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If you are in the Newport News, VA area on Saturday, the Jefferson Lab is having an open day from 9AM to 3PM. https://www.jlab.org/

Also the press release from the lab itself about the Proton pressure QUARKS FEEL THE PRESSURE IN THE PROTON

If you are in the Newport News, VA area on Saturday, the Jefferson Lab is having an open day from 9AM to 3PM. https://www.jlab.org/

Also the press release from the lab itself about the Proton pressure QUARKS FEEL THE PRESSURE IN THE PROTON

Exactly what heavy metals incorporated into PV panels are you talking about??

Silicon, not a dangerous metal, you'll find silicon dioxide in vast quantities at any beach(sand), it also makes up 43% of earth's crust
Aluminum frame, not really, Al2O3 makes up 7% of earth's crust, also recycles real well.
Glass, a mixture of SO2 and few other harmless compounds.

A little bit of copper, also recyclable, soo what are you writing about??

Like sheep! Baaaah. Silly primates with their ordinal fixation, it was inevitable for the counters of cows and sheep to become counters of protons.

"How is everything that is different different from everything else?" Fair question, perhaps the ultimate question. So we started with four elements: "One, two... three... four! A ha ha ha ha!" says the Count. Then we got real and stuffed the periodic table with critters.

Q: How do I find the number of protons? A: You look it up in a table of the elements, silly! Baaa, wrong answer. Q: How did the scientists count the number of protons? A: They counted them just like you would, one by one. Baaaa. Wrong answer but I wish I'd said it. Q: Is there a certain way to count the protons in an element when identifying them? A: [quoted below] now we're getting somewhere...

[Bruce Alexander] There is a technique called mass spectrometry that is pretty good at counting protons, albeit indirectly. If you take an element, and strip of an electron you make it slightly positively charged. If you ping it through a gap between two oppositely charged plates (one negatively charged, and one positively charged), then the positively charged element will be repelled by the positive plate and attracted to the negatively charged plate. How fast the element moves towards the negative plate depends on how heavy the element is and, as the weight of an element depends on how many protons it has (as well as neutrons) you can 'count' the number of protons by measuring how fast the element moves towards the negative plate.

Okay so you're confidently shaving off what you think is an individual electron, observing the behavior of the resulting mass to infer a number of what you presume are individual protons. Q: How many decimal places of surety does this give us that in fact we are dealing with an ordinal number of things that act out on a linear scale? I wonder. How many electron licks does it take to get to the proton center of an atom-pop? Let's ask Mr. Owl. Mr. Owl just bit and swallowed the damned thing. Then I passed out of boring ordinal space into dream-time. In my dream I wondered how the fabric of reality knits together. Is the Hand Of God counting, "a-one, a-two, a-threee... crunch!" for every atom? What is the Hand with those wiggly ordinal fingers? Then I thought of entropy and radiation, the dances of the little electron chicks in their shells.

In order to build an atomic firmament suitable for every day use -- a quantum boundary of is-ness below which things are not just made of smaller things, al absurdium, nature must change the rules. At this boolean primordial level there can only be is-ness and is-not-ness, one and zero so the only way to change the rules is to NEGATE them. In other words, a flav fly groovy flip in which things are different from other things because of the absence of something, not the presence of something. Bizarre. What would that something that is absent, be? Because I like prime numbers one meta-universal topic came to mind. It may be the only possible answer.

FACTORABILITY. What if... what we know as discrete atomic elements are the shapes of relative stability that are BEST represented -- not by ordinal proton count -- but by prime numbers, as islands in a seething quantum foam, their stability arising by nature's inability to factor them further? What if the quantum firmament is continually 'factoring' thing

Increased awareness, new federal laws holding manufacturers responsible for meeting the marking of their items, etc. I suspect it's still a problem though, just not as widespread as it once was. There is a good pdf guide from the gov on counterfeit bolts and other hardware items (I love the completely cosmetic gas cutoff valve on pg. 32)

Boeing still gets a $163M contract while the DOE's FEL in Newport News gets cut?

http://www.wired.com/dangerroom/2011/06/power-down-senate-zaps-navys-superlaser-railgun/

So much for science ...

I was being facetious about the chrome painted missile but you are wrong about mirrors and high power lasers.

