Time derivatives!
- Rate of change in position is called velocity
- Rate of change in velocity is called acceleration
- Rate of change in acceleration is called jerk
- Rate of change in jerk is called snap
- Rate of change in snap is called crackle
- Rate of change in crackle is called pop
And if I recall correctly
- Rate of change in pop is called lock
- Rate of change in lock is called drop
When the fuck could those possibly be useful? 😆🙃
Not sure about anything past crackle, but minimum snap trajectory is widely used in efficient path planning for quadcopters.
IIRC the James Webb had/has max snap, crackle and pop tolerances. Not sure about these two.
I can’t even comprehend what something beyond jerk means in reality or how to even produce it by physical means
Well these are higher order derivatives, so they do have physical meaning but the latter ones are increasingly abstract and subtle from our normal earthly perspective.
If you think of a stable and perfectly circular orbit, that’s a steady and constant acceleration. Then if you thrust to make it elliptical, you’re changing the acceleration which can be measured as jerk. But then if that thrust itself is variable, you can measure its changes as snap. And then of course the rate of how much you change that is crackle, and so on.
If I was working with those concepts, I’d just start using numbers.
Like, acceleration is v2, jerk is v3, and so on.
These are n th order mathematical derivatives so I’m pretty sure physicists do something very similar to that whenever n matters.
Getting them just right is important for driverless cars learning to brake in a way that feels comfortable to humans
They aren’t useful. It is just scientists memeing. Any research that involves anything past jerk would be esoteric.
In aerodynamics I guess
This explains the sounds when I move to get up, these days.
Is it snap? You might have to slow down your rate of jerk
I hope it’s not it Canonical might sue them.
Snap crackle pop and Bob’s your uncle, easy peasy
Wait, what. 🤩
Don’t forget jitter, now!
Which one is jitter?
Jitter is a technical term for latency variations between Internet packets over time.
High jitter is bad for VoIP and online gaming and potentially streaming if the jitter is caused by packet loss and retransmits.
None of those, but I think a series of irregular jerks could be considered jitter.
So trump, elon and hegseth form a jitter?
I only know jitter as irregularity in data flow (e.g. network packets).
Jerk is sometimes called jolt though. Both terms seem fitting to me. Supposedly in roller coaster design, having too much jerk/jolt can be quite unpleasant for riders. Which kind of makes sense, if the acceleration varies too wildly I could see that making me sick.
I only know jitter from electronics as well, but it could be applied in mechanics as well. Iirc, jitter is the irregularities in the intervals in a periodic signal, like data transfer. But jitter will be present in anything with a period, it doesn’t have to be digital signal. A jerk is a single action, so there is no period and there can be no jitter. A series of jerks could have a seemingly regular period, but when measured more accurately, the intervals between jerks will have small variances: jitter. Hence why imo a series of irregular jerks could be considered jittery.
Noone ever uses it that way though and I’m not even sure that I phrased it correctly, but because of the word “jerk” I find it a mildly fun play on words.
There’s 10⁹ living cells in a gram of surface soil, and in 20 km depth that reduces to 10⁶ cells per gram, but they’re still alive and actively metabolizing down there! eating rock, mmhm tasty rock oh yeah! :p
they have cell turnover rates of hundreds of years though, so they age very slowly and multiply very slowly due to energy shortage.
Life uhh… find a way.
I wonder if they ever check samples from like meteors, asteroids or moon rocks for evidence of that kind of organism.
Yes, it’s done often.
Thank you for posting that, i had no idea
If you took all the DNA from every cell of one person and laid it in a straight line they would die
Relevant xkcd: How long would you survive with no DNA?
There a more hydrogen atoms in a single molecule of water, than there are stars in the entire solar system.
Told that joke to my daughter. Didn’t understand it. Fine, hydrogen, atoms molecules… thought one for a 10 y/o with no particular interest in science.
But then I asked how many stars our solar system had.
Answer: “I don’t know”
Asked with emphasis on “our solar system”.
