Strange Definition and 588 Threads

I had a rough night of sleep tonight and woke about 3:30. At one point I was awake on my side and noticed a small burst of light in the room, which I found a bit odd, being familiar with all the things that blink, etc., and not expecting any. But I figured it was just one of those. Then, about...

I have received this image from someone in Namibia recently at the Kiripotib Astrofarm. Has anyone an idea what could cause such a strange trajectory?

The behavior of those two function keys at the top of my Dell Windows 10 laptop recently changed, and I'm trying to figure out how to change it back to normal. At the upper right of my keyboard there are these function keys with 2 functions apiece shown: prtscr/F10 home/F11 end/F12...

There are some weird things happening with my browser. These started quite some months back; don't remember exactly when. First and foremost, whenever I want to visit PF, I get this screen: Next, and the more irritating issue: Regardless of which website I intend to visit, Chrome will often...

I wasn't sure if I should post this in astrophysics or particle physics, so I'll try particle physics first, mods feel free to move it to a more appropriate forum. So I was wondering if hypothetical Strange stars exist, would the strange quarks arrange themselves into baryons (i.e. Lambda-0 or...

Some post involving diodes made me reconsider pn junctions, with I first learned almost 40 years ago. Coming from a chemistry background, something always felt strange, but I could not tell what. Now I realized: While e.g. Gallium arsenide is a semiconductor itself and can be described roughly...

I have a problem with this Hamiltonian: two identical particles of mass ##m## and spin half are constrained to move on the surface of a sphere of radius ##R##. Their Hamiltonian is ##H=\frac{1}{2}mR^2(L_1^2+L_2^2+\frac{1}{2}L_1L_2+\frac{1}{2}S_1S_2)##. By introducing the two operators...

(edit.. not the red light, that's my emergency power outage light in every frame, I'm referring to 3:57am and exactly 15 seconds, blink and you will miss it) turn up the volume Strange white/yellow flash appeared in my room and the sound it made when the light hit my security camera sounded...

By chance, I have read a paper that left me in shambles. I would like you to help me figure out if it makes sense or not. I tried to follow Bridgman's logic, without a complete success. The extraordinary claim is that, if you start with a system consisting of a 1cm^3 copper cube where 2 faces...

PHOTOGRAPHIC REDUCTION OR ENLARGEMENT The proportions of a circle never change. But... Question: If a circle is always a circle, then how is it possible that the S/L and {[S/L]/R} ratios of a circle can vary as a function of the radius size?

Hello, Something I’ve wondered about is those amazing air bubbles that are sometimes found in underwater caves. In particular, I was wondering how the depth of the water does or does not affects them. In my Figure 1 example, the water is 50 feet deep and air bubble in the cave has 3 feet of...

Hiya, I'm an... Ameture I guess you could call it, and I'm trying to make this prop/cosplay/replica watch thay has odd requirements. It's hard to explain, probably due to my, newness to the craft. If it helps the device I'm trying to replicate is called the Omnitrix. Able to do anything but...

No, I don't mean the kinky ones. You know, like these thing kids do when walking on the sidewalk, stepping only on tiles and avoiding gaps (hey, these are wires, they can electrocute you!), or quite the opposite - stepping only on gaps and cracks (everyone knows sidewalk is actually a mesh of...

Hi. I've just come across something rather strange, I believe, about the micro-canonical derivation of the BE-distribution (as well as the Boltzmann and FD-distributions). See for example https://en.wikipedia.org/wiki/Bose%E2%80%93Einstein_statistics#Derivation_from_the_microcanonical_ensemble...

In lecture notes at a university (I'd rather not say which university) the following definition for Hermitian is given: An operator is Hermitian if and only if it has real eigenvalues. I find it questionable because I thought that non-Hermitian operators can sometimes have real eigenvalues. We...

https://www.physicsforums.com/attachments/284341

Hi to everyone! I'm currently working on a University project and one of my crazy ideas needs me to get my hands on a pretty strange electromagnet. the measurements are 40cm by 40cm with a height of 3 to 5 cm (doesnt matter a lot) i don't need this magnet to be very powerful (just enough to...