It is not as simple as spraying krylon chrome paint on a substrate to create a laser mirror and cooling is an issue but even high power lasers utilize mirrors in the optical cavity with a Q switch outcoupler mirror on one end.

For your reference here is a picture of the outcoupler from the Jefferson Lab FEL being worked on.

There some more information to be found here: http://www.jlab.org/FEL/ You could also watch the video http://www.jlab.org/FEL/Movie28.mov , but that was a bit disappointing (no KABOOM).

There some more information to be found here: http://www.jlab.org/FEL/ You could also watch the video http://www.jlab.org/FEL/Movie28.mov , but that was a bit disappointing (no KABOOM).

I interned in the instrumentation and control group of the Jefferson Lab FEL the summer I graduated from high school. My main project was working with the optics guys to write some spot-size detection software in C. Until my current job, it was definitely the most fun I've ever had in my life that didn't involve rafting. Of course, back in 2002, they had just started the 10kW upgarde project from 1kW, so a little over 10 years to get it working at 10x that capacity is pretty sweet.

the project website for all the real, nerdy, details is here if anyone is interested.

There are about 1.33*10^50 atoms in earth (Source). 250 Exabytes are 2000 Exabits, or 2*10^21 Bits. Thus for each bit, there are about 6.65*10^28 atoms in the earth.

I'm a bit skeptical of your claims about lead decay in electronics. While some isotopes of lead are radioactive, those are products of uranium decay, which as any good geek knows, goes through alpha and beta decay until it ends as a stable particle of lead-206. In that pathway there is lead-214 and lead-210 that have half-lives of half an hour and 22 years respectively. However, unless they are putting uranium in your electronics, the only lead present is going to be from mined ores that have had plenty of time to decompose into a stable form.

The best chart of lead isotopes I found is here http://education.jlab.org/itselemental/iso082.html. I'm not sure why, but it lists a half life for lead-204 even though I thought it was supposed to be stable. Most half lives are a few minutes or hours.

...sounds like a great choice as resources to use. As Sand is basically silicon and readily available, magnesium is also the 7th most abundant in th earths crust. It seems like this thing could go a long way towards very cheap mass production of all sorts of solid things very cheaply. There is also the RepRap project but they use plastics which I'm afraid are quite expensive as resource, although they kind of target a different area. I'm excited by this, I've been following these ideas for a while and it seems to be going somewhere, I guess we're getting closer to general purpose building machines.

The problem with the ABL is that it is a chemical laser based system and as such it is almost already obsolete in the laboratory. Chemical lasers have huge logistical problems and can only fire so many shots, and require huge space, which is why the ABL has cost a fortune and requires a 747.

The future really belongs to the Free Electron Laser, which is making leaps and bounds. If we were to wave the mantra of intraservice rivalries around, then one should say that while the US Navy has had an awful time actually building ships, they've pretty much been whipping on the US Air Force when it comes to both aircraft and lasers and missile defense systems.

Jefferson labs has pushed a Free Electron laser to 14kw.

http://www.jlab.org/fel/

And, the US Navy has Raytheon has been awarded a contract for a 100KW Free Electron Laser

http://raytheon.mediaroom.com/index.php?s=43&item=1292&pagetemplate=release

And indeed, some are noting that it will soon be possible to carry these things in the nose of a fighter aircraft, not just a 747.

Awesome. I love the way you pointed out the numerical editorializing done by the author (despite claims of non-editorialization).

Now, for the sake of completeness:
Let's assume that we're only counting people atoms (and not luggage, clothing, etc).

Atoms transported == people*miles * (atoms/person)

Per this site, there are about 7*10^27 atoms in an average person.

So we're talking 7*10^27 * 11.6*10^9, so roughly 8 * 10^37. In long form, for enhanced visual impact:

We have only one terrorist attack per each 80,000,000,000,000,000,000,000,000,000,000,000,000 atom*miles !11!!!one!eleventyone!

How's that for perspective?

There is also the CEBAF. However, there is apparently a difference between particle physics and atomic physics, which I hope someone more knowledgeable than myself can explain, 'cause i'm not sure exactly what it is...

