Physics

If something in subatomic particles is neutral direction whether if relative or fixed, it acts as centre of gravity so other subatomic(s) point to it (gravitational attraction)... could that be possible? "Thought experiment approaches have been suggested as a testing tool for quantum gravity theories.[9][10] In the field of quantum gravity there are several open questions – e.g., it is not known how the spin of elementary particles sources gravity, and thought experiments could provide a pathway to explore possible resolutions to these questions,[11] even in the absence of lab experiments or physical observations." From link: https://en.wikipedia.org/wiki/Quantum_gravity

This thread is in response to questions in the Speculations forum about exactly what a metric is and this level of detailand discussion is neither speculation nor really on topic for the older thread. I am posting it in Physics as most instances of metric at SF are connected with coordinates. Also Maths is rather dry with its format of "Let us state an axiom or axioms and see what we can do with them." Physics can be more chatty. First a little backgorund. Yes indeed a set with a notion of distance between its elements. But we really need more than a notion, so let us examine the sort of things we want 'distance' to do for us or not do for us. As so often in maths we ga…

Hi all. Perhaps already posted years ago but from a foggy memory and poor search skills am revising it. A magnet M with poles (N /S) has loooong polepieces as parallel iron bars (=======) at each pole. N=========================================================================E M S=========================================================================E Is the attraction to an iron part placed across the bars near the magnet M , or halfway across the length of the bars, or across the end E showing attenuation according to distance from M ? -Trying to build a 3 metres long unwanted ferrous scrap picker/collector across a conveyor belt with a magnet at one end and two bars …

Maxwell equations have both retarded and advanced solutions, also their convex combinations are allowed: Wheeler-Feynman assumes symmetric 1/2-1/2 contributions, but e.g. energy loss shows asymmetry instead - which should depend on the boundary conditions, e.g. Huw Price says it is because of more absorbers than emitters ( https://link.springer.com/article/10.1007/BF00733218 ). Seems nearly everybody assume 1-0 only retarded instead, but maybe it is worth to verify experimentally, especially that emitter/absorber imbalance might not be perfect? ( https://arxiv.org/pdf/2512.20692 ) Where do you think this Asymmetry of Radiation comes from? Should it be really perfect 1-0…

Hi all. Photons transitioning from air into yellow tinted water decelerate the same amount if entering green tinted water ? Or, a red color light beam and a violet color light beam get different deceleration entering into clear water ? What changes crossing trough media ? Its energy, its wavelenght, both, other ? Do photons crossing into a rainbow outputted by a prism experience several changes of speed according the color they are crossing ? (high chance for poor terminology above 😟)

Question Does geometrical base volume multiplied by geometrical density multiplier (or v multiplied by d) make sense? Why I'm trying to learn a bit of basic mathematics with a goal of applying it to my physics self-teach learning, with hope of better understanding the nature of geometry and gravity. Formula Cube object's base geometrical volume number (v) multiplied by geometrical density multiplier (d) so formula: v multiply by d Picture See my attached screenshot picture I took of 3-D objects I made - titled, "3D Conceptual Representation of Geometrical Objects and Density Multiplier". It was made with a 3-D software by myself, for conceptual illustration. A) 4 * 1 = 4…

Hello all. Did not know on which subforum to post. Here it goes. If a LED is flashed for a tenth of a second, it is easily discernible. - For the same current/power pulse; if the time of a single flash is reduced to a hundredth of a second, it also is. What about 1 millisecond ? And 10 microseconds ? Shorter ? What determines the shortest time for perception ? Should it vary by observer ? Would color sensitivity be a factor ?

While special relativity says inertial mass is equivalent with energy, there are at least two more types of mass, for which equivalence seems not so certain - let me briefly summarize and ask for more arguments for/against their equivalence. Gravitational mass is hypothesized to be equal by equivalence principle, and gravitational interaction of antimatter now seems nearly certain to be the same (?) However, all these tests are for baryons and bulk matter made of them, for non-baryons I am aware only of this 1967 Witteborn, Fairbank test for electron - measuring maximal time for thermal electrons reaching upper electrode tmax=sqrt(2h/g), which turned out infinite, sugges…

Hi all, good day. Cannot find if long ago, already posted about this. Memory fading fast. Am unable to create an animation, or ask 'artificial intelligence' to make such animation or prove the concept. Please lend me your brains and skills to confirm if am wrong.. A boat with a rope at the keel near its bow. The rope tied forwardish of a submerged plane-form (not airplane form !) ballast. Rising sea surface waves make the rope tension pull up and glide forward the ballast because of its fixation angle point. Next the boat descending into the valley of the seawave surface allows the slack ballast rope to descend aiming downwards pulling also forward. Can the …

While physics is believed to be CPT symmetric in equations, this symmetry is clearly violated in solution we live in, e.g. by entropy growth. I would like to ask about different asymmetry in solution: that circulating electron loses energy due to synchrotron radiation, but in CPT perspective it is also circulating charge - now gaining energy. Can we say that this asymmetry comes from that there are more absorbers in our future than emitters in our past?

Photon in QFT is e.g. a coupling between two electrons using below Feynman diagram - requires both emitter and absorber, they are switched in perspective of CPT symmetry. So can photon be emitted if there is no absorber on the way? A practical example: from radiotelescope with thermally excited resonator - while it is focused on absorption, in theory its antenna could also emit e.g. thermal excitations (seen as negative signal), but used frequencies are very difficult to absorb, often such directional EM wave would just travel to infinity through space, so from CPT perspective would have no emission mechanism. Can radiotelesope emit if such EM wave would just travel to in…

How are Bayesian analysis methods using Monte Carlo sampling applied to estimate the parameters of dark energy models based on observational data? I have come across references to Markov Chain Monte Carlo (MCMC) in the context of CMB and supernova analyses, but it is unclear how to interpret the resulting posterior distributions. I would appreciate any clarifications or references to tutorials or review articles.