Answer: “Infiite number of stars”
Asked how many stars are in out living room
Answer: “Zero”
Asked how many stars are on our planet
Answer: “Zero”
Me thinking we are on track and that she understood the scoping error in her first assessment asking the original question again with emphasis on sun (in german its sonnensystem, I.e. sun system, so it makes sense)
Answer: “Zero”
Lovely seeing extrapolation in real live.
I’m sorry, you are raising an AI.
Good one
Heehee, you’re clever.
At least read the top comment before you write the exact same thing.
Sorry I don’t have it sorted by top :p
Fundamentally everything and everyone, even nothing, is made of the same fields of invisible…stuff. We can measure them in very accurate detail. We are all connected. We are all ripples and waves in those fields. Everything is. If only you could see the entire spectrum of light, you would see one of those fields.
All I can see when I look in your eyes are the waves of love that connect us.
Apt username
E: Invalid operation username
Blue birds fly beyond the rainbow, why oh why can’t I?
It’s like no matter what we do we will go extinct
Male ducks have a corkscrew penis almost as long as their body. Female ducks have vaginas that corkscrew in the opposite direction, with false endings. Ducks do not have consent, so nature found a way.
The rape labyrinth
Trump branded hedge maze
Does the male spin his body around in an impossible way until he’s fully inserted? Or does he just shove it straight in, painfully eviscerating her?
Even better! They just kinda fire out and expand like a balloon you’d use for a balloon animal.
Wait…m have you never seen the spinning ducks on the lake before?
Well those would have gone on my bucket list, but then towards the end, as I was searching for them to name the chemical responsible;
He and his team are still trying to identify the chemical compound responsible for the hallucinations in L. asiatica. Current tests suggest it is not likely related to any other known psychedelic compound. For one, the trips it produces are unusually long, commonly lasting one to three days after an onset of 12 to 24 hours, and in some cases even causing hospital stays of up to a week. Because of the extraordinarily long duration of these trips and the chance for prolonged side effects such as delirium and dizziness, Domnauer has yet to try the raw mushrooms himself.
A few days to a week? I’m very much reconsidering.
Snakes have two dicks.
“Hemipenis”
See also: Brodozer and Pavement Princess.
I mean… Everyone who’s scrolled on e621 for 2 mins knows this
So there are two mes inside me. One of them looked up what that is and then promptly told the other me not to.
Like a… bifurcated one similar to their tongue or they have two in different parts of their body? And do females also have two holes? Are snake threesomes a thing?
So many questions!
If snake make male and female both had 2 genitals, you could create an infinite sex chain.
They’re Klingons?
Clouds.
- polar stratospheric clouds play an important role in creating the ozone hole
- the highest clouds on earth are about 80 km high
- in the mid-latitudes most rain is cold rain, that means it leaves the clouds as ice and melts on the way down
- pure water droplets without an aerosol inside (cloud condensation nucleus) freeze at about -40°C, sea salt aerosols make cloud droplets freeze at about -38°C, …
And there’s much more to be found.
98.62% of the uranium-235 in the Little Boy bomb was blown apart before fission. That leaves 1.38% that actually fissioned. That was 0.7 grams of U-235, about the size of a bb and the weight of a butterfly that destroyed Hiroshima.
There’s more ships in the ocean by weight than there’s fish.
[edit]
See my other comment below, probably more accurate to say the total weight of all ships is around the same as the total weight of all ocean fish.
And there’s far more biomass of farm animals than what we’d usually think of as “wildlife”.
Human chemical plants now do most of the nitrogen fixation in the nitrogen cycle, too.
Humans have taken over the biosphere.
There are more aeroplanes in the ocean than ships in the sky.
By how much?
(And how do we know this?)
From an old XKCD What-If, which put it at 2.15 gigatons ships vs 2 gigatons fish. But that uses quite old numbers.