Jefferson Lab is apparently doing some hardronic experiments, but the 12GeV upgrade still isn't done -- and it was started around ~2001? I know it was in early phases when I interned there in 2002, while we were upgrading the FEL from 1KW to 10KW.

I'm curious - is this based on intuition or is there evidence to suggest that space-time really is continuous at the Planck scale? Or a prediction of string theory? Certainly I'll agree that it appears continuous as far as we have probed.

This [...] will definitely be possible at the LHC

I will accept your source at face value; however, carbon is the 6th most abundant element in the Universe. ;-)

One good reason is that aluminum is a limited resource. Although there's lots of it around, current estimates show that it will only last for about 200 more years ( source).

I don't have a copy of that book, so can't read it in context, but I still have to call bullshit on this.

Aluminum (Aluminium for you Brits) is the most abundant metal in the Earth's crust. While smelting it is energy intensive, recycling it is significantly less so. There is so much that has already been used, and available for recycling, I can't see us running out in the next couple of centuries, if ever.

2^128 = 3.40282367 × 10^38, says the Googles.

This page says "A 70 kg body would have approximately 7*10^27 atoms." So enough for all the atoms in all the people on Earth.

As closely as I can figure it, there are about 11_515_262_616_000 metric tons of Uranium-235 in the earth's crust.

The numbers work out as follows: The mass of the earth is about 5.98e24 kilograms. The crust is about .099% of that. Uranium occurs at a rate of about 2.7 milligrams per kilogram in the crust, and about 0.7204% of that is Uranium-235.

Some of that would undoubtedly take more energy to mine, purify and enrich to usable levels than it would produce as output -- but even if only one percent is usable, it still works out to quite a large energy supply. Enrichment isn't necessarily needed -- but if you don't enrich the Uranium, you typically also have to moderate your reactor with deuterium, and it takes a fair amount of energy to purify deuterium from normal water as well. In any case, once you've purified the Uranium, enrichment is roughly a fixed cost regardless of the original source.

There's also Uranium in sea water, though the rate is quite low (3.2 micrograms per liter). That might be a practical supply as well, but I don't know enough about how difficult it is to purify from sea water to be certain. My immediate guess is that if the only alternatives were things like solar or wind power, somebody could figure out a practical way to do it.

It exists in the atmosphere at 1ppm. http://education.jlab.org/itselemental/ele036.html

"You need massive resources like a ton of uranium and a nuclear proccesing plant to get 100 micrograms of polonium. It also has a half-life of 138 days so you don't have too long to use it either."

Not entirely true.

You can make Polonium 210 from Bismuth: (From http://education.jlab.org/itselemental/ele084.html )

Due to its scarcity, polonium is usually produced by bombarding bismuth-209 with neutrons in a nuclear reactor. This forms bismuth-210, which has a half-life of 5 days. Bismuth-210 decays into polonium-210 through beta decay. Milligram amounts of polonium-210 have been produced by this method.

It does, however, require a nuclear reactor...

If those became common it would be trivial to write a program that would interpret them. For example, there are a limited number of 'quantity' or 'counting' words. All I'd have to do was look for the word {first,second,third,fourth,...} and then from the second word group, where word groups are delimited by {;,:,.,...}, and count that many words in and insert it. Even if the machine was only right 50% of the time, that would still be acceptable for a botnet that can do it every few seconds.

True text-based CAPCHAS would require something more complicated. Basically, a reading-comprehension test that's beyond the known ability of natural-language processing AIs. For example (and I'm just assuming that an AI couldn't do this, I'm not involved in AI research), something like this. Note that you'd really have to do the whole test on that page, too; you can't just do one multiple-choice test, because then you'd have a 20% false-pass rate, when an attacker could choose randomly and get it right. (For a 1% false-pass, you need to have at least 3, 5-option multiple choice questions, and you can't allow any retries.) If you used that page's test, you'd have 7 4-option questions, giving you a (if I did my math right) 0.000061% chance of passing using random answers.

