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12:16 AM
Refering to the discussion "Does helium ionization process release energy?" physics.stackexchange.com/questions/491850/…
Can anyone confirm his claim that n leq 23 from a 90 degree bend radius? I cannot confirm his result from any of my calculations
1 hour later…
1:48 AM
Conductor can be insulator in high frequency. Can someone give some reference?
2 hours later…
3:53 AM
@CangYe hi :-)
I'm in the UK so when you posted it was 1 a.m. for me :-)
I'm generally around from 04:00 to 12:00 UTC (05:00 to 13:00 UK time)
waiting to hear back from an instructor application: stressful
writing the reply email when they say they're interested: somehow even more stressful
^ but exciting
@JohnRennie hi.
@Nobodyrecognizeable hi :-)
4:33 AM
@JohnRennie you're up early
@RyanUnger I get up about 5 a.m. (it's currently 05:34 in the UK). How quickly I get to the chat room depends on how zombified I am :-)
2 hours later…
6:38 AM
@JohnRennie that's often when I go to bed these days.
A Nordic country would reply you who fills that position you apply for and have a time period when you can repeal.
But they only tell you the name of that position winner, so how can you find information to repeal?
@CaptainBohemian when I was a student I would stay up late and get up late, just like you. Over the years I've gradually shifted earlier and earlier. I still sleep for the same number of hours, I've just shifted them to earlier in the day.
last morning close to 5 am I went out to try the luck of capturing the view of partial lunar eclipse though I think it's very unlikely to catch the eclipsed moon whose altitude was like 3 to 4 degrees. Indeed, I can't see the moon at all. The buildings around are so high that it seems unlikely to see a celestial object at so low altitude. I keep wanting to see Mercury but seem to have not had that luck.
7:11 AM
the night before yesterday I did saw the apparently full moon with a star-like object on its right which should be Saturn. The Earthsky says [The moon sweeps 0.2 degree south of Saturn as seen from the center of the Earth on July 16, at 7:27 UTC. From the Earth’s surface, the moon passes farther away from Saturn at more northerly latitudes, yet closer to Saturn at more southerly latitudes.]
I am in the northen latitude, but I saw the Saturn is more like to be the east, rather than south, of the moon.
8:02 AM
Can this be flagged as Not An Answer? physics.stackexchange.com/a/477405/123208
8:37 AM
Riddle me this
If I have a second order variation under a square root
Do I keep it around?
Like $\sqrt{X + \delta X + \delta X^2}$
Let's keep it around for now
$$\sqrt{X + \varepsilon f + \varepsilon^2 f^2} \approx X + \varepsilon f + \varepsilon^2 f^2$$
I guess it don't really matter
9:25 AM
Consciousness and free will are messed up...
It's like people are trying to make sense of those words, when they really don't have to
Is it so hard to realize that consciousness is us refusing to accept the fact that we are mere machines.
I believe brain and mind are one, consciousness is an illusion created by the brain. I don't know what people mean by free will at all. I mean, I believe a specific stimulus triggers specific thoughts and idea in our brains, that's it. If you now say "I can do something with my free will" and lift your left hand up, the thought to do that is trigger by the idea of showing that you have free will.
Someone woke up poetical today haha
Are we "mere machines"? How are you so sure? What would that even mean?
may your concioussness telling you you have no free will and that you are a machine is the real illusion
@Gyromagnetic What would it mean to not be mere machines? You think we have a soul?
9:40 AM
Why do you think machines do not have souls
What is a soul?
There isn't a universally accepted definition of consciousness nor free will so we have nothing to talk about :P
@NovaliumCompany depends on what you mean by "soul". I do believe that people have some degree of agency that is inaccessible to non-human things.
I lost my free will in a rollerblade accident
9:47 AM
@Slereah I'm so sorry, fast recovery buddy
I believe free will doesn't exist and our thoughts and actions are triggered by specific stimulus. The story with consciousness is a bit different because I have no idea of a formal definition of it.
