en-US Physics Forums RSS Feed This is the official global feed for PhysicsForums.com Fri, 10 Apr 2026 09:06:05 +0000 Fri, 10 Apr 2026 09:06:05 +0000 Physics Forums https://www.physicsforums.com/ Does a moving particle count as a wave? Fri, 10 Apr 2026 08:54:14 +0000 https://www.physicsforums.com/threads/does-a-moving-particle-count-as-a-wave.1084781/ 1084781 invalid@example.com (far far away) far far away According to the definition of a wave from Wikipedia:
A wave is a propagating dynamic disturbance (change from equilibrium) of one or more quantities.


Now, imagine a particle as a disturbance in mass density that propagates through space and time. From this perspective, I cannot think of a...

Read more]]> 33 Black hole questions Fri, 10 Apr 2026 08:36:56 +0000 https://www.physicsforums.com/threads/black-hole-questions.1084727/ 1084727 invalid@example.com (EdwardRo) EdwardRo To start off, please understand that as much as I love physics and try to keep myself immersed in everything, my education in it doesn't extend past high school courses. I'm aware that I have a lot of holes in my knowledge and understanding, so please be gentil with me.

Today I was watching an...

Read more]]> 21 Wordle Lovers - Play the NYT Daily Game Fri, 10 Apr 2026 07:33:54 +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.]]> 8314 Understanding the Coriolis force Fri, 10 Apr 2026 06:18:20 +0000 https://www.physicsforums.com/threads/understanding-the-coriolis-force.1083779/ 1083779 invalid@example.com (brotherbobby) brotherbobby 1767861312645.webp
I copy and paste the relavant paragraphs and images from the text. I might have to do it several times, each time underlining in red what I failed to follow. Here's the first.

Statement : "Here the acceleration is in a plane perpendicular to ##\mathbf\Omega##".

Sure...

Read more]]> 10 This One Moved Me Fri, 10 Apr 2026 05:46:05 +0000 https://www.physicsforums.com/threads/this-one-moved-me.1084780/ 1084780 invalid@example.com (bhobba) bhobba See:


Thanks
Bill]]> 4 Live data from Artemis 2? Fri, 10 Apr 2026 04:19:58 +0000 https://www.physicsforums.com/threads/live-data-from-artemis-2.1084771/ 1084771 invalid@example.com (LightningInAJar) LightningInAJar I was wondering if there is live data from Artemis 2 for the public? Like location in space beyond distance from earth? I would love to see a live path of travel. Hoping Universe Sandbox creates a simulation of the trip after they return.]]> 5 Free‑Carrier Index Modulation in Thin Transparent Layers at Visible Wa Fri, 10 Apr 2026 03:57:49 +0000 https://www.physicsforums.com/threads/free-carrier-index-modulation-in-thin-transparent-layers-at-visible-wa.1084804/ 1084804 invalid@example.com (rcc01) rcc01 I’m an electronics engineer trying to understand the physical limits of using free‑electron density to modulate the refractive index of a thin, transparent layer at visible wavelengths. My original thought involved a low‑density gas plasma, but based on recent feedback here, I now understand...

Read more]]> 1 “Appropriate Modeling Approach for Thin Plasma Layers” Fri, 10 Apr 2026 00:20:52 +0000 https://www.physicsforums.com/threads/appropriate-modeling-approach-for-thin-plasma-layers.1084797/ 1084797 invalid@example.com (rcc01) rcc01 I’m trying to understand how to model EM wave propagation through a very thin, low‑density plasma layer (micron‑scale thickness). The plasma frequency is well below optical frequencies, so the layer remains transparent.

My questions are:

  1. Can such a thin plasma sheet be treated using...

Read more]]> 5 The Secrets of Prof. Verschure's Rosetta Stones Thu, 09 Apr 2026 22:31:43 +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]]> 153 Artemis 2 launch - humans return to the Moon after 54 years Thu, 09 Apr 2026 22:28:51 +0000 https://www.physicsforums.com/threads/artemis-2-launch-humans-return-to-the-moon-after-54-years.1084732/ 1084732 invalid@example.com (mfb) mfb The Artemis program in the US aims to return to the Moon, land, and work on long-term expeditions and a permanent Moon base. At least for initial missions, astronauts will launch in an Orion capsule on top of the Space Launch System (SLS), and return in Orion. SLS and Orion made a first uncrewed...

Read more]]> 67 Can alpha radiation make other materials radioactive? Thu, 09 Apr 2026 22:12:44 +0000 https://www.physicsforums.com/threads/can-alpha-radiation-make-other-materials-radioactive.1054787/ 1054787 invalid@example.com (ErikSwan) ErikSwan Most general sources that describe the basics of ionizing radiation assert that the only type of radiation that can directly make other materials radioactive is neutron radiation (via "neutron activation").

Googling "does radiation make things radioactive?" produces a few examples, for...

Read more]]> 9 Trying to find research opportunities but I am doing something wrong Thu, 09 Apr 2026 21:47:22 +0000 https://www.physicsforums.com/threads/trying-to-find-research-opportunities-but-i-am-doing-something-wrong.1084803/ 1084803 invalid@example.com (Jark5455) Jark5455 Hi,

I am currently a 2nd year undergraduate student and I graduate in a semester. I do want to go to grad school for physics but my overall gpa is really weak (~3.2). I am currently trying to supplement it with research experience but I haven't been able to join any groups so far. 2 semesters...

Read more]]> 2 Is our definition of 'cosmic voids' misleading the H₀ discussion? Thu, 09 Apr 2026 21:14:53 +0000 https://www.physicsforums.com/threads/is-our-definition-of-cosmic-voids-misleading-the-h-discussion.1084801/ 1084801 invalid@example.com (qql504) qql504 The voids being discussed in local H₀ measurements are actually sub-voids inside superclusters like Laniakea. They are underdense relative to the supercluster, but their absolute density is still above the universal average. That's why the local H₀ comes out high (~73).

