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3.5 Billion km Divided by 7 Years Divided by 365 Days Divided by 24 Hours gives you the aproximate velocity at which Cassini was travelling for the last 7 years in Km/h

Travel Velocity: 2,976,190.48 Km/h
Speed of Light: 1,079,252,849.00 Km/h(link)

Using the equation: KE = 1/2 * Mass * Velocity Squared (link) we get

Mass: 1 ton = 907.18474 kg - 6 tons = 5443.10844 kg (Ton Conversion Number Link)
Velocity: 2,976,190,476 m/h is = 178,571,428,560 m/s

KE = 0.5 * (5443.10844) * (178,571,428,560.0)^2 = 86,784,254,453,177,329,714,641,182.592 Joules
8.68 x 10 25 J (Amount of energy it takes for Cassini to go that fast)? Can someone help me with this? If so, how is this accomplished?
9.53 x 10 19 J (Consumption of energy by the USA in 1995) (link)

Considering that gold leaf is thick in comparision (100+ nm [ref]) I find this pretty amazing.

OK, burn coal or gasoline and the nitrogen stays in the air and doesn't chemically combine with anything. If you don't burn it in air....

But if the air gets hot (like in any thermal engine), some nitrogen reacts with some oxygen and you get some NOx. And hydrogen is pretty much the same or somewhat worse than gasoline with respect to this property depending on how you look at it.

If you look at the autoignition temperatures (the lowest temperature a fuel will burn) hydrogen's is 530 C. And the autoignition temperature of gasoline is about 260 C. So you can make gasoline produce much less NOx than hydrogen with some effort.

Hydrogen's flame temperature is 2045 C in air. Gasoline's is 2197 C, almost the same. This is the worst case temperature for the two. Sloppy engines will probably put out about the same NOx.

(Info from http://www.fuelcellstore.com/information/hydrogen_ safety.html,
http://www.hut.fi/Units/AES/projects/renew/fuelcel l/posters/hydrogen.html and http://hypertextbook.com/facts/2003/ShaniChristoph er.shtml.)

Did you read my post?

Yes, but the way you wrote it, it sounded like you mentioned the 20% without actually doing the figures for it. Sorry, for some reason I just had a lot of trouble parsing what you were saying.

That's per square meter, and that's where 55.3Mj:day comes from (3.75m^2:day). Even at your 10% efficiency, that's 2764s, or 46 minutes of cruising, more than ample for driving.

Is it? 2 kw is EXTREMELY low. We're talking about the cruising rate on the Interstate after you've reached ~60 miles per hour. In town traffic saps energy much faster.

Perhaps we should do a better comparison here. According to this link, there's 8.76 kWh per liter of gas. Converting that to joules per gallon, we find that a gallon of gas contains 119.2Mj. Your 55.3Mj works out to about one half a tank of gas. That is sufficient to get *some* people to the store and back. Unfortunately, quite a few people are just outside that range. I probably couldn't even get my Cavalier to work and back on that. (~12 miles round trip)

It *might* work if you built it as light as a Geo Metro, but keep in mind that all those panels, electrolysis equipment, and hydrogen storage is heavy. You're much better off buying a home fueling station that you mount on your roof. Not only will you have a lot more solar surface area, but you could mount fans to acquire wind power as well.

Efficiency of solar->electric->hydrolysis is much worse than direct hydrolysis can be.

Direct hydrolysis from what? If we're talking from a wall socket, then it's out of the range of this discussion.

I would call 21,379 m space...

You had to ask didn't you? Well, I asked google how many burning libraries of congress(es?) in one gram of antimatter... And google was stumped :(

So, here we go... 1 gram of antimatter -> burning libraries of congress(es?):

For the sake of argument, lets assume that the Library of Congress is entirely non-flamable and only the books contribute to the heat. Furthermore, lets assume that all the books are made of 100% wood or equivilant.

Now, 1 gram of wood when completely burned produces 3000 calories.

The Library of Congress contains approximately 128 million items. Again, some of these are recordings of various natures and will not burn as well as books... so to compensate we'll deviate from our initial assumptions and assume that the burning of the 530 miles of bookshelves compensate for any lack of flamability of the old records.

So... our average paperback weighs under 1lb and our average hardcover book weighs between 1 and 2lbs. Seems reasonable enough. Lets assume a distribution between hardcover and paperbacks so as the average book weight in the LOC is 1lb.

