en-US Physics Forums RSS Feed This is the official global feed for PhysicsForums.com Wed, 01 Jul 2026 20:08:45 +0000 Wed, 01 Jul 2026 20:08:45 +0000 Physics Forums https://www.physicsforums.com/ Zeros of functions analytic in 2 variables Wed, 01 Jul 2026 20:01:14 +0000 https://www.physicsforums.com/threads/zeros-of-functions-analytic-in-2-variables.1085606/ urn:xenforo:thread:1085606 invalid@example.com (Paul Colby) Paul Colby This question crops up in solving electromagnetic boundary value problems. For problems with rotational symmetry, if ##f## has a node at ##(\theta,\phi)## then ##(\theta,\phi')=0## for all other ##\phi'##. This (I think) implies that, $$f(\theta,\phi)=F(\theta)G(\phi)$$ which, for the problems...

Read more]]> 3 Why can coefficient "a" between spacetime intervals depend on velocity between systems? Wed, 01 Jul 2026 19:47:11 +0000 https://www.physicsforums.com/threads/why-can-coefficient-a-between-spacetime-intervals-depend-on-velocity-between-systems.1066804/ urn:xenforo:thread:1066804 invalid@example.com (Mike_bb) Mike_bb Hello!

I read Landau & Lifshitz' Classical Theory of Fields [Link to copyrighted textbook redacted by the Mentors] (see pic below) and I was confused when I saw in proof that coefficient "a" between spacetime interval (ds)2 and (ds')2 can only depend on the absolute relative...

Read more]]> 35 M 7.5 Earthquake - 28 km SE of Yumare, Venezuela Wed, 01 Jul 2026 19:29:14 +0000 https://www.physicsforums.com/threads/m-7-5-earthquake-28-km-se-of-yumare-venezuela.1085582/ urn:xenforo:thread:1085582 invalid@example.com (Astronuc) Astronuc

M 7.5 - 28 km SE of Yumare, Venezuela​

https://earthquake.usgs.gov/earthquakes/eventpage/us6000t7zp/executive
  • 2026-06-24 22:05:11 (UTC)
  • 10.435°N 68.472°W
  • 10.0 km depth
Shallow earthquake! Also, an interesting note: "This earthquake was the second event in a doublet...

Read more]]> 5 Another nice mech problem Wed, 01 Jul 2026 19:19:59 +0000 https://www.physicsforums.com/threads/another-nice-mech-problem.1085607/ urn:xenforo:thread:1085607 invalid@example.com (wrobel) wrobel subj from an old Polish physics olympiad problem book

A thin, light, and flexible paper tape is wound around a spool that has the shape of a uniform cylinder (shaft). The end of the tape is attached to the clamp of a spring dynamometer. At the initial moment, the system is positioned as shown...

Read more]]> 5 NCNN vs ONNX vs Tensorflow vs PyTorch Wed, 01 Jul 2026 19:15:59 +0000 https://www.physicsforums.com/threads/ncnn-vs-onnx-vs-tensorflow-vs-pytorch.1085618/ urn:xenforo:thread:1085618 invalid@example.com (geekynerd) geekynerd i have a model compiled in all this framework which is suitable for connecting with flutter app. it must run on the device in which it is installed. it is a lightweight model which even worked on rasberry pi but need to choose one framework to connect the model with the app]]> 1 Considering transitioning to physics, any advice? Wed, 01 Jul 2026 19:07:00 +0000 https://www.physicsforums.com/threads/considering-transitioning-to-physics-any-advice.1085620/ urn:xenforo:thread:1085620 invalid@example.com (Logical12345) Logical12345 I am an undergraduate in the US at an Ivy league school and entering my senior year. I have been studying computer science and mathematics, and have done research in (empirical) machine learning (ML) throughout college.

In CS, I have taken essentially all of the theoretical CS and ML...

Read more]]> 1 Using Latex Code for Circuit Diagrams Wed, 01 Jul 2026 19:02:57 +0000 https://www.physicsforums.com/threads/using-latex-code-for-circuit-diagrams.1080111/ urn:xenforo:thread:1080111 invalid@example.com (neilparker62) neilparker62 Hi

Just wondering if there's any example Latex code to draw a simple electrical relay with the usual n/o , n/c and common terminals. Maybe with n/o attached to some kind of load ? I see there are circuit diagram packages for Latex but I don't know how to use them at all]]> 27 Electrostatics - given V, find rho and Q Wed, 01 Jul 2026 17:56:51 +0000 https://www.physicsforums.com/threads/electrostatics-given-v-find-rho-and-q.1085612/ urn:xenforo:thread:1085612 invalid@example.com (Rick16) Rick16 TL;DR: Griffiths, problem 2.46

Here is the problem statement:

The electric potential of some configuration is given by the expression ##V(r) = A \frac {e^{-\lambda r}} {r}##, where A and lambda are constants. Find the electric field E(r), the charge density ##\rho(r)##, and the total...

Read more]]> 9 Collection of Lame Jokes Wed, 01 Jul 2026 17:51:30 +0000 https://www.physicsforums.com/threads/collection-of-lame-jokes.25301/ urn:xenforo:thread:25301 invalid@example.com (quddusaliquddus) quddusaliquddus Lamest joke you know ... :zzz:]]> 24121 Entanglement might be the result of an underlying law? Wed, 01 Jul 2026 17:47:49 +0000 https://www.physicsforums.com/threads/entanglement-might-be-the-result-of-an-underlying-law.1082618/ urn:xenforo:thread:1082618 invalid@example.com (wavering) wavering This is still a great mystery, Einstein called it ""spooky action at a distance"

But science and mathematics are full of concepts which at first cause great bafflement but in due course are just accepted. In the case of Quantum Mechanics this gave rise to the saying "Shut up and calculate". In...

Read more]]> 33 Realta Fusion claims electrical generation from fusion! Wed, 01 Jul 2026 17:42:35 +0000 https://www.physicsforums.com/threads/realta-fusion-claims-electrical-generation-from-fusion.1085617/ urn:xenforo:thread:1085617 invalid@example.com (Astronuc) Astronuc
Realta Fusion is touting a “first-of-a-kind achievement” for the fusion energy field, having demonstrated direct energy conversion of plasma kinetic energy into electricity.

The Madison-based company yesterday announced it’s the first commercial fusion energy company to achieve the...

Read more]]> 0 Need some help to generate non AI ideas Wed, 01 Jul 2026 17:40:41 +0000 https://www.physicsforums.com/threads/need-some-help-to-generate-non-ai-ideas.1085616/ urn:xenforo:thread:1085616 invalid@example.com (geekynerd) geekynerd going for a hackathon which focuses on

We offer engineering students a platform to develop solutions addressing key challenges in Automotive, Industrial Heavy Machinery, and Aerospace industries. These can be tackled using Edge AI, leveraging technologies like AI, Generative AI, Agentic AI...

