Gilded

What I'm especially wondering about are the applications, if any, where helium is quite necessary; where it would be very difficult to replace with any other gas. (By the way does anyone have any info regarding the constancy of helium concentrations in the atmosphere? I suppose it's creeping out of the earth at a fairly constant rate (when discussing periods of even thousands years, considering the long half-lives of thorium and uranium) and is floating off into the higher layers of the atmopshere at a rather constant rate. It would be interesting to know whether even the mentioned 1ppm concentration is actually mostly uncaptured helium from tapped natural gas sources, rather than helium rising somewhat uniformly from the earth around the globe.)

Some time ago I read this article and started wondering about how important helium actually is. But besides not having vitally important and amusing helium balloons, how big of a deal a helium shortage would actually be? Many applications of helium just rely on it being inert but we have four other (stable) noble gases for that purpose. Because of helium's impressively low melting point one important application is of course the cooling of superconductors, but assuming superconductor technologies have improved by the time we hit the shortage it won't probably be a problem.

What's the definition of "Earth like"? Has water and is in the green zone? The version of the equation on Wikipedia is rather different.

This is all very interesting but what are these "women" and "money" that tall people normally have by the truckloads?

I'm 6'4'' and I'm somewhat aggressive if provoked, but I'm quite shy and have never bullied anyone intentionally. I know someone of similar height who has cracked a guy's head open with an ashtray or something and once smashed his fist through a window. He's also the kind of guy who's likely to get mad if he doesn't win at something. So I suppose that the "tall man syndrome" could actually exist to some extent.

Hmm, do the initial fissions produce neutrons fast enough to fission other U-238? That definitely complicates things.

Yes I know, I was just wondering how much depleted uranium you can surround a thermonuclear bomb of a certain yield with. Like let's say you have a 20Mt thermonuclear bomb; it releases a certain amount of high energy of neutrons which can fission U-238, but the neutrons from the U-238 can't fission other U-238 nuclei so there has to be some sort of limit. I suppose you could calculate the maximum increase if you know the fission energy of U-238 (which I couldn't find) and the amount of neutrons from the fusion and assume that optimally all of them fission a uranium nucleus.

One of the ways to reduce the yield of Tsar Bomba from 100Mt to 50Mt was the replacement of the depleted uranium tamper with a lead tamper. As some of you might know this was because while U-238 is not fissile it is fissionable with the high energy neutrons from the fusion reaction. This made me wonder; How much uranium can you actually wrap around a thermonuclear weapon to increase its yield? It's pretty scary actually since it doesn't just increase the yield but also contributes quite a bit to the resulting fallout.

Why so serious?

I admit that voting for YT is a smart move but chose "other" as I have other loyalties too which go deeper... into the ocean that is!

If someone reads this who hasn't been on the channel yet I'll stress that IRC is not a "helpdesk", and you won't probably get a response immediately when you join. Many people have IRC on whenever their PC is on and some might have highlights that alert them if you mention their nickname. We've seen so many people just join, say "hi" or "anybody there?" and then quit right afterwards, probably because they expect an instant response. People who stay on IRC all the time are supercool and never get hit by bolts of divine wrath!

http://redwing.hutman.net/~mreed/ Just heard about the site for the first time a few days back. I've been on quite a few forums in my days so I was amused how I could immediately associate many of the "warriors" with certain users. A brilliant example of "it's funny because it's true".

As Klaynos said just spending more and more money on fusion isn't really feasible. Besides, I think that it's great that such grand fusion research projects such as the National Ignition Facility and Laser Mégajoule are actually underway.

As far as I know many western countries allow minors to drink beverages with alcohol contents below 1.5% or so, for example Finnish sima. I'm not sure what's the limit in the U.S.

We don't have a solid theory about quantum gravity yet so it's hard to address issues like this. However, just because gravitons are (possibly) gauge bosons you shouldn't assume they're nearly identical to photons. And what's the void in the spectrum you're talking about?

I thought that wasn't "until" Hamiltonian mechanics?

Force as a concept regarding acceleration doesn't magically disappear when discussing quantum mechanics, although it can be expressed differently/explained further. But certain forces and concepts are definitely more relevant in, let's say nuclear physics than classical mechanics concerning a ball rolling down a hill. But as booker said, most of the stuff is redifined, especially since you can't make the classical kind of approximations anymore to describe things accurately.

I don't think there is a very good scientifical and precise definition of the present/"now". It's a rather philosophical concept. It is also a biological thing, if we assume that it's just the chemistry and neural activity of the brain that makes us perceive linear time and such a thing as the present. If we look at this from a physical relativistic viewpoint there's no such thing as an absolute present time. To quote Einstein: "People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion."

Glue some neodymium magnets on both sides. If someone thinks that it makes you look like an idiot you can always mess up their credit cards and whatnot.

I'm pretty sure those moments are caused by invisible space gnomes who try to knock you out and steal your socks. At least that's what I was taught in high school. (By the way contrary to popular belief these gnomes steal only pairs of socks; if single socks go missing from the washing machine or the sock drawer it's because of a poorly understood macroscopic phenomenon somewhat similar to the Pauli exclusion principle. You should try to collapse the wavefunctions of your socks every now and then, just in case.)

That was quite good but I prefer MC Hawking as far as physics rap goes. (Hmm... Didn't remember he had a song called "Why Won't Jesse Helms Just Hurry Up and Die?". I suppose that one isn't really topical anymore.)

Right'o! So, uh, what is it you want to discuss? Risks of knowing "too much" about the universe? H.P. Lovecraft has written some nifty stories about that.

Bromine is pretty nifty (I have an ampoule of it), but I think hydrogen is my favorite. It doesn't have to be heavy, solid or extremely toxic to prove it's freaking awesome. Whether it's organic compounds, water, stars or thermonuclear weapons (or my tritium key fob ) you can find hydrogen wherever you look. After all, it is the most abundant element in the universe by mass (and thus especially by the amount of atoms), even though it is the lightest of them all.

Every compound forms a solid eventually when the temperature goes down/pressure increases. It's just a matter of mass and intermolecular forces. CO2 molecules aren't polar so there's very little attraction between molecules but their mass is huge compared to H2 for example, hence the higher melting point. I suppose you can call polar molecules like H2O or NH3 "sticky", or perhaps compare them to tiny magnets as opposed to tiny, essentially nonmagnetic objects. Edit: Also, note that basically everything in this crazy place we call the universe is "intrinsically sticky" due to the Casimir effect. But that's more complicated physics perhaps outside the scope of the topic at hand.

Also, I can't quite discern the legal difference between chocolate, flowers and jewelry vs. cash. Btw I'm not too sure about the porn thing. Sure it's legal if you pay two people (of age) to have sex with eachother but if you're the director and the actor at the same time, so to speak, it might be illegal. I suppose one way to circumvent this is to give some money to a friend to be the film maker and then have him pay you and the prostitute with that money.