Now, Google can help us some more here. Our friendly search engine lets us know that one pound is 453.59237 grams. We'll round that off to 453 grams, since we're averaging book weight anyway.

So, the LOC has (453*128,000,000) or 57,984,000,000 grams worth of books. At 3000 calories per gram, burning down the LOC would produce 173,952,000,000,000 calories of energy. For the sake of sanity, lets convert that to joules. Google says that 173 952 000 000 000 calories = 7.27815168 × 10^14 Joules

Now, our space shuttle main tank (and engines, NOT including boosters which are more powerful) produce 1,987,500,000 Watts of energy, and burn for 8.5 minutes. That's (510*1,987,500,000) 1013625000000 Watt/seconds of energy. Converted to joules, that is remarkably 1013625000000 Joules.

So.. One space shuttle fuel tank of energy is 1013625000000 Joules. 23 space shuttle tanks of energy is 23313375000000 Joules. For convienence, one space shuttle tank is 0.23313375x10^14 joules.

So... it comes down to one burning LOC is 7.27815168 × 10^14 joules. 23 space shuttle fuel tanks are 0.23313375*10^14 joules. So, one gram of antimatter combining with one gram of matter is approximately 0.032 Burning Libraries of Congress(es?). I actually expected it to be more.

Now how do I get Google to include space shuttle fuel tanks and burning libraries of Congress(es?) as acceptable measurements?

the "guardians" are the ones making war. are you telling me that we need ... the guardians... to protect us all from... the guardians? if nobody had a military, nobody would need one. there is no causal relationship there... it's the same as nuclear proliferation. either we all have them, or we all don't, and there's no in-between.

First, I didn't call you "naive", but I'm sorry if you took offense at my statement anyway. Now let me respond to your counterpoints.

1. I never claimed that competition had to be violent. I agree that nonviolent competition is often more productive (i.e. largely a positive sum game rather than zero sum).

4. Your claim is comparable to saying that police officers are "clearly failing at their tasks" because there still exists crime. You have it backwards. The existence of crime/war CREATES the need for the guardians. It does not prove that they are failing whatsoever.

5. This (armed citizenry providing checks on centralized control) is a rathole of an argument to fall into, but I will make this simple analogy: Native people are less likely to take advantage of elephants and other dangerous animals for food because those prey are dangerous to them. Often mysticism, religion, and politics evolve up around this basic concept, but the reality is that the weak generally end up being taken advantage of in one way or another. This is not pessimistic, it is real. I am an optimist like you, but that means I am a pragmatist first, and push policy to create positive outcomes overall rather than advancing unstable facades of a utopia that requires constant propping up.

And Albert Einstein was a brilliant scientist, but he led a disasterous personal life, and his idealism forced him into many incorrect conclusions throughout his life, particularly exemplified by his wholesale renouncement of pacifism in the face of the horrible Nazi threat and writing of a famous letter in 1939 to President Roosevelt suggesting that the U.S.A. had better build an atomic bomb before the Germans or face defeat and destruction.

Of course after the war, he was free to return to his idealistic pacifism and encourage disarmament while there were no huge threats looming, but he also is famous for the recognition that bad people build bad weapons: "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones."

Plutonium has a half-life of 24,100 years. Ten half-lives reduce radiation by a factor of 2 to the 10th, which is 1024. Reducing the radiation of Plutonium by a factor of 1,000 is not enough to make it safe. In 241,000 years, the Plutonium will still be one of the most poisonous substances on earth.

--
U.S. Gov.: Borrowing money to kill Iraqis. Feel safe?

The critical mass of plutonium is 10 - 100 kg. (I assume weapons grade plutonium would be more towards the 10kg range).
I would split it up into 5kg bars and do a few trips. If there is a crash or whatever it wouldn't go critical. And it's not enough for a bomb is someone nicked it.
5kg / 19,816 kg/m^3 in cm^3 is ~ 250cm^3 which is 5 by 5 by 10 cm.
Pretty strange that the entire consignment is smaller than a shuttle case.

Well, considering that is somewhere in the neighborhood of 1/10th of the words estimated to be in the English language, there are quite a few not in the list. The actual number varies by source however, estimated between approximately 800,000 and 1,000,000 words.

