it might have been as ineffient as the methods mentioned in the article we're discussing.

Wait - don't we already have a method of storing hydrogen in a dense form, that we use everyday? Remember what gasoline is made out of - long hydrocarbons chains. Perhaps the answer is here? Maybe instead of trying to use hydrogen directly - we should look at methods to take pure hydrogen and carbon, and form hydrocarbons. A system in which you could put hydrogen and carbon in one end, and get hydrocarbon based fuels out the other - could be the ideal method. It would probably take a lot of energy input, but perhaps that energy could come from solar power (ie - a solar furnace or something similar). The hydrogen could come from huge algae bioreactors (if they can get them working better for industrial use). The carbon could come from the atmosphere (CO2). Vehicles could use this fuel (which would end up being something like gasoline - could even be identical to gasoline, maybe - this may help with the answer) - such a fuel might even burn cleaner than today's gasoline, it might even work in current engines. Perhaps we can sequester the carbon monoxide output for recycling back to the refineries making the stuff

There are more people alive right now than have ever lived in the entire history of man kind.

Here's a snippet from a better explanation than I was going to write:

"A transparent material is one in which the charged particles can't permanently absorb any photons of visible light. While these charged particles all try to absorb the visible light photons, they find that there are no permanent quantum states available to them when they do. Instead, they play with the photons briefly and then let them continue on their way."

The FCC is endangering the lives of midwesterners with this move. I cry "Terrism!"

Weather Radar on birds with ISAR can do this.

http://www.madsci.org/posts/archives/2004-09/10940 49193.Ph.r.html

I've exchanged email with NOAA about hurricane photos and have been told that some of them are inface ISAR radar images that have been colored.

The blurb there for the story sounds like a Press Release there from Mr Nair, chairman of the Bangalore-based Indian Space Research Organisation (Isro).

It's about $10000/pound, so a kilo would be $4500 - just a small fraction of the cost of the black box.

Yes, but if there is a BABY blind from birth they can give them these artificial eyes, and let them see *from birth*. Yes, it won't help people who are already older and blind from birth, but in the future there is a potential of no one ever being blind, is there not?

I was about to mod you as "insightful" (...and you deserve it!), but instead I felt to need to respond.

I _can_ see a future where no one is blind from birth, but not anytime soon.

A baby grows at an enourmous rate, doubling in size every so-many months. Granted, the skull and brain do not grow in size at nearly the same rate; but my point remains valid. Will the chip that interfaces with the child's retina and/or optic nerve be able to adapt to a changing eye size? (For those about to reply that babies' eyes are already full-size, see this. Yes, I had to look it up myself 'cause urban legend says otherwise ;-)

Can the "bionic eye" adapt to eye growth? My intuition says "no". If my intuition is correct, then the child would require repeated surgeries over the course of childhood, and probably adolesence.

To replace or repair a child's eyes at birth (I think) requires a more "elegant" technology...a technology out of reach of current and near-future science. Of course, perhaps some non-computer-like biotechnology is the answer. Stem cells come to mind, as they can supposedly be coaxed into forming any type of body tissue.

Note: I have worked with and spent a great deal of time with many blind adults. Most lead a very happy and normal life, and they will surprise you with how much they truely "see".

Regards,
jtcm

Here is AllTheWeb.com's top 4 results - all contain the answer:

http://www.straightdope.com/columns/010518.html
http://www.madsci.org/posts/archives/nov98/9113122 69.Ot.q.html
http://www.thewildones.org/Animals/flamingo.html
http://www.madsci.org/posts/archives/nov98/9113122 69.Ot.r.html

(The last is the answer to the 2nd.)

Here is AllTheWeb.com's top 4 results - all contain the answer:

http://www.straightdope.com/columns/010518.html
http://www.madsci.org/posts/archives/nov98/9113122 69.Ot.q.html
http://www.thewildones.org/Animals/flamingo.html
http://www.madsci.org/posts/archives/nov98/9113122 69.Ot.r.html

(The last is the answer to the 2nd.)

http://www.ncpa.org/iss/bud/pd112801b.html
http://www.madsci.org/posts/archives/jun99/9288629 30.Ph.r.html
http://www.atomicinsights.com/apr95/waste_myth.htm l
http://www.nmcco.com/education/facts/waste/waste_h ome.htm
how's that?