I'll go take a shower and then to the beach. Brb later. Thanks everybody for being such an awesome online community.
2 hours later…
12:05 PM
The comments section here :/
12:22 PM
12:36 PM
I made a huge mistake
I looked up D-branes on nlab
Now I yearn for death
12:50 PM
I'd sooner face death than Dirichlet
I was in the bus and I was sitting backwards (in the opposite direction of movement) and I thought that what I see represents the past, what I don't see (behind me) is the future. The bus was travelling in the direction of time. The vehicles around that moved faster, went forward in time and therefore the analogy the faster you move, the slower time flies for others.
Good morning/afternoon/night for everyone!

The Schrödinger's equation is a Wave equation or a Diffusion equation? I've had a discussion with some friends last month and this particular point confused me a bit.
1:22 PM
If I have a definite integral of a distance(x)-time(t) graph, the integral will be of v(t) dt right? Also does the integral tell us the whole x distance in meters?
@Slereah 'An abstractly defined n-dimensional quantum field theory is a consistent assignment of state-space and correlators to n-dimensional cobordisms...' what a joke
nlab does love its cobordisms
1:40 PM
@bolbteppa do you not like math?
I do, but this perspective is simply an abomination :p
2:20 PM
University prepared me poorly to do actual Lagrangian mechanics, rly
I'd have to check my old notebooks but I'm pretty sure most of the math was thrown under the bus
@Slereah what don’t you know
Now I'm mostly alright
but variations were very poorly explained
Also basically nothing on boundary issues
2:40 PM
Apr 4 at 16:47, by PM 2Ring
I like the attitude of the Discworld trolls: we're actually traveling backwards through time, because we can see where we've been, but not where we're going. ;)
@PM2Ring The troll who came up with that must have been at a fairly low temperature.
@JMac True, but I get the impression that it's ancient troll wisdom, from when they all lived in the cold regions near the Hub.
By the way, I've been making good progress on the AM Nightwatch series. I'm already up to the Fifth Elephant. Not many other books can make me laugh out loud or gape like discworld does
Like when they were talking about putting up a new king (second book I think?) and someone goes "Which captain are you talking about?" obviously just playing off the fact that the reader is expecting Carrot, and someone else responds "Captain? I was talking about a corporal." The way he played it off had me dying.
3:10 PM
@M.N.Raia see:
Q: Connection between Schrödinger equation and heat equation

Kevin KwokIf we do the wick rotation such that τ = it, then Schrödinger equation, say of a free particle, does have the same form of heat equation. However, it is clear that it admits the wave solution so it is sensible to call it a wave equation. Whether we should treat it as a wave equation or a heat e...

Q: Schrödinger equation derivation and Diffusion equation

user56963I am aware of the debate on whether Schrödinger equation was derived or motivated. However, I have not seen this one that I describe below. Wonder if it could be relevant. If not historically but for educational purposes when introducing the equation. Suppose that we have the time dependent Sch...

@M.N.Raia maybe even the experts dont have the whole answer/ picture... o_O
@JMac Yep, that's from Men At Arms. A classic example of Pratchett's understated British humour. I'm sure you'll enjoy The Fifth Elephant. It does have some rather dark elements, and possibly less humour, but it's one of my favourite Discworld novels. Although, to be honest, it's very hard for me to choose favourites amongst them, and even ones I wasn't so impressed by on my initial reading grew on me on subsequent visits.
3:49 PM
A: How is the Schroedinger equation a wave equation?

DaniHBoth are types of wave equations because the solutions behave as you expect for "waves". However, mathematically speaking they are partial differential equations (PDE) which are not of the same type (so you expect that the class of solutions, given some boundary conditions, will present different...