Looking at up to date data from the UN there’s 2.4 gigatons of ships. Note that this is dead-weight tonnage, so fully loaded. Empty is probably more like ~0.5 gigatons, so it’d depend on how fully loaded the ships are.
And a quick search turns up this paper which references several estimates for fish biomass form other papers, which would put fish biomass somewhere between 0.4 and 4.9 gigatons depending on estimate.
So I put it too strongly saying “more”, it’d be more accurate to say fish biomass and ship mass is within the same order of magnitude. Also note that it’s only fish, not like plankton, shrimp, etc.
Biologist: “define what you mean by ‘fish’.”
ducksandruns sorrynotsorry
https://medium.com/illumination/there-is-no-such-thing-as-a-fish-eca048dd6163
Not every category of animal has to be based on phylogeny, you freak!
JK, love you! /puts on Clint’s Reptiles.
Pluto is smaller than RussiaEdit: this fact seems to rely on a contested measurement for pluto. I guess it would still be true if we look at volume but that’s kinda weird.
What
Edit : apparently, counting surface areas, it’s wrong, but by surprisingly little
Maybe the factoid first became popular when the USSR existed
I see 17 million sq km for Russia, and 16 million sq km for Pluto.
Idk I saw something like 17.1 for Russia and 17.4 for Pluto
Yeah it seems that Pluto got bigger since I learned this fact, and AI summary is also out dated
Edit to add: I hope it’s obvious I meant our estimate of the surface area of Pluto increased, not that I think Pluto is growing.
Out of curiosity, if they had Ukraine–would they then surpass it?
80% of the neurons in your brain are in your cerebellum
On average the universe is empty space.
The Milky Way and Andromeda are on a direct collision course and in all probability there won’t be a single star collision at least on the first pass.
I’m sure you’re also referring to empty atoms too heh
Entropy is a record of everything that’s ever happened in the universe. The units for it are Joules per Kelvin.
How did you come upon this interpretation?
That’s an interpretation from physics in the context of information theory. Leonard Susskind’s Black Hole War explains some of these concepts, and I researched it further for a project getting my B.S. in physics. It’s been a while but I’ll do my best to break it down.
Imagine that a murder has happened and the murderer wants to cover up the crime. The gun and body contain physical information that the cops could use to reconstruct the murder, so the killer throws them in the river.
Why is the river useful to the killer? Because it’s a chaotic (entropic) system that contains a bunch of particles doing all sorts of things. The information contained in the gun isn’t actually lost or destroyed, it’s just made harder to access by mixing it with this “junk” information. Likewise, the blood of the body mixes with with the water and is diluted to the point of being impossible to find, but the it isn’t actually destroyed, it’s just mixed in.
Suppose we could freeze time and examine that river down to the particle level. If we found a single particle of blood, we could look at it’s position and momentum, and that of every particle it interacted with, and we could trace it all the way back to the body (this might be easier to understand if instead of a river, we say the water is crystal clear and uniform). Obviously, this isn’t something that could be done feasibly, but theoretically, there’s no reason you couldn’t put Humpty Dumpty together again.
When you put two liquids in a flask and shake it, the information of precisely how you shook it is contained in the particles in that liquid. Every particle now has a story: before, they were sitting around with all their particle friends but then the shake happened and everyone wound up in a slightly different location because of the precise way that the shake affected them as opposed to their neighbors. The information about the shake is there in the particles in the flask.
To say that a system is more entropic is to say that more physical events have happened in that system. The particles become more dispersed because more things have happened to them leaving behind physical impressions that become harder and harder to trace back as the amount of things that have happened to that system increase, because there’s more information to sort out. This is where we can think of entropy as “a record of everything that’s ever happened.”
Still with me? Ready for extra credit?
Can physical information ever actually be destroyed, erased from the universe entirely, as opposed to just being scrambled? That’s the question at the heart of one of the biggest unresolved paradocies in the modern understanding of physics: The Black Hole Information Paradox.