There are definitely possibilities there, but you'd probably get people complaining that it discriminates against people who don't have the linguistic or cultural background to pass the test, although they're human. That might be fine in an online forum (where knocking out people that don't speak English isn't really a big loss to them or you), but for a government website it would probably not pass muster. At least not unless it was in a country that had a single official language.

actually there are about 2^166 atoms in the world according to http://education.jlab.org/qa/mathatom_05.html. That gives 2^38 atoms that can't be addressed. I know. I got too much time

That didn't even make any sense... gamma rads don't hang out like alpha or beta... *brain snaps* ARRGGHHH!! KILL!!! *whips out his 'Environmentally Friendly Shotgun (TM)'*

A previous AC reply suggests avoiding lead shot to avoid annoying your "friends" for the remainder of their (shortened) lives. I disagree. As you forcibly instill your mixture of the three stable isotopes of lead, you can explain how the encapsulation and delivery method you're demonstrating will provide protection against any radioactive exposure -- topical, ingested, or inhaled -- for their entire post-treatment lifetime.

well, while there's "no such thing" as a "gold electron", a gold atom must have electrons.

According to here: http://education.jlab.org/qa/electron_config.html a neutrally charged gold atom has 79 electrons.

I haven't bothered to go an do the research to work out what the difference in the number of electrons is when the atom is positively or negatively charged.

I also leave it to you to work out the atomic weight of a gram of gold (or use the appropriate troy measurement), and then work out how many electrons you'd have, and what they'd be worth at the current price of gold.

Oh, and keep in mind, that once the electron leaves the gold atom, it's not a gold electron anymore, since electrons are all the same.

The specific heat of steel is 452 joules per kilogram per degree C.

The melting temperature of steel is 1370 degrees C (room temperature is 20 degrees), so the the lightsaber has to raise the temperature 1370-20=1350 degrees C).

Now (to pull some numbers out of my ass) let's say our hypothetical jedi swings a 1-meter-long-and-.02-meter-wide lightsaber through a bulkhead in a circular fashion, sweeping out a 120 degree arc. The volume of steel he has to melt is (120/360) * (pi*r^2) *width, where r = 1 meter and width = .02 meters -- 0.0209 cubic meters of steel.

The average density of steel" is 7.85 grams/cubic centimeter. According to google calculator, 1 gram per cubic centimeter equals 1000 kilograms per cubic meter; therefore, 7.85 grams/cubic centimeter = 7850 kilograms/cubic meter.

Thus: the lightsaber must melt (7850 kilograms/cubic meter) * (0.0209 cubic meters) = 164.065 kilograms of steel. This will require (164.065 kilograms) * (452 joules per kilogram per degree C. ) * (1350) = 100112463 joules of energy. QED.

Everyone has always acted like water in the universe was scarce and Earth had some special circumstances that allowed liquid water to exist.

That belief has always puzzled me.

Let's see now; H is the most common element in the universe, and the current estimates for other elements have O in third place. So H and O atoms stand a very good chance of meeting each other nearly everywhere, to form HO. HO in turn is highly likely to bump into another H after a short trajectory. There's also a good possibility of that O bumping into an H2 molecule, since much of the universe's H outside stars is in the form of molecules.

Astronomers will tell you that water is one of the most common chemical compounds in the universe. It takes special conditions, mostly plasmas inside stars, to avoid having a lot of water on hand.

Current estimates are that most of the satellites of the gas giants, as well as Pluto and Charon, are around 50% water.

Of course, at the 70K equilibrium temperature around Saturn, you'd expect water to be mostly a rather hard mineral. It doesn't even sublimate at that temperature.

So for Enceladus to have liquid water, even temporarily, implies that there's a heat source somewhere inside. That's the interesting part of this story.

Some people like to argue that the current administration is actually increasing funding for research, something in the order of billions of dollars. True, missions like the one to Mars, which may not be feasible, do get more attention. Now, let me illustrate what effect the actual decrease of funding in nuclear research has on science. Last year, Dr. Christoph Leemann, Director of the Thomas Jefferson National Accelerator Facility (JLab) sent a clear message (read it!) to all staff and users at JLab. This is alarming! For most people outside the scientific community it is probably hard to imagine what the loss of 45 jobs at JLab means. The situation at other labs, such as the Brookhaven National Laboratory is very similar, if not worse. Let me assure you that this cut has serious consequences for a lot of people at many research labs and universities in the US. We will see how this changes education in the US.
There is more information available at the APS Public Affairs web site.