4:01 PM
"Actually, a wave equation is any equation that admits wave-like solutions"
Does anyone happen to know (a way of finding) the highest Ramsey T_2 (so T_2^*) measured in a transmon? I haven't been able to track it down myself
@PM2Ring I'm fine with less outright humour. What's great about Discworld is that the humour is baked right into the world. All the absurdities about the setting and characters are pretty funny even if they deal with somewhat serious topics
4:17 PM
@RyanUnger does 0 count as a wavelike solution
Or the Dirichlet function
4:30 PM
@JMac You might want to go back soon & read some of the books that aren't in the Night Watch sequence. Maybe one of the stand-alone books like Pyramids. Or start reading the Death or Witches sequences. Personally, I love Pyramids but for some reason it has a mixed reception among hardcore fans.
@Slereah I was quoting what David Z wrote
@PM2Ring I actually just finished Reaper Man (was waiting for another audible credit to keep reading nightwatch). I'm probably going to keep going with the Death series or a standalone next.
@JMac Excellent. I think the ending of Reaper Man is one of the best of all the Discworld books.
4:47 PM
If I have a definite integral of a distance(x)-time(t) graph, the integral will be of v(t) dt right? Also does the integral tell us the whole x distance in meters (apart from the area)?
@PM2Ring Pyramids is probably about the only Discworld book in the series where I couldn't tell you off the top of my head what it's about
@NovaliumCompany No and no. The integral will be $\int x(t)\mathrm{d}t$ and doesn't really tell you anything.
@ACuriousMind So it's not about pyramids?
@JMac Also check out the Discworld annotations. The APF started life on Usenet, when Pterry was active there.
@JMac Heh. :P I meant that I couldn't tell you anything about the plot
It didn't stick well in my memory, and I've never gotten the urge to reread it as many times as most of the others
@PM2Ring Oh nice. I had heard APF mentioned but never looked into it. I like reading author annotations
4:51 PM
@NovaliumCompany Everything you said would be correct if it was a velocity-time graph.
@PM2Ring Wait is APF annotated by prachett or others?
@ACuriousMind Oh ok, thanks
@JMac Yes, it's about pyramids, and a river kingdom that bears a striking resemblance to ancient Egypt. It also features some weird spacetime stuff. But an early portion of the book is set in Ankh-Morpork and gives us a glimpse of life in the Assassins Guild.
@ACuriousMind Pyramids?
Sure, it could be a comedic novel about Ricci flow. As good as guess as any
4:56 PM
@PM2Ring It plays on the notion of "pyramid power" doesn't it?
Before I decided I was going to get into discworld I read somewhere that (of course) pratchett made that psuedoscience actually apply somewhat on the disc, so pyramids actually did something magic
@JMac By others, but in its formative days they had access to Pratchett. However, Pterry did not like to come down heavily with Word of God answers to questions, and enjoyed seeing what the fan base could discover for themselves.
@JMac Yes.
5:22 PM
I want to learn about different topics. I mean, I want to diversify my information input sources but I don't know where I can see things I can learn. I have apps like Curiosity and Google News but is this enought? I'm also planning on reading books on absolutely diverse topics.
Enough for what? If you just want random information, spending an evening clicking around Wikipedia is a good start. :P
5:44 PM
You never know what will be helpful in the future or what info will contribute to the emergence of good ideas.
@ACuriousMind how many clicks from any wiki page to Perelman
@RyanUnger You can reach Perelman from "Russia" with one click, and a lot of stuff links to Russia. Same mechanism as with Germany and Hitler, so Perelman is not harder to reach than Hitler
6:02 PM
I keep sending Hitler emails but he never responds
@Slereah lol good luck
@ACuriousMind hmm
how about Daniel Tataru
is there a wiki page which is not linked anywhere?
Where on Wikipedia can I see list of different topics? (cuz my main problem is, I don't know what to learn)
6:10 PM
@NovaliumCompany Pick a good recent survey paper and learn everything you don't understand
I can suggest a place to start
@RyanUnger Same mechanism, since he's both on "List of Romanian Americans" and "List of Romanians", which are quickly reachable once you get to any country
This is scientific papers, I want everything, as random as it gets. Not useless, random.
