en-US Physics Forums RSS Feed This is the official global feed for PhysicsForums.com Wed, 10 Jun 2026 21:22:20 +0000 Wed, 10 Jun 2026 21:22:20 +0000 Physics Forums https://www.physicsforums.com/ The ugliest moon in the solar system. Wed, 10 Jun 2026 21:05:44 +0000 https://www.physicsforums.com/threads/the-ugliest-moon-in-the-solar-system.1085449/ 1085449 invalid@example.com (Algr) Algr In this universe, mankind looked up at the sky and said... Yuck. Humans looked upwards. In our world they saw hope, romance, and delicate beauty. In that world they saw this thing. Their eyes turned down, they continued to exist as mortals, but the civilizations and cultures withered and...

Read more]]> 1 Probability puzzle Wed, 10 Jun 2026 20:55:13 +0000 https://www.physicsforums.com/threads/probability-puzzle.1085380/ 1085380 invalid@example.com (WMDhamnekar) WMDhamnekar Two players start 1 meter away from a target. They simultaneously begin moving towards the target at a same constant speed. If the left player shoots when he is X meters from the target, his shot hit with a probability 1-X...

Read more]]> 21 Today I Learned Wed, 10 Jun 2026 20:49:41 +0000 https://www.physicsforums.com/threads/today-i-learned.783257/ 783257 invalid@example.com (Greg Bernhardt) Greg Bernhardt Every day we learn new things. Sometimes it's just a small fact or realization. No matter how trivial or random, let's start recording our daily lessons.

Please start off with "Today I learned". Keep commentary to a minimum and just LIKE posts. I'll start!

Today I learned that you clean...

Read more]]> 6951 Is AI Overhyped? Wed, 10 Jun 2026 20:33:00 +0000 https://www.physicsforums.com/threads/is-ai-overhyped.1080669/ 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]]> 441 The History of Various Anesthetics and Remedies.... Wed, 10 Jun 2026 20:27:32 +0000 https://www.physicsforums.com/threads/the-history-of-various-anesthetics-and-remedies.1084995/ 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]]> 20 Textbook Sequence Request: Entering B.Sc. Physics (Theoretical Focus) Wed, 10 Jun 2026 20:17:54 +0000 https://www.physicsforums.com/threads/textbook-sequence-request-entering-b-sc-physics-theoretical-focus.1085306/ 1085306 invalid@example.com (okabe rintarou) okabe rintarou Hello, I have recently completed high school (Class 12, CBSE board in India). I have a solid foundational grasp of standard high school mechanics, electromagnetism, and modern physics based on that curriculum. However, I want to rebuild and elevate my foundations rigorously for university...

Read more]]> 11 Random Photos Wed, 10 Jun 2026 20:01:49 +0000 https://www.physicsforums.com/threads/random-photos.994801/ 994801 invalid@example.com (Point Conception) Point Conception A topic for random photos: Ko-Larn island 7 km West of PattayaIMG_20200717_114141.jpg]]> 3789 Weird News Compilation Wed, 10 Jun 2026 19:04:01 +0000 https://www.physicsforums.com/threads/weird-news-compilation.878428/ 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]]> 2151 Wordle Lovers - Play the NYT Daily Game Wed, 10 Jun 2026 18:36:34 +0000 https://www.physicsforums.com/threads/wordle-lovers-play-the-nyt-daily-game.1016903/ 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.]]> 8544 About Snapping Turtles Wed, 10 Jun 2026 18:17:21 +0000 https://www.physicsforums.com/threads/about-snapping-turtles.1085448/ 1085448 invalid@example.com (.Scott) .Scott I never gave much thought about the species range of snapping turtle until I read this article - about a snapper found a few miles north of Swansea, UK.

The snapper photographed in the article probably has a shell that's about a foot long. That's a full grown snapper, but not at all as...

Read more]]> 2 Collection of Lame Jokes Wed, 10 Jun 2026 18:14:24 +0000 https://www.physicsforums.com/threads/collection-of-lame-jokes.25301/ 25301 invalid@example.com (quddusaliquddus) quddusaliquddus Lamest joke you know ... :zzz:]]> 24091 New Member Here! Wed, 10 Jun 2026 17:53:58 +0000 https://www.physicsforums.com/threads/new-member-here.1085430/ 1085430 invalid@example.com (EruedraithH) EruedraithH Hello everyone!

I'm a college student with a passion for math, physics, philosophy, etc. I wanted to get more involved with the general physics community to meet others with common interest and to continue learning.

Thank you!]]> 12 Use of AI (ML/DL) in Science Wed, 10 Jun 2026 16:12:37 +0000 https://www.physicsforums.com/threads/use-of-ai-ml-dl-in-science.1083649/ 1083649 invalid@example.com (Astronuc) Astronuc We have many threads on AI, which are mostly AI/LLM, e.g,. ChatGPT, Claude, etc. It is important to draw a distinction between AI/LLM and AI/ML/DL, where ML = Machine Learning and DL = Deep Learning.

AI is a broad technology; the AI/ML/DL is being developed to handle large data sets, and even...

Read more]]> 8 Limit behaviour of Fibonacci sequence Wed, 10 Jun 2026 15:33:22 +0000 https://www.physicsforums.com/threads/limit-behaviour-of-fibonacci-sequence.1085422/ 1085422 invalid@example.com (PeroK) PeroK I thought this might be quite interesting to anyone who hasn't seen it before.

Consider any Fibonacci sequence, where ##F_1 > F_0 \ge 0## and ##F_{n+1} = F_n + F_{n-1} \ (n > 1)##. We want to show that the ratio of consecutive terms, ##a_n = \dfrac{F_{n+1}}{F_n}## tends to the Golden Ratio...

