swansont

The repulsion occurs because the electrons are moving, and the force is perpendicular to the motion. You run into a problem with your geometry because [math]\vec{\nabla}\bullet \vec{B} = 0[/math], meaning your field lines that come from the north pole have to exit somewhere to meet up with the south pole. I don't think it will behave the way you think it will. IIRC you can do 2-D confinement with permanent magnets, but you have to use a coil for the third dimension.

With mishmash dressing.

The 5-year mean will oscillate because of solar output variation on the sunspot cycle (and possibly other reasons). Decadal oscillations are much smaller because of the ~11 year period of sunspot activity. Once you start averaging over sunspot cycles, though, you see that the average solar output does not account for the warming. edit: that should be "fluctuations in the average solar output"

Nature is under no obligation to make any sense. That's not an argument. The particles annihilate because they are opposite in every characteristic that is conserved for matter (which we know because we create them in pairs).

Well, yeah, since you speak of solidifying the ether when the concept of the ether was smashed over 100 years ago.

Bingo! It can easily be a factor of 10 difference, depending on the actual wavelengths involved. Beware: some green lasers will say that it's as bright as a 50 mW red laser, and end up being a 5 mW laser (or some other values with a similar scale disparity), because of the sensitivity difference. It's not so common anymore, but was standard practice a few years ago when the green lasers had just come out, and more than a few mW was tough to get. Merged post follows: Consecutive posts merged Laser diodes use lenses, but they are built into the casing when you buy a laser pointer. Bare diodes have horrendous diffraction and astigmatism — the gain medium is rectangular, and the light diverges but has a different focal point for the x and y directions. The outgoing beam is elliptical but the long direction changes by 90º near the laser. It's a real pain to get a good beam from them — you end up throwing away a lot of light. Good thing they're relatively cheap, as lab lasers go.

You won't be able to get a super well-defined rectangle, but using a cylindrical lens will expand a beam in one direction. You can also use anamorphic prism pairs to do this. 7 feet, though, means that you will want to use mirrors rather than lenses.

In the absence of support for the "groupthink" claim (i.e. examples of rationalizing, ignore the consequences of their actions, etc.), this is simply an ad hominem/appeal to motive fallacy

Two gammas (or more), and the attraction is electrostatic. But yes, a gamma of at least 1.02 MeV can produce an electron/positron pair

Reflection happens at interfaces between media if differing index of refraction. Typically when we say something reflects, we say it's caused by the material with the higher index. So technically speaking it would if you could have an interface with a lower index. You're pretty much restricted to a dilute gas or vacuum (or perhaps helium or hydrogen) [math]R=(\frac{n_1-n_2}{n_1+n_2})^2[/math] But a distinct boundary between air and those gases, or a vacuum, would be exceedingly hard to achieve Pedantically, though, there is a solution. If you liquified the air you would have a reflection. The situation described, though, is not reflection since there is no interface. What you describe is scattering. Light does scatter in air which is why the sky is blue (Rayleigh scattering) but this is very weak on the scale under discussion.

That's right. The strong force acts between nucleons (protons and neutrons) but not leptons (e.g. electrons). The weak force acts between leptons and quarks, but has a very short range.

A photon splitting up into a particle/antiparticle pair does not conserve momentum (assuming it conserves energy). You need something around to recoil for the pair production to occur.

Because the focus on those discussions is the nuclear aspect. The chemistry is being ignored, because it has no effect on the stability if the nucleus. The converse in not the case, though. My point with the K decay is not that we get a noble gas (but one should also note that Radon is a noble gas and is in the decay chain of Uranium, so you do have this issue), it's that a singly-charged particle can cause multiple electrons to be stripped from the atom. That kind of disruption calls the viability of the chemical bond into question, and an alpha is going to be worse than a beta. More importantly, perhaps, is Atheist's point about the recoil, that will exceed the chemical binding energy — the recoiling nucleus will have more than 4% (4/92) of the decay energy, which means it will be a few hundreds of keV. So there's simply no point in worrying about the chemistry. You will have to re-form bonds after the daughter comes to rest and neutralizes.

I can't help but notice you didn't answer the question I asked.

One problem here is that "determined" has more than one definition. The state of a system is determined by the laws of physics, even if we don't know what that state is. So when you ask "How are the initial conditions of an experiment determined by the laws of physics?" which definition are you using? "Known" or "conforming to"? I believe Moo's point is that if the laws were in place already, then the initial conditions would have to conform to them. You seem to be claiming that no laws were in place. I am asking how you would be able to test either scenario.

How can they not be determined by the laws of physics? Wouldn't they have to violate the laws of physics in order to not be determined by the laws? —— If the initial conditions of the universe are random and not determined by the laws of physics, how would you test this? If they are, how do you test this? If the laws were created at the time of the big bang, or were in existence prior to it, how do you test this?

Newton's third law always involves two different objects that feel the reaction force (or torque) It's not clear to me if you are using it properly here.

Found it

That's true, but I'd argue not necessarily intuitive. From my perspective it's pretty obvious that fixing something before it breaks ends up being cheaper in the long run, but I also have experience with people (they live in budgetland) who have the attitude that money not spent is money saved. Cutting back on maintenance is a cost-saving exercise, because it results in reduced expenditures now. AFAICT they do not see a causal connection to the spending that occurs when their ill-maintained widget later fails.

Why? Does the current Antarctic ice only disappear because it is exposed to above-freezing air temperatures, and for extended periods of time?

Right. After the decay you might expect the U to have 2 extra electrons, but it's more likely that the decay ionizes several electrons. When I was trapping radioactive K, studying the effects of decay, we found that the beta-plus decay of K-37 would only rarely leave you with Ar- or Ar0. More often you'd end up with Arn+, with n = 1, 2 or 3. i.e. very often the decay would strip off several electrons. This is only from a beta, i.e. a single charge and little nuclear recoil. So after a U decay in an oxide, I don't think you can assume you have a molecule anymore.

No. Really, if you come into a situation where it appears that physical law is broken, one really needs to re-evaluate the data and the analysis. That's invariably where the problem is. Angular velocity, or angular speed? There's a big difference. For the angular velocity to be constant, the rotation axis must always point in the same direction. Precession, by definition, is the change in the orientation of this axis.

Generally reactor products are contained within the cladding of the fuel.

The light that can get refracted back to your eye must have a constant angle with respect to the light source. That geometry describes a cone, whose base is a circle.

Thanks for including the link. This is why we insist on references, though: You have quoted the statement that is being superseded by new evidence. The article's whole point is that the melting is happening faster than what you have quoted. The lead-in of the article is this: New research shows that man-made climate change could cause the Greenland ice sheet to break up in hundreds, rather than thousands, of years, the chair of a United Nations panel of scientists said on Monday. I don't know what that last sentence is supposed to imply — predictions from models assume certain conditions. If you change the conditions, the prediction no longer applies, without affecting the validity of the model. Why would humans have to do anything in 200 years if the models are unreliable and there's really no problem? I don't see how this article supports your contention that Antarctica has no realistic chance of melting in the next ~thousand years. Care to try again?