Some people like to argue that the current administration is actually increasing funding for research, something in the order of billions of dollars. True, missions like the one to Mars, which may not be feasible, do get more attention. Now, let me illustrate what effect the actual decrease of funding in nuclear research has on science. Last year, Dr. Christoph Leemann, Director of the Thomas Jefferson National Accelerator Facility (JLab) sent a clear message (read it!) to all staff and users at JLab. This is alarming! For most people outside the scientific community it is probably hard to imagine what the loss of 45 jobs at JLab means. The situation at other labs, such as the Brookhaven National Laboratory is very similar, if not worse. Let me assure you that this cut has serious consequences for a lot of people at many research labs and universities in the US. We will see how this changes education in the US.
There is more information available at the APS Public Affairs web site.

Some people like to argue that the current administration is actually increasing funding for research, something in the order of billions of dollars. True, missions like the one to Mars, which may not be feasible, do get more attention. Now, let me illustrate what effect the actual decrease of funding in nuclear research has on science. Last year, Dr. Christoph Leemann, Director of the Thomas Jefferson National Accelerator Facility (JLab) sent a clear message (read it!) to all staff and users at JLab. This is alarming! For most people outside the scientific community it is probably hard to imagine what the loss of 45 jobs at JLab means. The situation at other labs, such as the Brookhaven National Laboratory is very similar, if not worse. Let me assure you that this cut has serious consequences for a lot of people at many research labs and universities in the US. We will see how this changes education in the US.
There is more information available at the APS Public Affairs web site.

From the following website:

Blood-forming organ (Bone marrow) syndrome (>100 rad) is characterized by damage to cells that divide at the most rapid pace (such as bone marrow, the spleen and lymphatic tissue). Symptoms include internal bleeding, fatigue, bacterial infections, and fever.

Gastrointestinal tract syndrome (>1000 rad) is characterized by damage to cells that divide less rapidly (such as the linings of the stomach and intestines). Symptoms include nausea, vomiting, diarrhea, dehydration, electrolytic imbalance, loss of digestion ability, bleeding ulcers, and the symptoms of blood-forming organ syndrome.

Central nervous system syndrome (>5000 rad) is characterized by damage to cells that do not reproduce such as nerve cells. Symptoms include loss of coordination, confusion, coma, convulsions, shock, and the symptoms of the blood forming organ and gastrointestinal tract syndromes. Scientists now have evidence that death under these conditions is not caused by actual radiation damage to the nervous system, but rather from complications caused by internal bleeding, and fluid and pressure build-up on the brain

Other effects from an acute dose include:

            200 to 300 rad to the skin can result in the reddening of the skin (erythema), similar to a mild sunburn and may result in hair loss due to damage to hair follicles.

            125 to 200 rad to the ovaries can result in prolonged or permanent suppression of menstruation in about fifty percent (50%) of women.

            600 rad to the ovaries or testicles can result in permanent sterilization.

            50 rad to the thyroid gland can result in benign (non cancerous) tumors.

As a group, the effects caused by acute doses are called deterministic. Broadly speaking, this means that severity of the effect is determined by the amount of dose received. Deterministic effects usually have some threshold level - below which, the effect will probably not occur, but above which the effect is expected. When the dose is above the threshold, the severity of the effect increases as the dose increases.

I got zip googling for "World Trade Center firetrap". Changing it to "'World Trade Center' firetrap" I got one from IMDB, their page about Dean Cain. Ah, I got a bunch when I mootered "'World Trade Center' firetrap". Looking at the first 10 results, only one said it was one without any data supporting the claim. Most results were about other buildings being firetraps and one was about a floating boat that was one.

What melted the steel was the burning of the office furniture, paper, etc., and this didn't require jet fuel.

Office furniture doesn't burn hot enough to melt steel, also the smoke from such a fire would be black and not the white that was seen. Steel often melts at around 1370 degrees C (2500F). Yet in the WTC there were temperature in a few hot spots greater than 800F in these hot spots (some over 1300F). Even using the 1300F temperature, that's still below 2500F. That's a big difference between what the temperature in the WTC was and the melting point of steel.

Falcon

When I say quarks come in threes, I mean they come in multiples of three - usually -1, 0, or 1 multiple of 3.

