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> Not to be confused with gravitational waves from massive stellar bodies, [gravity waves] are an atmospheric phenomenon when a packet of air rises and falls du
by colanderman 2y ago
> Not to be confused with gravitational waves from massive stellar bodies, [gravity waves] are an atmospheric phenomenon when a packet of air rises and falls due to variations in buoyancy.
For those similarly confused by the title as I.
- stronglikedan 2y agoI used to thing programmers were bad a naming things until I became interested in physics.
- DiggyJohnson 2y agoRelated to this discussion, astronomers’ usage of ‘metal’ is a fun example.
- hamilyon2 2y agoAnd musicians!
- dylan604 2y agoSalts in chemistry too
- dmoy 2y ago"it can't be that bad, can it?" > astronomers use the word metals as convenient shorthand for all elements except hydrogen and helium what, ok
- kadoban 2y agoYeah, fun, right? I've looked up why before, tldr it's just because historically astronomers have never had to care in any detail about chemical reactions (this is not strictly true of course, but somewhat close for at least a large subset). So they just need a term for "crap that came from stars".
- adastra22 2y agoEh, that grosses over the defining difference that hydrogen, helium, and a little bit of lithium are everywhere everywhen all at once because of The Bog Bang, whereas everything else is concentrated due to being produced in supernovas and neutron stars.
- wavemode 2y agoReminds me of: https://xkcd.com/2205/ https://xkcd.com/2205/
- dataflow 2y agoIsn't there predicted to be liquid metallic hydrogen in Jupiter's core?
- danparsonson 2y agoMetallic as an adjective, behaving like a metal - due to the insane pressures. Different usage of the word "metal".
- TeMPOraL 2y agoSo for astronomers, metallic means "behaving like everything else other than hydrogen and helium". In fact, I'm guessing "metal" (noun) came from use of "metallic" (adjective). The mention of helium betrays it - helium is what hydrogen behaves like normally "due to the insane pressures" (and heat), so what it basically says is just "not hydrogen".
- Sharlin 2y ago"Metal" to astronomers simply means "non-primordial". As in, not created by the primordial nucleosynthesis.
- layer8 2y agoTo keep on topic, that makes Earth's and Mars' atmospheres consist of metals.
- cjfd 2y agoHydrogen can be a metal too. https://en.wikipedia.org/wiki/Metallic_hydrogen https://en.wikipedia.org/wiki/Metallic_hydrogen
- Sharlin 2y agoPoint is, not in the astrophycisists’ use of the word (and not really in any other use either – metallic hydrogen is not a metal, just behaves in some aspects like metal). To astrophysicists, hydrogen is not a metal by definition, which is literally "everything except hydrogen and helium". No matter how exotic a phase. Nb. The subset of astronomers who call everything after helium "metals" is mostly disjoint from the subset that’s interested in gas giant interiors.
- bane 2y agoWait until you spend time learning probability, or worse, biology.
- andrewflnr 2y agoWorse than math, where set theory, type theory, group theory, and category theory all exist and refer to barely-related things?
- lucasoshiro 2y agoI really can't see why they are called categories... Do we have anything that we categorize and get categories from it? Looks like another synonym to "set" and "group" that wasn't used so far.
- AnimalMuppet 2y agoSo in a thread about Mars's atmosphere, we wind up at category theory. Never change, HN, never change.
- andrewflnr 2y ago[dead]
- TeMPOraL 2y agoReminds me of that article[0] that says the trebuchet is a gravity weapon. That's because it's the gravity that does both the launching and the dropping. With some interesting consequences that sort of justify calling it that. -- [0] - https://michaeldominik.substack.com/p/physics-rediscovered-interlude-my https://michaeldominik.substack.com/p/physics-rediscovered-i...
- erkt 2y agoI am cynical but, I am pretty sure the ambiguity was intentional
- NotYourLawyer 2y agoSeriously, what a dumb title. Anybody who knows what gravity waves are is gonna read it and go “what?? no.”
- pfdietz 2y agoYou are confusing gravity waves and gravitational waves. Gravity waves are waves where the restoring force on some medium comes from gravity. Waves you see on the surface of water, for example, are gravity waves.
- deleted 2y ago[deleted]
- NotYourLawyer 2y agoOk, that’s a good point. But gravity wave is commonly used as shorthand for gravitational wave.
- pfdietz 2y agoBut not in this case, so your criticism was unwarranted.
- farts_mckensy 2y agoNo. It's your criticism that is unwarranted.
- pfdietz 2y agoYou're totally onboard with the scurrilous "dumb title" slur?
- farts_mckensy 2y agoYeah I love slurs
- divbzero 2y agoOne type of gravity waves can be seen on Earth where its atmosphere meets large bodies of water. These are commonly known as ocean waves.