True cosmic voids — far...

Read more]]> 1 Positive wing wash-in dynamic soaring one side Thu, 09 Apr 2026 20:49:37 +0000 https://www.physicsforums.com/threads/positive-wing-wash-in-dynamic-soaring-one-side.1084794/ 1084794 invalid@example.com (ds3227) ds3227 Hello,
While dynamic soaring 3 of my rc ships seem faster in left tilted loops with left wing washin not just the tip.
No rolling tendency is noted why is this. This is slow speed just 70 mph.

I wonder what would happen with this setup on a large ds location.
Is a tilted loop the same as a...

Read more]]> 7 Finding the minimum distance between two curves Thu, 09 Apr 2026 20:14:41 +0000 https://www.physicsforums.com/threads/finding-the-minimum-distance-between-two-curves.1084661/ 1084661 invalid@example.com (Charles Link) Charles Link The other day a friend of mine gave me the above problem which I found rather interesting. I was able to get a numerical solution. I'll post how I solved it later in the thread. Others may want to try it and see what they come up with.]]> 34 Feasibility of Micro‑Plasma–Induced Refractive‑Index Phase Modulation Thu, 09 Apr 2026 20:06:09 +0000 https://www.physicsforums.com/threads/feasibility-of-micro-plasma-induced-refractive-index-phase-modulation.1084787/ 1084787 invalid@example.com (rcc01) rcc01 Hello everyone,

I’m exploring a conceptual question involving the optical behavior of micro‑plasmas in thin, sealed cavities. The idea is to use a very thin low‑pressure gas layer between two transparent substrates. When an electric field is applied, the gas forms a micro‑plasma confined within...

Read more]]> 5 Epothilone B study connected to 'Hard Problem of Consciousness' Model Thu, 09 Apr 2026 19:36:48 +0000 https://www.physicsforums.com/threads/epothilone-b-study-connected-to-hard-problem-of-consciousness-model.1065532/ 1065532 invalid@example.com (.Scott) .Scott A new study published in eNeuro reports the results of administering Epothilone B to rats that are being anesthetized with isoflurane gas. Those results are described in light of the microtubule involvement on consciousness as theorized by Stuart Hameroff's - and famously advocated by...

Read more]]> 9 A question about leverage and stability of shelf support Thu, 09 Apr 2026 15:46:37 +0000 https://www.physicsforums.com/threads/a-question-about-leverage-and-stability-of-shelf-support.1084785/ 1084785 invalid@example.com (confusedlabs) confusedlabs In this picture, I depicted a shelf that has two sides (black). On each side, there are holes for the shelf supports (red). They can be inserted into the holes and are supposed to hold a bookshelf (blue).

My question is the following: While the depth of the holes stays the same, does the length...

Read more]]> 8 ChatGPT Examples, Good and Bad Thu, 09 Apr 2026 14:58:27 +0000 https://www.physicsforums.com/threads/chatgpt-examples-good-and-bad.1048757/ 1048757 invalid@example.com (anorlunda) anorlunda I've been experimenting with ChatGPT. Some results are good, some very very bad. I think examples can help expose the properties of this AI. Maybe you can post some of your favorite examples and tell us what they reveal about the properties of this AI.

(I had problems with copy/paste of...

Read more]]> 477 Semiconductor surface engineering Thu, 09 Apr 2026 14:51:20 +0000 https://www.physicsforums.com/threads/semiconductor-surface-engineering.1084795/ 1084795 invalid@example.com (LUFER) LUFER Regarding surface engineering, specifically the reflection and scattering of a semiconductor material, I have the following question in response to the problem below.

On a surface with reflectance R = 0.35, a power of 5 x 10⁻⁵ W/µm² is applied. Knowing that the total power scattered by the...

Read more]]> 0 Diodes and low grade thermal energy harvesting Thu, 09 Apr 2026 14:14:11 +0000 https://www.physicsforums.com/threads/diodes-and-low-grade-thermal-energy-harvesting.1084773/ 1084773 invalid@example.com (ADesilets) ADesilets Infrared is ubiquitous and to do with dark current -> real meters have finite resistance, no real meter is a superconductor, if you can measure dark current: there's emf.

Since we can measure and quantify 0 bias dark current generation and we can see the measurements certified on manufacturers...

Read more]]> 11 VFD for powering a car lift Thu, 09 Apr 2026 13:32:15 +0000 https://www.physicsforums.com/threads/vfd-for-powering-a-car-lift.1084275/ 1084275 invalid@example.com (Guineafowl) Guineafowl Power supply to the 7.5kW rotary is 1ph, 240Vac. Supply voltage drop at full load is within 5%.

The rotary outputs (roughly) 415Vac 3ph to the screw-type car lift, capacity 2.7 tonne.

The lift motor is a 3.5kW, 50Hz, 4-pole, asynchronous induction motor with a power factor of just 0.65. Phase...

Read more]]> 28 Collection of Lame Jokes Thu, 09 Apr 2026 11:59:37 +0000 https://www.physicsforums.com/threads/collection-of-lame-jokes.25301/ 25301 invalid@example.com (quddusaliquddus) quddusaliquddus Lamest joke you know ... :zzz:]]> 23994 Could anyone offer some advice on my college choice for Physics/Astro? Thu, 09 Apr 2026 08:51:04 +0000 https://www.physicsforums.com/threads/could-anyone-offer-some-advice-on-my-college-choice-for-physics-astro.1084768/ 1084768 invalid@example.com (AZeee1781) AZeee1781 Hi everyone! So I am a current high school senior (international) who has just finished college applications and received results. I plan to major in Astrophysics or Physics (if the school does not offer an Astrophysics major) and eventually enter an Astrophysics PhD program, so I am looking for...