Read more]]> 0 Not Penrose Wed, 01 Jul 2026 17:38:11 +0000 https://www.physicsforums.com/threads/not-penrose.1085609/ urn:xenforo:thread:1085609 invalid@example.com (.Scott) .Scott They did it with Richard Feynman and now they're doing it with Sir Roger Penrose - and I find it irritating.

There is now a youtube channel called "The Roger Physics" that uses an AI-generated Roger Penrose to explain Physics topics.

The "Roger" they present never appears as interested...

Read more]]> 16 Collection of Science Jokes P2 Wed, 01 Jul 2026 17:35:57 +0000 https://www.physicsforums.com/threads/collection-of-science-jokes-p2.847743/ urn:xenforo:thread:847743 invalid@example.com (Greg Bernhardt) Greg Bernhardt Old thread: https://www.physicsforums.com/threads/science-jokes.4463/page-44

My wife just drew this

12376697_762331814307_4982172134413525429_n.jpg]]> 4089 Share Animal Pictures: For Animal Lovers Wed, 01 Jul 2026 17:35:04 +0000 https://www.physicsforums.com/threads/share-animal-pictures-for-animal-lovers.583729/ urn:xenforo:thread:583729 invalid@example.com (micromass) micromass Post your favorite animal pictures here!]]> 3038 AI Enriched Problem Solving Wed, 01 Jul 2026 17:16:22 +0000 https://www.physicsforums.com/threads/ai-enriched-problem-solving.1084382/ urn:xenforo:thread:1084382 invalid@example.com (Greg Bernhardt) Greg Bernhardt
This article is written by way of a reference for my longstanding PF colleague and prolific poster of challenging Maths/geometry problems @chwala . The particular post this article will discuss is an example of one such problem which he raised on Physics Forums.
...

Read more]]> 27 Motor building help needed please! Wed, 01 Jul 2026 16:14:51 +0000 https://www.physicsforums.com/threads/motor-building-help-needed-please.1085615/ urn:xenforo:thread:1085615 invalid@example.com (Thecat123) Thecat123 As stated earlier the coils are wound in the same direction, the magnets are not too far away and the brushes swap over at the correct time. I thought possibly friction could be the answer however after checking with my multimeter, the voltage through the commutator was only 0.3 volts when using...

Read more]]> 2 Replacing "inertial" with "elastoid-inertial" in rotating systems Wed, 01 Jul 2026 15:37:03 +0000 https://www.physicsforums.com/threads/replacing-inertial-with-elastoid-inertial-in-rotating-systems.1085507/ urn:xenforo:thread:1085507 invalid@example.com (Simon F) Simon F In 1959, rotating systems were still studied through "elastoid-inertial" oscillations.
https://journals.ametsoc.org/view/journals/atsc/16/2/1520-0469_1959_016_0199_anooat_2_0_co_2.pdf

This expression was clever and profoundly meaningful because it exactly describes what physics lies...

Read more]]> 6 Wordle Lovers - Play the NYT Daily Game Wed, 01 Jul 2026 14:25:35 +0000 https://www.physicsforums.com/threads/wordle-lovers-play-the-nyt-daily-game.1016903/ urn:xenforo:thread:1016903 invalid@example.com (fresh_42) fresh_42 This thread is for all who like the daily Wordle game of the New York Times as much as I do.

The rules:

1) https://www.nytimes.com/games/wordle/index.html
2) Post your result.
3) Do not spoil the answer.]]> 8593 Cover songs versus the original track, which ones are better? Wed, 01 Jul 2026 14:20:51 +0000 https://www.physicsforums.com/threads/cover-songs-versus-the-original-track-which-ones-are-better.1050205/ urn:xenforo:thread:1050205 invalid@example.com (pinball1970) pinball1970 Which songs were performed, arranged or produced better in a cover than the original version?
Which songs should have been left well alone?

Also, I think restricting the covers just to released singles will restrict some interesting stonkers and stinkers so album tracks are allowed.]]> 2497 Running older induction motors on VFDs Wed, 01 Jul 2026 13:53:57 +0000 https://www.physicsforums.com/threads/running-older-induction-motors-on-vfds.1085581/ urn:xenforo:thread:1085581 invalid@example.com (Guineafowl) Guineafowl The ‘spiky’ output of variable frequency drives (VFDs) can damage the insulation of older motors. They’re often used to run three phase motors on single-phase supplies in hobby workshops. (Modern motors have upgraded insulation and are designated ‘inverter-duty’.) I wonder what cheap and...

Read more]]> 15 Space Stuff and Launch Info Wed, 01 Jul 2026 13:46:42 +0000 https://www.physicsforums.com/threads/space-stuff-and-launch-info.879196/ urn:xenforo:thread:879196 invalid@example.com (1oldman2) 1oldman2 Due to the constant never ending supply of "cool stuff" happening in Aerospace these days I'm creating this thread to consolidate posts every time something new comes along. Please feel free to add random information if its relevant. So to start things off here is the SpaceX Dragon launch coming...

Read more]]> 1664 "The wavefunction never collapses" Wed, 01 Jul 2026 13:40:04 +0000 https://www.physicsforums.com/threads/the-wavefunction-never-collapses.1085610/ urn:xenforo:thread:1085610 invalid@example.com (sevensages) sevensages I recently read Max Tegmark's book Our Mathematical Universe. In Our Mathematical Universe, Tegmark asserts that Niels Bohr and other scientists supported the Copenhagen Interpretation that the wavefunction collapses. Tegmark asserts that Hugh Everett originated the competing thesis that the...

Read more]]> 21 The History of Various Anesthetics and Remedies.... Wed, 01 Jul 2026 13:29:28 +0000 https://www.physicsforums.com/threads/the-history-of-various-anesthetics-and-remedies.1084995/ urn:xenforo:thread:1084995 invalid@example.com (sbrothy) sbrothy Disclaimer: I have no medical training or schooling.

I know my website is a mess. I'm investing more time in the English version than in the Danish, which might be a little silly as my intended audience really is here at home in Denmark.

Unfortunately my laptop can hardly run Visual Studio...

Read more]]> 52 Estudante de física (Physics Student) Wed, 01 Jul 2026 01:42:20 +0000 https://www.physicsforums.com/threads/estudante-de-fisica-physics-student.1085611/ urn:xenforo:thread:1085611 invalid@example.com (valeska martins) valeska martins Estudante brasileiro .]]> 1 How does the geometry of magnetic bodies influence torque? Tue, 30 Jun 2026 21:53:23 +0000 https://www.physicsforums.com/threads/how-does-the-geometry-of-magnetic-bodies-influence-torque.1085603/ urn:xenforo:thread:1085603 invalid@example.com (swissgirl1999 Refer) swissgirl1999 Refer If I take two rectangular neodymium magnet like these (N35, 20 × 10 × 10 mm ),
9b35e72b-449b-4b97-84b4-786c8a8fd67a-1_all_37908.webp
map the faces 1 and 2, and on the body 3, 4, 5 6, and test all 64 possible combinations (switching 1 and 2 and rotating 3, 4, 5 and 6 ) , what would be the outcome (attraction-repulsion ratio) ? Why...