- About 190

- Too many! No, seriously, there's Judaism (sp?), Catholicism, Prodestantism, Islam(ism?), Bhuddism, Zoerastrianism (that can't be the right spelling!), and Scientology (joke!) - that makes 6, plus or minus a couple

- 40000km ; 3/10 the total (cheat, I know!) ; 20000km^2

- 10 days ; 4 ; depends on the car, but about $200 (Cdn)

Now, with google, the answers are:

- 192 (Including East Timor)

- 22! (I knew there were too many, though that includes the serene rastafarians)

- 40,075.16 km (damn, I was close!) ; 148,300,000 km^2 (technically I was right, because the total is 510100000km^2) ; 9,161,923 km^2 (not even close! I should have known that..)

The final question is a little vague, depending on your driving habits, etc, so I won't bother googling it. Anyway, all of this goes to show you : 1. I'm not qualified to be President of the United States of America, and 2. I'm bored.

Adios,
AC

2^128 is about 3.4e38. Now, let's be generous and asume we can control the spin of every electron we come across and incorporate it into a quantum storage device, such that each electron represented a bit of information (either left- or right-spin). Now, because I'm still being generous, I'm going to say the Earth's oceans contain 2e9 km^3, or 2e18 m^3 (compare here) Assuming all this water is liquid, its density is 1000 kg/m^3 (abouts), so we have 2e24 g of water.

2e24 g of water contains about 1e23 moles of water molecules, or about 1e46 individual water molecules. With about 10 electrons per molecule, that's 1e47 electrons. So if we indeed "boil the oceans" in order to harvest the electrons to feed into our massive quantum storage system, we would have 1,000,000,000 spare electrons for things like hydrogen fuel cells.

But this does not exceed the quantum limits of earth-based storage, even by a long shot. Bonwick even admits it: You couldn't fill a 128-bit storage pool without boiling the oceans. Boiling the oceans is definately an earth-based option for quantum storage, as we wouldn't have to import the materal from space. We also have other ways of harvisting electrons, like boiling humans and evacuating the atmosphere. To give you an idea, there's something like 10^54 electrons on earth, give or take a few hundred trillion. We'd need at least a 192-bit system to approach Earth's quantum (electron-based) limits.

Actually NASA just said it hit at 193 mph. Terminal velocity varies according to the density, weight and area of a falling object but I thought 100 mph that everyone else was quoting seemed somewhat slow for something coming in from space.

The damn things are designed to go 18,000 miles an hour. If 140mph wind caused problems, I'd want my money back.

The cheap-ass thermos bottle you (well those of us out of our youth) carried to school didn't work all the well a) because glass conducts heat pretty good and b) the vacuum in them was poor and easily broached.
Um no. Well, at least no to part 'a'. Glass conducts heat about 12 times more slowly than stainless steel: Thermal Conduction, but you're right about the 'easily broached' part. I broke more thermoses as a kid than I can count (before they went to cheap plastic).

Have you ever seem a simple neural network? I took a couple of artificial nerual network classes in college because of some pedestrian interest in the subject. How abotu a 7-neuron text-to-speech engine with 95% accuracy? How about only 30 neurons to keep a car on the road?

Now, consider that the human brain has on the order of 100 billion neurons. Can you even begin top fathom the near-infinite number of states this huge system can be in? Think of the thousands of inputs from all over ytour eyes, ears, nose, tongue, skin. Think of the huge variations of nerual network configurations in the brain.

I for one am not naive engouh to suggest that we are anywhere NEAR ready to simulate this level of complexity, nor measure and predict it. Even in the Matrix, they simply tapped the inputs and the outputs. I do believe it is entirely possible that "free will" is just a conventient label for that big mess of neurons, and its connections to the environment. It's one big feedback loop.

water surface are of earth: 361,800,000 sq km

/ 100,000 cm/km (i.e. * 0.00001 km (1cm) )

= 3618 cu km

= 3,618,000,000,000 cu m

total worldwide usage of water per year is 169 cu km (1995)

assuming 100% efficiency, 20 times the total water currently consumed has to be filtered/processed to get one year of energy.

i really have dont have a clue what kind of energy requirements that alone would take, maybe specially designed ships could perform this task.

