I guess I should modify my simplistic claim, which reflects generally accepted traditional beliefs about total information loss in a black hole. Those interested in reading more can refer to this discussion of the black hole information paradox, although frankly it makes my head hurt. Briefly, there’s hypothetically (and very controversially) something called the Page curve governing black hole evaporation as a consequence of Hawking radiation, which suggests that at about the halfway point of such black hole evaporation (which for realistic black holes would be on the order of trillions of years) the Hawking radiation starts to become increasingly correlated with the putative information content inside the black hole.
FWIW, this strikes me as being more math than physics, forever untestable, eternally elusive and immune to any actual evidence.
“Moment”, in physics, is a lot broader concept than “dipole moment” specifically, and it’s consistent in its meaning across many different concepts. It’s not particularly related to the “short time” meaning, though I’m not actually sure which came first.
“Helium” was discovered (spectroscopically) in the Sun, and named for the Greek sun god Helios; the “-ium” ending means ‘thing’ or ‘stuff’. So far, so good.
Then they discovered other noble gas elements, and gave them all names that end in “-on”, also meaning ‘thing’. They should’ve named the heavier noble gases “-ium”, to match the first one, or gone back and changed helium to match the emerging convention.
The reasoning I heard is that the force from the sun’s gravity on the moon is greater than that of the Earth and thus the moon’s orbit is never concave wrt the sun. But I think this is just rationalisation, and the real reason is that the moon is large compared to the body it orbits.
Okay, those are cool names. But every language can have its own name, so ‘Eurocentricity’ hardly seems like a reasonable criticism.
Worst named scientific concepts:
‘cold-blooded’ - not actually cold, means their body temperature depends on the environment rather than being internally controlled.
‘survival of the fittest’ - makes it sound like being fit and strong is what matters for evolution, rather than whatever animal is best adapted.
‘organic chemistry’ - probably the fault of marketers, but it sounds like it’s related to organic food, and that’s a whole other kettle of worms.
‘quantum leap’ - sounds like a big change, rather than just a discontinuous one.
Both of these are perfectly good names that subsequently got abused by people who had no clue what they were talking about. Blame the clueless people, not the scientists.
“Butterfly effect” - does it mean “a butterfly flaps its wings and causes a hurricane halfway across the world,” or “someone steps on a butterfly and alters the course of history à la ‘A Sound of Thunder’”? Who knows? Who cares? Call it something else!
(1) “Any of various functions describing torsional effects, generally having the form of the product of a force and a distance; spec. the turning effect produced by a force.” – first quotation from 1830
(2) “The distance between the two poles of a simple bar magnet, or the two charges of an electric dipole, multiplied by the strength of either pole, as a measure of the turning effect produced by an applied magnetic or electric field, respectively.” – first quotation from 1865
However the more common “short time” meaning is much older:
(3) “A very short period or extent of time, esp. one too brief for its duration to be significant; a point in time, an instant.” – first quotation from 1382
(4) “A period of time (not necessarily brief) marked by a particular quality of experience or by a memorable event.” – first quotation also from 1382
Kind of the latter but it is indeed popularly taken to mean either:
The energy of the butterly flapping its wings grows into a hurricane
This butterfly might be special in some way, and lead to an improbable set of events, but most small things don’t affect anything
…neither of which is true. (Or at least the second totally misses the point but might happen to be (unknowably) true for a given time boundary)
In fact “chaos theory” in general is misleading. AIUI, someone can correct me if I’m wrong, but I think it only makes sense to talk about chaotic behaviour in deterministic systems. So it is not really random in the way people imagine.
I can’t think of a better name for it, maybe it’s one of those where just taking someone’s surname would have been better.
Determinism means that if you had perfect information, you could make perfect predictions. This remains true in chaos theory.
What determinism does not mean is that with almost-perfect information, you could make almost-perfect predictions. This is where chaos theory comes in. In a chaotic system, after some amount of time (probably shorter than you’d think), even almost-perfect information helps you almost not at all in making predictions. Where the proverbial butterfly comes in is that even a deviation as slight as not accounting for the flapping of a single butterfly’s wings might be enough that you can’t make any meaningful predictions.
'Zactly. Pre chaos, the assumption was you could. Chaos shows you can’t. But that doesn’t correspond to the conventional colloquial meaning of “chaos” as utterly unpredictable Calvinball where literally anything might happen.
The frontier of tight predictability collapses very, very soon. As you rightly say. The point of attractors is the general possibility space remains probabilistically bounded even as specific trajectories through it remain incomputable.
Weather is unpredictable past a few days. But surface temps being below 150F remain fully absolutely positively completely predictable nonetheless.
At least in 2025. Ask me a liitle later about the year 2225.
Well, yes, but things that we think of as random aren’t “really random” either. If I try to roll a pair of dice in the same way twice, they’ll probably come up different, not because the dice rolls aren’t subject to deterministic laws, but because they’re so sensitive to small changes in the initial conditions of the roll—which is a key feature of chaos theory.
Sure, but I was just saying that “chaotic” behaviour is about deterministic systems.
Whether our universe includes actual random events is debatable. As I tentatively understand it, events like the timing of an unstable nucleus releasing an alpha particle are necessarily unpredictable, and not for the reason that chaotic systems are unpredictable, so meet at least some of the definitions of random.
…and I’ll leave it there because probably I’ve already gone wrong.