Read more]]> 3 The Nuclear Power Thread Wed, 10 Jun 2026 14:07:16 +0000 https://www.physicsforums.com/threads/the-nuclear-power-thread.9091/ 9091 invalid@example.com (russ_watters) russ_watters I'd like to start a discussion/debate of nuclear power for the purpose of informing people about it. I am participating in a thread in another forum http://www.badastronomy.com/phpBB/viewtopic.php?t=9370 where we are discussing an article about Germany planning to phase out nuclear...

Read more]]> 1225 Back to School! Wed, 10 Jun 2026 13:53:41 +0000 https://www.physicsforums.com/threads/back-to-school.1085447/ 1085447 invalid@example.com (cnh1995) cnh1995 Hello everyone,
It's been a long time since I posted anything here on PF.

After graduating in 2017 with a bachelors degree in EE, I have been working in software domain for the past 8.5 years (2.5 years in Japan).
I recently took the national-level entrance test for masters in Engineering in...

Read more]]> 2 Ampère's mercury experiment and Aharonov-Bohm: same message? Wed, 10 Jun 2026 13:41:56 +0000 https://www.physicsforums.com/threads/amperes-mercury-experiment-and-aharonov-bohm-same-message.1085446/ 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]]> 13 The effect of a radio wave on an electron Wed, 10 Jun 2026 10:35:18 +0000 https://www.physicsforums.com/threads/the-effect-of-a-radio-wave-on-an-electron.1085236/ 1085236 invalid@example.com (brotherbobby) brotherbobby Statement of the problem : The problem is a solved example in Kleppner and Kollenkow's book, p. 21. The example is titled : "The Effect of a Radio Wave on an Ionospheric Electron". I copy and paste the example below and underline the last bit in red, which is my area of doubt...

Read more]]> 34 Another dumb SocMed quiz Wed, 10 Jun 2026 06:48:39 +0000 https://www.physicsforums.com/threads/another-dumb-socmed-quiz.1085444/ 1085444 invalid@example.com (DaveC426913) DaveC426913 1781050618201.webp

I say yes he will. Electricity follows all paths, including the path from one hand to the other.

The current he will receive will be proportional to the resistance of the wire (very small) over the resistance of his body (very large) - which will thus be very small, but not...

Read more]]> 5 AI Enriched Problem Solving Wed, 10 Jun 2026 05:07:42 +0000 https://www.physicsforums.com/threads/ai-enriched-problem-solving.1084382/ 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]]> 24 Photons and free quantum particles Wed, 10 Jun 2026 03:48:18 +0000 https://www.physicsforums.com/threads/photons-and-free-quantum-particles.1085420/ 1085420 invalid@example.com (hokhani) hokhani Consider a light source, like lamp, that radiates photons in vacuum. Can we detect a particular photon, moving in a specific direction, always at one point or the photon is localised and moves from one point to another? In other words, I would like to know that like free quantum particles...

Read more]]> 5 Small Hopper and Silo Design for Green Coffee Wed, 10 Jun 2026 01:08:36 +0000 https://www.physicsforums.com/threads/small-hopper-and-silo-design-for-green-coffee.1085443/ 1085443 invalid@example.com (zleb00) zleb00 Hey all,

I'm trying to design a small silo for green coffee for my small business. That 4'-10" is my max. height and I want it to be around 4' wide.

This silo will be square since that will be a little easier for my fabricator to put together.

How important is it that the walls be approx. 60...

Read more]]> 2 Is bioelectricity considered more physics or biology? Wed, 10 Jun 2026 00:15:39 +0000 https://www.physicsforums.com/threads/is-bioelectricity-considered-more-physics-or-biology.1085442/ 1085442 invalid@example.com (BeablossomR_) BeablossomR_ Hi everyone,

I’ve been trying to understand bioelectricity, especially how neurons transmit signals, and I’m not sure whether it’s better approached from a physics or biology perspective.

From a physics point of view, I’ve seen it compared to basic electrical systems, while biologically it...

Read more]]> 3 Kitten Lovers: Cuteness Overload Tue, 09 Jun 2026 23:59:57 +0000 https://www.physicsforums.com/threads/kitten-lovers-cuteness-overload.130472/ 130472 invalid@example.com (Evo) Evo This was just so damned cute, it deserved it's own thread.

Whenever I see cute kittens I can't help thinking of MIH, Tsu, Ivan, and Integral, and now Moonbear.

Moonbear, how's the kitty doing? We need an update!

This is quite the socially adept kitten, covering a yawn.

yawnmf9.jpg]]> 3884 Geometry Puzzle: Cut The Figure to Make Two Identical Parts Tue, 09 Jun 2026 23:52:08 +0000 https://www.physicsforums.com/threads/geometry-puzzle-cut-the-figure-to-make-two-identical-parts.1085396/ 1085396 invalid@example.com (bob012345) bob012345 Here is a little puzzle from Pierre Berloquin’s book 100 Geometric Games. The goal is to cut the figure once to make two identical parts. Have fun!

IMG_5751.webp]]> 21 Space Stuff and Launch Info Tue, 09 Jun 2026 21:53:25 +0000 https://www.physicsforums.com/threads/space-stuff-and-launch-info.879196/ 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]]> 1657 Rush Redux 2026 Tue, 09 Jun 2026 21:30:52 +0000 https://www.physicsforums.com/threads/rush-redux-2026.1084378/ 1084378 invalid@example.com (Astronuc) Astronuc Geddy Lee and Alex Lifeson apparently decided reform Rush for a new road tour in 2026-2027.

Lifeson came over to Europe for some health checks, and Lee decided to come with him. Once they were here, they decided they may as well talk to some journalists about Rush’s upcoming R50 reunion...