Read more]]> 13 Astronomy: Orbit Terminology Thu, 09 Apr 2026 08:35:45 +0000 https://www.physicsforums.com/threads/astronomy-orbit-terminology.1084772/ 1084772 invalid@example.com (Pixelworks) Pixelworks I am looking for the terms that describe, or rather differentiates the difference between the direction of orbit and the 'anti-orbit' direction.

If my understanding is correct, the terms retrograde and prograde motion both refer to the motion but only in regard to the body being orbited. E.g...

Read more]]> 19 Guidance for using mica strip heaters Thu, 09 Apr 2026 01:32:22 +0000 https://www.physicsforums.com/threads/guidance-for-using-mica-strip-heaters.1084790/ 1084790 invalid@example.com (Ryoko) Ryoko [Mentor Note: See the following link for background on this question]

I need to make an oven to anneal aluminum strips. I am looking at using strip heaters inside a long tube as a makeshift...

Read more]]> 1 My glasses are giving me a neck cramp Wed, 08 Apr 2026 20:57:22 +0000 https://www.physicsforums.com/threads/my-glasses-are-giving-me-a-neck-cramp.1084788/ 1084788 invalid@example.com (DaveC426913) DaveC426913 Just realized after all this time why my neck is so sore at work.
I use a secondary monitor that sits behind my lappie (not to the side, that just makes it worse).

The secondary monitor is not too high. The top of the monitor is horizontal to my eye and I look down at the centre of the...

Read more]]> 3 Hey it’s confusedlabs Wed, 08 Apr 2026 20:18:18 +0000 https://www.physicsforums.com/threads/hey-its-confusedlabs.1084783/ 1084783 invalid@example.com (confusedlabs) confusedlabs Hello everyone,

I’m just a regular young person with just a little general knowledge on physics who is helpless answering myself some questions that end up interesting me when they rise up in daily life.
Sadly it is impossible to discuss them with my friends, because despite their lack of...

Read more]]> 2 Prof Mike Wiest's proposed link between quantum and consciousness Wed, 08 Apr 2026 19:59:38 +0000 https://www.physicsforums.com/threads/prof-mike-wiests-proposed-link-between-quantum-and-consciousness.1082604/ 1082604 invalid@example.com (nomadreid) nomadreid I am not sure if this belongs in the biology section, but it appears more of a quantum physics question.

Mike Wiest, Associate Professor of Neuroscience at Wellesley College in the US. In 2024 he published the results of an experiment on anaesthesia which purported to point to a role of...

Read more]]> 25 Does memory follow classical or quantum methods? Wed, 08 Apr 2026 19:54:39 +0000 https://www.physicsforums.com/threads/does-memory-follow-classical-or-quantum-methods.1084764/ 1084764 invalid@example.com (grzz) grzz In my daily routine, I read several short extracts. The same extracts, every day, every year, so that I can now repeat them by heart. I make no effort to remember anything. I just let words flow out...

Read more]]> 6 Do old CRT and O-scopes degrade to emit harmful X Rays? Wed, 08 Apr 2026 18:15:29 +0000 https://www.physicsforums.com/threads/do-old-crt-and-o-scopes-degrade-to-emit-harmful-x-rays.1084643/ 1084643 invalid@example.com (Albertgauss) Albertgauss Hi all,

Presently I use an old oscilloscope and old cathode-ray-tube computer monitor as a demo/lab where students can bring a magnet near either device. In the case of the old oscilloscope, the magnet they bring near deflects the beam; in the case of the old computer monitor, colored circles...

Read more]]> 16 Retired Engineer Investigating Plasma‑Based Optical Phase Control Wed, 08 Apr 2026 15:54:54 +0000 https://www.physicsforums.com/threads/retired-engineer-investigating-plasma-based-optical-phase-control.1084786/ 1084786 invalid@example.com (rcc01) rcc01 ?
Hello everyone,My name is Ronald Coleman, and I’m a retired engineer and inventor based in Temescal Valley, California. I spent many years working in advanced imaging and materials environments, and I’m now focused on exploring a new optical concept involving thin‑film structures and...

Read more]]> 1 Most Hard-Driving Music? Wed, 08 Apr 2026 15:50:53 +0000 https://www.physicsforums.com/threads/most-hard-driving-music.1078565/ 1078565 invalid@example.com (Hornbein) Hornbein What's the most hard-driving music ever recorded? Some might go for the MC5 and their Kick Out The Jams but either of these two gets my vote. I'd have to flip a coin.



]]> 122 RIP Andrzej Trautman (1933 - 2026), relativity and gravitational waves Wed, 08 Apr 2026 14:46:09 +0000 https://www.physicsforums.com/threads/rip-andrzej-trautman-1933-2026-relativity-and-gravitational-waves.1084601/ 1084601 invalid@example.com (robphy) robphy https://en.wikipedia.org/wiki/Andrzej_Trautman

1774370260259.webp
http://ktwig.fuw.edu.pl/1,1,7,p-40,prof-andrzej-trautman.html
https://trautman.fuw.edu.pl/ (has links to many papers... see below)


https://www.ego-gw.it/blog/2026/03/03/goodbye-andrzej-trautman/...

Read more]]> 4 First law of this universe Wed, 08 Apr 2026 14:21:54 +0000 https://www.physicsforums.com/threads/first-law-of-this-universe.1079947/ 1079947 invalid@example.com (Anti10188) Anti10188 While studying certain aspects of physics, chemistry, biology, and psychology, I noticed that everything follows a single "law": energy always moves along the path of least resistance / least effort.

I observe this law in evolution, in every living organism, in every thought and decision...