You can justify all you want, but the truth is that any objection against gambling is purely moral. I'm always amazed at how ass-backward conservative Slashdot is when it comes to things like gambling, but I guess that's the US mentality of "gambling evil" at work.

Well..

I don't think that gambling in and of itself is morally or ethically wrong, but the problem is that it lends itself to addiction through a random reward stimulus, and that addiction ends up creating a burden for society.

Described here (end of second paragraph), here (fourth paragraph), and here (particularly insightful).

If you give a rat a button which randomly either provides a shock, or a reward, the rat will press it obsessively. Contrast that to a button which either provides purely reward or punishment, and the reaction will be markedly decreased. As much as we'd like to think so, we're not that different from our less talkative mammallian counterparts. Throw in the fact that gambling/casinos never close, and games never actually end per se, unless you run out of money, or you can manage your desire to keep playing and quit while you're ahead. Sure, not everybody gets addicted, just like not everybody gets addicted to the pleasure reward of alcohol, tobacco, or less socially/legally acceptable substances, but casinos and other industries profit most from the ones who do get hooked. It's their meal ticket. The people who can consistantly get up and walk away when they're up aren't the people who keep coming back, and if they do, they're asked to leave.

Online MMOGs, specifically EQ but also others, provide a random reward as well. While the short term consequences of compulsive gaming might not be glaringly obvious, in my personal experience, there's a trend for people to withdraw from their real-world responsibilities and even hobbies and interests to pursue the virtual world of "exciting," pseudo-random reward stimulus.

I don't believe that any of these activities should be illegal. Once you turn 18, the hand holding is over in my book.. if you screw up your life, that's your mistake. But to believe that gambling doesn't pose a real risk of problem behavior, and that society doesn't shoulder the burden, is simply naive.

On a related note, I can't wait to go back to Vegas. ;)

The exoskeleton does nothing

These things are already as small as they can be.

Electrical chips run far below 1% of c.

Yeah, the flow of electrons in wire is extremely slow, but the work is really done by the electrical field generated, so that as one electron is pushed into the wire, it "pushes" the sea of electrons forward so that an electron at the other end of the wire is shifted forward. This "shift" occurs pretty close to c. I

Since the earth's mass is 2/3 water

The earth's surface is 2/3 water, not the earth's mass. This site says that the hydrosphere makes up 0.04% of the earth's mass.

you're telling me that the water won't get thrown out away from the center thereby slowing it back down?

I'm not completely sure on this one, but I don't think that's how it works. The oceans are still being held quite strongly in their basins by gravity, which is many times stronger than the centripetal force the rotation of the earth imparts on the oceans...

The article said 90% less electrons, and true, electrons (or holes) make up current, but that's not what they meant. They said it was 90% less electrons stored in each cell -- This is just a small portion of the total current used in the memory.

An ampere of current is 6.24 * 10^18 electrons/second, so to write at 12 megabits/second (USB speed) would require only 1 billion electrons/second, or 0.173 nanoamps -- the rest of the chip will probably take milliamps and dwarf the actual number of electrons flowing into the cells.

Most of the current is used to combat the capacitance on the bit lines - since the X & Y grid wires are so close to other wires (protected by an insulator, of course), a natural capacitor forms. If you want to change the voltage on these bit lines quickly, the capacitance will demand current. You'll get the current back when you eventually try to remove the voltage, but so far it isn't really worth it to recover this current because, after resistive losses, it's at a slightly less voltage. (there are some cool schemes to pump that current into the next bitline to be accessed, but this happens more with synchronized clocks).

Power is also dissipated by the analog sense amplifiers at the edges of the FLASH memory that convert low-level voltages to more usable digital signals.

Power dissipation is more of a problem for processors & not FLASH memory. FLASH is all about density and cost.

well this random post seems to claim that 1 mA can kill a sick person, and 100 mA can kill a healthy person... so my "an amp can kill a person" should actually say "an amp could kill 1000 sick people... or 10 healthy people... or some combination thereof..."

There is one "free" energy source. Thermonuclear fusion. Running fusion reactors for a hundred generations at full world energy capacity would lower the level of the oceans by 1mm. Again and again and again we come back to this in these conversations about future energy supplies. Fusion is the only realistic long term, clean and safe solution to the world's "constant on" high energy density and high power density needs. Yet even today we languish in pissing contests over where the first demonstration reactor will be built. Fusion is an extraordinarily difficult but ultimately solvable problem, and we will solve it. We have to solve it.