• 1-1 quarks (quark/anti-quark). Examples: pions et al
• 3 quarks. Examples: proton, neutron, $\Lambda^0$
• -3 quarks. Examples: antiproton, antineutron, etc.
• 2-2 quarks (2 quarks/2 anti-quarks). Defined as: 4-quarks
• 4-1 quarks (4 quarks/1 anti-quark). Defined as pentaquarks
• 1-4 quarks. Defined as anti-particles of above.
• 6 quarks. Examples: neutron-pairs or proton-pairs
• -6 quarks. Examples: anti-particles of above.

I do remember in the early 1960's that the Atomic Engergy Museum in Oak Ridge had a Californium 252 http://education.jlab.org/itselemental/ele098.html / source in a tank of water, with a chute that would direct a quarter to the source, hold it for a few seconds, then let it roll on out. Cf252 is a stong neutron source, which activated the silver to a very short-lived isotope. We had fun running quarters through as fast as posible to see how hot we could get them. But, they had to shut it down in 1964, because the copper isotopes (US Treasury changed the quarter to a silver sandwich of copper) lasted much, much longer.

According to this link uranium occurs about 4ppm in the earth's crust.

This site seems to agree, although I'm not overly sure how the whole "log" thing works with abundance - it's parts per million, but put into a log scale. Perhaps a geologist would like to comment on that.

Neither one suggests that uranium is the 8th most abundant material in the earth's crust As far as the mantle and core go, who cares? It's not like we'll be able to get to them any time soon.

These Links both suggest that uranium is certainly not the 8th most abundant element in the crust. although they disagree on if it's potassium or magnesium. Uranium isn't anywhere near those scales, since 4ppm is 0.0004%.

Comments from someone with geology training would be helpful here.

Sources: Found in natural gas deposits & in the air (5 parts per billion) Constantly lost to space; replenished by radioactive decay (alpha particles). Helium is the second most abundant element in the universe by mass (25%).

The nice people over at Jefferson Lab Education site confirm this:

Helium makes up about 0.0005% of the earth's atmosphere. This trace amount of helium is not gravitationally bound to the earth and is constantly lost to space. The earth's atmospheric helium is replaced by the decay of radioactive elements in the earth's crust.

Also in the "it leaks into space" camp are HowStuffWorks.com and Encarta.

there's just not enough sodium borohydride in the entire world to produce enough fuel for this to work on a large scale.

The question is not that important. Sodium borohydride (NaBH4) is made up of sodium (quite common, as in sodium chloride), hydrogen (common too) and boron is fairly common too, according to this link. The fact you don't find steel, carbon fiber or many modern materials in nature does not mean it is a problem. NaBH4 is supposed to be a carrier of energy, not a source: it is converted to sodium borate during use, and this is later regenerated to sodium borohydride.

Not yet. But the photons themselves do communicate instantaneously. For an example of this, see http://www.jlab.org/news/internet/1997/spooky.html /.

The entanglement method just discovered only allows them to read the state of the photons. The photons themselves still have to travel a distance.

But the fact that paired photons remain somehow connected over any distance, and that this connection permits intantaneous action, means that faster than light communication is theoretically possible, even if we don't currently know of a way to take advantage of it.

Actually, steel melts around 2,500 degrees Fahrenheit.

Memory cards melt around 9,980 degrees Fahrenheit.

Wait--what? Memory cards aren't made of neutronium?

Oh, sorry, nevermind.

Helium makes up about 0.0005% of the earth's atmosphere. This trace amount of helium is not gravitationally bound to the earth and is constantly lost to space. The earth's atmospheric helium is replaced by the decay of radioactive elements in the earth's crust. Alpha decay, one type of radioactive decay, produces particles called alpha particles. An alpha particle can become a helium atom once it captures two electrons from its surroundings. This newly formed helium can eventually work its way to the atmosphere through cracks in the crust.

So, yeah, you're right it's leaving, but it's also being replaced by natural radioactivity so that even after all the hydrocarbons are used up, natural gas wells will still be producing helium for millions of years.

According to Praxair, fifty percent of current natural gas consists of helium. So, it's not all that rare which helps to explain why it's not all that expensive.

For a while I thought it was the Jefferson Lab - if am not mistaken, parts of it now belong to the Science Museum of Virginia - but then the JLab is still open so, can that be ruled out?

