Recent content by zephyr5050

The reason such a closely flat universe is so surprising is that once the universe starts out slightly not flat, it will evolve to become extremely not flat extremely quickly (to put it in Layman's terms). Thus we should find that the ##\Omega_0 \ll 1##, ##\Omega_0 = 1## (exactly), or ##\Omega_0...

Homework Statement I'm currently trying to work through some issues I'm having with tensor and vector analysis. I have an equation of the form $$\textbf{a} \bullet \textbf{b} = \textbf{c} \bullet \textbf{d}$$ where all quantities here are vectors. I want to solve for ##\textbf{b}## by finding...

Homework Statement A particle of mass ##m## is constrained to move between two concentric hard spheres of radii ##r = a## and ##r = b##. There is no potential between the spheres. Find the ground state energy and wave function. Homework Equations $$\frac{-\hbar^2}{2m} \frac{d^2 u}{dr^2} +...

Do you happen to know the paper which proposed this commonly accepted line? If any?

I've been working with NFW Dark Matter Halos recently. This is a particular density model for the halo developed by Navarro, Frenk, & White (NFW). The density structure has the form \rho (r) = \frac{\delta_c \rho_c}{(r/r_s)(1+r/r_s)^2} where \delta_c = \frac{200}{3}...

Thanks so much. That makes it abundantly clear.

I've always heard that the cross product only exists in a well defined way for 3 and 7 dimensions. From my own reading I've found that a cross product in 3 dimensions is nothing more than the product of two quaternions with only pure imaginary components (that is, the real part is zero)...

Hello all, Sorry about the crappy title. I'm actually not sure what the call the thing I'm here to ask about, which is why I'm here. In the process of reading about gravitational lensing, I've run across an odd mathematical thing that I just don't know how to handle. When a spherical...

This is just from my personal experience, but I find the best way to really learn the material is through repetition. Read the material, try to derive the results yourself (don't just look it over), work on problems. And here's the key - after a time, reread the material, go over it all again...

Hello Mikeal. I'd just like to say initially that I think Jtbell makes a very good point. I know this might be a slight departure from the rest of the thread, but I think historically the double slit was not designed to show both the particle and wave aspect of light/particles. Often the...

Alright, thanks for your help TSny, and you too tiny-tim.

But that seems absurdly simple. I don't even have to do any math for that. I suppose that is the answer, but it just feels like its not enough to satisfactorily answer the question.

I'm not sure how exactly you determined the maximum of the electric field. It appears that all you did was divide the charge by the radius. This is not a correct formula and doesn't even give you the units of an electric field. My suggestion would be to use Gauss' Law to find the electric field...

Well, the free charge would be anything which can move freely around the system, whereas the bound charge is any charge confined to an atom, but which is creating an electric field due to the fact that it has been pulled away from the rest of it's atom. I believe it should be considering it...

It would be true that you have to show beta radiation is not present, and also that both alpha and gamma radiation must be present. I think on approach is to first consider what exactly alpha and beta radiation is composed of, and then ask what this form of radiation does when a magnetic field...