I have accidentally derived a very wrong result from the contracted Bianchi identity and I can't see where the error is. I'm sure it's something obvious, but I need someone to point it out to me as I've gone blind. Thanks! Start with the contracted Bianchi identity, $$ \nabla_a \left(...

So various articles and videos suggest that if a piece of strange matter, or a strangelet, were to touch the Earth, the entire Earth would eventually get converted into strange matter too. Now, from what I've read strange quarks have a half-life of ##10^{-10}## s, so I can't see how it would...

https://www.scientificamerican.com/article/alien-hunters-discover-mysterious-signal-from-proxima-centauri/?fbclid=IwAR0HOFRU-cvFaU66Wbqql-hoo91hA1WnCl9Azwqa84ly-zS6cjBiDFzlK8o Excerpt: Most curiously, it occupies a very narrow band of the radio spectrum: 982 megahertz, specifically, which is a...

Hello all, Here's the deal. It's weird, but it's true. I will swear on "The Precious" if necessary. (gratuitous Ring reference) Due to the unique circumstances surrounding my life, I have lived in a major depressive with borderline personality traits state for the better part of 40 years...

I am trying to solve the following exercise. In a H atom the electron is in the state described by the wave function in spherical coordinates: \psi (r, \theta, \phi) = e^{i \phi}e^{-(r/a)^2(1- \mu\ cos^2\ \theta)} With a and \mu positive real parameters. Tell what are the possible values...

I found this funny pattern in a slightly damp concrete paved parking area. Any ideas what it is?Detail :

There is a beautiful demonstration, available in the text Robert S. Elliot, Antenna theory and Design, Wiley-IEEE Press, page 17 (Stratton-Chu solution), which shows how the electromagnetic field at each point ## \mathbf { r} ## of a volume ## V ##, with boundary ## S_1, ..., S_N ##: can be...

https://arxiv.org/abs/0805.3819 Approximating the Standard Model and gravity with dust on \mathbb{R}^{0|18} Robert N. C. Pfeifer [Submitted on 25 May 2008 (v1), last revised 11 Jul 2020 (this version, v14)] This article describes a single species of non-interacting massless dust on...

Hi PF. I'm over ten years out from graduate school in physics, and I still enjoy re-reading my textbooks. I came across the word curvilinear, and thought how strange a word it is; a juxtaposition of curved and linear, which are at times understood to be opposites. The textbook was describing...

I am thinking to make a strange thermometer, based on the thermal expansion of a small aluminium-like rod/cylinder. I would attach one end of this aluminium rod to a vertical ceramic wall, and the other side would push against a piezoresistive material. I would then measure the resistance of...

This question stems from one of the recent homework threads. I'm familiar with the derivation given here regarding mass accretion and ejection, where the general idea is to define a system around body and all of the incoming/leaving mass so that we can once again apply NII to the whole thing. I...

I observed a strange optical phenomenon when lighting a candle in front of a tv screen, in the dark (attached picture). There seems to be two lines forming an 'X' figure with a colored pattern (of diffraction, I suppose). I think it must be related to the material structure of the TV screen...

I have observed that when i throw a card and give it a angular velocity, it "aim" to vertical and depending on direction start to rotate. For example if it rotates to the left in horizontal, vertically left side of cart goes up and right goes down. Conversely for the right rotation. I am not...

Hey everyone, So I'm trying to figure out what could be causing this problem: I have a DEWENWILS Wireless Remote Wall Switch which takes a 12V battery 60 mAh(23A battery), when I replace the battery with a 12V 500 mA DC power supply, the unit stops working properly. I'm able to use the Power...

So something weird just happened along the way in my experiment, here is a little background of what I'm doing. I have created a roughly 3x5mm inner diameter rectangular shaped channel for MHD liquid testing for one other project of mine, it's a simple conduction type MHD pump where the...

In the attached picture, I’ve drawn a crude schematic of the motor circuit. It is fed from a switchgear feeding 3 total motors. The feed contains 2 parallel conductors on each phase and ground. The equipment ground reads 12a going back to the switchgear, 6a per conductor. From the starter to...

I found an strange phenomenon while observing the moon. When the moon is seen through the window screens, strange light lines will appear: Half open screen: Closed screen: Why is this happening? I saw similar things on street lights, car headlights, etc through screens.