Read more]]> 6 Hello, New Member Here! Zleb00 Tue, 09 Jun 2026 20:07:13 +0000 https://www.physicsforums.com/threads/hello-new-member-here-zleb00.1085441/ 1085441 invalid@example.com (zleb00) zleb00 Hey All,

New Member here, I'm interested in asking questions about factory processes and applications!]]> 1 Simulating an RBMK-1500 like the one in Ignalina Tue, 09 Jun 2026 17:52:08 +0000 https://www.physicsforums.com/threads/simulating-an-rbmk-1500-like-the-one-in-ignalina.1085438/ 1085438 invalid@example.com (KriegerTomate) KriegerTomate I have set myself a project on making a simulation of the RBMK-1500 at the Ignalina NPP.
i know this will take a very long time to do but i have hit a wall it seems.
i cannot find any real close up photos / diagrams of the control room panels, anunciators, buttons etc. Does anyone know where i...

Read more]]> 1 Spacing between metal sheet and dielectric radome for best RCS Tue, 09 Jun 2026 17:04:39 +0000 https://www.physicsforums.com/threads/spacing-between-metal-sheet-and-dielectric-radome-for-best-rcs.1085439/ 1085439 invalid@example.com (Silvester) Silvester I'm working on a project about designing a radome for a reflector/scattering object like RIS or reflectarray. I run simulations on HFSS. For simplicity and the purpose of seeking regularity, i start with a dielectric radome(with relative permittivity = 3) and copper sheet.

Suppose that (1)large...

Read more]]> 3 Physics Tue, 09 Jun 2026 14:20:37 +0000 https://www.physicsforums.com/threads/physics.1085440/ 1085440 invalid@example.com (Sakhile Sizwe Nyembe) Sakhile Sizwe Nyembe My Name is Sakhile Nyembe I am a student who love physics,and wishing to pursue a carrer in Theoretical Physicsist.]]> 1 ATARS system Tue, 09 Jun 2026 13:19:16 +0000 https://www.physicsforums.com/threads/atars-system.1085426/ 1085426 invalid@example.com (LTT9) LTT9 Does anyone happen to know what kind of image source Red6's ATARS system uses? Does the 18,000-nit brightness specification listed on the official website refer to the display's brightness?]]> 6 Speaking of Lorentz-Fitzgerald Contraction... Tue, 09 Jun 2026 12:18:00 +0000 https://www.physicsforums.com/threads/speaking-of-lorentz-fitzgerald-contraction.1085421/ 1085421 invalid@example.com (sbrothy) sbrothy 1780838603649.webp]]> 1 Does the Lorentz factor aid understanding of SR, or obscure it? Tue, 09 Jun 2026 10:18:57 +0000 https://www.physicsforums.com/threads/does-the-lorentz-factor-aid-understanding-of-sr-or-obscure-it.1085404/ 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]]> 14 A question about quantum entanglement Tue, 09 Jun 2026 10:09:34 +0000 https://www.physicsforums.com/threads/a-question-about-quantum-entanglement.1085391/ 1085391 invalid@example.com (BadgerBadger92) BadgerBadger92 How do a pair of particles via entanglement “know” what the other particle is doing? Any help is appreciated.]]> 30 Could the Foucault precession be an incomplete forcing? Tue, 09 Jun 2026 07:59:39 +0000 https://www.physicsforums.com/threads/could-the-foucault-precession-be-an-incomplete-forcing.1085435/ 1085435 invalid@example.com (Simon F) Simon F The standard explanation of the Foucault pendulum is purely kinematic: the plane of oscillation stays fixed in inertial space while the planet rotates beneath it. But Norman Phillips (2000, 2001) showed that real forces — the horizontal component of Newtonian gravitation and centrifugal...

Read more]]> 2 Singularity Theorems Tue, 09 Jun 2026 06:39:06 +0000 https://www.physicsforums.com/threads/singularity-theorems.1085431/ 1085431 invalid@example.com (Matterwave) Matterwave My (very) rough sketch of the set up of the time-like singularity theorems as presented by Wald:

1. Get Raychaduri eqns and find that caustics form within finite proper time (given SEC and initially negative expansion).
2. Find conjugate points corresponding to those caustics between points in...

Read more]]> 8 Why ##a^0=1##? Tue, 09 Jun 2026 03:56:04 +0000 https://www.physicsforums.com/threads/why-a-0-1.1084807/ 1084807 invalid@example.com (Mike_bb) Mike_bb Hello!

I have problem in understanding why ##a^0=1##.

I represent ##a^x## as ##1*a*a*a*a*...*a## (x times)

Why ##a^0=1##? Why is ##a^0## not equal to ##0##?

Thanks.]]> 44 Musing on the Foundations of Statistical Mechanics Tue, 09 Jun 2026 03:54:29 +0000 https://www.physicsforums.com/threads/musing-on-the-foundations-of-statistical-mechanics.1085368/ 1085368 invalid@example.com (Matterwave) Matterwave Hello~

I've been reading about the Foundations of Statistical Mechanics recently and found the topic of foundations Entropy quite interesting (although I haven't actually gotten to the section on Entropy yet in the book I'm reading -- A. I. Khinchin Foundations of SM). I was wondering if this...

Read more]]> 15 About wavefunction collapse and explaining single outcomes in different interpretations Tue, 09 Jun 2026 02:13:31 +0000 https://www.physicsforums.com/threads/about-wavefunction-collapse-and-explaining-single-outcomes-in-different-interpretations.1084870/ 1084870 invalid@example.com (olgerm) olgerm Suppose one photon goes through an interferometer and then hits a screen. A device detects the hit position, digitizes it, and later a person Bob reads the output.

1. Before detection​

Initially the total wavefunction ##\Psi## describes:
  • the photon moving toward the interferometer...