Read more]]> 26 Latest Notable AI accomplishments Wed, 08 Apr 2026 13:02:37 +0000 https://www.physicsforums.com/threads/latest-notable-ai-accomplishments.937195/ 937195 invalid@example.com (gleem) gleem Developments in AI and machine learning continue to progress at a rate that may be surprising and not just in playing games but in pattern recognition and image analysis in medicine, astronomy and business. One of the challenges to AI is effective natural language processing. Last week both...

Read more]]> 70 Fast Food Discussion: Mexican Pizza at Taco Bell Wed, 08 Apr 2026 11:19:50 +0000 https://www.physicsforums.com/threads/fast-food-discussion-mexican-pizza-at-taco-bell.1015976/ 1015976 invalid@example.com (kyphysics) kyphysics This thread shall be a place where we can talk about anything fast-food related.

Does anyone here actually dislike fast food? I know it's not healthy, but it's sure darn good.

...The Mexican pizza is back at Taco Bell. I like certain items at Taco Bell, but this is not one of them. I...

Read more]]> 313 Random Photos Wed, 08 Apr 2026 09:45:15 +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]]> 3604 Ramsauer and Townsend effect: history and explanation Wed, 08 Apr 2026 08:43:02 +0000 https://www.physicsforums.com/threads/ramsauer-and-townsend-effect-history-and-explanation.1084778/ 1084778 invalid@example.com (haushofer) haushofer Dear all,

I'm writing an article about the didactics of teaching quantum physics, and in particular the phenomenon of resonant transmission, as discovered by Ramsauer and Townsend in 1920. The phenomenon was used in a Dutch physics exam in 2023, and in it the question states

"To explain the...

Read more]]> 1 How do you apply perturbation theory to a magnetic field Hamiltonian? Wed, 08 Apr 2026 04:26:34 +0000 https://www.physicsforums.com/threads/how-do-you-apply-perturbation-theory-to-a-magnetic-field-hamiltonian.1084776/ 1084776 invalid@example.com (Danielk010) Danielk010 I understand that the first order results would be ##\langle \phi_n^0 | -\mu * B | \phi_n^0 \rangle## = ##\langle \phi_n^0 | -\frac{gq}{2mc}\hat{S} * B | \phi_n^0 \rangle##, the second order results would be ##\sum_{k \ne n} \frac{|\langle \phi_n^0 | -\mu * B | \phi_n^0 \rangle|^2} {E_n^{(0)} -...

Read more]]> 2 Physics Careers: Expectations vs. Reality Wed, 08 Apr 2026 03:23:08 +0000 https://www.physicsforums.com/threads/physics-careers-expectations-vs-reality.1084279/ 1084279 invalid@example.com (Surf_and_Sky) Surf_and_Sky Hi Everyone. I graduated with a PhD in physics from UC Irvine. I'm struggling a bit in my career because I'm wondering if my expectations for the type of work that is actually available in industry to physics PhDs isn't really in line with reality. I spent my time in graduate school working in a...

Read more]]> 14 Collection of Science Jokes P2 Wed, 08 Apr 2026 02:29:55 +0000 https://www.physicsforums.com/threads/collection-of-science-jokes-p2.847743/ 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]]> 4070 Is Gravi-GUT a candidate theory of everything? Tue, 07 Apr 2026 20:59:09 +0000 https://www.physicsforums.com/threads/is-gravi-gut-a-candidate-theory-of-everything.1082728/ 1082728 invalid@example.com (kodama) kodama this thread is to open up discussion on Gravi-GUT as theories of everything

GUT or Grand Unified Theories attempt to unify the 3 forces of weak E&M and strong force, and Gravi-GUT want to add gravity.

this peer reviewed paper in a journal on Gravi-GUT

Chirality in unified theories of...​


Read more]]> 22 Star Wars Galaxy map just dropped Tue, 07 Apr 2026 19:45:38 +0000 https://www.physicsforums.com/threads/star-wars-galaxy-map-just-dropped.1084774/ 1084774 invalid@example.com (DaveC426913) DaveC426913 https://www.starwars.com/star-wars-...TG2qI52irn7XucvQoz_aem_WIahRW0UaTWTKkagGUQptA

To save y'all a little trouble, I nerded up a...

Read more]]> 4 I need to lock in Tue, 07 Apr 2026 13:52:59 +0000 https://www.physicsforums.com/threads/i-need-to-lock-in.1084779/ 1084779 invalid@example.com (orheanne) orheanne I'm a high schooler, aspiring to be an engineer. Physics and Mathematics are the subjects I love and understand the best. But due to time mismanagement I have lacked practice, though I excel in class in these subjects and get hold of concepts faster than anyone else, I fumble when it comes to...

Read more]]> 4 Why is water pressure increased in a plastic bag in a bucket? Tue, 07 Apr 2026 13:09:34 +0000 https://www.physicsforums.com/threads/why-is-water-pressure-increased-in-a-plastic-bag-in-a-bucket.1083804/ 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]]> 74 I don't understand Dedekind cuts Tue, 07 Apr 2026 04:50:59 +0000 https://www.physicsforums.com/threads/i-dont-understand-dedekind-cuts.1084757/ 1084757 invalid@example.com (Warp) Warp I have now tried for an hour to make ChatGPT make me understand how this works, without success, so I humbly ask for a clearer explanation.

The succinct way to express what I don't understand is this:

A "Dedekind cut" simply splits the set of numbers into two, without dropping any values and...

Read more]]> 12 ZBLAN fiber simulation Matlab Tue, 07 Apr 2026 04:16:57 +0000 https://www.physicsforums.com/threads/zblan-fiber-simulation-matlab.1084777/ 1084777 invalid@example.com (Field123) Field123 Hello everyone,
I am working on mid-infrared fiber laser simulation based on ZBLAN fibers.
I am looking for ZBLAN fiber simulation codes (MATLAB).
Rare-earth doped ZBLAN fiber models (Er³⁺, Tm³⁺, Ho³⁺) are highly preferred, such as:
Rate equation models
Fiber cavity simulation
Power / wavelength...