One of us is confused about relativity. I'm not sure if it is you or me, and I feel confused, so it might be me.

Let's assume constant acceleration, 3g. I'm not sure what that would do to human health, but lets just assume that we'd be okay, or that we figured some way around it. Here is the calucation done to reach .99c. It takes us 3 years to get to .99c. Time dilation at that speed is a factor of 7. This means: That it would take us, the pilots, 10 years to go 70 light years, and the rest of the universe would have slightly over 70 years pass.

Add some time for slowdown&speed up.

If you go .999c, the dilation factor increases to 22. We can get within 222 light years, no sweat. The heat death of the universe is still quite aways away. While it is painful to think about travelling half-way across the universe (as if that statement meant anything), our local region is definietly within the realm of human life, even from the perspective of observer, not pilot. Outside of one generation ! necessairly = outside of humanities grasp.

The otherside of the cosmos, however, might be.

Now, if I can only think of a way to build my DIY Alcubierre drive :)

IMHO, this is what we need: Cheap, easy to store energy. Antimatter, or something. Purely inductive drives, or some kind of low-fuel requirement ramscoup thing. Longegevity treatment.

If we live forever, or a REALLY long time, the heavens can still be ours, even though breaking the FTL problem might be impossible.

Ah-hrm. A covalent bond (or an individual atom, if you wish) is on the order of a tenth of a nanometer (an Ångström) or more. Anything as tiny as a single nanometer can hardly be more than a small-ish molecule. There's a page about virus sizes here.

The most coherent definition of nanotech I've encountered is along the lines of "anything with features as small as 100nm or less". The point would be that that's when micrometers give you annoyingly many leading 0s.

Electrolysis can be greater than 70% efficient at converting electrical energy into chemical energy (splitting water). How efficient is the electrolysis of water?

System effciencies will depend on the efficiency of your electrical power generation as well as the electrolysis processes. Some slides in here indicate 25-30% with conventional electric power plants and large scale electrolysis.

Higher system efficiencies approaching 50% are possible using thermochemical water splitting processes.

Yeah hydrogen is NOT a good energy source in our terrestrial environment. It is a very good battery (energy/mass) and a system built upon its use for energy storage and transport, and for distributed portable power generation (cars), may be substantially more energy efficient and substantially less polluting than our current one.

http://www.madsci.org/posts/archives/mar97/8589845 31.Ns.r.html.

We can't currently pick up ET signals equivalent to what Earth is broadcasting to space, even if they were coming from Alpha Centauri; they're just too weak.

This is an analog problem of signal to noise ratio, far more than anything else, so faster processing won't help a bit.

A cryogenic Allen array (to minimize thermal noise), especially in space far from Earth, or on the far side of the moon, would help a tremendous amount.

Usually discussions about SETI itself don't bring that up, because of issues of optimism and such, but it was easy to find web hits on the eseentially identical question: can ETs pick up Earth signals?

"No", says this Seti League guest editorial "ET Detection of Earth TV Unlikely" that goes into a little technical detail.

Similar comments by John Dreher, Staff Astronomer, SETI Institute, although he goes on to assume that ETs would be able to pick up weaker signals than humans are able to -- assuming implicitly that ETs will have better analog technology than we do (maybe they do, but that doesn't help us to do the same).

What about ETs actually beaming a signal at us? Maybe they do so to all nearby stars, one by one. Maybe...would we do that?

"...it has been agreed by all relevant groups that we should not be actively sending out messages to try to reach other civilisations", says another page

Ok, so we would not be so foolish as to attract undue attention from an unknown and possibly hostile galaxy, but maybe ETs will be more naive than that. Or a lot more confident (play ominous music here ;-)

So, bottom line, this is a cool topic, but are we planning to build a cryogenic Allen array in space in the next two decades?

I think we should, but any predictions really should be based largely on that one issue.

P.S. the recent lab verification of photons having orbital angular momentum, able to carry arbitrary amounts of information per photon, implies a new medium we'll need to check for ET signals. Maybe that's what all advanced civilizations use.

