Top new questions this week:

Why does LIGO do blind data injections but not the LHC?

The LIGO group has a team that periodically produces fake data indicating a possible gravitational wave without informing the analysts. A friend of mine who works on LHC data analysis told me that ...

experimental-physics large-hadron-collider ligo

asked by tparker 44 votes answered by Luboš Motl 49 votes

Difference between sunrise and sunset?

Other than knowing which direction is east and which direction is west, or observing for a sufficient timespan (to determine the direction of motion), is there any way of telling whether what one is ...

visible-light atmospheric-science geophysics

asked by Mikhail Katz 22 votes answered by Luboš Motl 27 votes

How far can we separate two bound quarks?

If we try to separate two quarks bound into a meson or a hadron, the energy in the gluon field eventually will be large enough to spawn a quark-antiquark pair. How far can we stretch that gluon ...

quantum-chromodynamics quarks estimation confinement

asked by Calmarius 18 votes answered by AccidentalFourierTransform 12 votes

Why is the simple harmonic motion idealization inaccurate?

While in my physics classes, I've always heard that the simple harmonic motion formulas are inaccurate e.g. In a pendulum, we should use them only when the angles are small; in springs, only when the ...

newtonian-mechanics harmonic-oscillator anharmonic-oscillators

asked by Lucas Henrique 16 votes answered by Jacob Austin 25 votes

If water is essentially incompressible, why are there tides?

So recently we were taught in school that tides are formed because the moon 'cancels out' some of the earth's gravity, and so the water rises because of the weaker force. But if water is not ...

newtonian-mechanics newtonian-gravity earth tidal-effect

asked by Giulio Crisanti 16 votes answered by anna v 22 votes

Two contradictory groups of statements from two different books on quantum physics

There are two contradictory groups of statements from two different famous books on quantum physics. Which one is correct? Group (1) : Following statements are from Berkeley Physics Course Vol. 3, ...

quantum-mechanics wave-particle-duality

asked by atom 16 votes answered by Rococo 2 votes

Does Heat Cause Time Dilation?

Since heat is defined as the movement of molecules, and because of relativity time slows for faster moving objects, would a hot object be in a slower time frame then a cooler object, because the hot ...

special-relativity relativity

asked by Tesseract 15 votes answered by Jaywalker 16 votes

Greatest hits from previous weeks:

Why the bulb glows brighter?

If the total current is divided into the branches in a parallel configuration and it is constant in series. How come the bulbs glow brighter when connected in parallel than when connected in series?

electricity electric-circuits electric-current

asked by Krishanu Singh 3 votes answered by Brian 4 votes

Can the Heisenberg Uncertainty Principle be explained intuitively?

I have heard several pseudoscientific explanations about the Heisenberg Uncertainty Principle and find them hard to believe. As a mathematician mainly focusing on functional analysis, I have a ...

quantum-mechanics uncertainty-principle

asked by D1X 79 votes answered by John Forkosh 96 votes

Can you answer these?

Integrating out heavy fields while preserving symmetries

The basic a-b-c for integrating out heavy fields what one learns when making the example of Fermi theory, is that if you have a Lagrangian $L= -\frac{1}{4}F^{\mu\nu}F_{\mu\nu}+\frac{1}{2}M^2 V^\mu ...

quantum-field-theory effective-field-theory

asked by Giorgio Busoni 2 votes

High pressure deformation of metals

Does copper undergo elastic recovery after being exposed to high pressures (above 30 GPa in a diamond anvil) at room temperature?

condensed-matter experimental-physics crystals metals x-ray-crystallography

asked by Jimmy 1 vote

Which quantum gravity theories do predict a growing number of space dimensions?

In this 2013 Nature article there is a short presentation of the causal dynamical triangulations approach to quantum gravity, where it is said Intriguingly, the simulations also hint that soon ...

cosmology universe quantum-gravity

asked by Stéphane Rollandin 2 votes