Read more]]> 0 Geodesics in quantum gravity Missing Link Tue, 07 Apr 2026 03:12:38 +0000 https://www.physicsforums.com/threads/geodesics-in-quantum-gravity-missing-link.1084551/ 1084551 invalid@example.com (kodama) kodama

​

what do you think of the relationship between the cosmology constant and MOND ao, coincidence that they are close or a quantum mechanical reason​


Sabine Hossenfelder, think that

Physicists Find Missing Link Between Quantum Mechanics and Gravity​

...

Read more]]> 7 An electrolytic capacitor keeps charging by itself Tue, 07 Apr 2026 02:13:51 +0000 https://www.physicsforums.com/threads/an-electrolytic-capacitor-keeps-charging-by-itself.1060829/ 1060829 invalid@example.com (Philip Koeck) Philip Koeck This is related to an earlier post (https://www.physicsforums.com/threads/an-electrolytic-capacitor-charges-by-itself.1008156/), but there's a new angle to it, therefore the new thread.

I have two 100 microF electrolyte capacitors in my office, one is connected to a volt meter, the other...

Read more]]> 15 Is A.I. more than the sum of its parts? Mon, 06 Apr 2026 19:58:31 +0000 https://www.physicsforums.com/threads/is-a-i-more-than-the-sum-of-its-parts.1084008/ 1084008 invalid@example.com (webplodder) webplodder Given that neuroscience cannot definitively explain where consciousness originates - whether as an emergent property of the brain or something transcendent - is it be possible for complex chatbots to develop behaviours that can’t be predicted by simply analyzing the sum of their parts?]]> 404 Exploring Implicit Assumptions and Foundations of Quantum Mechanics Mon, 06 Apr 2026 19:38:36 +0000 https://www.physicsforums.com/threads/exploring-implicit-assumptions-and-foundations-of-quantum-mechanics.1084767/ 1084767 invalid@example.com (Anton_A_Lipovka) Anton_A_Lipovka Question about the role of postulates and implicit assumptions in quantum mechanics

Hi everyone,

I’m trying to better understand the structure of the postulates of quantum mechanics and whether there is a meaningful hierarchy among them.

In the standard presentation, we usually assume...

Read more]]> 2 DH Mt Bike - Optimizing Drop Landing Ramp Profile Mon, 06 Apr 2026 19:32:17 +0000 https://www.physicsforums.com/threads/dh-mt-bike-optimizing-drop-landing-ramp-profile.1084657/ 1084657 invalid@example.com (erobz) erobz I do downhill Mt Biking - and this question popped into my head; Is there a kind of "optimal" landing profile mathematically for a drop feature that is not obvious in the sense that it is not what we "intuitively design" for landings on these features?

1774718288052.webp


My idea is that the bike...

Read more]]> 36 A.I. - Human Job Replacement Mon, 06 Apr 2026 18:35:04 +0000 https://www.physicsforums.com/threads/a-i-human-job-replacement.1067043/ 1067043 invalid@example.com (erobz) erobz I asked Chat GPT which field is more likely to be replaced by A.I.: For example: physicians or engineers. It comes to the conclusion of engineers. I did it for other professions too, it doesn't look good for engineering as a human endeavor in the future. Agree with A.I.?

Now that think of it...

Read more]]> 87 The wrong turn of string theory: our world is SUSY at low energies Mon, 06 Apr 2026 16:40:39 +0000 https://www.physicsforums.com/threads/the-wrong-turn-of-string-theory-our-world-is-susy-at-low-energies.485247/ 485247 invalid@example.com (arivero) arivero In post #549 here I answered:

arivero said:
This is the blindness -the wrong turn- I try to fight in the last years: our world IS susy at low energies, and because of it we confused the pion with the muon in the fifties.

It was a very prepostereous thing to say, so five minutes after proposing it...

Read more]]> 351 Why can’t we observe all regions of the universe? Mon, 06 Apr 2026 15:38:14 +0000 https://www.physicsforums.com/threads/why-cant-we-observe-all-regions-of-the-universe.1084589/ 1084589 invalid@example.com (Astro Santi) Astro Santi My understanding is that light from distant regions has been traveling toward us since the early universe. Therefore, if the expansion rate of the universe were always less than the speed of light, I would expect that we should eventually receive light from all regions.


However, I have read...

Read more]]> 3 Equal heat added to two spheres: why is the hanging sphere hotter? Mon, 06 Apr 2026 15:18:38 +0000 https://www.physicsforums.com/threads/equal-heat-added-to-two-spheres-why-is-the-hanging-sphere-hotter.1084770/ 1084770 invalid@example.com (sol_2001) sol_2001 My initial thought was that the hanging sphere would end up at a higher temperature because the contact area between the sphere and the insulating thread is much smaller than the contact area between the other sphere and the insulating plate. I thought that if heat could be exchanged through the...

Read more]]> 2 Dark energy might not be constant after all Mon, 06 Apr 2026 13:57:55 +0000 https://www.physicsforums.com/threads/dark-energy-might-not-be-constant-after-all.1061524/ 1061524 invalid@example.com (Filip Larsen) Filip Larsen https://arstechnica.com/science/2024/04/dark-energy-might-not-be-constant-after-all/
https://www.desi.lbl.gov/2024/04/04...recise-measurement-of-the-expanding-universe/

Interesting preliminary indications from DESI (which I did not know...