See e.g. Photons Spin More Data

I don't think that's necessarily true... This explanation makes sense - the water does expand at freezing point, but contracts again as it continues to get colder. Unless it's a particularly sunny part of the antarctic, I think it would be cold enough that the whole lot could freeze. I'd put my bets on geothermal.

Actually, blades of grass being thrown through objects during storms is well-documented. Just one site I found that explains this is Here.

As far as the stars are concerned, I understand what you are saying. I also know that I did see stars as impossible as that may seem... the sky was completely black.

Burroughs cut up experiments were certainly influenced by the exquisite corpse game, and by Tristin Tzara's technique, but he did change the technique, by reusing words, using cut ups of phrases, pulling from multiple sources, etc. He also did some very interesting cut up experiments involving audio tape. There's a CD out called "Break Through In Grey Room" for those who are interested in such things (and unlike most WSB audio recordings, it's deemed safe by RIAA Radar).

Unfortunately, it's paranoia of getting sued that drives this. Companies all over the place do things they know are ridiculous to cover themselves in the event that someone does a really stupid thing that they should know better. The company I work for has just annoyed over a thousand customers by insisting that advertising "lightboxes" are moved inside as we have been informed that there is a very slight chance that if someone touches it when it is very wet that they may get a minor electrical shock.

Of course companies need to act responsibly when they determine that a danger exists. However, the issue of mobile phones at petrol pumps is similar in many ways to the infamous do not eat stuff you find all over the place. Design something idiot proof, and they'll design a better idiot. People manage to hurt and main themselves doing all kinds of really stupid things.

* Petrol = Gasoline for Americans who don't what I'm on about

There is no point wasting resources to search for an ark that couldn't have been there. The "great flood" is clearly impossible.

To summarize, during the day the presence of "masking" sounds makes it more difficult to hear distant sounds. At night, fewer masking sounds are present.

Maybe someone would like to put out a version of firefox using a logo which is a picture of a firefox, not of a fox.

Just a thought.

> Since then Linux has traveled around the sun ten
> times but its still in the same old place. :P

OT, but Linux (and Linus) has travelled nearly seventy billion kilometers in the last ten years, courtesy of Sol's orbit around the galaxy. ;)

--
-JC
coder
http://www.jc-news.com/parse.cgi?coding/main

Who said Mars had no atmosphere? Any object with a gravitational pull that exceeds the mean escape velocity of gas molecules (over-simplifying here - better explanation here) will have an atmosphere. The moon has a gravity below that mean (think of it as a vertical line on a bell curve, but before the bell), hence it has little/no atmosphere.

Mars, on the other hand, is a much larger body and hence has enough gravity to retain an atmoshphere of about 1-9 millibars, depending on altitude. Indeed, it's the very existence of this atmosphere that allowed the lander to slow from 12,000mph to 1000mph before the parachute opens.

We left mirror reflectors on the moon so that we could bounce laser beams off them and accurately measure how far away the moon really is. More info here and here.

Hey, I found exactly this question addressed.

I would guess that it has nothing to do with supercooling. Human blood freezes at -2 or -3 degrees. Slightly different chemistry could make the freezing point lower for the squirrels.

... but rats are:

Rats have a 21 day gestation period, and it takes them 21 days to before they can be weaned from their mother.

CC.

Question for someone who might know: How was the ice supposed to survive for billions (or for that matter, even thousands) of years? Ice sublimates. (You can see it directly that you don't even necessarily need low pressure environments; make ice cubes in your freezer and leave them for a few weeks. The ice cubes slowly but surely shrink.)

Once the ice/water vapor gets into the sun, it'll leave the lunar surface, since simple observation shows the Moon isn't capable of holding water vapor (or it would).

So how, theoretically, is the ice supposed to survive, even at the poles? Drop a few million tons of ice onto the Moon, even in a crater, and it'll disappear in a geologic blink of an eye. Maybe I'm missing something but I never expected to find ice on the moon because of this effect.

I only have one problem with the whole dyson sphere idea. Assuming you are trying to walk around inside it, what is going to keep you on the ground? Not gravity.
One of the problems we had to deal with in my college physics courses was figuring out the effect of gravity on an object inside a shell, resultant from that shell. And you know the answer we came up with? Zero, Zilch, the gravity from the shell counteracts itself no matter where you are in the shell. Simply put, even though you are might be closer to one spot on the shell, the fact that most of the mass of the shell is now on the other side of you, cancels out the effect of the distance.
Here is a reference, for those that don't trust me.
So my point is, why would anyone build a dyson sphere in the first place, unless its just a collector and the people live elsewhere?

