Talk:Radial velocity

relative to Earth or Sun

It is not clear to this naive how the Earth's orbit is accounted for. I assume the radial velocity is relative to the Sun even though the measurements are made from Earth. 103.227.170.9 (talk) 03:15, 22 September 2014 (UTC)103.227.170.9

wrong animation

the animation File:Planet reflex 200.gif isnt the right one to correctly show radial velocity. the right animation would show the shifting spectral lines.[1] -- 99.233.186.4 (talk) 00:56, 27 October 2009 (UTC)

Moon

It was written "For the figure on the right, the radial velocity of the moon is 0 because the distance between the moon and Earth does not change". Is that true? --Email4mobile (talk) 10:49, 4 April 2010 (UTC)

Disambiguation Header

I've added the header because some texbooks use radial velocity to refer to angular velocity, and I myself was confused. — Preceding unsigned comment added by Hacky (talk • contribs) 03:32, 5 February 2012 (UTC) Actually, I'm the only one confused here. Never mind about the header. Carry on --hacky (talk) 03:40, 5 February 2012 (UTC)

"cohemispherical" is not a common term

I'm not sure if user:Fgnievinski was making up the term "cohemispherical" or if they had a source, but this is not a standard term, or even an unusual-but-known term. I can find precisely one source using it in this sense in Google scholar, and that source spells it "co-hemispherical" and just applies the term in passing without defining it (a small handful of others use "cohemispherical" to mean something different). I find precisely zero Google scholar results for "cohemispherical vector" or "cohemispherical direction". I don't think Wikipedia should be either coining new words or adopting extremely obscure words and authoritatively suggesting they are standard. user:Fgnievinski: Please just describe what you mean explicitly in the text (e.g. "two vectors with positive dot product") instead of leaning on such an obscure term. I would also recommend deleting the newly created redirect page Cohemispherical direction. –jacobolus (t) 07:14, 4 September 2023 (UTC)

I thought one source was sufficient to avoid WP:OR. But I agree it's not a common term, so I've requested the speedy deletion of the objectionable redirect. I've also rewritten the radial speed's sign definition in a longer form. I'd be curious if a a similar concept is known under a different name elsewhere; it seems related to Orientability. fgnievinski (talk) 07:31, 4 September 2023 (UTC)

Thanks.

Personally, I don't mind if some claim in an article is made with one source, but it seems like too much to start defining terms that aren't ever defined elsewhere: it seems likely to confuse readers. (I'm also not convinced this particular name is especially obvious or natural. I wouldn't mind if someone wants to talk about e.g. a "set of co-hemispherical points" on a sphere; then the word is just being applied as a description, rather than as new jargon, and I think readers would understand the intended meaning [i.e. points that are all within a single hemisphere] from context. But "co-hemispherical vectors" is a couple of hops of abstraction away.) –jacobolus (t) 08:44, 4 September 2023 (UTC)

It seems "obtuse directions" (or "obtuse vectors") -- meaning non-cohemispherical, after obtuse angle -- is a far more common term: [2] [3]. Would you object to the creation of such redirects? They represent useful concepts. fgnievinski (talk) 08:02, 4 September 2023 (UTC)

These do not seem common either. Each has only a handful of sources, and some of those look irrelevant ("There are notable discussions on the intentionally obtuse directions used in Las Vegas," "Because the [musical] chords are going by so fast and they're going in such weird, obtuse directions," "Conversation might tum from local gossip to philosophy, sometimes wandering in obtuse directions", etc.). Why do you feel a need to add definitions and create redirects for terms nobody is looking for? represent useful concepts – on its face this claim seems contradicted by the evidence. But we should leave it to the "marketplace of ideas" to come up with a name for this and wait to add it to Wikipedia until it is in common currency or at least until there are some secondary sources clearly defining it. –jacobolus (t) 08:47, 4 September 2023 (UTC)

Formulation edits

The recent edits to the "Formulation" section, to me, seems to reduce readability. The inclusion of the non mathematical acronym "LOS" also conflicts with the original intent of a pure mathematical derivation with minimal superfluous terms. Quirian (talk) 07:23, 21 April 2024 (UTC)