Read more]]> 8 Will anyone alive today see a permanent colony on the Moon or Mars? Mon, 06 Apr 2026 12:01:28 +0000 https://www.physicsforums.com/threads/will-anyone-alive-today-see-a-permanent-colony-on-the-moon-or-mars.1084051/ 1084051 invalid@example.com (BWV) BWV Curious if there is a consensus here]]> 56 Gravitons/Gravity passing through objects Mon, 06 Apr 2026 06:22:43 +0000 https://www.physicsforums.com/threads/gravitons-gravity-passing-through-objects.1084758/ 1084758 invalid@example.com (Josiah) Josiah Hi
I was wondering what determines whether the Graviton(assuming they exist) get absorbed or pass through an object?]]> 9 What is the proof of the Σqᵢcosθᵢ = constant theorem for colinear charges? Mon, 06 Apr 2026 03:48:30 +0000 https://www.physicsforums.com/threads/what-is-the-proof-of-the-sq-costh-constant-theorem-for-colinear-charges.1084665/ 1084665 invalid@example.com (Ajinkya78910) Ajinkya78910 What is the proof of the theorem for n colinear charges,
Σqᵢcosθᵢ = const. when θis measured in same sense?]]> 1 Programming Jokes: Lame, Science & Math Jokes! Mon, 06 Apr 2026 02:36:10 +0000 https://www.physicsforums.com/threads/programming-jokes-lame-science-math-jokes.1046996/ 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:

]]> 481 Share Animal Pictures: For Animal Lovers Mon, 06 Apr 2026 00:32:03 +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!]]> 3010 Towards a purely gravitational effective theory of dark matter Sun, 05 Apr 2026 19:44:14 +0000 https://www.physicsforums.com/threads/towards-a-purely-gravitational-effective-theory-of-dark-matter.1060158/ 1060158 invalid@example.com (mitchell porter) mitchell porter "The Price of Abandoning Dark Matter Is Nonlocality" (Deffayet, Woodard)

written in response to

"What is the price of abandoning dark matter? Cosmological constraints on alternative gravity theories" (Pardo, Spergel)

In a nutshell, as explained after equation 34, by adding a...

Read more]]> 21 Slalom Ski Racing Sun, 05 Apr 2026 16:35:45 +0000 https://www.physicsforums.com/threads/slalom-ski-racing.1084598/ 1084598 invalid@example.com (Hornbein) Hornbein Skier Mikaela Shiffrin this year achieved complete dominance in slalom ski racing, winning nine of ten races by large margins. In the tenth she placed second by one one hundredth of a second. What were the physics of how she did this?

It may be seen here that her style is noticeably...

Read more]]> 1 Anthony Leggett obituary Sun, 05 Apr 2026 16:31:56 +0000 https://www.physicsforums.com/threads/anthony-leggett-obituary.1084724/ 1084724 invalid@example.com (physika) physika

​

Anthony Leggett obituary​

https://www.nature.com/articles/d41586-026-01010-z

a great theoretical physicist in foundations of physics.

(can register for free, for the article)]]> 2 Dr. Leila Denmark Sun, 05 Apr 2026 16:26:52 +0000 https://www.physicsforums.com/threads/dr-leila-denmark.1084740/ 1084740 invalid@example.com (BillTre) BillTre co-developed the pertussis (whooping cough) vaccine in 1932.

Screenshot 2026-04-01 at 3.40.21 PM.webp]]> 1 What are the most fundamental entities in the SM and QFT? Sun, 05 Apr 2026 12:33:35 +0000 https://www.physicsforums.com/threads/what-are-the-most-fundamental-entities-in-the-sm-and-qft.1084586/ 1084586 invalid@example.com (Loulougaga) Loulougaga What are the most fundamentals entities in the SM and QFT?
Is information or particle first?
What if information preceed particles?]]> 6 "GR from RG" (dynamical gravity from renormalization group flow) Sun, 05 Apr 2026 12:01:39 +0000 https://www.physicsforums.com/threads/gr-from-rg-dynamical-gravity-from-renormalization-group-flow.1084236/ 1084236 invalid@example.com (mitchell porter) mitchell porter There's a paper from Iran making a startling claim that at least survives initial scrutiny:

"GR from RG: Gravity Is Induced From Renormalization Group Flow In The Infrared" (Sheikh-Jabbari, Taghiloo)

There is an old idea due to Sakharov, called induced gravity, according to which there...

Read more]]> 1 Photon dilemma for MOND-like dark matter Sun, 05 Apr 2026 11:34:20 +0000 https://www.physicsforums.com/threads/photon-dilemma-for-mond-like-dark-matter.1051040/ 1051040 invalid@example.com (mitchell porter) mitchell porter "Superfluid dark matter in tension with weak gravitational lensing data" (Mistele, McGaugh, Hossenfelder)

Regarding this paper, Sabine Hossenfelder tweets

It's about superfluid dark matter but highlights what I believe is a general problem of hybrid approaches.
The issue...

Read more]]> 16 All possible models to explain the hierarchy problem? Sun, 05 Apr 2026 11:25:37 +0000 https://www.physicsforums.com/threads/all-possible-models-to-explain-the-hierarchy-problem.1055723/ 1055723 invalid@example.com (Suekdccia) Suekdccia There is an interesting paper by Arkani-Hamed and collaborators (https://arxiv.org/abs/1607.06821) to address the hierarchy problem.

There, they consider many possible models of fundamental particle physics where they all have an exact copy of the Standard Model but with different Higgs...

Read more]]> 1 Interpreting VIA PCB through TDR and TDT Sun, 05 Apr 2026 10:47:03 +0000 https://www.physicsforums.com/threads/interpreting-via-pcb-through-tdr-and-tdt.1084749/ 1084749 invalid@example.com (yefj) yefj Hello ,I have simulated a basic VIA (shown in the photo) in CST EM simulator from 0 to 40GHz and extracted its attached S2P.
using the code below I resampled it and made IFFT with multiplied the normalised hamming window.
I got the following plots in MATLAB.
Is there a way to interpret the VIA...

