## Top new questions this week:

### If we threw a baseball from the ISS, could we deorbit the ball?

Clearly this is a hypothetical question. Say we bring a star baseball player into NASA, prep them appropriately for a mission in space, and fly them up to the International Space Station. They go on ...

newtonian-mechanics newtonian-gravity orbital-motion vacuum drag

### The scope of physics, as taught in modern times

I am asking this question based on my recent experience as a physics major at a well-known school of science and engineering. My basic question is, Why does the field of physics (at least at an ...

soft-question education

### Same photon or different photon?

Consider a typical optical focusing system: A small light source, then a collimating lens, then a focussing lens, and then a detector (e.g. CCD). Assume that source intensity is so low that only one ...

### Is the existence of a sole particle in an hypothetical infinite empty space explicitly forbidden by QM?

Suppose the universe is completely empty with one sole particle trapped in it. To simplify, I will only be looking at the one dimensional case. However, all arguments are applicable for three ...

quantum-mechanics hilbert-space schroedinger-equation approximations

### Light's inverse square law: Does it require a minimum distance from the source?

Does the inverse square law begin to take effect the moment light leaves its source? For example, does light's intensity decrease, i.e. does the area in which the photons might land increase, at a few ...

So, I have my exams in physics in a week, and upon reviewing I was confused by the explanation of de Broglie wavelength of electrons in my book. Firstly, they stated that the equation was: $\lambda = ... waves electrons diffraction matter  asked by Kasper 8 votes  answered by DarthPlagueis 8 votes ### How can dimensional regularization "analytically continue" from a discrete set? The procedure of dimensional regularization for UV-divergent integrals is generally described as first evaluating the integral in dimensions low enough for it to converge, then "analytically ... quantum-field-theory renormalization dimensions analyticity dimensional-reg  asked by tparker 7 votes  answered by yuggib 1 vote ## Greatest hits from previous weeks: ### Linear acceleration vs angular acceleration equation I'm learning about angular velocity, momentum, etc. and how all the equations are parallel to linear equations such as velocity or momentum. However, I'm having trouble comparing angular acceleration ... rotational-dynamics vectors angular-velocity  asked by Griffin 4 votes  answered by Bernhard Heijstek 7 votes ### What exactly is the difference between advection and convection? After reading Wikipedia articles on advection and convection, I still cannot determine whether there is a consensus on a difference between these two terms. Sometimes, the term convection seems to ... fluid-dynamics heat terminology convection  asked by Wok 19 votes  answered by John Rennie 8 votes ## Can you answer these? ### Uncertainty principle and digital camera I recently got into a discussion in how far (miniaturized) digital cameras are affected by the uncertainty principle. Specifically the question was, whether the uncertainty principle is one of the ... uncertainty-principle  asked by dliw 1 vote ### What are the Higgs masses for$SU(2) \times U(1)$goes to$U(1)$symmetry breaking with a complex triplet? Consider an$SU(2)\times U(1)_Y\rightarrow U(1)_{EM}\$ theory that is broken via a complex triplet with hypercharge 2. The potential is of the form \begin{align} V(\Phi) = -m^2\Phi^\dagger\Phi + ...

homework-and-exercises quantum-field-theory mass symmetry-breaking higgs