better double check my math

The vacuum in space is much much better than the best laboratory plasmas and the surface of the moon is comparable to lab plasmas.( 1 particle per cubic cm for space, 10^6 to 10^5 for the the moon, and 10^5 to 10^4 for the lab) or in atmospheres ( 10^-20, 10^-13 to 10^-15, 10^-12 to 10^-15 ) source:http://hypertextbook.com/physics/matter/pre ssure/
The real problem is that you still need a plasma facing surface and to generate a magnetic field. All that mass is expensive to get to the moon, and the constraint on the physical size of the magnets (bigger is more expensive) and the need to protect them from the plasma would result in a very similar vessel being constructed on the moon. So there would be very little direct benefit. There is the remote possibility of using the exotic D-He3 fusion reaction - one that is much more difficult to create, but that is essentially neutron free. Since He3 is only found in any concentration in the surface of the moon where it is deposited by the solar wind.

I have a horse and a half microwave and a 3500 watt lawnmower!

Sounds like a pretty powerful lawnmower, doesn't it? That is, until you realize that gasoline has an energy density of 45.7MJ/kg. It takes one hell of a lot of energy to push our cars around! Running a car engine at the "300 horsepower" many dealers advertise, would produce 223.7 kilowatts!

Thank God that cars don't normally run at high horsepower levels. At 300hp, you'd burn through a gallon of gasoline in about 3.4 minutes! It's no wonder that we're having trouble finding alternative ways of powering cars. There's simply no viable fuel with an energy density greater than petroleum.

I say we go for nuclear powered cars. At least then I wouldn't have to worry about stopping at a gas station for a few (hundred) years. ;-)

Further numbers for thought:
Most cars are smaller that 3 meters wide and 5 meters long. Solar power density is peak at 1.44 kW/m^2 (or lower, depending on reference source) as a best case for noon on the equator in a vacuum.

Google gives these unrealistic best case numbers (EG, perfect efficiency, full spectrum, big car, straight down solar intercept, no atmospheric absorption, etc.) a value of about 29 watts.

> Don't try this at home it might kill you and will if your stupid enough.

I just measured my resistance from my hand to ground as about 1 megaohm (2 if i'm in my chair, infinity if i'm jumping...). By ohm's law, 240V / 1 megaohm = 0.24mA

0.24mA won't kill you.

Now if you jab the electrodes into your heart you might get 1.2A over your heart, and that will kill it. But the stabbing killed you first.

According to http://hypertextbook.com/facts/2000/JackHsu.shtml, you need 15mA to lose muscle control. Assuming the resistance between my hands is about 600Kohms (which it is), I would need 9000 volts to achieve this.

If I'm only touching one wire (I'm grounded, and the wire I'm touching isn't), then I need 15kV. So it's pretty hard to hurt yourself with DC.

AC is different due to the body's power factor (I guess), and you need a bit less current to lose muscle control, but more to kill (I _think_).

Anyway people die because they play with more than 15kV. Tesla coils are at least 60kV. 15kV makes X-rays, though. Fun stuff...

A Microwave oven works by transmitting the resonate frequency of water "Your microwave oven operates at a frequency of 2.45 GHz (gigahertz)" This is also the center frequency of 802.11 transmitters.

The human body is mostly made of the water that this frequency resonates.

From here the flammable range for gasoline is 1.4-7.6% (of vapor in the air) which may be wide for hydrocarbons, but is narrower than the 4%-74% range for Hydrogen. I couldn't find a list for ignition temps for hydrogen gasoline is only 530-550 F (pretty low). Yeah it does evaporate like the dickens though. My understanding from the movie stunt explinations is that your tank has to be nearly empty for there to be any likelihood of an explosion (sans dateline fireworks triggering it).

And then there's goild and coppier and silvier, which work even better!

16000 bullets per second, assuming each of them is 2 inches (5cm) long, makes 80000 cm=800m of bullets per second if no space is left in between. The bullets would have to travel at least at 800 m per second. According to this, that should indeed be reachable.

Somebody once commented about the physics of movies that Rambo couldn't possibly keep firing and firing and firing all that much time because the weight of all the bullets he fired would get to be way too heavy to carry around.

I'm not very well informed about weaponry, but if a bullet weighs ten grams, then a minute worth of bullets (1 million of them) weighs 10 million grams or 10000 kilograms. I don't know, but basically such a fast gun to me seems not much more than a great way to overload your apache chopper, and a fantastic way to run out of bullets real fast.

