sol Definition and 31 Threads

I finally got around to watching the movie "Avatar", which takes place in the Alpha Centauri system. I was thinking that a great little scene between the 2 main characters (i.e., the paraplegic Earthling and the Centauri woman) would have been looking up at the night sky and seeing Sol as a...

So, I know that Sol lies roughly in the 25 000 light years from the core and from the edge of the galaxy and thus the approximate the position when seen from "above." But what a search today has not given me any idea of is where Sol is (thought/estimated to be) in relation to, well...

I use the ##(-,+,+,+)## signature. In the Schwarzschild solution $$ds^2=-\left(1-\frac{2m}{r}\right)dt^2+\left(1-\frac{2m}{r}\right)^{-1}dr^2+r^2d\Omega^2$$ with coordinates $$(t,r,\theta,\phi)$$ the timelike Killing vector $$K^a=\delta^a_0=\partial_0=(1,0,0,0)$$ has a norm squared of...

1. The problem is the following: Starting from stillness @ t = 0, we are looking for the acceleration @T=0 of the 2 wheels (rolling without slip, in particular in point P4 we have a gear wheel contact so we can have that the reaction R2y of the plane could be also in direction y2, in this case...

Homework Statement So I think I found an error in the solution were it attempts to find q_2^ I'm asked find the orthornomal basis for the column space of matrix A. Homework EquationsThe Attempt at a Solution [/B] My question is in what it puts for q_2^ A_2 = [4/3 4/3 -2/3]^T ||A_2|| =...

Hello, I noticed that the solution of a homogeneous linear second order DE can be interpreted as the kernel of a linear transformation. It can also be easily shown that the general solution, Ygeneral, of a nonhomogenous DE is given by: Ygeneral = Yhomogeneous + Yparticular My question: Is it...

What type of "graph paper" do I need to graph an arbitrary solution, Ψ, of the Dirac equation in 3+1 dimensional spacetime? Assume the "graph paper" has the minimum dimensions required to do the job. Would this work? At each point of spacetime we need a complex plane which takes care of the...

So I don't feel as freaked out as I did before reading the Tips sticky about making sure every bit of science is plausible. I would like to try and keep it believable for the immersion though. http://gizmodo.com/could-the-sun-be-extinguished-by-a-bucket-of-water-just-1669914928 It all started...

Hello all, I am doing a SOL 600 analysis but Nastran gives me an error of "zero thickness" in some elements. Obviously, I checked those elements and they have properly defined their properties so I don't know what can I do. I've done a lot of linear and nonlinear static analysis in that...

"Find x_0 and the largest interval, I, for which y(x) is a sol[...]" Homework Statement Given that y = –2/x + x is a solution of the differential equation xy' + y = 2x, find ##x_0## and the largest interval, I, for which y(x) is a solution of the initial-value problem: xy' + y = 2x...

Homework Statement Find the general solution: $$\frac{dy}{dx}=(x+y+3)^{2}$$ Homework Equations The Attempt at a Solution Methods I have learned: separation of variables, integrating factor for linear equations, exact equations, and substitution. I don't even know where to begin...

Hi, Referring to Jackson's Electrodynamics 3ed, page 197, line 5. He assumes that the magnetization can be divided into volume part and surface part, thus generating eqn 5.100. This is fine. In a straightforward way, I wanted to do the same but for electrostatics, eqn 4.32:∅= (1/4πε) ∫dv...

$$ u(x,y) = \frac{4}{\pi}\sum_{n = 1}^{\infty}\left[\frac{\sin(2n - 1)\pi x\sinh\left[(2n - 1)\pi (1 - y)\right]}{(2n - 1)\sinh(2n - 1)\pi} + \frac{\sin(2n - 1)\pi y\sinh\left[(2n - 1)\pi(1 - x)\right]}{(2n - 1)\sinh(2n - 1)\pi}\right]. $$ How do I construct a contour plot of this?

I know that in scenarios where QM and GR are both applicable the answerers come out ridiculous. I believe this may be one of those scenarios. It is also possible that I have some misunderstanding that leads to a ridiculous answer. My question is which of these is the case. A photon is...

So, I've read here http://en.wikipedia.org/wiki/Interstellar_medium that the Interstellar medium varies greatly throughout space. Of the categories listed; Molecular clouds, Warm Neutral Medium, Clound Neutral Medium, Warm Ionized Medium, H II regions, and Coronal Gas/Hot Ionized Medium...