In the picture a CD is held in front of a ruler. The light source is an ordinary lamp. You can see a shadow of the CD on the ruler. Remarkable is the shadow on the screen behind it, because you can see that the CD is fully visible and the ruler bulges instead. Does anyone know this optical...

Hi to all! The ordinary Gauss theorem states that ##\Phi\left(\vec{E}\right)\,=\, \frac{\sum_{i=1}^{n}q_{i}}{\varepsilon_{0}}## where ##\sum_{i=1}^{n}q_{i}## is the sum of all charges internal of a closed surface and ##\varepsilon_{0}## is the dielectric constant in the empty. Now I ask to the...

The last couple days at work, one of the microwave ovens in the kitchen has been acting strangely. Today it seemed to get potentially dangerous, so I marked it "Out of Order" for now, and would like to figure out if it is hopeless, or if it can be recovered easily. I first noticed a couple...

In my latest post to the thread https://mathhelpboards.com/analysis-50/application-supremum-property-further-questions-garling-remarks-theorem-3-1-1-a-26167.htmlI encountered a strange problem ... ***EDIT*** PROBLEM SOLVED ... i retyped offending text ... still don't know what went...

Any theory what could be causing the excess gamma ray and the strange dips in the sun? https://www.quantamagazine.org/gamma-ray-data-reveal-surprises-about-the-sun-20190501/ "A decade’s worth of telescope observations of the sun have revealed a startling mystery: Gamma rays, the highest...

I am curious about the case where two electric or magnetic fields cancel each other out (I'm assuming this is possible). If a charged particle travels through the region where the cancellation exists, I am assuming the particle behaves as if no field exists. Does that area still have electric...

The Born frame field (see ref below) describes a rotating system and the proper acceleration ##\vec{a}=\nabla _{{{\vec {p}}_{0}}}\,{\vec {p}}_{0}={\frac {-\omega ^{2}\,r}{1-\omega ^{2}\,r^{2}}}\,{\vec {p}}_{2}##. If ##\omega## depends on coordinate ##r## then...

Hi A few days ago while at a sea terminal at night i noticed a strange liquid floating on top of the water, it has a light brown color and when it floats undisturbed by any thing falling on it like for example Sand, Stones, or any thing else, it is just a Light Brown liquid, the strange thing...

Hi i have seen in abook the dot product defined as follows: Dot(A,B)=(1/4)[Norm(A+B)^2-Norm(A-B)^2] how this definition connect with the common one: Dot(A,B)=Sum(ai*bi) Thanks!

Good day. Resently, I bought the Hamamatsu R928. But when I connect to power suply and connect output to the osciloscope I have strange signal. Maybe someone know the origin of this signal?

A recent paper in Nature describes a new phenomena found in superconducting materials: https://www.nature.com/articles/s41567-018-0334-2 Quanta magazine wrote about it here: https://www.quantamagazine.org/universal-quantum-phenomenon-found-in-superconductors-20181119/

I have found some odd Nucleation points that appear inside of the top area of a bottle of Diet Pepsi (the area right near the cap as shown in pictures below). The nucleation sites appear either as soon as you open the bottle, or after the first drink (I will test this once more and see exactly...

Hi. I want to show a publication from the middle of the 20th century. http://rsta.royalsocietypublishing.org/content/253/1025/205 I have been surprised by the subject it deals with. I would like to understand why the Royal Society digitizes that old document, which has never been received by...

As shown in the image below, I tried to integrate a large integral. However, the result is strange. According to the result, the integral is always zero whatever the values of w, h, L, P, S and k. However, when I try to put some "test values", the result is not zero. test values...

I wasn't quite sure what to call this thread or where to put it. I left a one gallon jug of water sitting in the kitchen floor. When I came back maybe 4 or 5 hours later there was a pool of water around the jug. I looked at the jug and found water slowly streaming out of the top. The jug was...

hi, i tried to simulate a simple capacitor and resistor charging circuit like this i used an imaginary resistor value "10M ohm" the result as you see appear to be strange, why this happened? is capacitor's charge is relative to the voltage on the capacitor it self? and i need some...