101,246 reputation
4146259
bio website ratsauce.co.uk
location Chester, United Kingdom
age 53
visits member for 3 years, 7 months
seen 5 mins ago

Semi retired old time computer nerd who started programming on a Commodore Pet.

Since I'm also active in the Physics forum I should add that I started as a theoretical chemist, moved into solid state photochemistry and finally worked in industry as a colloid scientist. I only became a full time computer nerd in 1997.


Aug
26
comment Arguments for finite speed of physical processes
Yes, sort of. For example quantum electrodynamics also obeys Lorentz invariance, and I think QED would be regarded as more fundamental then Maxwell's equations. So Lorentz invariance is more fundamental than both of them. In fact, as far as we know everything respects Lorentz invariance making it about as fundamental as it's possible to get.
Aug
25
comment The charm of the gyroscope
There must be a thousand articles out there in Googlespace discussing the mechanics of gyroscopes.
Aug
25
comment Angular momentum, what is it, is it conserved, and how do we know?
Conservation of angular momentum about a point is just a consequence of rotational symmetry about that point, courtesy of Noether's theorem. That seems to me to be a reasonably fundamental property.
Aug
24
comment Gravity vs. Velocity Time Dilation
I really don't understand why someone downvoted this. The equation firtree gives for $d\tau/dt$ is the most general equation for the time dilation, and indeed it's the equation I used in the Q/A I linked in my answer (albeit in a simplified form). The cynic in me suggests this is an example of a downvote meaning I don't understand this answer rather than this answer is wrong.
Aug
24
comment Why batteries in serial don't discharge each other?
@LDC3: I can't think of one offhand, but I'm not confident enough to swear under oath that no such batteries exist :-)
Aug
24
comment Why batteries in serial don't discharge each other?
@BrandonEnright: if you connect the batteries in parallel that will happen, but not when they're connected in series.
Aug
24
comment Optical absorption in a semiconductor for $E<E_g$
The question I've linked is about an isolated atom/molecule rather than a band structure in a solid, but the same argument applies.
Aug
24
comment How did the gravity of the particles/objects behave at the edge of the expanding universe moments after big bang?
See Excluding big bang itself, does spacetime have a boundary?. Spacetime didn't have an edge shortly after the Big Bang, and indeed has never had an edge.
Aug
23
comment A Sphere of Black Holes
Good luck working out the equations of motion. Describing the merger of two black holes is still an ongoing research effort. Describing the merger of a sphere of them is way out of reach.
Aug
23
comment A Sphere of Black Holes
Do you mean a collection of black holes arranged on the surface of a sphere and allowed to move inwards until their horizons overlap?
Aug
23
comment Why don't atoms emit gravitational waves?
Does an atom have a changing quadrupole moment? Surely the eigenfunctions of the Hamiltonian are time independant?
Aug
23
comment Vectors-Can anyone explain me the concept of sense in vectors?
@user146181: Yes. But you should note that the article I linked was (probably) written by a mathematican. I've never heard a physicist use the term sense - we just talk about direction. It isn't obvious to me why you would decompose direction into orientation and sense, though I'm sure there is a good reason. Maybe you should ask in the MathSE.
Aug
22
comment Are Both figures correct?
Well, yes, you're not told what the distance from P to Q is. If the PQ distance was 600m the second drawing would be correct. I have to say that my immediate assumption was that the PQ distance is 120m and that the first diagram is correct, and I imagine this is what your teacher meant.
Aug
22
comment Quantifier problems of equations in physics
Back in the 70s we were taught the equation $E = mc^2$ is always true with $m$ being the relativistic mass. Your equation would have been written $E^2=m_0^2c^4+p^2c^2$.
Aug
22
comment Compatibility of effects implies compatibility of POVM's?
POVM = positive-operator valued measure?
Aug
22
comment Good explanation of phase transitions, second law of thermodynamics
possible duplicate of Book recommendations
Aug
22
comment Is light so important in special relativity?
$c$ is special because it's the only speed a massless particle (like a photon) can travel at, and any massive particle must travel slower. Whether a neutrino is massless or massive, if it travelled at $> c$ that would break special relativity.
Aug
22
comment Is light so important in special relativity?
possible duplicate of What is so special about speed of light?
Aug
22
comment Why doesn't the light from galaxies appear stretched?
possible duplicate of How distorted does the Andromeda Galaxy appear to us due to the speed of light?
Aug
22
comment What are the current size limitations of NIR spectroscopes?
This question appears to be off-topic because it is about a specific model of refliction IR spectrometer