Could this be real? Possibly. Practical? I doubt it. There's only so much more benefit of spitting out even more bullets per second.

If all the ice in the world melted, the sea level would rise by about 70 meters. That leaves ~2400 meters wanting for the seabed, if this boat was only half way up the mountain (assuming the parent got that height right, and 2,500 meters isn't that high)

Let's assume this shortfall was made up by plate techtonics. I haven't read the bible, but I'm assuming they're dealing with a relatively short time frame here, since the Noah story was supposed to have taken place. Let's give them a good chuck of time, say 7200 years to keep things nice a mathematically simple.

So, to give plate techtonics the credit, the Ararat area would therefore have to be moving 33cm a year, or 1mm every single day for the last 7200 years, vertically.

Continental drift occurs at, on average, at the same speed your fingernails grow, or ~5-10cm a year. Now three time the average would be something special, but three times the yearly average purely vertically would have geo physicists very interested, esspecially considering the Arabian plate is esitmated to have an average tectonic movement of around 4cm per year (this is largely horizontal movement, remember).

OK, so let's give a little give and say the 4cm/y was purely vertical over the last 7200 years, that's 288 meters, leaving us still 2,112 meters short of the sea level, even if all the ice had melted.

So, tectonics would have had to have being working overtime and a half to have made up for this shortfall.

Let's think about this from the perspective of the geological record. From observation by many different people around the world of sedimentary strata, from gas sample taken from ice cores along with many other observations, it is agreed in the scientific community that sea level was about 6 meters higher ~8,000 years ago.

Now, truth is that ~8,000 years ago (7600 to be a little more precise), there were huge floods, as the weather was very unstable, but the flooding that occured certainly didn't cover the Earth (there'd be some wicked Quaternary formations if it did), which leads me to thinking that the story of Noah's ark should be taken more in terms of a fishing tale (thiiiiiiis big), rather than an accurate record of a historical event.

Besides, need we get into the debate about exactly how big that arc would have to have been in order to contain two of every species on earth? Or that for a gentically viable population, you need around 10-20 breeding pairs (according to a genetics scientist friend of mine). Or that reforesting the Earth would have taken hundreds of thousands, if not million of years. Or that the bible has been rewritten, translated and modified many, many times (but let's not go there) .

Wow, I'm pro-nuclear power, but not like that :)

Ford was worse. At one point, they wanted to put a nuclear reactor into a car! :-)

Whats the energy density of rice?

Pathetic. About 15 MJ/kg. And it's pretty hard to come up with kilograms of rice or corn when compared to other fuels.

It always amazing me how little food we animals need to eat to continue functioning and moving around.

Well, your body is generating about 200 watts of constant power. That means that you need about .72 MJ per hour to operate. For cars, you tend to need a lot more horsepower. Here's the conversion:

1 Watt = 0.00134102209 horsepower

For a 150HP engine, you're talking about an energy drain of about 112 KW. That's 403 MJ of energy per hour. Realistically, cars only expend a lot of energy when accelerating. Thus an economy car tends to use more like 20 HP for cruising. That works out to a constant power requirement of about 15 KW. 15KW is 5.4 MJ per hour.

I started wondering about how fast 5000 mph really is. From simple math, thatt's 1.38 miles per second. That is, in fact, faster than the fastest speeding bullet (how fast is a speeding bullet?) So what could you do with a vehicle that fast?

Well, my commute (from Brooklyn to Manhattan) takes 35 minutes to go 7.63 miles. I could cut that commute by 34 minutes and 54 seconds. On the other hand, if I didn't mind the commute but wanted to live a little further out from the city, I could live in Los Angeles - my commute to Manhattan would still be just 33 minutes.

Segway, shmegway! I want a personal scram jet!

So, the difference is (assuming the lower figure for gas) like 12700 for gasoline vs 121 (the current figure for LMP). 100 times -- that is a lot of difference! Increasing the energy density for batteries up to 180 (and that is projected) ain't going to change the picture much.

Further, "re-charging" the fuel tank can be done in 2 minutes, while the batteries take ... who knows, certainly hours. Further, the fuel tank can be refilled practically infinitely many times, while the batteries are good after only so many re-chargings.

The history and composition of pennies!

Right, a simple test case is a good way to prove the concept. So let's do it!

