> 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 278 days ago [-]
I used to thing programmers were bad a naming things until I became interested in physics.
DiggyJohnson 278 days ago [-]
Related to this discussion, astronomers’ usage of ‘metal’ is a fun example.
dmoy 278 days 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
layer8 278 days ago [-]
To keep on topic, that makes Earth's and Mars' atmospheres consist of metals.
kadoban 278 days ago [-]
Yeah, 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".
Eh, 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.
dataflow 278 days ago [-]
Isn't there predicted to be liquid metallic hydrogen in Jupiter's core?
danparsonson 278 days ago [-]
Metallic as an adjective, behaving like a metal - due to the insane pressures. Different usage of the word "metal".
TeMPOraL 278 days ago [-]
So 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 278 days ago [-]
"Metal" to astronomers simply means "non-primordial". As in, not created by the primordial nucleosynthesis.
Point 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.
dylan604 278 days ago [-]
Salts in chemistry too
hamilyon2 278 days ago [-]
And musicians!
TeMPOraL 278 days ago [-]
Reminds 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.
Worse than math, where set theory, type theory, group theory, and category theory all exist and refer to barely-related things?
lucasoshiro 278 days ago [-]
I 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 278 days ago [-]
So in a thread about Mars's atmosphere, we wind up at category theory.
Never change, HN, never change.
andrewflnr 278 days ago [-]
[dead]
bane 278 days ago [-]
Wait until you spend time learning probability, or worse, biology.
divbzero 278 days ago [-]
One type of gravity waves can be seen on Earth where its atmosphere meets large bodies of water. These are commonly known as ocean waves.
erkt 278 days ago [-]
I am cynical but, I am pretty sure the ambiguity was intentional
NotYourLawyer 278 days ago [-]
Seriously, what a dumb title. Anybody who knows what gravity waves are is gonna read it and go “what?? no.”
pfdietz 278 days ago [-]
You 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.
278 days ago [-]
NotYourLawyer 278 days ago [-]
Ok, that’s a good point. But gravity wave is commonly used as shorthand for gravitational wave.
pfdietz 277 days ago [-]
But not in this case, so your criticism was unwarranted.
farts_mckensy 277 days ago [-]
No. It's your criticism that is unwarranted.
pfdietz 277 days ago [-]
You're totally onboard with the scurrilous "dumb title" slur?
For those similarly confused by the title as I.
> astronomers use the word metals as convenient shorthand for all elements except hydrogen and helium
what, ok
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".
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".
Nb. The subset of astronomers who call everything after helium "metals" is mostly disjoint from the subset that’s interested in gas giant interiors.
With some interesting consequences that sort of justify calling it that.
--
[0] - https://michaeldominik.substack.com/p/physics-rediscovered-i...
Never change, HN, never change.
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.