Modern and Theoretical Physics

If Helium, when cooled to a few degrees above absolute zero, becomes a superfluid with all sorts of gnarly properties, would it be possible to cool it even more so that is freezes solid? What would that be like, d'you think?

I was just doing some work out by my pool today. I stared at the sky and looked at the moon. Then for some wierd reason I started thinking about string theory, and I wonder if I could explain the other dimensions. To make this short, I started wondering. Each dimension is an expandature of the last. The first dimension is thought to be the line, while the second dimension is thought to be the plane, and the third the cube. But I began to think. If the first dimension were the line, wouldn't the line have originated from an infinitesimal point? It is confusing to explain. Say this. A point in geometry is imaginary, because a dot has a two dimensional plane. But …

So I recently got a 600mm (2ft) 20W UV blacklight which is quite cool... anyway, the thing with UV light is that it only reflects off (generally, there are some exceptions,) white surfaces, and only some white surfaces. So for example it reflects of most normal A4 paper but not the white paint on my ceiling. What I was wondering is that when the UV light reflects off a white surface you see white light... how is that a single-high-frequency UV can be reflected as multiple-lower-frequency white? I understand how different materials reflect different frequency light which is affected by the electrons in the material. Also, whenever it comes to visible light we say …

say mass doesn't directly bend spacetime. say the graviton is what actually bends spacetime. massive particles just emit gravitons. the farther the gravitons get from the source, the more spread out they are, therefore the force is weaker (which makes sense, with the inverse-square law). gravitons don't need to be absorbed, they just are emmitted. i am guessing the mass would determine the graviton emmission rate. i wouldn't even know how to start making equations to compare to gr. i don't even know how to do tensor calculus, so i couldn't compare with gr if i had the equations. there is probably some qm stuff that i need to factor in. this is just a base idea for now. in…

Bismuth Power? "Will the orienting of the electron dipoles in Bismuth (by, say, rapidly placing within, say, 1 mm of a strong magnetic pole) create a measurable amount of heat? I imagine you would have to measure it in a vacuum and neutral-G environment to be sure. Also, would sheathing a bar magnet to the halfway point with a certain thickness (TBD) of Bismuth create a sort of monopole effect with the B measured off each pole showing disparity? If so, then you would (of course) have the makings of a weak space drive (against a planet's magnetic pole to a certain (TBD) distance outward). Spin the magnet-Bismuth combo to help avoid 'flipover.' The above has bee…

I (however behind the times i am) have basically just discovered that a fascinating area of science has been spawned from the discover of quarks. Of coarse i've heard of them before, but not realized how involved it all is. So i wanted to read up on the subject, and i cant tell what the hell is going on. Can someone direct me toward a book or such that could help me understand the basics of quarks and related particles, without making it a lifelong study for comprehension? Something simple enough me to understand (within reasonable range of effort), but goes in enough depth to be exciting. Appreciate anything ya'all can offer.

Electron microscope makes use of the collisions of electrons on the object to form the image. It's quite similar to the way which photons hit the object and reflect to give us an image. Moreover, photons form electric field , it is also similar to electrons. Their masses are very small as well. Is there any example/evidence to give the contradiction?

I’m just trying to visualise a water molecule. As if it was as big as a solar system. for water, I need two Oxygen atoms and one Hydrogen atom. So I have three solar systems interplaying with each other. the planet Hydrogen has one moon (electron) and so on. Are the moons staying around their own planets or are they being swapped?

This is just something I thought up when reading about carbon nano-tubes. It boils down to this: could carbon nano-tubes or other super tiny structures be used to create an "antenna" for light? We use lengths of conductors to absorb radio waves, which generates a current in the conductor which is then amplified and converted to sound. Radio waves and microwaves can also be absorbed by a mesh of conducting material. The kicker for both these methods is that they must be around the size of the wavelength of the absorbed wave. I know for a faraday cage (the conducting mesh) the spaces in the mesh must be smaller than the wavelength they are going to absorb. I know a…

This is going to sound like a stupid question, but what is Stephen Hawkings known for?

I'm a senior student majoring in physics. I was asked to take a five-week seminar this summer holiday. Can anybody provide some interesting subjects of theoretical physics? Maybe after the holiday you will find a good cooperator to discuss and work with.

Why a glass barrier can seperate a fire? Energy can transfer even there's no particles. I can hardly imagine the way the glass act as a barrier.