Read more]]> 17 Spinor calculus Sun, 05 Apr 2026 08:54:26 +0000 https://www.physicsforums.com/threads/spinor-calculus.1084582/ 1084582 invalid@example.com (grzz) grzz What are the conventions for the spinor metrics and their inverses?]]> 2 Relativistic Uniform Circular Motion Sat, 04 Apr 2026 22:58:35 +0000 https://www.physicsforums.com/threads/relativistic-uniform-circular-motion.1084750/ 1084750 invalid@example.com (renormalize) renormalize (This post is inspired by: KE of rotating disk.)
A Single Particle in Uniform Circular Motion
In an inertial frame, I begin by examining a single dust particle of mass ##m## moving in a plane with instantaneous position vector ##\vec{r}\equiv r\hat{r}\left(t\right)##...

Read more]]> 15 Possibility of spellcheck feature? Sat, 04 Apr 2026 19:01:31 +0000 https://www.physicsforums.com/threads/possibility-of-spellcheck-feature.1084482/ 1084482 invalid@example.com (DaveC426913) DaveC426913 Don't know if such a feature exists.

I spend a lot of cycles proofing my posts for SPaG (Spelling, Punctuation and Grammar - learned that from my writing forum). 90% of that happens after I've posted - which means it becomes PF's problem.

Any such thing as a spellchecker feature that...

Read more]]> 17 Kitten Lovers: Cuteness Overload Sat, 04 Apr 2026 18:46:26 +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]]> 3874 A philosopher who challenges the basics and their assumptions Sat, 04 Apr 2026 17:36:02 +0000 https://www.physicsforums.com/threads/a-philosopher-who-challenges-the-basics-and-their-assumptions.1084760/ 1084760 invalid@example.com (Master of the Basics) Master of the Basics I'm a philosopher who has challenged some basic assumptions, particularly physics. I produced and published an anomalous experiment on Zenodo that challenges the predictive energy model of gravity.

Despite an extremely high engagement rate and 1,240 downloads in 18 weeks, I haven't received any...

Read more]]> 1 What are the speed limits of a maglev track? Sat, 04 Apr 2026 14:51:30 +0000 https://www.physicsforums.com/threads/what-are-the-speed-limits-of-a-maglev-track.1084736/ 1084736 invalid@example.com (amorphos_b) amorphos_b What are the speed limits of a maglev track? If say, you wanted to use them to launch craft into space? Or indeed if you wanted to send segments of maglev track to say the moon and mars?]]> 5 Is Prof. Claus Kiefer's application of Gödel (+ infinity) justified? Sat, 04 Apr 2026 12:56:27 +0000 https://www.physicsforums.com/threads/is-prof-claus-kiefers-application-of-godel-infinity-justified.1084752/ 1084752 invalid@example.com (nomadreid) nomadreid I have just looked through
https://arxiv.org/abs/2305.07331
by the physicist Prof. Dr. Claus Kiefer (Institut für Theoretische Physik; Universität zu Köln, Germany) .

The reason I am putting this in the logic thread instead of a physics thread is as follows. It appears to me that the...

Read more]]> 2 Why is gravity a fictitious force? Sat, 04 Apr 2026 09:32:11 +0000 https://www.physicsforums.com/threads/why-is-gravity-a-fictitious-force.1084666/ 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!]]> 65 KE of rotating disc Sat, 04 Apr 2026 04:13:52 +0000 https://www.physicsforums.com/threads/ke-of-rotating-disc.1084603/ 1084603 invalid@example.com (Ibix) Ibix Consider a disc of radius ##R## with a uniform mass distribution and total mass ##M## rotating in its own plane. In its COM's inertial rest frame it has angular velocity ##\omega## about its center. In the obvious polar coordinates in that frame the kinetic energy of a small part of the disc at...

Read more]]> 87 Solar Activity and Space Weather Update thread Fri, 03 Apr 2026 22:53:36 +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]]> 451 Marcus Jensen Fri, 03 Apr 2026 20:36:22 +0000 https://www.physicsforums.com/threads/marcus-jensen.1084756/ 1084756 invalid@example.com (SucramNesnej) SucramNesnej My name is Marcus Jensen. I am 14-years-old. I live in Denmark, and I LOVE physics and chemistry. I first discovered my interest in the subject when I was around 12 years old. I read about all of the big stuff, like The Big Bang Theory and such, and it always fascinated me how everything was...

Read more]]> 2 Half wave voltage doubler Fri, 03 Apr 2026 18:54:38 +0000 https://www.physicsforums.com/threads/half-wave-voltage-doubler.1083590/ 1083590 invalid@example.com (PhysicsTest) PhysicsTest 1766499535927.webp
The input is sine wave vi= Vmsin(wt), the problem is it is increasingly difficult to analyze these kinds of circuits for sinusoidal inputs and with positive and negative portions, most of the time i analyze in the mind without the equations and to remember the states is tough. Do we...

Read more]]> 15 Today I Learned Fri, 03 Apr 2026 17:00:56 +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]]> 6905 Curl of velocity vector in rotational motion Fri, 03 Apr 2026 16:59:22 +0000 https://www.physicsforums.com/threads/curl-of-velocity-vector-in-rotational-motion.1084745/ 1084745 invalid@example.com (brotherbobby) brotherbobby 1774865847447.webpAttempt : I draw the diagram of the problem to the right. A circular plate of radius ##a## rotates with an angular velocity ##\vec\omega = \omega_0\hat k##, assumed constant for the moment. A particle P at rest with the plate lies on the rim along the ##x## axis, as...

Read more]]> 7 Large Synoptic Survey Telescope -> Vera C. Rubin Observatory Fri, 03 Apr 2026 14:37:55 +0000 https://www.physicsforums.com/threads/large-synoptic-survey-telescope-vera-c-rubin-observatory.982871/ 982871 invalid@example.com (mfb) mfb She might have been left out with the Nobel Prizes (she died in 2016), but now one of the next generation telescopes was named after her: The Vera C. Rubin Observatory will image all the available sky areas every few days with observations starting this year and full operation from 2022...