Read more]]> 14 Independent researcher seeking arXiv endorser in gr-qc Mon, 08 Jun 2026 23:35:44 +0000 https://www.physicsforums.com/threads/independent-researcher-seeking-arxiv-endorser-in-gr-qc.1085432/ 1085432 invalid@example.com (Andrew_Jeremiah) Andrew_Jeremiah Hello, I am Andrew Jeremiah, an independent researcher from Brazil with a background in architecture. I have developed a geometric framework for emergent gravity — Quantum Granodynamics of Spacetime (QGDS) — in which spacetime is modeled as a collection of topological boundaries between two...

Read more]]> 1 -6dB loss phemonena in differential pair signaling Mon, 08 Jun 2026 23:20:10 +0000 https://www.physicsforums.com/threads/6db-loss-phemonena-in-differential-pair-signaling.1085326/ 1085326 invalid@example.com (yefj) yefj In differential port 1 we have same power going threw 1 SE and 3 SE. we get the ouput at 2 SE and 4 SE.

suppose 2SE is faulty.What whould be the value of SDD21?how SDD21 in that case? What is the mathematical logic we get -6dB in SDD21? Thanks.
1780110344773.webp]]> 8 How best to learn? How to get 100%? Mon, 08 Jun 2026 22:02:03 +0000 https://www.physicsforums.com/threads/how-best-to-learn-how-to-get-100.1085382/ 1085382 invalid@example.com (IneedA) IneedA Homework Statement: I see people saying to understand concepts instead of memorizing.
Relevant Equations: Barely gonna start calculus-based physics. My question is how do i understand concepts and when do i know i have understood them fully? I would like a step by step to this with...

Read more]]> 53 Why is the growth of exps & logs so fast & slow, respectively? Mon, 08 Jun 2026 20:12:46 +0000 https://www.physicsforums.com/threads/why-is-the-growth-of-exps-logs-so-fast-slow-respectively.1053974/ 1053974 invalid@example.com (mcastillo356) mcastillo356 Hi, PF, there goes the theorem, questions, and attempt
THEOREM 4 If ##x>0##, then ##\ln x\leq{x-1}##
PROOF Let ##g(x)=\ln x-(x-1)## for ##x>0##. Then ##g(1)=0## and

##g'(x)=\displaystyle\frac{1}{x}-1\quad\begin{cases}>0&\mbox{if}\,0<x<1\\
<0&\mbox{if}\,x>1\end{cases}## (...)...

Read more]]> 6 Material property comparison based on TDR and delta L Mon, 08 Jun 2026 19:39:04 +0000 https://www.physicsforums.com/threads/material-property-comparison-based-on-tdr-and-delta-l.1085407/ 1085407 invalid@example.com (yefj) yefj Hello ,As you can see in the plot bellow I have made several TDR of different materials on one plot.
I need to deside which is the best material to use.
Also I know that based on (S21_10inch-S21_5inch)/L I find the loss per inch.
Two questions:
1.after I find the loss per inch how do I find the...

Read more]]> 4 The Quantum Mechanics of Experiments Mon, 08 Jun 2026 19:02:00 +0000 https://www.physicsforums.com/threads/the-quantum-mechanics-of-experiments.1085220/ 1085220 invalid@example.com (Morbert) Morbert A paper some people might find interesting: https://arxiv.org/abs/2603.25335

Froehlich's work has come up a few times here (E.g. https://www.physicsforums.com/threa...e-deeper-meaning-of-quantum-mechanics.972179/ ). It's a stochastic, histories based approach, but...

Read more]]> 2 How valid is the indivisible interpretation of quantum mechanics? Mon, 08 Jun 2026 18:21:24 +0000 https://www.physicsforums.com/threads/how-valid-is-the-indivisible-interpretation-of-quantum-mechanics.1085197/ 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.]]> 40 Greetings! New Member here Mon, 08 Jun 2026 15:00:50 +0000 https://www.physicsforums.com/threads/greetings-new-member-here.1085392/ 1085392 invalid@example.com (BeablossomR_) BeablossomR_ Hello everyone,


I’m a new member. I joined this forum to learn more about physics and related topics. I’m still a beginner, but I’m interested in understanding concepts better and improving my knowledge over time.


I’m looking forward to reading discussions and learning from the community...

Read more]]> 2 M7.8 offshore southern Mindanao, Phillipines Mon, 08 Jun 2026 12:30:12 +0000 https://www.physicsforums.com/threads/m7-8-offshore-southern-mindanao-phillipines.1085428/ 1085428 invalid@example.com (davenn) davenn Off my Sydney seismo this morning ......

M 7.8 - 26 km SW of Kablalan, Philippines​

    • 2026-06-07 23:37:41 (UTC)
    • 5.592°N 125.047°E
    • 55.2 km depth
High gain and low gain sensors]]> 1 Share Animal Pictures: For Animal Lovers Mon, 08 Jun 2026 02:03:26 +0000 https://www.physicsforums.com/threads/share-animal-pictures-for-animal-lovers.583729/ 583729 invalid@example.com (micromass) micromass Post your favorite animal pictures here!]]> 3033 Quantum field theory vs. super string theory? Mon, 08 Jun 2026 00:45:46 +0000 https://www.physicsforums.com/threads/quantum-field-theory-vs-super-string-theory.1085393/ 1085393 invalid@example.com (BadgerBadger92) BadgerBadger92 I know that a particle or wave (correct me if I’m wrong) is an excitation of underlying quantum fields.

Then there’s string theory which says that particles are “strings.”

Are these two theories connected in some way?]]> 4 The problem of energy appearing out of nowhere Sun, 07 Jun 2026 20:15:10 +0000 https://www.physicsforums.com/threads/the-problem-of-energy-appearing-out-of-nowhere.1085408/ 1085408 invalid@example.com (DanteKennedy) DanteKennedy To help with the idea, imagine a box sits in lab in frame S. At some moment, it somehow spontaneously creates 10 J of energy from nothing, without any push, so its momentum doesn't change: ΔE = 10 J, Δp = 0.
Observer S' moves past at v = 0.6c (so γ = 1.25).
Does this energy-creation event look...