Let's immagine a very simple baloon that only picks itself up and then falls down. We will cheat a little by having compressed H/He available on the ground. We will imagine our baloon has some structural weight, W, and that it's large enough to have bouyancy to lift that W. Our baloon must have a pump and a tank inside so that the boyancy can be reduced so the baloon can decend. The only energy we need, then, is enough energy to reduce the volume of H/He enough to descend. The energy available is mgh, or Wh the weight times the height. If, like most baloons, we can take it to the edge of space there should be plenty of energy available to compress our H/He. The only practical problem is capturing that energy. So, how much energy would we need to capture?

A 5Kg mass taken to 10,000m would give us about half a million joules. Givent the relative densities of air and H/He, we will need between 4 and 5 cubic meters of gas to lift 5Kg. It would take, roughly, 250,000 joules to compress that volume by half and give you 2.5 Kg of downward force. Oh dear, at 10,000m this is looking like a wash out. Fortunately, manned balloon flight can get to 30,000m, so this is theoretically possible. Just don't try to do it like this

So it's pretty much totally worthless for the coming centuries. Mars is a different story. While its atmosphere is toxic and its air pressure too low the temperature around the equator wouldn't bother a Canadian (gets above freezing at times). It also has water. Pretty decent planet.

The result: The planet Krypton weighed an absolute minimum of 7.299x10^19kg. By comparison, our sun weighs 2x10^30kg.

And 30 seconds on Google would tell you that the Earth has a mass of approximately
6x10^24 kg. So here's a new problem for you:
Assuming that:
- Krypton was approximately 1000 times denser than Earth, and
- Kryptonite was scattered mostly in the Northern hemisphere, landing chiefly in North America and Soviet Asia,

... where was Krypton, really?

Keep in mind that while chemical-to-heat reactions can be made over 90% efficient, chemical-to-heat-to-motion reactions in a typical portable generator are more comparable to car engines - 30-40% efficient (non-portable large-scale multi-stage turbine generators can do more like 60-70%). If you're storing the resulting electricity in a lead-acid battery, that's only 70% efficient.

Assume that you have an average 35%-efficiency generator charging lead-acid batteries. That system has an efficiency of 24%.

Given that gasoline stores about 130 megajoules of energy per gallon, and you can recover 31MJ of that (same as 8.61kWh), and it costs you $1.50, then the break-even point is $1.50/8.61 (or $.174) per kWh. If you're not charging batteries, then the break-even point is $.118/kWh.

For me at least, the grid is significantly cheaper. As it should be.

Also, if you need the waste heat from the generator anyway (and can rig up a way to exchange it without dying from carbon monoxide), that could make generation a lot more worthwhile.

Note that there are about 70 sextillion stars in the universe. That's a 7 with 22 zeroes. Even if only one in a billion stars has a planet orbiting it with intelligent life on it, that still means there are 70000000000000000 such planets in the universe.

Ofcourse, distances between galaxies are so large we can only reasonably search within our own galaxy, the milky way. The guesses here go from 3 billion stars to 100 billion stars. With the previously mentioned 1 intelligent species homeworld per billion stars this would result in 3 to 100 such homeworlds.

The odds ofcourse of intelligent life evolving are not known, because we don't understand yet how life evolved to the finest detail. So most guesses have to be taken with a grain of salt. Still, the odds can be pretty slim and still result in intelligent life being pervasive in the galaxy.

Also, you have to take into account the age of civilizations. If an intelligent civilization developed 1 billion years ago around alpha centauri, it would be long gone by now, so we wouldn't be able to pick up their communications. Why wouldn't the civilization keep existing? Simple, the older a civilization get the likelier it becomes it destroys itself in one way or another. And if somehow a civilization doesn't destroy itself, it would either turn inwards (not communicate with the rest of the universe) or turn outwards (colonise the rest of the universe). Since we haven't seen any alien colonists schedule up an interplanetary zoning meeting with Bush, it seems unlikely there are any colonising civilizations out there. Although, I did like the idea from Star Trek where they only made young civilizations aware of the existance of the federation once the civilization developed intersolar travel.

Given the size of the universe, it's indeed pretty likely there is intelligent life out there. I fully expect we will find at least one intelligent extraterrestrial lifeform before our species disappears. What I'm curious about is how this is going to be retrofitted into religion, which very much assumes we are $DEITY's chosen ones.