Read more]]> 15 Help with problem in MIT open course general relativity Fri, 03 Apr 2026 10:36:50 +0000 https://www.physicsforums.com/threads/help-with-problem-in-mit-open-course-general-relativity.1084655/ 1084655 invalid@example.com (DavidL070949) DavidL070949 Hi! Apologies in advance for a somewhat long post.

First, by some background: Long ago in what seems like a galaxy far away, I got a Ph.D. in physics (statistical physics) before switching gears and going into law. The nature of my grad school was such that there wasn't any coursework - you...

Read more]]> 18 How does this configuration not create E field inside the conductor? Fri, 03 Apr 2026 09:27:39 +0000 https://www.physicsforums.com/threads/how-does-this-configuration-not-create-e-field-inside-the-conductor.1084664/ 1084664 invalid@example.com (harmyder) harmyder Suppose an uncharged hollow metallic sphere has a non-centered charge inside. In this case, the charge distribution and field lines are like this
metal-conducting-sphere-non-centered.webp

Wouldn't such an uneven charge distribution on the inside and outside of the conductor create a field inside the conductor?]]> 4 Why percent yield is sometimes less than 100% in chemistry experiments? Fri, 03 Apr 2026 09:09:53 +0000 https://www.physicsforums.com/threads/why-percent-yield-is-sometimes-less-than-100-in-chemistry-experiments.1084478/ 1084478 invalid@example.com (harveycannon) harveycannon Also, when calculating percent yield, do we always use the same formula?

I understand that percent yield compares actual and theoretical yield, but I want to make sure I'm doing the calculation correctly.]]> 6 Solve the given second order differential equation Fri, 03 Apr 2026 06:57:41 +0000 https://www.physicsforums.com/threads/solve-the-given-second-order-differential-equation.1060853/ 1060853 invalid@example.com (chwala) chwala Going through ode's,
My lines,

Let solution be of the form, ##u =x^s##
...
Characteristic equation is;

##4(s(s-1)+12s-4=0##

##4s^2+8s-4=0##

##s_1=\sqrt 2 -1## and ##s_2 = -(\sqrt 2+1)##

thus the two linearly indepedent solutions are,

##u_1(x)= x^{\sqrt 2 -1}## and ##u_2 =...

Read more]]> 16 Sidney Coleman's opinion on interpretation in his Dirac lecture Fri, 03 Apr 2026 02:38:10 +0000 https://www.physicsforums.com/threads/sidney-colemans-opinion-on-interpretation-in-his-dirac-lecture.1084496/ 1084496 invalid@example.com (gentzen) gentzen pines-demon quoted from Sidney Coleman's Dirac Lecture "Quantum Mechanics in Your Face" (https://arxiv.org/abs/2011.12671)
The other day I was looking at a British videotape of Feynman explaining elementary concepts in science to an interrogator, whom I think was the producer...

Read more]]> 140 We needed a backstory for our Traveller sci-fi RPG ... Fri, 03 Apr 2026 01:47:28 +0000 https://www.physicsforums.com/threads/we-needed-a-backstory-for-our-traveller-sci-fi-rpg.1084748/ 1084748 invalid@example.com (DaveC426913) DaveC426913 This was my submission:


We just wanted to dance!

It was our dream: tour the galaxy and dance.

We caught the eye of the great-great-great grandson of the legendary Simon Cowell, in association with Celebrity Starships, they agreed to be our corporate sponsors. They donated a vessel...

Read more]]> 1 Random Thoughts 7 Thu, 02 Apr 2026 18:39:12 +0000 https://www.physicsforums.com/threads/random-thoughts-7.1056780/ 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]]> 1996 Geiger Counter Question Thu, 02 Apr 2026 14:27:47 +0000 https://www.physicsforums.com/threads/geiger-counter-question.1084712/ 1084712 invalid@example.com (worriedsick79) worriedsick79 Hi,

I’ve recently purchased two geiger counters from Amazon, GQ GMC-800 and GQ GMC-300S, because someone in my life was supposed to receive RAI. Ended up my relative didn’t need the treatment. I’ve heard about granite countertops being potentially radioactive, so decided to open the devices and...

Read more]]> 22 Union Micro-Macro Thu, 02 Apr 2026 13:46:55 +0000 https://www.physicsforums.com/threads/union-micro-macro.1084739/ 1084739 invalid@example.com (Bolivar7) Bolivar7 ¡Saludos a todos los físicos, a los matemáticos ya todos los que aman la ciencia.

[Translation via Google Translate by a Mentor]
Greetings to all physicists, mathematicians, and everyone who loves science!]]> 1 Biographies, History, Philosophy of Physics Thu, 02 Apr 2026 12:26:36 +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]]> 271 Our Beautiful Universe - Photos and Videos Thu, 02 Apr 2026 10:16:28 +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]]> 2418 Self studying Taylor's Classical Mechanics Thu, 02 Apr 2026 07:15:36 +0000 https://www.physicsforums.com/threads/self-studying-taylors-classical-mechanics.1084733/ 1084733 invalid@example.com (euok124) euok124 Im 1st year engineering student (ECE) but im interested in self studying physics. I want to self study taylor classical mechanics this summer preferably including analytic mechanics chapters but i want to know if my math is enough for it. By the end of this year i will have:
Partial derivatives...

Read more]]> 10 First Time Here! Thu, 02 Apr 2026 01:05:24 +0000 https://www.physicsforums.com/threads/first-time-here.1084738/ 1084738 invalid@example.com (sol_2001) sol_2001 Hello this is my first time here,
I was looking for an alternative to reddit as It was much too politically motivated and aggressively left-leaning which was extremely distracting and off-putting in my journey of knowledge.
Even though I have completed an undergraduate in BESS, I have always...

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