Read more]]> 3 Hantavirus outbreak aboard ship MV Hondius; virus present in Argentina Tue, 30 Jun 2026 20:47:37 +0000 https://www.physicsforums.com/threads/hantavirus-outbreak-aboard-ship-mv-hondius-virus-present-in-argentina.1085074/ urn:xenforo:thread:1085074 invalid@example.com (Astronuc) Astronuc Several days ago, an outbreak of Hantavirus was reported aboard cruise ship MV Hondius, which apparently set sail from Argentina.

PRAIA, Cape Verde (AP) — Footage obtained by The Associated Press of a cruise ship at the center of a rare-virus outbreak shows deserted decks and...

Read more]]> 21 Penrose-Dosi Model Tue, 30 Jun 2026 17:11:11 +0000 https://www.physicsforums.com/threads/penrose-dosi-model.1085354/ urn:xenforo:thread:1085354 invalid@example.com (Ssnow) Ssnow Hi to all! I want to ask the opinion of the forum about the conjecture on the collapsing wave function ##\psi## due to the presence of the gravity as assumed in the model of Penrose-Dosi ... It seems the only "true" way to understand the quantum mechanics (at least it is possible to verify it...

Read more]]> 3 How valid is the indivisible interpretation of quantum mechanics? Tue, 30 Jun 2026 16:25:16 +0000 https://www.physicsforums.com/threads/how-valid-is-the-indivisible-interpretation-of-quantum-mechanics.1085197/ urn:xenforo:thread:1085197 invalid@example.com (DarkloidNeos) DarkloidNeos I was reading up on the theory and apparently it's saying stuff that is in direct opposition with current views like how there is no wave function, but that quantum processes occur by randomness? I'm not sure how valid it might be but all I know is that it's a massive departure from the usual stuff.]]> 52 Investigating the real roots of a cubic equation Tue, 30 Jun 2026 14:21:44 +0000 https://www.physicsforums.com/threads/investigating-the-real-roots-of-a-cubic-equation.1085564/ urn:xenforo:thread:1085564 invalid@example.com (brotherbobby) brotherbobby 1782369139521.webpStatement of the problem : Let me copy and paste the problem as it appears in the text. [Riley, K.F., Hobson,M.P., Bence,S.J. (2006) Mathematical Methods for Physics and Engineering. (3E)].

Attempt : One real root is guaranteed, as ##n =\;\text{odd}##...

Read more]]> 13 Great circle between two points on the Earth's surface Tue, 30 Jun 2026 13:17:14 +0000 https://www.physicsforums.com/threads/great-circle-between-two-points-on-the-earths-surface.1085605/ urn:xenforo:thread:1085605 invalid@example.com (brotherbobby) brotherbobby 1782802365171.webpProblem statement : I copy and paste the problem as it appeared in the text. [Kleppner, D., Kolenkow, R. (2014). An Introduction to Mechanics. Cambridge University Press (2E)]. The statement itself is rather long-winded. The question to be answered appeared towards the...

Read more]]> 2 Calculating the Degrees of Freedom Tue, 30 Jun 2026 13:15:40 +0000 https://www.physicsforums.com/threads/calculating-the-degrees-of-freedom.1084950/ urn:xenforo:thread:1084950 invalid@example.com (jojosg) jojosg Image_20260426191052.webp
Just unsure if I did it correctly. I identified G as an idle Degree of Freedom. Should I exclude it from DOF calculation? But is I do that The Current DOF would be more than 2 which is definitely the wrong answer.

attempt.webp]]> 1 Uncertainty and particle in a box Tue, 30 Jun 2026 11:03:10 +0000 https://www.physicsforums.com/threads/uncertainty-and-particle-in-a-box.1085601/ urn:xenforo:thread:1085601 invalid@example.com (hokhani) hokhani As far as I know about the position -momentum uncertainty if a quantum particle is more confined, we expect its momentum to be more uncertain. However, I think, as a counterexample one may take the particle in a box. Each sin wave function (which is the solution of particle in the box) is always...

Read more]]> 6 Why must residential electrical systems be connected to Earth (soil)? Tue, 30 Jun 2026 10:28:21 +0000 https://www.physicsforums.com/threads/why-must-residential-electrical-systems-be-connected-to-earth-soil.1083711/ urn:xenforo:thread:1083711 invalid@example.com (gen x) gen x Why is grounded electrical system safer than isolated system?]]> 44 Is Water's Volume Expansion Upon Freezing an Intrinsic Property? Tue, 30 Jun 2026 00:59:04 +0000 https://www.physicsforums.com/threads/is-waters-volume-expansion-upon-freezing-an-intrinsic-property.1085545/ urn:xenforo:thread:1085545 invalid@example.com (swissgirl1999 Refer) swissgirl1999 Refer The standard physical chemistry and thermodynamics literature states that water expands upon freezing due to the crystalline structure of ice (hexagonal ice I_h), which occupies approximately 9% more volume than liquid water at the same mass. This expansion is treated as an intrinsic property of...

Read more]]> 60 How to measure the diameter of a shaft without a caliper? Mon, 29 Jun 2026 21:39:33 +0000 https://www.physicsforums.com/threads/how-to-measure-the-diameter-of-a-shaft-without-a-caliper.1085578/ urn:xenforo:thread:1085578 invalid@example.com (harveycannon) harveycannon I'm working on a small mechanical project at home and need to determine the outside diameter of a steel shaft. Unfortunately, I don't have a vernier caliper or a micrometer.

Is there a reasonably accurate method to measure the shaft's diameter using common household tools?

I'm not looking for...

Read more]]> 34 Why weren't there lynchings in New England in late 1800s & early 1900s? Mon, 29 Jun 2026 21:09:24 +0000 https://www.physicsforums.com/threads/why-werent-there-lynchings-in-new-england-in-late-1800s-early-1900s.1084390/ urn:xenforo:thread:1084390 invalid@example.com (sevensages) sevensages Thousands of people were lynched in the American South in the late 19th century and early 20th century. Although most lynchings occurred in the South, there were still plenty of lynchings in the North. The lynching of Thomas Shipp and Abram Smith in Indiana and the Duluth lynchings in...

Read more]]> 21 Random Photos Mon, 29 Jun 2026 20:30:30 +0000 https://www.physicsforums.com/threads/random-photos.994801/ urn:xenforo:thread:994801 invalid@example.com (Point Conception) Point Conception A topic for random photos: Ko-Larn island 7 km West of PattayaIMG_20200717_114141.jpg]]> 3818 Giving dog access to go potty when we're out Mon, 29 Jun 2026 18:32:32 +0000 https://www.physicsforums.com/threads/giving-dog-access-to-go-potty-when-were-out.1085558/ urn:xenforo:thread:1085558 invalid@example.com (DaveC426913) DaveC426913 I just can't seem to find a satisfactory solution to this. I'm not sure you will either, I'm just hoping maybe some external thoughts will inspire a new line of thinking.
  • We have a 50lb big black Spitz. Arthritic. Old, kinda crotchety and anxiety-wrought. Yells at anyone except us.
  • We...