But yes, you're right - these days it is hard to find brain-farms, as you put it. However, this also raises the alarming question - an open economy/free-state like the US is finding it hard to have brainfarms, but how about a government agency in a country like, say, China? How hard would it be for China to force its scientists to work there at a brain farm? I can think of a quintillion advatages of such a large conglomeration of intellectual capital, so this could mean that the intellectual edge that the US has _may_ just be at a disadvantage.

The only thing that can help this again is the advent of a threat of war, or something like space-race.

Just wondering, even though the atmosphere is only 0.000524% Helium, would it still be possible to extract enough from the surrounding air to keep the airship pumped up? Could probably stay aloft for months at a time then...

Fluorine gas is nasty, nasty, nasty stuff - it reacts with pretty much everything except stainless steel, teflon, and platinum. Fluoride salts are pretty nasty in high doses, but nowhere near as toxic or reactive as fluorine; I haven't found any research that shows 1ppm long-term exposure causes any problems, though.

Nitrogen is the most abundant element in the atmosphere. However, oxygen is the most abundant element in the Earth's crust, making up nearly half of it by weight. It's just all bound up with other elements. Think of how many compounds contain oxygen, even leaving aside simple oxides.

When you add in the amount in the atmosphere and the truly enormous amount in the oceans (half as much as hydrogen by atoms, but eight times as much by weight), that's a whole lotta oxygen. The tough part really is getting it to stay still by itself - that took a billion years of planetary evolution all on its own.

I was fudging a bit, because iron is actually the most abundant element in the Earth by weight. The core is pretty much locked away, though, and a large part of the reason for its total mass is that it's the heaviest element present in any quantity (once a star begins to fuse iron to make heavier elements, it dies in seconds). Oxygen is heavier than most of the other common elements too, but not to the same degree.

What metal could withstand 1,650 C?

Here is the melting point of few metals:

Scandium 1814 K (2805.8F), Titanium 1941 K (3034.4F), Vanadium 2183 K (3470F), Chromium 2180 K (3464.6F), Zirconium 2128 K (3371F), Niobium 2750 K (4490.6F), Molybdenum 2896 K (4753.4F), Technetium 2430 K (3914.6F), Ruthenium 2607 K (4233.2F), Rhodium 2237 K (3567.2F), Hafnium 2506 K (4051.4F), Tantalum 3290 K (5462.6F), Tungsten 3695 K (6191.6F), Rhenium 3459 K (5766.8F), Osmium 3306 K (5491.4F), Iridium 2719 K (4434.8F), Platinum 2041.4 K (3215.12F), etc

From the Periodic Table, not all, I might even have picked one or two that aren't actually metals. The question not wether is they exist, the question is weight, price, flexibility, strength, availability, etc.

I still have more faith in carbon 3823 K (6422F) though.

3. If you're behind a firewall, and you really should be, Only allow outgoing SMTP from your mail server(this keeps the worm from spreading FROM your organization).

This is a big one. Where I work they closed outgoing connections to port 25. I was pissed at first because my server was not sending mail, but once I relayed all mail through the central mail server, everything was fine.

Network admins, are you listening?

A proton consists of two "up" quarks and a "down" quark. Let's take a look at the mass balance:

particle rest mass
-------- ---------
Up quark: 3 MeV
Up quark: 3 MeV
Down quark: 6 MeV
---------
Total: 12 MeV

Proton: 938.3 MeV

Here is yet another reason why it makes sense to ascribe mass to photons; it has to do with "gravitational lensing": The gravitational field around a black hole bends spacetime, so that light follows a curved path instead of a straight line in its vicinity; an observer percieves this as the light being accelerated towards the black hole. Now, Newton's third law, actio=reactio, dictates that the black hole must therefore also experience an acceleration towards the light beam. This is only possible if the light beam (i.e. the photons) bend spacetime, too. Since the curvature of spacetime is commonly attributed to the presence of mass, it makes sense to regard photons as having a dynamic (as opposed to rest) mass!

Bismuth-209 is the most common isotope of bismuth (with its mean atomic mass being 208.98038), so it would be acceptable to say ' Bismuth No Longer the Heaviest Stable Element', according to webelements and The Jefferson Lab.