@ACuriousMind wtf there's a list of romanians?
Why not
@NovaliumCompany There's a "random" button on Wikipedia. If you really want to learn just anything, go nuts
6:13 PM
They just have lists of tagged pages
@ACuriousMind you mostly get random towns and people
Hope you like to learn about polish villages and russian footballers
@RyanUnger Wiki has lists of everything. And lists of lists. And a list of list of lists
Does it have a list of lists that do not contain themselves
@Slereah To be fair I've wasted hours just by reading about a random person and clicking links, reading more, etc.
@ACuriousMind this violates the Russel paradox.
Well no
List of lists is fine
6:14 PM
list of lists of lists isn't
@Slereah Yes, but trying to access it returns HTTP error code 666
@ACuriousMind ohhh yeaaaaah
@RyanUnger why nit
@ACuriousMind and also en.wikipedia.org/wiki/…! ;-)
@NovaliumCompany just start reading arxiv.org/list/math.DG/recent
6:16 PM
Just read every book ever in chronological order
Start with the epic of gilgamesh
start with the elements
@ACuriousMind ok Robert Strichartz
don't tell me there's a list of American Americans
@RyanUnger Interesting, sixdegreesofwikipedia.com constructs paths via Elias M. Stein, but the other more famous people (reachable via countries) it claims are linking to Elias M. Stein aren't (or at least I can't find the links on their pages)...
What are the two articles which are the furthest apart
I wonder
"The worst offenders were the subpages of List of named asteroids as each is only linked from the previous one, and it takes about 70 links to get from anywhere to the last one. So, you find that the two articles furthest from each other are List of asteroids/145701-145800, linked to by List of asteroids/145601-145700, linked to by List of asteroids/145501-145600, and so on for 70 links until you get back to some vageuly normal article."
@ACuriousMind what is your starting point
6:31 PM
@RyanUnger random sites
@ACuriousMind Yeah I have no idea why Stein would be on von Braun's page
I'm starting at Hitler
I think your tool is broken
getting to Stein is of course the best method
so probably France -> Fourier -> Fourier transform -> Stein
@RyanUnger how much of The Elements have you read?
Do people unironically read that 2000 yr old math book?
@skullpetrol none?
@SirCumference doubt it
yet you advise other to?
6:40 PM
he was joking (at least I think) :P
do as I say, not as I do
@ACuriousMind can you please unstar that
Why did you say it?
because it's true
I don't think it should be starred out of context
6:44 PM
Hmmm...the entire star wall is stars out of context
Then say it in context
@ACuriousMind I agree with unstarring Ryan's. We need to keep the announcement of coolmathgames alive
That's why you never say "I'm starting with Hitler" when your online account has your name attached. Hopefully "Ryan Unger" is the name of a nemesis, or at least someone you wish to slightly besmirch.
6:45 PM
@JMac Nah, his real name is just Uan Rynger
maybe I'm writing a book about dictators
@ACuriousMind Well that's a really common name, so there's not a whole lot to worry about.
sounds like an esperanto name
Uan sounds like Ian
how the hell are you pronouncing uan
6:47 PM
seems more like some sort of Juan variation to me
that's what came up on spellcheck :P
@RyanUnger I want to reqd diverse topics, not differential geometry....
differential geometry is pretty diverse
do you still watch the sopranos?
6:58 PM
Never heard of it :P
I'm from Bulgaria (although not an excuse)
7:01 PM
classic gangster series
start with Scarface :P
I'm watching A LOT of movies. Try me.
The godfather
The raging bull
After 2007
(except Matrix and Donnie Darko)
Anything after 2007 I should know.
7:10 PM
watch some classics
Don't you dare say Endgame or Harry Potter are not classics.
The difference between now movies and "classics" is video quality
Test me on after 2007
Sopranos? :P
not knowing the godfather is actually bad
@RyanUnger some mafia movie?