I am not an expert on this subject, though I played one on TV (really... but that's a long story). I know enough about meteorites to be a little dangerous.

Though the CNN article credits Press Trust of India, a search on PTI's site found nothing (for me at least).

When the articles talked about burning fragments, it didn't ring true. So, I went to Google to do a little quick research.

Except for those really huge impacts, smaller meteorites are relatively slow movers in the lower reaches of the atmosphere and lose their heat rather quickly. Let me steal some work from:

Date: Mon Nov 30 23:28:41 1998
Posted By: Robert Macke, Grad student, Physics, Washington University
Area of science: Astronomy

If you have a baseball-sized meteorite of density 3.2 g/cc, using a value of 1.2 kg/m^3 for the density of air, you will find that the meteorite will slow from its approach velocity of roughly 11000 meters per second to its terminal velocity of 60 m/s in a mere 28 seconds, having traveled only 3 km. (By comparison, the speed of sound is roughly 315 m/s.) It then spends another 100 mins or so falling before it hits the ground, giving it ample time to cool down below its original temperature it gained during entry into the atmosphere. (At 60 m/s, it's moving like a fastball, but not much more. It'll still cause a lot of damage if your car or house is in the way, but it wouldn't start a fire or create any appreciable crater. It would probably be a bit warm to the touch.

Any learned assistance would be appreciated. I'm not adverse to being shown to be wrong in a subject that I have little more than passing knowledge.

0x0d0a: you're right, of course. I meant to type "Actually, SPEED itself is not dangerous." My bad.

Guppy: respectfully, I have to ask this:

How fast do you change lanes at freeway speeds? I ask, because I drive on LA's freeway system daily at speeds in excess of 75mph, and I don't experience anything that could even begin to be considered rocking.

Back to business. Regarding the torque thing, you might be wrong. Check this link, and consider that two vehicles side-by-side at the same speed that bounce off one another will be applying force on the x-axis, which is the axis of rotation of the wheels, so no torque will be imparted. Control will likely be maintained.

On the other hand, if there is a significant difference in speed between the two cars, some force resulting from the difference in speeds will be applied on the y-axis, so the torque would be imparted on the z-axis. That certainly could cause wheel hop or similar, which could easily wrench control from the driver.

Interesting - I would have thought that was not true, but see this breakdown of the differences between SRAM and DRAM. Static RAM is indeed static - I would have thought the flip-flops would pass current all the time (making them comparable to DRAM), but they actually don't.

In any case, I often wondered if the photo from Time or Newsweek was faked.

My wife is a Marine Biologist and has been answering questions there for several years. They're a pretty enthusiastic bunch.

Evolution is a 'theory', just like gravity. If you don't like it, go jump off a bridge.

This is just not the case. Gravity is a Law, not a Theory. It accurately describes something, but does not explain "how" something works. Only that it does. Evolution, OTH, attempts to explain how a process works. Very little if any progress has been made towards this end WRT Gravity.

A quick Google search for "difference between a Theory and a Law" should provide an explanation of the differences. It was not too long ago that this distiction was pointed out to me, while making the same assertion you have. This page explains it better.

I was all about to come back with a snappy "Huh? Did Wohler have a fusion reactor to synthesize his own damn carbon?", and then I read this:

What is the difference detween an inorganic and organic compound?.

After eliminating the guidelines I'd typically used, (and two I hadn't though of!), it appears that the best definition is indeed that "An organic compound is whatever an organic chemist says it is; an inorganic compound is whatever an inorganic chemist says it is."

Thus endeth the lesson. I hope.

Photographic memory is a myth

There's a reasonably good explanation of why grapes do this here.

I'd attempt a synopsis, but the picture on this site makes it much easier to explain.

Brant

Here is a link to one man's list of criteria of what makes something "alive." He admits that there is some disagreement among scientists about what "life" is. From his list, virii: (1) don't have cellular organization, and (2) don't grow or have a motabolism but they can (3) spread their genetic information to offspring.

Since it does not possess two of his three required traits, virii aren't alive.