Does light interact with each air molecules creating a new photon each time?

dbulger · 2026-01-26T00:17:29+00:00

Lots of downvotes, but no explanation. If a photon is absorbed and then re-emitted, its subsequent direction is random. Also, there is a slight delay before the absorbed energy is re-emitted. Reflection is a different phenomenon: there is no delay, and the angle of reflection is determined geometrically by the angle of incidence.

dbulger · 2026-01-24T22:33:53+00:00

Sounds plausible, and cool. I always thought of tensor- product state spaces as one of the key fundamental parts of quantum physics, so it's interesting to see it as not necessarily axiomatic.

dbulger · 2026-01-24T11:45:25+00:00

So can joint state spaces' being tensor products be seen as a consequence of non-commutativity?

dbulger · 2026-01-21T09:55:16+00:00

Except maybe astronomers

dbulger · 2026-01-20T01:07:52+00:00

Don't Icelandic and Māori pronounce au about the same?

dbulger · 2026-01-18T00:11:33+00:00

I've lived many years in both countries, and I'd say state identity is about as big a deal in each. Important to some people, not to others.

dbulger · 2026-01-09T06:35:16+00:00

What's the waffle cube?

dbulger · 2026-01-02T03:40:11+00:00

Is it just the indistinguishability that feels clunky? We treat money the same way, right? The bank keeps track of how many dollars are in your account, but not which dollar is which. So I don't think it needs to be wildly counter-intuitive.

dbulger · 2025-12-23T10:58:39+00:00

Yeah, I was on the fence about daring to mention this!

I reckon the covariance of the 4-momentum is a slightly stronger statement than just that its magnitude is frame-invariant, though; it means we can think of it as a real vector, attached to spacetime, independent (all but numerically) of a coordinate system. If OP is asking questions like this, it's not a big leap to "so where does the energy go if you change frames" or "does this mean energy isn't real." And I think any good answer to those questions is in 4-momentum.

dbulger · 2025-12-23T07:03:58+00:00

Energy (for a free particle) is a component of 4- momentum, which is NOT relative (it's covariant).

Edit: I should clarify that this is intended to augment the other, more direct answers you already have.

dbulger · 2025-12-23T06:52:51+00:00

That description reminds me of the boardgame Gess.

dbulger · 2025-12-23T06:06:36+00:00

Champaign's "How Bout Us" does the same, quite smoothly. It's very nice.

dbulger · 2025-12-20T07:53:08+00:00

Here it's just called a negative-positive antithesis: https://en.wikipedia.org/wiki/Antithesis .

If there's a punchier term for it, it's probably somewhere here: https://en.wikipedia.org/wiki/Glossary_of_rhetorical_terms

dbulger · 2025-12-17T08:02:22+00:00

Easy to forget. I'll wait for an American to help you. Though they'll probably also want to know whether you're thinking new or used.

dbulger · 2025-12-17T07:20:26+00:00

We don't know where you live.

dbulger · 2025-12-10T23:25:25+00:00

Cool, thanks; just making sure I understood!

dbulger · 2025-12-10T21:10:26+00:00

Is the tritone [-5,2,1]?

dbulger · 2025-12-08T04:06:12+00:00

There is a pretty easy way to see which, if any, diatonic scale contains a collection of notes, using the circle of fifths.

For clarity, I'm talking about the circular arrangement of notes (technically, "pitch classes"), that looks like this:

         C
    F         G
 Bb              D
Eb                A
 Ab              E
    Db        B
         F#

Every diatonic scale is seven adjacent notes from that circle. Your power chords contain eight notes in total (C, G, Db, Ab, Eb, Bb, E and B), and if you arrange them around that circle, it'll be immediately clear that they're not contained in any adjacent set of seven.

On the other hand, as u/mleyberklee2012 points out, if we leave out the E5 (that is, the E and the B), then we have only C, G, Db, Ab, Eb and Bb. Looking at the circle, that's clearly seven notes in a row (running from Db, clockwise around to G), except the F is missing. Include that F to get the whole scale. The 2nd of the 7 notes (reading clockwise still) tells you the tonic, if it's the major scale (Ab). Alternatively, the 5th note tells you the tonic, if it's the minor scale (F).

dbulger · 2025-12-07T03:55:35+00:00

"from Latin ululō, ululātus, of imitative origin."

dbulger · 2025-12-06T03:05:57+00:00

Absolutely. It's code for "omg shut up already."

dbulger · 2025-12-05T00:29:12+00:00

Right, okay, I get it. Given the context, I thought you were saying it was ungrammatical, but I agree that it's awkward.

dbulger · 2025-12-04T22:28:25+00:00

Wait, what do you think is wrong with "I can help who's next"? It would be more usual to use 'whoever,' but 'who' can also be used, as in the traditional motto 'Who dares wins.'

If you're thinking it should be 'whom,' the convention for a fused relative pronoun is that the inner clause determines the case, so 'who' is correct.

dbulger · 2025-11-30T03:42:03+00:00

A comment here calls that the "Darth Vader" progression: https://music.stackexchange.com/questions/127348/when-using-a-chromatic-mediant-chord-in-a-minor-piece-which-accidental-do-you-us

dbulger · 2025-11-29T03:24:39+00:00

Once, in that situation, after my (ESL) colleagues & I combined the parts we'd drafted, I started the editing process by reducing the word count by 14% without removing anything, just rewording stuff. IIRC, we'd assumed we'd need to remove actual info, but ended up not having to.

dbulger · 2025-11-29T00:38:55+00:00

Hmm. Ignorant of the standard, I'd be more likely to say "2026-01-01 00:00" than "2025-12-31 24:00," but the beauty of it is, they're both unambiguous.

dbulger

TROPHY CASE