Read more]]> 16 Could new separate domains provide safe access for kids? Mon, 29 Jun 2026 16:00:55 +0000 https://www.physicsforums.com/threads/could-new-separate-domains-provide-safe-access-for-kids.1085597/ urn:xenforo:thread:1085597 invalid@example.com (synch) synch There is a concern about kids access to social media and so on, and some countries are banning access under 16.
Would it be realistic to add kids country-level domains and then use devices locked to that type of access ?
Eg Australia uses ".au", that could be supplemented by something like...

Read more]]> 8 Biographies, History, Philosophy of Physics Mon, 29 Jun 2026 15:41:33 +0000 https://www.physicsforums.com/threads/biographies-history-philosophy-of-physics.1060020/ urn:xenforo:thread:1060020 invalid@example.com (sbrothy) sbrothy arXiv: physics.hist-ph. History, philosophy:

Berta Karlik -- The Grande Dame of the Vienna Radium Institute

Berta Karlik was an Austrian physicist who was not only among the early radioactivity researchers and nuclear physicists in Vienna, but also pioneered a woman's academic...

Read more]]> 303 Hi im new here Mon, 29 Jun 2026 10:19:34 +0000 https://www.physicsforums.com/threads/hi-im-new-here.1085587/ urn:xenforo:thread:1085587 invalid@example.com (Gravastar_9023) Gravastar_9023 i'm not sure what to put here but hello all]]> 2 I would like to get recommendations for graduate level physics books Mon, 29 Jun 2026 08:09:26 +0000 https://www.physicsforums.com/threads/i-would-like-to-get-recommendations-for-graduate-level-physics-books.1085588/ urn:xenforo:thread:1085588 invalid@example.com (Rick16) Rick16 I got a bachelor in physics 11 years ago, and I did not continue my studies. I have now decided to embark on a complete review of undergraduate physics, on my own, as a hobby. I have chosen 7 books for this purpose:

Mary Boas: mathematical methods in the physical sciences

John Taylor...

Read more]]> 9 Using Hydrogen in natural gas pipelines Mon, 29 Jun 2026 02:43:10 +0000 https://www.physicsforums.com/threads/using-hydrogen-in-natural-gas-pipelines.1079748/ urn:xenforo:thread:1079748 invalid@example.com (synch) synch Decades ago, our domestic gas supply was changed from coal gas to natural gas, and I watched on as our kitchen oven had different jets fitted. As coal gas had a large fraction of hydrogen, obviously the pipes etc in use at the time were ok with hydrogen. Now the times have changed and there...

Read more]]> 20 What is new with Koide sum rules? Sun, 28 Jun 2026 23:32:00 +0000 https://www.physicsforums.com/threads/what-is-new-with-koide-sum-rules.551549/ urn:xenforo:thread:551549 invalid@example.com (arivero) arivero I am detaching this to BSM because it is already getting too much parameters in the bag.

What has happened this year is that Werner Rodejohann and He Zhang, from the MPI in Heidelberg, proposed that the quark sector did not need to match triplets following weak isospin, and then empirically...

Read more]]> 344 Question about using Newton's Method to solve a system of equations Sun, 28 Jun 2026 23:24:45 +0000 https://www.physicsforums.com/threads/question-about-using-newtons-method-to-solve-a-system-of-equations.1085591/ urn:xenforo:thread:1085591 invalid@example.com (Ax_xiom) Ax_xiom So the formula used to solve non-linear equations using the Newton-Raphson method is this $$ X_{k+1} = X_k - J^{-1}(X_k)F(X_k) $$ and instead of finding ##J^{-1}(X_k)##, we solve for the change that will be applied to ##X_k## (##\Delta X_k##) using this relation $$J(X_k) \Delta X_k = -F(X_k)$$...

Read more]]> 4 Banana Ball Sun, 28 Jun 2026 21:05:31 +0000 https://www.physicsforums.com/threads/banana-ball.1085596/ urn:xenforo:thread:1085596 invalid@example.com (BillTre) BillTre My daughter got me tickets to a Banana Ball game for my birthday. The game was today. There will be another tomorrow.

It was way more fun than the videos. :biggrin:

The show was in the Ducks' (U. of O.) Autzen Stadium. The stadium was full (60,000). There was a really long lasting wave that...

Read more]]> 2 Why is ##x=e^y## the inverse of ##y=\int_1^x \frac{1}{t} dt##? Sun, 28 Jun 2026 20:43:51 +0000 https://www.physicsforums.com/threads/why-is-x-e-y-the-inverse-of-y-int_1-x-frac-1-t-dt.1085554/ urn:xenforo:thread:1085554 invalid@example.com (Mike_bb) Mike_bb Hello!

I have a problem in understanding why ##x=e^y## is inverse function of ##y=\int_1^x \frac{1}{t} dt##.

This question seems strange but I'll try to describe my problem.

As is known, the function ##y= \int_1^x \frac{1}{t} dt## is defined as ##y=ln(x)## but I can't understand why.

In...

Read more]]> 43 Good drawing of Earth's orbit for model? Possibly vector file? Sun, 28 Jun 2026 17:48:18 +0000 https://www.physicsforums.com/threads/good-drawing-of-earths-orbit-for-model-possibly-vector-file.1085531/ urn:xenforo:thread:1085531 invalid@example.com (LightningInAJar) LightningInAJar I would like to create a 3D printable model of the earth's orbit around the sun and slice it into the months of the year. So basically a calendar. Except I wanted to add heights for relative local weather conditions for a given year. Does anyone know the best way to draw our orbit?]]> 24 Open circuit resonator not acting according to theory Sun, 28 Jun 2026 14:04:17 +0000 https://www.physicsforums.com/threads/open-circuit-resonator-not-acting-according-to-theory.1085476/ urn:xenforo:thread:1085476 invalid@example.com (yefj) yefj Hello, I have tried to implement an open circuit microstrip resonator .
I got the microstrip resonating at 5Ghz as shown below.
However the S-parameters is very bad.
Is there a way to improve the matching so It will have a better dip in 5GHz.
1781373834133.webp
1781373681499.webp
1781373734539.webp
1781373807233.webp...

Read more]]> 5 Why is there gauge freedom in ADM formalism? Sun, 28 Jun 2026 12:53:42 +0000 https://www.physicsforums.com/threads/why-is-there-gauge-freedom-in-adm-formalism.1085595/ urn:xenforo:thread:1085595 invalid@example.com (concerned citizen) concerned citizen In ADM formalism there are evolution equations only for spatial metric and extrinsic curvature, but nothing about lapse and shift. I understand that the latter two are essentially just choice of coordinates. However, if I already choose coordinates, shouldn't be their evolution also be...