If you commit a murder on a spaceship and then fly that spaceship into a black hole, is there any way, even theoretically, to recover the information of what happened on that spaceship? Has the information merely been scrambled like the body in the river, or is it truly destroyed and erased from the universe entirely? If it is just scrambled, then where is that information contained?
This is what Susskind’s book I mentioned before is all about. Stephen Hawking once maintained that the information was completely erased, while Susskind argued that this was incompatible with quantum mechanics and the second law of theromodynamics, that by erasing information, entropy was being decreased in a closed system. Hawking later changed his position and conceded that he’d been mistaken. Today, it’s believed that the information is scrambled, but what nobody knows is where the information is contained, and every proposed solution seems to contradict some fundamental aspect of our understanding of physics.
what nobody knows is where the information is contained
I expect such musings to be an affront to the other fellow who commented to answer my question by saying that
information is conserved microscopically and not macroscopicallybut, if you’ll hear me out, has anybody looked into the possibility that the amount information retained by the … carrier … about some specific event approaches zero as it undergoes more interactions and acquires new state/information pertaining other events? That is, the system retains everything, but no single part holds a non-increasingly negligible trace. So while, theoretically, you could hunt down participants in all of its interactions and deduce meaningful evidence about its history, the technical act of doing so is practically impossible because the problem of discernment grows with the age of every other carrier within some volume; making it intractable or, at least, wasteful to the extent possible. Could this agree with what is usually meant by “entropy tending to disorder”?All that said, I often think this way of speaking of entropy is somewhat unhelpful in that there are many forms of entropy and not all should obey the second law. Some are constants, others vary with measurement, most are mutually unrelated, and some are in disguise. Take position entropy. One way to look at it is to see how many things are in the universe at different locations; if you count all that up you have a measurement (aka volume); maybe divide by the number of things for comparability’s sake and would you look at that? It’s density. Another chap chimes in saying something to the effect of “can’t fool me, position entropy’s just ħ/2Δp summed over all event participants”. Call me pedantic, but it’s not obvious that these measurements must agree; but they’re both physically and thermodynamically significant. Honestly, i really don’t know, but when i look at the 2nd law, i really wonder if that’s the whole picture. Does entropy really contain history or is it just a byproduct of the generation of information?
So while, theoretically, you could hunt down participants in all of its interactions and deduce meaningful evidence about its history, the technical act of doing so is practically impossible because the problem of discernment grows with the age of every other carrier within some volume; making it intractable or, at least, wasteful to the extent possible.
When we’re talking about things like following blood particles back through a river, we have fully left behind the realm of practicality and wastefulness. Information can be scrambled well beyond the point of making recovery feasible, but we’re talking about whether it theoretically exists.
One way to look at it is where the “cut-off” point would be. While the blood is streaming away from the body, we can see exactly where it’s coming from. What makes us lose track of it are the limitations of our instruments.
If you can find a trace of blood and reconstruct where it was even a second ago, then there’s no reason (apart from the practical ones) you couldn’t repeat that process and get the location a second before that, and so on.
All that said, I often think this way of speaking of entropy is somewhat unhelpful in that there are many forms of entropy and not all should obey the second law.
I don’t think there’s any way of getting around the second law, period.
Take position entropy. One way to look at it is to see how many things are in the universe at different locations; if you count all that up you have a measurement (aka volume); maybe divide by the number of things for comparability’s sake and would you look at that? It’s density. Another chap chimes in saying something to the effect of “can’t fool me, position entropy’s just ħ/2Δp summed over all event participants”. Call me pedantic, but it’s not obvious that these measurements must agree
Ngl, you lost me. Like I said, I’m rusty with this stuff.
Wild guess, as not-OP: Information is conserved at the microscopic level, while it’s really not macroscopically, and entropy is (the logarithm of) the missing piece. Ergo, it contains a record of everything that’s happened that’s no longer directly visible.
Which honestly says more about what temperature is than about entropy or information. (It can be defined as energy per entropy)