Read more]]> 33 Is my reasoning sound for challenging this exploratory analysis? Sun, 07 Jun 2026 20:05:49 +0000 https://www.physicsforums.com/threads/is-my-reasoning-sound-for-challenging-this-exploratory-analysis.1085412/ 1085412 invalid@example.com (mattmaci) mattmaci This is a real exploratory analysis conducted by a company and submitted to my country's environmental authority.

I would like to know your opinion on the analysis and whether my observations are valid. In particular, I would like to know whether, based on the formulation of the problem, it...

Read more]]> 5 AI vs. Humans as Processors in an Environment Sun, 07 Jun 2026 19:54:56 +0000 https://www.physicsforums.com/threads/ai-vs-humans-as-processors-in-an-environment.1085274/ 1085274 invalid@example.com (BillTre) BillTre Humans and AI systems have the possibility to be competing systems in an environment of limited resources. Where the use of both people (as communities) and large energy and water consuming sites in the same areas (areas supplied by some economically available source), competition will ensue...

Read more]]> 74 Problems with large LaTeX posts and Preview Sun, 07 Jun 2026 19:53:46 +0000 https://www.physicsforums.com/threads/problems-with-large-latex-posts-and-preview.1085429/ 1085429 invalid@example.com (PeroK) PeroK
kuruman said:
Is stuff missing from this post or is it my browser?
The Latex disappears. It comes and it goes. The software on this site has been problematic for years!

[Mentor Note: side discussion about LaTeX issue split off from original thread]]]> 14 Biographies, History, Philosophy of Physics Sun, 07 Jun 2026 19:10:54 +0000 https://www.physicsforums.com/threads/biographies-history-philosophy-of-physics.1060020/ 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]]> 301 Favorite songs (cont.) Sun, 07 Jun 2026 18:33:42 +0000 https://www.physicsforums.com/threads/favorite-songs-cont.1064857/ 1064857 invalid@example.com (DennisN) DennisN Hi, I'm starting a brand new thread for our favorite songs...
(the last one disappeared some time ago, and we have to have a new one, I think :smile:)

..a thread for any genre, any style of music, as Cole Porter once wrote, anything goes... :smile:

Anything Goes by Cole Porter...

Read more]]> 247 Who is your favorite Jazz musician and what is your favorite song? Sun, 07 Jun 2026 18:25:38 +0000 https://www.physicsforums.com/threads/who-is-your-favorite-jazz-musician-and-what-is-your-favorite-song.1051251/ 1051251 invalid@example.com (BadgerBadger92) BadgerBadger92 I have always liked Jazz music (and blues, electric blues to be particular)

Who is your favorite musician and song?

I’ve always liked Herbie Hancock, especially his song “Maiden Voyage.”

]]> 364 Some more of my photography Sun, 07 Jun 2026 13:31:03 +0000 https://www.physicsforums.com/threads/some-more-of-my-photography.1085230/ 1085230 invalid@example.com (BadgerBadger92) BadgerBadger92 IMG_0403.webpIMG_0408.webpIMG_0407.webpIMG_0406.webpIMG_0404.webpIMG_0401.webp]]> 20 Solar Activity and Space Weather Update thread Sun, 07 Jun 2026 13:26:36 +0000 https://www.physicsforums.com/threads/solar-activity-and-space-weather-update-thread.923468/ 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]]> 460 Is Energy conservation among sectors (EM,GR,QM) a principle? Sun, 07 Jun 2026 11:47:47 +0000 https://www.physicsforums.com/threads/is-energy-conservation-among-sectors-em-gr-qm-a-principle.1085183/ 1085183 invalid@example.com (Roberto Pavani) Roberto Pavani Considering QM,EM,GR "sectors" we know that the energy conservation apply but this is a principle.

Noether theorem provides a justification of it for each sector but for the combined (intra-sector conservation) it seem a circular loop:
Energy is conserved through sectors -> I can write a...

Read more]]> 28 Ubuntu slow for compute-intensive applications? Sun, 07 Jun 2026 10:56:53 +0000 https://www.physicsforums.com/threads/ubuntu-slow-for-compute-intensive-applications.1081038/ 1081038 invalid@example.com (jack action) jack action I used to have Linux Lite as an OS. I like it but it has one major flaw: you cannot upgrade between series (each series is based on a Ubuntu LTS version), you have to reinstall from scratch.

I was still on series 5 (Ubuntu 20.04 LTS) for which security updates ended this year. I chose to move...

Read more]]> 17 Obtaining NRQM from QFT: Issues, Folklores and Facts by Padmanabhan Sun, 07 Jun 2026 01:12:54 +0000 https://www.physicsforums.com/threads/obtaining-nrqm-from-qft-issues-folklores-and-facts-by-padmanabhan.1085370/ 1085370 invalid@example.com (gentzen) gentzen Padmanabhan's paper "Obtaining the Non-relativistic Quantum Mechanics from Quantum Field Theory: Issues, Folklores and Facts" (https://arxiv.org/abs/1712.06605) is long (58 pages) and substantial, therefore it deserves its own thread.

Here is a recent discussion about Padmanabhan's paper...

Read more]]> 5 Hi! Can someone explain about Differential Equations? Sun, 07 Jun 2026 00:54:56 +0000 https://www.physicsforums.com/threads/hi-can-someone-explain-about-differential-equations.1085338/ 1085338 invalid@example.com (Sandra Jane) Sandra Jane So I'm new to engineering and have studied some of the calculus but until now, I still have a hard time to understand what is exactly Differential Equations, what is it for and how can I use it in the future classes as an Engineering Physics student]]> 11 Textbook description of R##\ddot{\text o}##mer's light speed calculation Sat, 06 Jun 2026 23:28:26 +0000 https://www.physicsforums.com/threads/textbook-description-of-r-ddot-text-o-mers-light-speed-calculation.1085375/ 1085375 invalid@example.com (brotherbobby) brotherbobby Statement of the problem : I copy and paste the clip from the text, underling in red the sentences where, in my opinion, the author(s) have gone wrong. I annonate to the right of the text in blue, assuming they are both readable. The text in question is titled Special and...