@skullpetrol Movie
THE mafia movie
7:17 PM
Love you 3000
Will always remember you
Tony Stark is the one who inspired me to get into acience and tech actually
I have read some of The Elements
Wikipedia randomness is pretty interesting actually
It's not bad but you're better off reading Hadamard's book on geometry
Much better book for synthetic geometry
before even that though you should probably get an intro book to higher math
to get familiar with sets, etc.
@SirCumference Yes, they do. And you can read The Elements online, eg mathcs.clarku.edu/~djoyce/java/elements/elements.html For a couple of millennia, until the mid 20th century, virtually everyone with a mathematical education studied Euclid's Elements, which gave them a solid base of shared knowledge.
7:25 PM
Synthetic geometry doesn't use set theory
It's like pure axiom stuff
Not even basic familiarity with sets?
I mean it's useful, but the Hilbert axioms work by themselves
you just need basic logic
@Slereah Sorry but nope. Everyone decides for themselves according to their goals
I decide for all
Those are the rules
welp even catching up on basic logic could be helpful. you don't get taught e.g. what if and only if means in most high schools
7:27 PM
They didn't even believe there were negative numbers back then :P
at least not in my crappy hs
@SirCumference come to bulgaria, and your school will be heaven
@PM2Ring Yeah but nowadays there are much better texts :P
It mostly is talked about in the context of history of math
Even in the early 1960s, new editions of The Elements were being published. By the time I was doing geometry in early high school in the early 1970s, there were radical reforms in mathematics education and The Elements was considered very old fashioned, but we used an older geometry textbook that closely followed The Elements.
I'm actually pretty interested in math lately. I just don't want to rig myself to accept some rules and follow them. I mean, I feel like math will make my mind less creative and more follow rules type
7:31 PM
@NovaliumCompany Math is all about creativity. More accurately, it's about taking concepts you come up with, and putting them into a rigorous form
@SirCumference I should hope so! The Elements is a bit dreary. Twenty centuries of bored students sucked almost all the life out of it. :)
Many concepts exist only because people were clever/creative enough to figure out they were useful
@PM2Ring Was it by Moise and Downs?
I want to get a bit more deep into mathematics but are there any bad effects of math (please be honest)?
"bad" in what way?
7:37 PM
Still, for a book to last as long as it did as the definitive geometry text is quite an achievement. And the usefulness of having that shared knowledge base can't be underestimated.
Also bear in mind that it was only a few centuries ago that algebra was elevated to its modern status. Before that, geometry was "proper" mathematics, and algebra was merely a bunch of helpful tricks used for solving problems which were more properly expressed in geometric terms. Thus every proof in Newton's Principia is done geometrically.
@NovaliumCompany I should be clear, there's a difference between high school math and university-level math. High school math is much more rule based and about problem solving without an explanation in the concepts
Real math requires a lot of creative thinking, and honestly changes how you think
(In a good way)
@SirCumference no use arguing with him
he's not "arguing," he's trying to persuade him...
Well I'm more or less just offering my perspective on the topic :P
I've given up
7:41 PM
It's his choice after all
high school math is not math
what is it then?
I know that high school (and primary school) math is more about calculations than connecting concepts and ideas and seeing how they describe the world. What I mean by "bad" is limiting my creative/unique thinking. Bulgarian schools just tell you some rules and tell you to follow them and don't explain why or how something comes to be.
@skullpetrol No, it was an Australian book, by Jim Coroneos, who was also the author of most of the maths textbooks I used in high school.
high school math is physics
7:47 PM
Honestly in university, math courses tend to encourage creativity and different interpretations, a lot more than even physics courses do
@PM2Ring thanks, I'll look him up :-)
@PM2Ring I had heard every proof was done geometrically because people were skeptical on Newton's ideas, e.g. infinitesimals
So in the end, will math limit my creative, unique and "out of the box" thinking? (I know you are math fans, but please give me an honest answer)
@bolbteppa I've always considered it like a kind of "applied math", almost like what engineering is to the sciences. High school math teaches you relationships that allow you to be able to use math to solve problems; but doesn't really teach the theory in full depth. Similarly to how engineering often uses theoretical knowledge to come up with a way to apply the theory without requiring that the subtle aspects of theory are understood by the one applying them.