Read more]]> 2 Apparent contradiction in a simple circuit Sun, 28 Jun 2026 10:00:54 +0000 https://www.physicsforums.com/threads/apparent-contradiction-in-a-simple-circuit.1085589/ urn:xenforo:thread:1085589 invalid@example.com (palaphys) palaphys 1782562769110.webp

So I came across this simple looking circuit, and it seems to me that the uppermost branch and lowermost are parallel w.r.t AB.
applying the batteries in parallel formula, we get $$E_{net}=E $$ and $$R_{net}=R/2$$, simplifying the circuit as shown:

1782565757241.webp
From here, it seems...

Read more]]> 3 Simple kinematics problem — falling from a geostationary satellite Sat, 27 Jun 2026 23:04:00 +0000 https://www.physicsforums.com/threads/simple-kinematics-problem-falling-from-a-geostationary-satellite.1085357/ urn:xenforo:thread:1085357 invalid@example.com (AlternativePhysics) AlternativePhysics I know g at that altitude is 0.221 m/s² but I'm not sure how to integrate the increasing gravitational acceleration as the object approaches Earth. I attempted using kinematic equations but g is not constant during the fall.]]> 23 Why is gravity a fictitious force? Sat, 27 Jun 2026 22:45:26 +0000 https://www.physicsforums.com/threads/why-is-gravity-a-fictitious-force.1084666/ urn:xenforo:thread:1084666 invalid@example.com (Mike_bb) Mike_bb I read about equivalence principle. I tried to understand Einstein's thought experiment with elevator and I can't understand why we compare elevator in the space and elevator on the surface of the Earth and conclude that gravity is fictitious force.

Why?

Thanks!]]> 153 Question about causality in s-parameters Sat, 27 Jun 2026 21:22:13 +0000 https://www.physicsforums.com/threads/question-about-causality-in-s-parameters.1085553/ urn:xenforo:thread:1085553 invalid@example.com (yefj) yefj Hello, I am using VNA with ifbw=3KHz span 10MHz to 70GHZ step 10MHz.
I am measuring differential lines SDD11 for TDR uding IFFT.
If my IFFT TDR windows is 100ns then an event in 120ns will go to -20ns thus will create causality issue.
Anothe cause I know is deembeding creating ringing ,but i...

Read more]]> 7 Solar Activity and Space Weather Update thread Sat, 27 Jun 2026 20:34:07 +0000 https://www.physicsforums.com/threads/solar-activity-and-space-weather-update-thread.923468/ urn:xenforo:thread:923468 invalid@example.com (Stavros Kiri) Stavros Kiri I am picking this up as a continuation and extension of the idea laid out e.g. in @davenn 's thread
"The Sun today - 9 July 2017 - nice spot group"
https://www.physicsforums.com/threads/the-sun-today-9-july-2017-nice-spot-group.919696/

See also (for continuity purposes)...

Read more]]> 462 Japan Earthquake: nuclear plants Fukushima part 2 Sat, 27 Jun 2026 19:31:17 +0000 https://www.physicsforums.com/threads/japan-earthquake-nuclear-plants-fukushima-part-2.711577/ urn:xenforo:thread:711577 invalid@example.com (Greg Bernhardt) Greg Bernhardt Part 1 can be found here:
https://www.physicsforums.com/showthread.php?t=480200


Magnitude-5.3 earthquake hits Japan's Fukushima
http://www.usatoday.com/story/news/world/2013/09/19/japan-fukushima-nuclear-plant/2835493/

A magnitude-5.3 earthquake has hit the Japanese...

Read more]]> 1791 Hello from a New Physics Learner Sat, 27 Jun 2026 16:23:25 +0000 https://www.physicsforums.com/threads/hello-from-a-new-physics-learner.1085594/ urn:xenforo:thread:1085594 invalid@example.com (ashi kehan) ashi kehan Hello everyone,

I am new here. I am interested in physics and I often think about deep science questions. I want to learn how to ask better questions and understand physics concepts properly.

I am not a professional physicist, but I am very curious and serious about learning. I hope to learn...

Read more]]> 2 "Scientists have measured space to be flat to high accuracy" Sat, 27 Jun 2026 13:20:15 +0000 https://www.physicsforums.com/threads/scientists-have-measured-space-to-be-flat-to-high-accuracy.1085560/ urn:xenforo:thread:1085560 invalid@example.com (sevensages) sevensages In Max Tegmark's book Our Mathematical Universe, Tegmark wrote the following: "As we saw in the last chapter, we've measured our space to be flat to high accuracy" (99). Since space is three dimensional, I am totally baffled by Tegmark's statement that scientists have measured space to be flat...

Read more]]> 8 Is AI Overhyped? Sat, 27 Jun 2026 07:13:50 +0000 https://www.physicsforums.com/threads/is-ai-overhyped.1080669/ urn:xenforo:thread:1080669 invalid@example.com (SamRoss) SamRoss In my discussions elsewhere, I've noticed a lot of disagreement regarding AI. A question that comes up is, "Is AI hype?" Unfortunately, when this question is asked, the one asking, as far as I can tell, may mean one of three things which can lead to lots of confusion. I'll list them out now for...

Read more]]> 445 Particles' Intrinsic Properties in QFT Sat, 27 Jun 2026 04:39:24 +0000 https://www.physicsforums.com/threads/particles-intrinsic-properties-in-qft.1085562/ urn:xenforo:thread:1085562 invalid@example.com (LarryS) LarryS In single-particle nonrelativistic QM, a particle, say an electron, has intrinsic properties like rest mass, charge and spin magnitude and extrinsic/dynamic properties like momentum and energy. Does this intrinsic/extrinsic dichotomy carry over to, say, the electron...

Read more]]> 18 The countability paradox of computable numbers Sat, 27 Jun 2026 03:54:53 +0000 https://www.physicsforums.com/threads/the-countability-paradox-of-computable-numbers.1085518/ urn:xenforo:thread:1085518 invalid@example.com (Warp) Warp Famously, the set of computable numbers is countable. That's pretty much a result of their definition: The decimal expansion of a computable number can be generated to any arbitrary length by a finite algorithm. And since the set of all possible finite algorithms is countable, so is the set of...

Read more]]> 11 Applicability of Spin-2 Field Interpretation of GR Sat, 27 Jun 2026 03:11:04 +0000 https://www.physicsforums.com/threads/applicability-of-spin-2-field-interpretation-of-gr.1085586/ urn:xenforo:thread:1085586 invalid@example.com (Matterwave) Matterwave
PeterDonis said:
GR has its own set of interpretations: spacetime curvature is one, "spin-2 field on a flat spacetime background" is another. (The latter is technically limited to spacetimes with topologies that can have a flat background put on them.) The second is kinda sorta LET-ish, I suppose (the flat...