Read more]]> 27 I am new here Sat, 06 Jun 2026 21:52:18 +0000 https://www.physicsforums.com/threads/i-am-new-here.1085413/ 1085413 invalid@example.com (aleckx) aleckx estoy experimentando para ver hasta donde puede llegar la ia

[Mentor translation using Google Translate:]
I'm experimenting to see how far AI can go
]]> 1 Kilometers to Miles Numerology Sat, 06 Jun 2026 20:40:49 +0000 https://www.physicsforums.com/threads/kilometers-to-miles-numerology.1085409/ 1085409 invalid@example.com (kuruman) kuruman Screenshot 2026-06-06 at 9.44.18 AM.webpI recently had to convert 7,923 km to miles and used the web converter (see right). It turned out that 7,923 km = 4,923 mi ignoring the decimal change. The matching of the last three digits astonished me and I wondered if there is a systematic way to find additional conversion...

Read more]]> 6 Options due to Direct Message count limit on physicsforums system Sat, 06 Jun 2026 20:14:24 +0000 https://www.physicsforums.com/threads/options-due-to-direct-message-count-limit-on-physicsforums-system.1085401/ 1085401 invalid@example.com (symbolipoint) symbolipoint The point is, I am asking.
The Private Direct Message system on physicsforums is limited in how many messages are saved. Do we have some way of storing them off the system, or downloading the whole set of our PM's DM's at any time? Would members who become too active in the...

Read more]]> 2 Thermodynamics of capacitor filled with a linear ideal gas dielectric Sat, 06 Jun 2026 18:52:05 +0000 https://www.physicsforums.com/threads/thermodynamics-of-capacitor-filled-with-a-linear-ideal-gas-dielectric.1085242/ 1085242 invalid@example.com (frmn) frmn What I'm able to do so far :
The magnitude of the charge on the plates as a function of length L and ε should be
Q=CV_0=A_0ε/L × V_0 = A_0 V_0 ε / L
So the force on the top plate should be
F_elec = QE = A_0 V_0² ε / 2 L²
So for the process to proceed quasi statically, the force due to pressure...

Read more]]> 8 Help deciding between an applied math and physics bachelors Sat, 06 Jun 2026 16:05:51 +0000 https://www.physicsforums.com/threads/help-deciding-between-an-applied-math-and-physics-bachelors.1085405/ 1085405 invalid@example.com (gabriel202) gabriel202 Hi, I apologize if this question has been asked before. Where I'm from, the physics university is terrible (underfunded, professors who don't like lecturing, lack of students, etc). I want to one day do research in the areas of: theoretical physics, mathematical models used in theoretical...

Read more]]> 1 Colorado Rockies, Front Range, Water and Uranium Sat, 06 Jun 2026 16:00:44 +0000 https://www.physicsforums.com/threads/colorado-rockies-front-range-water-and-uranium.1085394/ 1085394 invalid@example.com (Astronuc) Astronuc

Reservoir built for nearly 1 million Coloradans stalls at 2% full after uranium is found​

https://www.yahoo.com/news/us/articles/reservoir-built-nearly-1-million-222500960.html

The reservoir is designed to hold Colorado River water for 12 growing Front Range communities...

Read more]]> 1 Clues to Homing Pigeon Navigation Mechanism Sat, 06 Jun 2026 15:46:30 +0000 https://www.physicsforums.com/threads/clues-to-homing-pigeon-navigation-mechanism.1085327/ 1085327 invalid@example.com (BillTre) BillTre Animal navigation, long mysterious, may about to become better understood.
An unexpected mechanism in homing pigeons appears to sense magnetic fields and transmit the signal to the nervous system in ill defined way.
Ferritin containing macrophages were found in the liver near nerve cells which...

Read more]]> 17 i like thoughtful observations Sat, 06 Jun 2026 15:23:54 +0000 https://www.physicsforums.com/threads/i-like-thoughtful-observations.1085406/ 1085406 invalid@example.com (rizzsea) rizzsea i am a 3rd year engineering cse student who likes to have look over every observable and mentioned phenomenon having strong curiosity to understand its functioning by reasonable scientific explanations provided by the people . I also like to add my own reasonings though no very sure if correct...

Read more]]> 1 Enviromental problems solver Sat, 06 Jun 2026 15:17:23 +0000 https://www.physicsforums.com/threads/enviromental-problems-solver.1085410/ 1085410 invalid@example.com (mattmaci) mattmaci Hi everyone.
I work for my country in enviromental projects.
Sometimes they get tough, and that's why I come here.]]> 1 The importance of SATs? Sat, 06 Jun 2026 12:44:05 +0000 https://www.physicsforums.com/threads/the-importance-of-sats.1085301/ 1085301 invalid@example.com (sbrothy) sbrothy I may have gotten the wrong impression from bad shows but it seems to me that, in the US, SATs are stupidly important for highschoolers to continue on college. In Denmark the only equivalent we have it admission to journalist academy. I mean if all I had to to was to score good on those...

Read more]]> 9 Iceberg A-23A turns blue, starts traveling and may break apart Sat, 06 Jun 2026 10:04:29 +0000 https://www.physicsforums.com/threads/iceberg-a-23a-turns-blue-starts-traveling-and-may-break-apart.1083800/ 1083800 invalid@example.com (Astronuc) Astronuc It is mid-Summer in the Southern Hemisphere

Massive iconic iceberg turns blue and is "on the verge of complete disintegration," NASA says
https://www.cbsnews.com/news/iceberg-a23a-turns-blue-verge-of-complete-disintegration-nasa/...