I'm not going to say I'm the most moral person in the world, but really guys, how can any scientist justify working on something like this? I have to think that, given the opportunity, I would turn down the opportunity to engineer a mega-virus capable of killing all life (or all of a particular kind of life) without any antiviral agent being simultaneously developed. What can these guys possibly be thinking when they wake up in the morning, head off to work, and gleefully create the next ice-nine?

I don't think I could look my son in the face if this was the kind of work I did.

(ignoring [or perhaps highlighting] the problems everyone else has already pointed out about the resources ['cause we like playing number games around here])
land surface area of earth: 148,300,000 sq km (approx.)
population density of Tokyo: 13,333 people / sq km
148,300,000 * 13,333 = 1,977,283,900,000 people if the totality of the land surface area of earth was packed as densely as Tokyo (!!!)

average person weight (guessing, 75 kgs) * 1,977,283,900,000 people = 148,296,292,500,000 kgs (aw. I was hoping for something like half the mass of earth or at least the moon)
And finally, converting to elephants (~5000 kg) we get 29,659,258,500.

The energy released is 180.737 kJ, in comparison, the nuke on Nagasaki released approx 84TJ , and the gravitational potential energy released by the fall of one of the Towers was 2.2TJ, the biggest ever explosion, the Novaya Zemlya Hydrogen bomb, produced 58 megatons, or 240,000 TJ.

WOW!!

The energy released is 180.737 kJ, in comparison, the nuke on Nagasaki released approx 84TJ , and the gravitational potential energy released by the fall of one of the Towers was 2.2TJ, the biggest ever explosion, the Novaya Zemlya Hydrogen bomb, produced 58 megatons, or 240,000 TJ.

WOW!!

On the expansion of substances, true, liquids and solids expand little compared with gases, but the rate of expansion with temperature for solids that make up the earth's crust are about two orders of magnitude less than that of water. And given the average ocean depth of about 3800 meters, only a small amount of expansion is necessary to raise the sea levels by a noticable amount. I confess that it never occurred to me to take into account the affect of the expansion of the earth's crust, but since below 100 ft or so its pretty much determined by the heating from the core, and it's rate of thermal expansion it negligible compared to water it wouldn't seem to be a significant factor. (A correction, the link in my OP was posted with a space, so I give it again here. Also, I referred to the bulk modulus and I should have said the coefficient of thermal expansion, which is related to the dependence of the modulus on temperature.)

I agree that there are many factors to consider in global warming modelling. You'd be surprised at how many factors are considered. (IANACM)

DAMMIT!

apparently pressing ctrl-enter submits ... same as how I submit tickets .. stupid habits die hard.

lets continue that.

Sears tower = 442m
so we have 248.8688 sears towers

Boxcar = 43 feet avg (source)
Avg freight train length=45 cars (some other site that won't load but is cached)
Avg lenght in feet = 1935 feet

google tells me theres 0.3048 metres in a foot so we have the avg freight train being 589.788m long.

That means we have 186.5077 freight trains (not counting engines) end to end


length of football field (cdn) = 100m
length of football field (us) = 109.1m (source

That leaves us with 1,100 cdn football fields, or 1008.2493 american fields.

a us dollar bill is 156mm long (source
so that gives us 705128.2051 dollar bills, end to end

asian elephants can grow to 340cm (3.4m) (source)
so thats 32352.9412 elephants

I think thats good enough for now. back to work.

The creator of the nuclear weapon didn't pull the trigger, but by your argument is somewhat liable for killing millions of Japanese. Aren't we, the scientists, just doing experiments?

Einstein didn't think so. He was a major influence in the creation of the nuclear bomb, and he did take responsibility for it, calling it the greatest mistake of his life.

http://hypertextbook.com/eworld/einstein.shtml#fir st

The better question is, what becomes scarce?

Err, energy?

With no atmosphere, there is no shockwave. Sure, the debris from the explosion would eventually hit you, but no one would seriously try to call actual matter hitting you "sound."

I repeat: Explosions in space have no shockwaves. A nuke detonated 10 feet over the surface of the moon would amount to little more than a small dust cloud a few feet in diameter (if anything) when the remaining atoms slammed into the surface. It would be nothing compared to a similar detonation on Earth.