Read more]]> 5 Talent Worthy of Wider Recognition Sat, 27 Jun 2026 02:57:40 +0000 https://www.physicsforums.com/threads/talent-worthy-of-wider-recognition.1064653/ urn:xenforo:thread:1064653 invalid@example.com (Hornbein) Hornbein The double lead guitar technique was invented by George Harrison on Your Bird Can Sing but the style didn't catch on. Jimmy Page put it on the map in Ramble On, then the Allman Brothers made it their signature. I like double lead guitar because that unique soaring sound is something no other...

Read more]]> 135 Programming Jokes: Lame, Science & Math Jokes! Sat, 27 Jun 2026 01:22:22 +0000 https://www.physicsforums.com/threads/programming-jokes-lame-science-math-jokes.1046996/ urn:xenforo:thread:1046996 invalid@example.com (Wrichik Basu) Wrichik Basu We have threads on lame jokes and science jokes. But then, we also have a thread on bad math jokes. So, why not create one specifically for programming jokes?

Let me start:

]]> 500 Simplified Special Relativity: Looking to get roasted on this Sat, 27 Jun 2026 01:22:11 +0000 https://www.physicsforums.com/threads/simplified-special-relativity-looking-to-get-roasted-on-this.1085565/ urn:xenforo:thread:1085565 invalid@example.com (DavidMiranda) DavidMiranda After doing some calculations, I found a model that leads to some of the same results as Special Relativity, specifically time dilation and the relativistic Doppler Effect, but that doesn't assume the same things.

In fact, in this model, the constant and equal speed of light in all reference...

Read more]]> 61 Some notes on LET for reference Sat, 27 Jun 2026 00:31:00 +0000 https://www.physicsforums.com/threads/some-notes-on-let-for-reference.1085585/ urn:xenforo:thread:1085585 invalid@example.com (robphy) robphy [Moderator's note: Thread spun off due to topic change, for reference only.]

(I'll ask my questions here [hoping for short answers].. and quote the earlier discussion below.)
  • Does Lorentz Ether Theory have its own predictive power?
    Or is it essentially a direct and straightforward...

Read more]]> 14 A review of Max Tegmark's book Our Mathematical Universe Fri, 26 Jun 2026 21:48:19 +0000 https://www.physicsforums.com/threads/a-review-of-max-tegmarks-book-our-mathematical-universe.1085491/ urn:xenforo:thread:1085491 invalid@example.com (sevensages) sevensages TL;DR: This thread is a review of the book Our Mathematical Universe.

This thread is a review of Max Tegmark's book Our Mathematical Universe. The thesis of Our Mathematical Universe is that not only does mathematics perfectly describe the universe, the universe is mathematics.. In...

Read more]]> 12 Leo Tolstoj and Progressivity... Fri, 26 Jun 2026 20:51:12 +0000 https://www.physicsforums.com/threads/leo-tolstoj-and-progressivity.1085511/ urn:xenforo:thread:1085511 invalid@example.com (sbrothy) sbrothy I'm currently "fighting" my way throgh Alexandra Tolstoj's biography of her father Count Lev Nikolayevich Tolstoy (The author of "War and Peace" among a ton of others). I say "fighting" because it's quite heavy and detailed, although the amount of information, both personal...

Read more]]> 1 Weird News Compilation Fri, 26 Jun 2026 20:33:15 +0000 https://www.physicsforums.com/threads/weird-news-compilation.878428/ urn:xenforo:thread:878428 invalid@example.com (Evo) Evo I'm always finding weird things in the news and thought it might be fun if we all shared odd stories we came across. Please feel free to post odd, funny or unusual stories in this thread.

Turns out that Zoobyshoe beat me in posting about this in another thread, so he will officially be known...

Read more]]> 2157 I've been reused but not credited Fri, 26 Jun 2026 17:32:35 +0000 https://www.physicsforums.com/threads/ive-been-reused-but-not-credited.1065656/ urn:xenforo:thread:1065656 invalid@example.com (DaveC426913) DaveC426913 This is me:
https://bigthink.com/starts-with-a-bang/electron-mass-vital-life-in-universe/

Or more specifically, that infographic "What Dave is Made Of" half way down the page is mine.

I made it many years ago, before I was smart enough to sign my work. At least I credited the author...

Read more]]> 16 Bad Math Jokes Fri, 26 Jun 2026 15:31:33 +0000 https://www.physicsforums.com/threads/bad-math-jokes.990191/ urn:xenforo:thread:990191 invalid@example.com (benorin) benorin Summary:: Ok, so let hear 'em, all your tasteful bad math jokes...

Found this on r/mathmemes

There's no solution for 31:
Doctor Who (Capaldi) on the sum of 3 cubes equalling a given integer

Ok, so let hear 'em, all your tasteful bad math jokes...]]> 446 Pinewood Derby Physics Fri, 26 Jun 2026 15:14:46 +0000 https://www.physicsforums.com/threads/pinewood-derby-physics.1085563/ urn:xenforo:thread:1085563 invalid@example.com (Hornbein) Hornbein

The most important thing is that the mass be toward the rear of the car. As a Cub Scout I participated in the Pinewood Derby in 1966 or so and no one knew to do that. Indeed I think most of these seven things were unknown.]]> 3 Sound waves on the Sun Fri, 26 Jun 2026 14:06:03 +0000 https://www.physicsforums.com/threads/sound-waves-on-the-sun.1085269/ urn:xenforo:thread:1085269 invalid@example.com (sevensages) sevensages I am reading Max Tegmark's book Our Mathematical Universe. On page 172, Tegmark wrote the following: "Two waves can pass through each other unaffected, like the circular waves in the water tank in Figure 7.6; at any time, their effects simply add together. In some places, we see peaks of the...

Read more]]> 11 Can anyone solve this age problem? Fri, 26 Jun 2026 08:20:03 +0000 https://www.physicsforums.com/threads/can-anyone-solve-this-age-problem.1067968/ urn:xenforo:thread:1067968 invalid@example.com (Curious Kev) Curious Kev This is from the front cover of Mathematical Conundrums, CRC Press, 2023.

<< When Holly was twice the age Ivy was 15 years ago, Ivy was half the age Holly will be in 12 years time.

How many years ago was that? >>

OK, but why isn't the age of Holly and Ivy given?]]> 38 RIP David Clayton Thomas, lead vocalist of Blood, Sweat & Tears Fri, 26 Jun 2026 06:33:53 +0000 https://www.physicsforums.com/threads/rip-david-clayton-thomas-lead-vocalist-of-blood-sweat-tears.1085577/ urn:xenforo:thread:1085577 invalid@example.com (Astronuc) Astronuc David Clayton Thomas (13 September 1941 – 24 June 2026) was a British-Canadian musician, singer, and songwriter, best known as the lead vocalist of the American band Blood, Sweat & Tears. He died at age 84.

https://en.wikipedia.org/wiki/David_Clayton-Thomas...