Read more]]> 5 Our Beautiful Universe - Photos and Videos Sat, 06 Jun 2026 08:53:22 +0000 https://www.physicsforums.com/threads/our-beautiful-universe-photos-and-videos.800540/ 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]]> 2427 Interpreting TDR properly Sat, 06 Jun 2026 07:13:28 +0000 https://www.physicsforums.com/threads/interpreting-tdr-properly.1085403/ 1085403 invalid@example.com (yefj) yefj Hello, the following photo represent TDR of differential straight line SDD11.my line is 8 inch BW is 67GHz.
Two questions:
1. I know that artificial ringing is accuring in TDR because we done have infinite BW.
How can I see the need for a window in the TDR and what type to use>

2.as you can...

Read more]]> 1 Design example for commercial high speed pcb Sat, 06 Jun 2026 05:10:13 +0000 https://www.physicsforums.com/threads/design-example-for-commercial-high-speed-pcb.1085229/ 1085229 invalid@example.com (yefj) yefj Hello ,Is there a PCB example which is routing differential signal over many layers.where there could be many differential ports in between then.
Is there such real life example I could try to do EM simulation from it?
Thanks.]]> 6 What Caused the Recent Power Outage in Spain, Portugal, and Southern France? Sat, 06 Jun 2026 04:56:57 +0000 https://www.physicsforums.com/threads/what-caused-the-recent-power-outage-in-spain-portugal-and-southern-france.1080043/ 1080043 invalid@example.com (Guineafowl) Guineafowl Can anyone offer some insight into the recent grid blackout in Spain, Portugal and southern France?

Possible causes/factors reported include a cyber attack, freak winds wrapping HV cables together, humidity and high temperatures causing physical oscillations and failures of cables, or a lack of...

Read more]]> 64 How can light be a wave and particle at the same time? Sat, 06 Jun 2026 02:29:38 +0000 https://www.physicsforums.com/threads/how-can-light-be-a-wave-and-particle-at-the-same-time.1085364/ 1085364 invalid@example.com (gronk) gronk I don't even have enough education in physics to even be considered a novice. And this might be a 'duh' observation. To begin with consider that we don't properly conceive what light really is. We define it in ways that we can work with it. What we define could just be like shining a...

Read more]]> 12 What is "x" in this definition of a basis? Sat, 06 Jun 2026 01:58:59 +0000 https://www.physicsforums.com/threads/what-is-x-in-this-definition-of-a-basis.1085331/ 1085331 invalid@example.com (Hill) Hill In this definition,
1780180214205.webp
what is ##x## in the property (ii)?

Did they mean, "(ii) For any open ##V \subset X## and any ##x \in V##, there exists some ##U \in \mathscr{B}## with ##
x \in U## and ##U \subset V##?
Or something else?]]> 4 Anyone see “Time After Time?” Fri, 05 Jun 2026 23:03:24 +0000 https://www.physicsforums.com/threads/anyone-see-time-after-time.1085395/ 1085395 invalid@example.com (BadgerBadger92) BadgerBadger92 I love this film, and everyone who is interested in time travel would love it.

It’s about HG Wells, who created a Time Machine chases Jack the Ripper in the future, who stole his Time Machine. Great movie.

Anyone else like this movie?]]> 1 Playing the guitar, the difference between being good and being a genius.... Fri, 05 Jun 2026 22:08:18 +0000 https://www.physicsforums.com/threads/playing-the-guitar-the-difference-between-being-good-and-being-a-genius.1080518/ 1080518 invalid@example.com (sbrothy) sbrothy In danger of blowing my own horn I consider myself moderately good at playing the guitar. Other people even tell me so. But, every time there's any danger of it going to my head I listen to this particular piece and I'm instantly put in my place:

]]> 140 How close are we to getting micro reactors? Fri, 05 Jun 2026 21:15:08 +0000 https://www.physicsforums.com/threads/how-close-are-we-to-getting-micro-reactors.1084891/ 1084891 invalid@example.com (Josiah) Josiah How close are we to getting micro reactors?]]> 7 Greetings from China – An independent amateur exploring fundamental physics Fri, 05 Jun 2026 17:37:30 +0000 https://www.physicsforums.com/threads/greetings-from-china-an-independent-amateur-exploring-fundamental-physics.1085389/ 1085389 invalid@example.com (tianchunsong) tianchunsong Hello,

I am an independent researcher working on a geometric framework for theoretical physics, based on the Berry connection on an information manifold. The framework derives from the single-electron double-slit experiment.

I am here to share my results and welcome technical feedback. I may...

Read more]]> 3 Does this equation (Einstein’s field equations in general relativity) equal 12? Fri, 05 Jun 2026 17:32:48 +0000 https://www.physicsforums.com/threads/does-this-equation-einsteins-field-equations-in-general-relativity-equal-12.1085334/ 1085334 invalid@example.com (BadgerBadger92) BadgerBadger92 This is a weird post but I posted on Facebook Einstein’s field equations in general relativity and I thought there could be numerous answers to this equation but some girl responded the answer was 12. Am I right in that there are numerous possible solutions or does it truly equal 12? Or is there...

