95,468 reputation
3132239
bio website ratsauce.co.uk
location Chester, United Kingdom
age 53
visits member for 3 years, 6 months
seen 45 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.


Jul
22
comment How would an X-ray scanner identify a mirror?
@JoeBlow: ah, yes. Weren't those the ones that could allegedly photograph you naked? With that sort of scanner the (hypothetical) X-ray mirror would appear to be glowing.
Jul
21
comment Frame dragging — is there a “non-tiny” example?
@JoeBlow: if you're interested I've shared a Google spreadsheet with the frame dragging calculations in.
Jul
21
comment Frame dragging — is there a “non-tiny” example?
@JoeBlow: re the bucket, if you put a stationary bucket inside a rotating spherical shell then the frame dragging will start to rotate the water in the bucket and make the surface curve. But your question says: if you have a bucket of water big enough, and spin it, it WILL NOT form the concave shape and that's what I don't understand.
Jul
21
comment Frame dragging — is there a “non-tiny” example?
@JoeBlow: as it happens I did a quick calculation of the frame dragging at the surface of the Sun and also at the surface of Jupiter. Both are about 100 times greater than the Earth, though note this is still only 100 times a ridiculously small number. The average density of a galaxy is so low that any frame dragging effect is effectively zero. To get a significant frame dragging you want a high density i.e. a combination of high mass and small radius.
Jul
21
comment Momentum acceleration in space?
If I understand your question correctly it's similar to Can relativistic momentum (photons) be used as propulsion for 'free' after the initial generation? except that you have a baseball bouncing to and fro instead of a light beam. Is this a fair comparison?
Jul
21
comment How does weight add up to press on things?
@Avva: yes, the compression of the block is related to the applied force by the bulk modulus.
Jul
21
comment My basis set isn't orthonormal?
I did a lot of HF-SCF calculations back in the late 70s, and it was routine to use non-orthonormal bases. As Emilio says it made the calculations slightly more demanding but then that's why God invented computers :-)
Jul
21
comment Could space itself be made out of particles?
I've suggested a question that I think goes some way to duplicating your question. As it stands your question is too broad to be usefully answered here. You might want to Google emergent spacetime or something similar to see what sorts of approaches have been suggested, though this is a speculative area with no well established theories. However I think it's safe to say that there are no (plausible) suggestions that spacetime is made out of particles in any literal sense.
Jul
21
comment Could space itself be made out of particles?
Also related: How does classical GR concept of space-time emerge from string theory?
Jul
21
comment Could space itself be made out of particles?
possible duplicate of Does String theory say that spacetime is not fundamental but should be considered an emergent phenomenon?
Jul
21
comment How would an X-ray scanner identify a mirror?
@placeholder: in airport luggage scanners?
Jul
21
comment What is invisible to x-rays?
@KevinFegan: no. That's because the band gap in glass lies in the uv. See this related question for more or search this site for something like glass transparent
Jul
20
comment Magnet insulation and Permanent magnets
@user7063: There is no such thing as a perfect insulator, either magnetic or electrical, but superconductors come pretty close to perfect magnetic insulators (though a superconductor will cease to be superconducting if you make the magnetic field too strong).
Jul
20
comment Electricity production
The OP seems prejudiced against chemical sources - see his response to ACuriousMind's comment.
Jul
20
comment Does “dark matter” explain how I can have -1 apples?
I'm not sure that your questions on photons have been dealt with as thoughtfully as they might have been, but that isn't a reason to start posting satyrical questions. What will you achieve except to get downvotes and the questions closed?
Jul
20
comment What are quasars?
This question appears to be off-topic because it shows insufficient effort
Jul
20
comment What are quasars?
Have you done any background reading before posting this question, for example the Wikipedia article on quasars? If so can you make your question more precise to explain what specific aspects of quasars you're seeking to clarify?
Jul
20
comment Introductory derivations of Heisenberg uncertainty principle
It's with some reluctance that I vote to close (for the "primarily opinion-based" reason) because I have considerable sympathy with the views of the OP. Maybe there's a site this question could be taken forward - is there an SE site for "physics education" type questions?
Jul
19
comment Why did nuclear testing not result in nuclear winter?
@Gx1sptDTDa: I've updated my answer to respond to your comment.
Jul
19
comment Experiment with spring and two light sources emitting light in opposite directions
Can you expand on what you are asking. The force on the light source due to the emission of the light is easily calculated, and the acceleration of the light source is just this force less the spring tension divided by the light source mass.