I'm a fan. Not a physicist or astronomer.. But this question is bothering me. If the mass of an object increases to infinity as it approaches the speed of light, does that also create infinite gravity at the object? And if so, if we consider the gas swirling around the black hole is very...

I have seen discussions of universes with different numbers of spatial dimensions, universes without a strong arrow of time, universes with differing physical constants, etc. but I was wondering (here it comes, you are wondering) (LOL) would our universe be substantially similar with a...

Verify that an exact solution exist for the logistic difference equation $$ u_{t+1}=ru_t(1-u_t),\quad r>0 $$ in the form $u_t=A\sin^2(\alpha^t)$ by determining values of r, A and alpha. Is the solution periodic? Oscillatory? I have yet to encounter a problem that says verify a solution...

The problem: Solution in the spoiler: I don't know how to do the problem (a), but I also don't understand the answer (top of coil 3?). Can you give me the process on how to do the problem (a), i.e. in general how do I assign dots to coils in circuits? :)

I wondered if just stating that the speed of light is 300,000 km/s in all reference frames does not give the whole picture. I heard Penrose say that time for light is 0. Wouldn't that mean from its point of view it goes everywhere instantly and thus has infinite speed?

Am I misunderstanding the measurements or what? The SIMBAD site has archived 17 measurements or Vega's radial velocity over the past 150 years and they are all negative (blue-shifted) averaging out to about 9.0875 miles per second. Since Vega is only 25.29 lightyears away this seems to...

Homework Statement Find out whether particle or heat diffusion determines the width of the SOL, and whether the ions or electrons are the determining factor. (just compare all of those). Give an expression to estimate the thickness of the SOL and evaluate the expression for Te = 10 and 100...

Find a particular solution for the following non-homogeneous dieren- tial equation by the method of undetermined coefficients: a. y'' + 8y' +12y = e^-2x + sin(2x) b. y'' + 11y' - 12y = 3x^2 + 4 + e^x I got for a. Yp(x) = 1/4xe^-2x + 1/40cos(2x) +1/20 sin(2x) b. Yp(x) = -1/4x^2...

Homework Statement solve: y" + 4y' + 4y = (3 + x)e-2x ... (1); y(0) = 2 & y'(0) = 5 Homework Equations using Undetermined Coefficients Method The Attempt at a Solution solving the associated homog. eq of (1) : y" + 4y' + 4y = 0 ... (2) we get: yc = c1 e-2x as m=-2 let...

I failed calculus due to personal issues at the very end of the course although I was doing fine in it, would have gotten an A. I have also withdrawn from a 2 other courses at my current institution. I am very near the beginning of my potential Physics degree and plan to CLEP out of...

Homework Statement i have a differential equation. ∂h/∂t + [g sin a h²/v]∂h/∂x = 0. where h = h(x,t). i need to show by substitution that the (implicit) general solution for h is h = f(x - (g sin a h²t/v)) where f is an arbitrary differential function of a single variable. The Attempt...

I need sol for this please httashment

Hello everyone. I'm having troubles understanding if I'm doing this right. I have the matrix \left( {\begin{array}{*{20}c} 2 & {-3} & {-3} & a \\ {-1} & 1 & 2 & b \\ 1 & {-3} & 0 & c \\ \end{array} } \right) I row reduced it to: \left( {\begin{array}{*{20}c} 2 & {-3} & {-3} & a...

ok I've been wondering about this for awhile when people say the speed of light slows down when going through an object (ie glass). does the speed of light actually slow down to 2x10^8 m/s or does the speed of light actually stay constant at 3x10^8, but the photons collide with the SiO...

Thought some of you may be interested in these stunning pictures of the Total Solar Eclipse in Antarctica, which happened yesterday, 24 November 2003. The views are from Casey, Davis and Mawson Stations (these are Aussie “Research” stations in Antarctica – mostly CSIRO). Awesome stuff...

It's fun to think about the far-out Type II and III civilizations, but how close are we now to Type I? M. Kaku says the output of our star is about "a billion trillion trillion ergs per second". That is, if I have done the arithmetic correctly, 10^33 ergs/sec or, dividing by 10^7, 10^26...