Read more]]> 1 Random Thoughts 7 Fri, 26 Jun 2026 00:28:36 +0000 https://www.physicsforums.com/threads/random-thoughts-7.1056780/ urn:xenforo:thread:1056780 invalid@example.com (Evo) Evo Time to start a new thread.

Here is the last page of part 6.

https://www.physicsforums.com/threads/random-thoughts-part-6.875108/page-317#post-6960672]]> 2031 The use of AI in self-learning Thu, 25 Jun 2026 22:24:36 +0000 https://www.physicsforums.com/threads/the-use-of-ai-in-self-learning.1085339/ urn:xenforo:thread:1085339 invalid@example.com (Sandra Jane) Sandra Jane So I've been confused about my learning methods lately.
I've been having a hard time understanding the way my lecturer explain things at the campus. So I have to learn it all over again myself after class. I've been using AI (ChatGPT) to study since I can't understand the topic whenever I tried...

Read more]]> 16 Our Beautiful Universe - Photos and Videos Thu, 25 Jun 2026 21:16:52 +0000 https://www.physicsforums.com/threads/our-beautiful-universe-photos-and-videos.800540/ urn:xenforo:thread:800540 invalid@example.com (DennisN) DennisN This thread is dedicated to the beauty and awesomeness of our Universe. If you feel like it, please share video clips and photos (or nice animations) of space and objects in space in this thread. Your posts, clips and photos may by all means include scientific information; that does not make it...

Read more]]> 2438 The Secrets of Prof. Verschure's Rosetta Stones Thu, 25 Jun 2026 18:48:23 +0000 https://www.physicsforums.com/threads/the-secrets-of-prof-verschures-rosetta-stones.1054432/ urn:xenforo:thread:1054432 invalid@example.com (Andy Resnick) Andy Resnick (Edit: since the thread title was changed, this first sentence is too cryptic: the original title referred to a Tool song....)

Besides being a favorite song by a favorite band, the thread title is a straightforward play on words. This summer, as a present to myself for being promoted, I...

Read more]]> 164 High-Energy Pb-Emulsion Collisions at CERN and x17 Thu, 25 Jun 2026 18:46:36 +0000 https://www.physicsforums.com/threads/high-energy-pb-emulsion-collisions-at-cern-and-x17.1085047/ urn:xenforo:thread:1085047 invalid@example.com (kodama) kodama this is a peer review journal

Journal of Physics G: Nuclear and Particle Physics

Search for new particles decaying into electron pairs of mass below 100 MeV/​

P L Jain and G Singh

Abstract​

We report results on 1220 electron pairs produced from a 207Pb beam at 160 A...

Read more]]> 1 Does the Lorentz factor aid understanding of SR, or obscure it? Thu, 25 Jun 2026 13:19:40 +0000 https://www.physicsforums.com/threads/does-the-lorentz-factor-aid-understanding-of-sr-or-obscure-it.1085404/ urn:xenforo:thread:1085404 invalid@example.com (Trysse) Trysse I had a look at a number of books that deal with Special Relativity.

Many, if not most, textbooks on the theory of Special Relativity introduce the Lorentz factor ##\gamma##
$$\gamma=\frac{1}{\sqrt{1-\frac{v^2}{c^2}}}$$
Different textbooks introduce ##\gamma## differently; some use it only as a...

Read more]]> 18 How would air work on the plane of water? Thu, 25 Jun 2026 09:53:19 +0000 https://www.physicsforums.com/threads/how-would-air-work-on-the-plane-of-water.1085556/ urn:xenforo:thread:1085556 invalid@example.com (some bloke) some bloke Hey everyone!

I'm a keen D&D-er and one of the unexplored regions of the planar map is the elemental plane of water. There's a few handwavey explanations of it, but I want to make it into an entire setting.

As much as one can on an infinite plane of water without a defined gravity field, I...

Read more]]> 2 Confused about the conservation of angular momentum Thu, 25 Jun 2026 03:16:25 +0000 https://www.physicsforums.com/threads/confused-about-the-conservation-of-angular-momentum.1085557/ urn:xenforo:thread:1085557 invalid@example.com (Rick16) Rick16 In his book "Take me to your leader", Neil deGrasse Tyson writes that rotating flying saucers cannot exist, because they would violate the conservation of angular momentum. I don't really understand this. If the thing rotates, it must have an engine, which produces a torque. When there is a...

Read more]]> 10 Spotting 1997 NC1 flyby on Fri/Sat Thu, 25 Jun 2026 03:07:02 +0000 https://www.physicsforums.com/threads/spotting-1997-nc1-flyby-on-fri-sat.1085561/ urn:xenforo:thread:1085561 invalid@example.com (DaveC426913) DaveC426913 This article.
https://earthsky.org/space/large-asteroid-visible-telescopes-pass-earth-june-27-2026/

Anyway, I'm having a really tough time locating exactly where to look for 1997 NC1 (152637) this weekend.

So I made my own from his screenshots.
1782346980679.webp
It's still not good...

Read more]]> 2 Hi everyone. Here to learn and pick your brain. Wed, 24 Jun 2026 23:12:32 +0000 https://www.physicsforums.com/threads/hi-everyone-here-to-learn-and-pick-your-brain.1085559/ urn:xenforo:thread:1085559 invalid@example.com (DavidMiranda) DavidMiranda Hi, I'm David.

I'm just your ordinary 40+ year old undergrad student in physics, studying for the sheer pleasure of learning, and the hope to one day contribute something to the state of the art (preferably before I go senile).

Thank you for having me here.

Cheers!]]> 2 Graphene and twistronics, Kavli Prize, 2026 - Rutgers, MIT, UT Austin Wed, 24 Jun 2026 11:08:36 +0000 https://www.physicsforums.com/threads/graphene-and-twistronics-kavli-prize-2026-rutgers-mit-ut-austin.1085455/ urn:xenforo:thread:1085455 invalid@example.com (Astronuc) Astronuc
Professor Eva Andrei and two other physicists — Pablo Jarillo-Herrero from the Massachusetts Institute of Technology and Allan H. MacDonald from the University of Texas at Austin — will share a $1 million prize for their work discovering how twisting ultrathin sheets of carbon at precise...

Read more]]> 3 Collins's Law Wed, 24 Jun 2026 10:46:27 +0000 https://www.physicsforums.com/threads/collinss-law.1085524/ urn:xenforo:thread:1085524 invalid@example.com (DaveC426913) DaveC426913 I have coined a new term: Collins' Law.

It is a variant/update of Cunningham's Law.

Collins's Law: The best way to encourage engagement on social media is not to post an interesting and well-designed problem; it is to post an interesting but ambiguously-defined problem and let the...