Hi. Again. A ship navigates against the river current, its engine developing 1000 horsepower and is not enough, advancing nothing, just maintaining position. Another identical ship next to it also maintains position as it is anchored. How many horsepower is the anchor developing ? 🙄

Long time no chat... I was trying to use AI to help me reconcile the two claims I commonly hear, but without success. Maybe someone here can help me better: claim 1: If you lower a rope below event horizon you are not able to pull it back claim 2: You can cross the event horizon of a supermassive black hole without even noticing. The two seem incompatible to me, but LLMs do not seem to be bothered.

There are recent claims for observations of up to redshift 25 objects by JWST, which are said too early to be formed by standard Big Bang models, e.g. https://www.scientificamerican.com/article/the-james-webb-telescope-may-have-found-primordial-black-holes/ Probably even higher redshifts will be found in the future, so I wanted to ask if some objects like black holes could e.g. "pass in safe distance" surviving Big Bounce - now being observed as having extreme redshifts? www.youtube.com/watch?v=EOowNVML4_I

For example, causing things to move at different speeds, one thing happens before another, causation, time passes when something is still and also when it moves.

Schwarzschild metric has a flaw. If you arrange steel balls from one end to another end across universe, would the one at the center melt due to gravity?is it no or yes? If You get it right, you could probably win noble price.💪

As a science populiser, Ethan Siegel must always be taken with a grain of salt, but here he is heads on: Why “vibe physics” is the ultimate example of AI slop. A must read for everyone at these fora who is using LLM's to support their 'new theories'. A nice read for everybody else who is very well aware of the limitations of LLMs.

Greetings. Would this contraption have some use; or is it somehow already done ? A plain single wall metal (black, aluminium?) chimney exposed to a sunny location and preferably shielded from wind direction; heats up the air inside. The air heated by the metal chimney rises and vents at the top end, pulling air trough the room at the bottom end of the pipe creating a flow as a fan does. Humble yes, not exactly air conditioning, but hey, it is a fan with its corresponding effect on skin. Does such thing exist ? The sunnier and hotter it is, the faster the ventilation flow. No increase in humidity as evaporative coolers do. No energy consumption, moving parts or motor…

The promise is a small device, which can be connected to a smart phone, and register, identify, display graphically (spectrum and in intensity in time; also on Google Street Maps or Open Street Maps), radioactive substances, better (and cheaper!) than traditional Geiger-Müller counters. Here is their website. Here is a report of a physicist playing around with it. Some excerpts: I always like to measure things around me: where am I and how high (GPS), what is the temperature, moisture of the air, water temperature of the lake near my house, and on and on. Maybe I am a bit nerdy...

I don’t believe the world is flat, but what is the evidence for the theory that it is a sphere? Is it approximately a sphere? And why would the planets form as a sphere in the first place? Would you say intelligent design or gravity is circular? Why can’t it be a cube with an irregular 3d surface that approximates a sphere? I’m quite serious. Why are we not looking for planets in different shapes? And why are black holes logarithmic spirals? I want to write a sci-fi story where instead of using ships to explore space we instead grow the Earths atmosphere. I mean we make space livable by growing the Earth’s protective atmosphere layers. No need for oxygen you already h…

If we were going to terrafotm Venus, besides cooling her down and giving her a breathsble atmosphere and a magnetic field, I guess we'd need to speed up her incredibly slow rotation to give a 24h day. I've read that this vould be theoretically achieved, if 2 or 3 asteroids about 350km across were fired at Venus in quick succession, presumably from the asteroid belt. But it's difficult to see how such huge bodies could be moved. However if a load of small asteroids with nuclear rocket engines all crashed together at 1 particular point, and at the right trajectories, could the resultant lump of rock and debris then speed towards Venus to do the job? A bit like snooker? Ch…

Introduction I think most of you are familiar with Newton Issac and Albert Einstein's gravity theory which seem to involving gravitational relationship between objects, whereas this I approach is singular (focus on an object or object's gravitational individuality as possibly fundamental which relation / relativity (e.g. general relativity theory) happen possibly because of it. Diagram A diagram of the gravity equation formulation developed by myself as part of self-learning with the gravity within both classical physics and quantum physics although is singular for time being, supposedly applies to an individual object - but not yet approach relation / relativity (e.g. ge…

I have always been comfortable with Quantum Mechanics' Shrodinger Equation but never made the jump to the relativistic QM formulation in my ( undergrad ) Physics education ( 45 yrs ago ). I knew of the Klein-Gordon equation and PAM Dirac's contributions, but never really had a need for a relativistic interpretation. Then I saw this guy's latest video, which explains how Klein-Gordon fails as a useful methodology, and introduces Dirac's matrix formulation. I hope others will find this as enlightening as I did The second part of this will delve into the prediction of anti-matter. I love this guy's videos Physics Explained - YouTube for their ease of understan…

and what would a definition of a "clock" be? Any oscillation can be used as reference to define some kind of time. the neutrino oscillation is an active research topic that is not yet fully understood. as of now, assuming the neutrino having a mass is just as much speculation given our current experimental results. There are even some conflicting data which are partially at odds with invariant nature, though there may still be other explanations. there is a reason why Lorentz violation is considered, including experiments that could test for it.