@NovaliumCompany We just told you math will enhance those thinking skills
Proofwriting requires out of the box thinking
7:51 PM
@SirCumference Great!
@bolbteppa It depends where you learn it. We were certainly introduced to mathematical proofs fairly early in high school. True, it wasn't very rigorous, especially in the early years, and we did have to learn some stuff without proof, but they tried to keep that to a minimum. I'm pretty sure that the UK is (or at least was) similar in that regard.
@NovaliumCompany Logical thinking and creative thinking are not opposites
I'm going to get deeper into math. Thanks guys. Problem is, I don't know what concepts I know cuz teacher is lazy to write the names...
@SirCumference Awesome! I'm excited
I can recommend a pretty good intro to higher math book, if ya need one
@SirCumference Go ahead. But is there a way to find out what topics I'm familiar witg?
7:57 PM
Ask your teacher the names @NovaliumCompany
@SirCumference Well, that's true too. But people had been messing around with that stuff in a geometrical context, off & on, since Archimedes. It got a renewed burst of interest from people like Fermat & Mersenne. But that's a side issue. The main issue is that Euclid's axioms & his methods of proof were the epitome of mathematical logic, and algebra just didn't have the same level of trust.
Don't let them get away with being lazy @NovaliumCompany
Remember, in Newton's time, the foundations of geometry seemed to be very solid. The stuff that led to non-Euclidean geometry was still in the future.
So geometric proofs were almost treated as God-given facts. And if you couldn't prove your algebraic ideas geometrically, they were considered to be suspect.
@NovaliumCompany do you like geometry?
if yes, there's an interesting book by Stefan Lozanovski called "A beautiful journey through olympiad geometry", check it out, it's free online.
Donno what I'll read yet but I want to choose it myself
I'm actually excited to learn math, now that I know it's power and effects to my brain
8:05 PM
Are you still in high school?
@NovaliumCompany lol! "any bad effects of math"? try this :P
@Luyw Unfortunately
Did you check out MIT's free online courses?
will do
but what exactly do you wish to study? calculus? logic? abstract algebra?
8:08 PM
I know I'm a bit annoying sometimes but I want to say that I really really value this community.
@Luyw Everything that seems interesting
lol bulgaria is a country too :P
@NovaliumCompany I have already recommended you a book if you like geometry, I'll however recommend another on the subject of proofs, "Book of proof" by Richard Hammack, also available online for free.
@NovaliumCompany I think you should check out Feynman's "Ode to the Flower"
@vzn Yeah, right. Next you'll be telling us that Finland is a real country
8:23 PM
as an idle observation, the Icelandic word for Iceland is "Ísland"
so yes, Iceland = the island nation of Ísland
8:46 PM
'bout to watch some Hawaii 5-0
pretty good stuff
@PM2Ring lol! must admit do enjoy conspiracy theories of which there has been some resurgence/ vindication lately :P
9:47 PM
@SirCumference Can you explain to me what an electron looks like, how fast it flows as well as how much potential energy it has?
10:04 PM
Q: A question erroneously labeled as duplicate

CleonisA question was submitted by user929403 titled: Balance of a spinning coin This question is about the case of rolling motion, as in, for instance, rolling down an incline. So you see a coin rolling over, say, the floor of a corridor, and it just keeps going. Another case is the one of a coin tha...

10:23 PM
> “If you think of gravitational waves like sound waves, the frequency we are trying to capture with levitated sensors is sort of like a dog whistle,” said Vicky Kalogera, a co-investigator on the LSD project, in a press release.
analogy of gravitational waves to sound waves! by a physics phd! heresy! o_O news.northwestern.edu/for-journalists/faculty-experts/show/41

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