Read more]]> 4 PhysicsForums mentioned on The Action Lab YouTube video Wed, 24 Jun 2026 09:41:43 +0000 https://www.physicsforums.com/threads/physicsforums-mentioned-on-the-action-lab-youtube-video.1085504/ urn:xenforo:thread:1085504 invalid@example.com (scottdave) scottdave I came across this YouTube Short from The Action Lab. I thought it was pretty cool that he searched Reddit and PhysicsForums when researching a reason for the effect.
]]> 9 Method of storing energy on the Moon Wed, 24 Jun 2026 08:40:24 +0000 https://www.physicsforums.com/threads/method-of-storing-energy-on-the-moon.1083971/ urn:xenforo:thread:1083971 invalid@example.com (Al_) Al_ Batteries bad

The article linked above says batteries are problematic in space. I propose a flywheel, which is suited to the Lunar environment. 1) It is in vacuum already. 2) Magnetic suspension is less demanding in 1/6 gravity. 3) Superconductors need very low temperatures which are...

Read more]]> 49 Can Curved Spacetime Enable Faster-Than-Light Travel? Tue, 23 Jun 2026 23:11:12 +0000 https://www.physicsforums.com/threads/can-curved-spacetime-enable-faster-than-light-travel.1051680/ urn:xenforo:thread:1051680 invalid@example.com (Marcarious Thomas) Marcarious Thomas Based on the current understanding of general relativity, it is possible that curving spacetime in the back of a spacecraft would allow for faster-than-light travel. In general relativity, the curvature of spacetime is determined by the universe's distribution of matter and energy. If a...

Read more]]> 13 Collection of Free Online Math Books and Lecture Notes (part 1) Tue, 23 Jun 2026 19:18:44 +0000 https://www.physicsforums.com/threads/collection-of-free-online-math-books-and-lecture-notes-part-1.1044710/ urn:xenforo:thread:1044710 invalid@example.com (malawi_glenn) malawi_glenn School starts soon, and I know students are looking to get their textbooks at bargain prices 🤑

Inspired by this thread I thought that I could share some of my findings of 100% legally free textbooks and lecture notes in mathematics and mathematical physics (mostly focused on...

Read more]]> 20 Ampère's mercury experiment and Aharonov-Bohm: same message? Tue, 23 Jun 2026 14:09:26 +0000 https://www.physicsforums.com/threads/amperes-mercury-experiment-and-aharonov-bohm-same-message.1085446/ urn:xenforo:thread:1085446 invalid@example.com (Roberto Pavani) Roberto Pavani I'd like to share an observation and ask if others find it compelling.

Consider a current-carrying loop that tends to expand. This is usually explained by the Lorentz force (IL×B) on each segment due to the field of the other segments.
Equivalently, one can describe it in terms of the...

Read more]]> 15 3I/ATLAS, Interstellar Comet Tue, 23 Jun 2026 13:42:44 +0000 https://www.physicsforums.com/threads/3i-atlas-interstellar-comet.1081721/ urn:xenforo:thread:1081721 invalid@example.com (Astronuc) Astronuc 3I/ATLAS, also known as C/2025 N1 (ATLAS) and formerly designated as A11pl3Z, is an iinterstellar comet. It was discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) station at Río Hurtado, Chile on 1 July 2025.

Note: it was mentioned (as...

Read more]]> 22 I completed 11th class suggest me the best IPMAT coaching in India Tue, 23 Jun 2026 12:52:42 +0000 https://www.physicsforums.com/threads/i-completed-11th-class-suggest-me-the-best-ipmat-coaching-in-india.1084476/ urn:xenforo:thread:1084476 invalid@example.com (rohanrathore) rohanrathore TL;DR: I’ve just completed my Class 11 exams and I’m planning to prepare for IPMAT to get into IIM Indore’s Integrated Program in Management.

I’ve just completed my Class 11 exams and I’m planning to prepare for IPMAT to get into IIM Indore’s Integrated Program in Management. Which...

Read more]]> 3 Two balls, dropped with a delay of ##\Delta t##, meet after rebound Tue, 23 Jun 2026 12:01:26 +0000 https://www.physicsforums.com/threads/two-balls-dropped-with-a-delay-of-delta-t-meet-after-rebound.1059162/ urn:xenforo:thread:1059162 invalid@example.com (brotherbobby) brotherbobby 1705564451496.png
I draw a series of images of the problem situation. In (a), the first ball in green is (just) dropped at time ##t=0##. In (b), the second ball in red is dropped at time ##t=2\;\text{s}##. In (c), the first ball rebounds after a total time of falling down ##t_d##. At this position...

Read more]]> 35 Why is water pressure increased in a plastic bag in a bucket? Tue, 23 Jun 2026 11:30:27 +0000 https://www.physicsforums.com/threads/why-is-water-pressure-increased-in-a-plastic-bag-in-a-bucket.1083804/ urn:xenforo:thread:1083804 invalid@example.com (ImaginaryTango) ImaginaryTango I'm not a physicist or even a physics student, I'm a pottery student and there's a conundrum that's been puzzling potters in my area for a while. We've found that if a block of clay dries out, the fastest and best way to revitalize the clay is to put it in a bag of water, tie the bag so it's...

Read more]]> 75 Published electroweak coincidences Tue, 23 Jun 2026 02:23:05 +0000 https://www.physicsforums.com/threads/published-electroweak-coincidences.1085257/ urn:xenforo:thread:1085257 invalid@example.com (arivero) arivero I have been told of a new preprint of Emilio Torrente-Lujan that revisits his publication Eur. Phys. J. C 74 (2014) 2744, arXiv:1209.0474 of coincidences in the electroweak scale. If I recall correctly we revised in the forum a lot of them, at the time of preprints, but I have...

Read more]]> 2 Question about a proof of the converse of Thales' theorem Tue, 23 Jun 2026 01:31:11 +0000 https://www.physicsforums.com/threads/question-about-a-proof-of-the-converse-of-thales-theorem.1081240/ urn:xenforo:thread:1081240 invalid@example.com (murshid_islam) murshid_islam I was watching this series of videos of Eddie Woo proving Thales' theorem and its converse. I didn't understand this part (at 2:15) where he considered (x–u)(x–v) = 0. He later used the result he got from considering that. But why consider it in the first place?

]]> 1 Is the massless survivor of an SMG gapped phase genuinely chiral? Tue, 23 Jun 2026 01:02:57 +0000 https://www.physicsforums.com/threads/is-the-massless-survivor-of-an-smg-gapped-phase-genuinely-chiral.1085470/ urn:xenforo:thread:1085470 invalid@example.com (albronco1) albronco1 Consider a vector-like lattice gauge theory whose fermion content has Weyl number ≡ 0 (mod 16) i.e. anomaly-free in the sense that admits symmetric mass generation, the 16 of SO(10) / one SM generation being the canonical example tuned near the lower edge of the conformal window. Now switch on a...

Read more]]> 11