Hi, just wondering what plasma is and what it is being used for.

http://rodan.physics.ucla.edu/pyrofusion/ Paper and supplemental materials available at: http://www.nature.com/nature/journal/v434/n7037/suppinfo/nature03575.html Christian Science Monitory story at: http://www.christiansciencemonitor.com/2005/0606/p25s01-stss.html

I have always wondered this, but every time I search for it I find confusing stuff. Anyway, I thought that inertia was just a property, and that it truly can't be measured. I thought it just belonged to matter, there isn't a type of matter that can have more inertia.

Does such a thing exist? Can it? We probably can't stop it, but it seems very hard to understand. Gravity holds together the protons and neutrons of atoms nuclei, so how can antigravity work? What I have trouble with is this. Is there an antimatter? Maybe antigravity exists because that is how antimatter and matter relate. Maybe antimatter is gravitational to antimatter. Yet matter to antimatter is antigravity. In fact, is there a proven such thing as antimatter? I have heard mentions of it, but I wondered if it were proven to exist in the scientific community.

this is one I`ve being working on for many years, and I think I`m getting close to a complete theory of the universe and the "Big Bang". for ages I`ve pondered the idea of HOW we can get something from nothing, the only answer is to create an equal and opposite deficit (like borrowing money from a bank, you have 10 credits from the bank but you OWE 10 credits to the bank) +1 and -1 =0 so what is the opposite in REAL terms? Matter Antimatter, in specific Positronium. given infinate time and vacuum long before any big bang came into being, particles popped into and out of existance continuosly, this has been observed. the point of Zero or Nothingness is …

The other day I came up with an idea for nearly instaneous communication. If I remember correctly magnetic fields are instaneous, meaning that the entire field comes into existence at the exact same moment. By using a long line of transmitters (magnetic field producers) and receivers (magnetometers) you could create a faster than light communications line. This would be like if you got a group of people to get in a long spaced out line, and once one person hears the message they yell it to the next person who repeats the process until it gets to the end. The transmission/field is automatically detected by the next receiver in line, that receiver also has a bu…

Wired has a cool article up about Peter Lynds, the New Zealand amateur physicist who's paper proposing that time has no discrete increments shook things up a bit last year. http://www.wired.com/wired/archive/13.06/physics.html Here's a very brief excerpt (the full story runs four pages):

can anyone tell me what the 11 dimensions that the String Theory talks about? or have they not been discovered yet? a new project.

Hello, There is a lot of discussion about whether photons are energy or matter. What do you think??? Pomlom

I was just thinking: some theoreticions believe that the universe will eventually collapse under its own gravitational pull and result in a Big Crunch? Some of these theoreticions would go even further and postulate that after this Big Crunch, the universe will once again be in the same state it was in before the Big Bang, and so another Big Bang will occur. If this were true, then the universe is simply a perpetual series of Big Bangs and Big Crunches, and it not only makes sense to project this series into the future but into the past as well, which means that the most recent Big Bang was not the absolute beginning of the universe but only the beginning of the current c…

As stereotypical as this may seem, I have recently read Brian Greene's "Elegant Universe." Concerning the weak and strong forces, Greene says on page 10, "the strong and weak forces are less familiar because their strength diminishes over all but subatomic scales." However, on page 177, he talks about how the strength of the weak and strong forces diminishes over short distances, because "the quantum cloud of particles eruptions and annihilations amplifies the strength of the strong and weak forces...and so the strengths of these forces get weaker when they are probed on shorter distances." This seems like a non-sequitur to me, wouldn't the forces INCREASE over non-sub-at…

I have my second year exams for Physics tomorrow and I've got something mixed up in my mind, and I'd really appreciate it if someone could set me straight. Why is water more effective than lead in slowing down fast neutrons? Also why do neutrinos interact weakly with material? (Their detection is proof enough that nuclear reactions are taking place, detection units are constructed and then taken under ground so as not to have the weak neutrino signal interferred with by other particles) Cheers. Wish me luck!

The lay man approach to time travel seems somewhat strange to me. Let us assume it is possible for a moment. Sorry to lower the tone, but the media (such as films and TV) shows theories of time travel that suggest that time is not linear and it is constantly warping through various states of existance - what I mean is, that if we were able to travel back through time and change events we would constantly be warping through various alternatative existances. I think it is more sensible to suggest that time is linear. Also, I agree with the theory of time dilation - time may be slowed down or sped up relative to time in a different space - as suggested by Einstein and…