Read more]]> 33 Long rod in orbit Fri, 05 Jun 2026 16:40:13 +0000 https://www.physicsforums.com/threads/long-rod-in-orbit.1085381/ 1085381 invalid@example.com (GTOM) GTOM Lets suppose we could place a long rod in orbit, at the distance of Moon.
Which would be the stabile position of the rod, perdendicular to the orbital path, or parallel to it?
I think parallel, to minimize tidal forces between the two opposite parts of the rod.]]> 14 Do you 'see' the CMB map as a 3D glass sphere/ellipsoid? Fri, 05 Jun 2026 15:51:59 +0000 https://www.physicsforums.com/threads/do-you-see-the-cmb-map-as-a-3d-glass-sphere-ellipsoid.1085386/ 1085386 invalid@example.com (Roberto Pavani) Roberto Pavani When I look at the standard Mollweide projection of the CMB, after a few seconds my brain seems to "un-project" it into a 3D object, as if I'm looking at a transparent glass rugby ball from the outside, with the CMB pattern painted on its surface.
I get the impression of seeing both the front...

Read more]]> 1 Physics/math: how much knowledge does a high school teacher need? Fri, 05 Jun 2026 15:37:45 +0000 https://www.physicsforums.com/threads/physics-math-how-much-knowledge-does-a-high-school-teacher-need.1084863/ 1084863 invalid@example.com (haushofer) haushofer Dear all,

as some of you may know I'm a math/physics teacher at a teachers education in Holland, where we prepare teachers at pre-university level high school. We focus mainly on teachers who are already licensed to teach in the first three years of pre-university high school ("2nd degree")...

Read more]]> 17 AI Disproves Unit Distance Conjecture Fri, 05 Jun 2026 15:35:00 +0000 https://www.physicsforums.com/threads/ai-disproves-unit-distance-conjecture.1085332/ 1085332 invalid@example.com (Hornbein) Hornbein
LLMs have solved Erdős problems before, but the one Price chose wasn’t just any Erdős problem. It was one that human mathematicians had worked on for 60 [Ed:80] years without success. The nature of the solution was also unusual. While previous LLM solutions to Erdős problems used standard...

Read more]]> 2 Cold fusion Fri, 05 Jun 2026 14:24:55 +0000 https://www.physicsforums.com/threads/cold-fusion.1085385/ 1085385 invalid@example.com (Josiah) Josiah Hi
I was just wondering if cold fusion works? If it doesn't why?]]> 5 Chua's oscillator circuit -- Intuitive picture Fri, 05 Jun 2026 11:49:58 +0000 https://www.physicsforums.com/threads/chuas-oscillator-circuit-intuitive-picture.1085317/ 1085317 invalid@example.com (Swamp Thing) Swamp Thing I have been trying to understand intuitively why Chua's circuit should want to toggle between modes as it does.

The aim is to internalize this concept the way a Steve Mould or a 3Blue1Brown might help me do :smile:

Which is closer to the truth:
(A) Rectification of the signal...

Read more]]> 47 Landau Mechanics Chapter 2 Problem 1: Direction of Potential Energy? Fri, 05 Jun 2026 09:27:12 +0000 https://www.physicsforums.com/threads/landau-mechanics-chapter-2-problem-1-direction-of-potential-energy.1085374/ 1085374 invalid@example.com (Rick16) Rick16 Problem Statement

A particle of mass m moving with velocity v1 leaves a half-space in which its potential energy is a constant U1 and enters another in which its potential energy is a different constant U2.
Determine the change in the direction of motion of the...

Read more]]> 12 Can Mathematical Models Explain Scenes from The Day the Earth Stood Still? Fri, 05 Jun 2026 02:52:39 +0000 https://www.physicsforums.com/threads/can-mathematical-models-explain-scenes-from-the-day-the-earth-stood-still.1054826/ 1054826 invalid@example.com (difalcojr) difalcojr This model diagram is possible when index0/index1=index1/index2=radius2/radius1 for the model's variables. 30 degree wave into a sphere. Reminded me of something out of that old science fiction movie, The Day the Earth Stood Still...

Read more]]> 120 FLRW metric challenged, Einstein-Euler equations as alternative? Fri, 05 Jun 2026 02:47:54 +0000 https://www.physicsforums.com/threads/flrw-metric-challenged-einstein-euler-equations-as-alternative.1085330/ 1085330 invalid@example.com (nomadreid) nomadreid The question concerns the article "The instability of critical and underdense Friedmann spacetimes at the Big Bang as an alternative to dark energy" by Alexander, Vogler & Temple in Volume 482, Issue 2338 (May 2026) of the Proceedings of the Royal Society A, found in the link...

Read more]]> 7 The Secrets of Prof. Verschure's Rosetta Stones Fri, 05 Jun 2026 00:58:31 +0000 https://www.physicsforums.com/threads/the-secrets-of-prof-verschures-rosetta-stones.1054432/ 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]]> 161 Philomena Cunk Interviews Brian Cox Thu, 04 Jun 2026 20:43:23 +0000 https://www.physicsforums.com/threads/philomena-cunk-interviews-brian-cox.1085335/ 1085335 invalid@example.com (Hornbein) Hornbein

I hope you may find this as hilarious as do I.]]> 15 Special relativity and diffracting beams Thu, 04 Jun 2026 19:31:04 +0000 https://www.physicsforums.com/threads/special-relativity-and-diffracting-beams.1085363/ 1085363 invalid@example.com (calacone) calacone Say there is a beam of light at 1 um (f=300 THz), and there is a particle traveling at constant speed along the axis of the beam, which is, say, a few mm or cm in diameter. Say the particle is going fast enough so that the shift brings the light down to the MHz level (v/c ~ 1- O(10^-16)). Then...

Read more]]> 3 Question about entanglement and spacetime Thu, 04 Jun 2026 16:52:05 +0000 https://www.physicsforums.com/threads/question-about-entanglement-and-spacetime.1085158/ 1085158 invalid@example.com (SchrodingersRat) SchrodingersRat Hi everyone, this is my first post.

As anyone interested in physics I am somewhat familiar with the concept of entanglement. Also I have read that contrary to what most people think about this phenomenon, the particles involved are not always exactly synchronized but one can actually seem to be...

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