77,261 reputation
178165
bio website ratsauce.co.uk
location Chester, United Kingdom
age 53
visits member for 3 years, 3 months
seen 7 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.


14h
comment Separation of radio frequency
The question obviously intends you to assume the transmitters are coherent, otherwise they wouldn't create a stable interference pattern.
16h
comment Rigid rectangle in Schwarzschild
Can you clarify what you're asking? Do you want your rectangle to have sides that are geodesics, or are you asking what the coordinates of a rectangle constructed in flat space would be in curved space?
1d
comment What is the notion of a spatial angle in general relativity?
Locally spacetime is flat and you can measure angles just as Euclid did. I don't see the problem with calculating the worldline of the outgoing photon. Why is this hard?
2d
comment Duration of Satellite orbit in the shadow of the Earth
I was going to sketch out the approach, but I found that doing this amounted to answering the question anyway. It's not clear to me this is set homework, though it's homework-like. If it was set homework I hereby apologise to Radda's teacher!
2d
comment How to use specific heats and temperature change in a system to calculate mass?
Can you give a sample problem of the type you're considering? Then we can show you how to work through that problem.
Apr
13
comment Why no longitudinal electromagnetic waves?
Yes, but they're really sound waves in a charged gas not EM waves.
Apr
13
comment Confused about fire?
@KirkWoll: everything that is hot emits light, whether it's carbon particles in a flame or metal heated in a forge. This is black body radiation. See the link in my answer, or have a read through the answers to What are the various physical mechanisms for energy transfer to the photon during blackbody emission?.
Apr
12
comment Why does diffraction depend on wavelength?
That's an awfully broad question. You're basically asking us to explain diffraction to you. I would start by browsing the Hyperphysics pages on diffraction and come back to us with specific questions.
Apr
12
comment why cannot fermions have non-zero vacuum expectation value?
The Higgs has a non-zero vev, but there's no reason to suppose this applies to other scalars. It's a special property of the Higgs.
Apr
12
comment Interpretation of Heisenberg's uncertainty principle
There are some relevant commentis in my answer to another question. This is about photons, but the comments apply to any particle.
Apr
12
comment why is universe neutrally charged?
You might be interest to read the paper The electrically charged universe
Apr
12
comment How is the Plane of the Solar System oriented to the Sun's motion through space?
I think the downvote is harsh. There's an obvious interpretation of the motion as discussed in my answer. It's an interesting question and one that had never occurred to me. It turns out the direction of motion seems oddly aligned with various major features of the universe - see the article I've linked for more details. Anyhow, +1 from me and ignore the downvoters!
Apr
12
comment Can you discern the cause of a time shift?
I think the trouble is that the question doesn't really make sense. The equivalence between gravitation and acceleration is local i.e. only local observations can't tell the difference. Looking out of the window would allow you to tell the difference. In this case, you could compare the Earth's position with what your ephemeris says it should be to help work out what had happened.
Apr
11
comment Does non-matter energy curve spacetime?
possible duplicate of What are the factors affecting the spacetime curvature?
Apr
11
comment Grover search algorithm for more than one marked elements
This question appears to be off-topic because it is about computer science
Apr
10
comment Why is $|\Psi|^2$ the probability density?
See this paper by Scott Aaronson. He considers other ways of calculating the probability density and shows that the 2-norm is the only physically reasonable one.
Apr
10
comment What is exotic matter and negative energy?
This is too broad a question to be a good fit for this site. You really need to go off and do some Googling (or just search this site) and come back to us with any specific questions.
Apr
9
comment Are retrograde capture orbits “easier” than prograde capture orbits?
Isn't it the case that we suspect a moon has been captured because it's orbit is retrograde? If it was prograde how would we distinguish it from the other moons?
Apr
9
comment Could a tetraquark $q \bar{q} q \bar{q}$ be colorless?
The Z(4430) is believed to be made up of quarks, or at least no-one is suggesting differently. It's just that it appears to be made up of four quarks not three.
Apr
9
comment Kinetic energy and temperature required?
How did you divide $10^{-14}$ by $10^{-23}$ and get $10^{-24}$?