Uhhh... Fantastic science there dude. So let me get this straight... a 10 to 100 MEGA ton weapon explodes 10 ft away from the moon and a small dust cloud a few feet in diameter is all that happens. AN EXPLOSION IS THE RAPID EXPANSION OF GASES!!!! For the love of god think before you open your mouth again. 1 Mega ton = 1 million tons of TNT (http://hypertextbook.com/facts/2000/MuhammadKalee m.shtml). That is not 1 mega ton = 1 million tons of force(units are wrong any way), but the force of 1 million tons of TNT exploding... A nuke does not need air around it to cause damage. It does not need air to create a shock wave; it provides it own super heated gases from the explosion. [W]hen the remaining atoms slammed into the surface... a nuke does not totally turn to energy. The bomb casing and a large portion of the radioactive material still remain to be flung about at incredible speeds. Come on paint chips in space are a real hazard to the space shuttle and they are only moving at a ~22K miles an hour (a href=http://www.wstf.nasa.gov/Hazard/Hyper/debris. htm>http://www.wstf.nasa.gov/Hazard/Hyper/debris.h tm.

How do you account for phenomena such as solar wind (http://science.msfc.nasa.gov/ssl/pad/solar/sun_wi nd.htm)? Basically the sun (a huge nuclear reaction) is spraying atoms into space as it "burns". Even the moon has a thin atmosphere (http://www.agu.org/sci_soc/prrl/prrl9826.html).

It is science fiction, not science fact. Hell all the cop dramas out there totally ignore the laws of this country. Does everything need to line up with realty to make a good show. HELL NO! Look at all the crap "reality" TV shows. Let watch the "realty" sci-fi show. You get to watch shuttle telemetry reading for 3.5 hours! YAY! You guys must be really bored with your lives if you sit around debate the science of TV and movies. LIGHTEN UP AN LIV A LITTLE.

Friendly

(I'm not an expert on the subject, but I'll take a stab at it anyway.)

That filiment inside the lightbulb gets really really hot (about 2500C [1]). If the glass were placed too close to the filiment, it would melt, crack, or otherwise be damaged by the heat. As a result, the glass has to be kept a certiain distance from the filiment in order to keep the glass relativly cool. This results in a roughly spherical shape (and a lot of "wasted" volume, as you put it.)

[1] Temperature of an Incandescent Light Bulb

Ahhh, the arrogance of the human race... nukes are very big, yes, but only on a human scale. The Earth is very large. Very very large. Let's do the math here:

Earth's Land Surface Area:
45,000,000 sqare miles
Destructive Blast Radius of a 25-Megaton Airburst:
10.7 miles
Number of Nuclear Warheads in Stock at Height of Cold War:
61,000

10.7*10.7*3.1415926 = about 360 square miles
45,000,000/360 = 125,000 warheads

Sorry, even assuming an even spreading, assuming all warheads are 25MT (most are much smaller), and assuming all blasts are airbursts (they wouldn't be), even at the HEIGHT of the cold war there weren't enough nuclear weapons in existence (and only half of those were/are in any condition to be deployed) to blast even half the land area of the earth, much less blast it three times over.

I'm not saying that nuclear weapons are good, or that a nuclear war would be fun. I just can't stand the mindless parroting of hysterical hyperbole as if it were fact. I agree with the sentiment, but I don't agree with the presentation. Much of the Nuclear Disarmament crowd is dismissed as wild-eyed, irrational hippies. Why? Because they act like wild-eyed, irrational hippies. Ignoring the mathematical reality and instead believing a impossibly fantastic doomsday scenario doesn't help.

Given that terminal velocity for a skydiver is around 200km/h, I'm guessing the CNN article got it right. I don't see how strapping a rather large wing to your back could manage to nearly double that speed.

-BbT

Normalize for population. =:) We have a rising copyright registration rate. Does it keep up per capita? If not, what does that tell us about laws that are designed specifically to increase copyright restistration, if not promote art itself?

"However, by diving or "standing up" in free fall, any experienced skydiver can learn to reach speeds of over 160-180MPH. Speeds of over 200MPH require significant practice to achieve. The record free fall speed, done without any special equipment, is 321MPH. Obviously, it is desirable to slow back down to 110MPH before parachute opening."

- http://hypertextbook.com/facts/JianHuang.shtml

How did he get enough speed to break the sound barrier? He would have needed a jet to speed his descent or something like that.

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