Discussion Definition and 284 Threads

Would it be offtopic to create a thread to invite people to discuss a preprint on Arxiv?

I need to find more fans of them and would love to discuss their albums!!!! I really love ICIMI and it's most definitely my favorite out of all of them. Um, It's Kind of a Lot has such a chokehold on me and it's the most relatable song ever. I also love Mitski, Msi (not them, just the music), a...

Hello everyone, Looking forward to some interesting discussions and to learning from all of you!

Hi My name is Virendra Singh Rawat, I am 63 years old male, staying at Indore, India. I did my B.Tech in Metullurgy from IIT Kanpur, India in 1985. I have no formal qualification or training in any dedicated field. I am fascinated by sky and love to see the dance of heavenly bodies. For 20 years...

I am interested in making an observation that involves the speed of light. It is widely stated that the speed of light is constant, but without saying what that means. I need to be precise, and would like a reference to an acknowledgement of the problem. When people talk about the speed of...

I always thought it meant "incompetent," but the dictionary says "unlucky." Huh. I now say that hapless is used as a euphemism for incompetence.

Hope to participate in discussions and find answers about certain topics like anti water hammer design.

As a physics enthusiast high-school student, I often run into troubles engaging with physics problems. In PF, I am going to seek a place for physics discussions. Thanks.

I am a retired associate professor from an engineering college. I am a fan of physics. I have published many papers in scientific journals and mathematical journals. I am very happy to join this forum.

I was just reading a thread which cited a Wikipedia article; I had thought that Wikipedia is to be considered as unreliable as the Public Broadcasting System (i.e., that has programs like NOVA, etc.), and therefore not appropriate since it is "pop science".

I was glancing through https://arxiv.org/abs/1605.07458 I don't fully get why scale invariance kicks in below a certain acceleration. Is this because the centripetal force becomes constant? I do see that Newton's second law with the centripetal force included is scale invariant. This symmetry...

Hello All : hope all are fine and well : during my scientific reading i may found a way to enhance the efficiency of some sort of simple engines , now i am working on a prototype which should be ready in few weeks for testing , the question is what next ? i am interested in solid state...

Been thinking about this since I was 12. Suppose you had a 1 lightyear long pole, and on the other end was a button 1 inch away that activates a light. The light is powerful enough for you to see it 1 lightyear away. You push the pole 1 inch forward. How long does it take for the light to reach...

As my current studies have proven conservation of energy is a universal law. How is it possible for two entangled particles to be equally or similarly affected when a force or energy is applied to a single member of the entangled pair? The production of such a pair would be invaluable to...

Various people like VN,Wigner thinks QM links to mental states,we know that. People introduced decoherence to kick consciousness out of the realm,as we widely accept.But even Zurek himself admits that there is a fundamental problem of why we only perceive one state and that solving the problem...

This is a thread for discussing the SF movie Dune (2021). Please post your opinions and reviews of the movie here, which may contain spoilers. There will be spoilers in this thread so please don't read it if you haven't seen the movie and don't like it spoiled! My short review: I really liked...

[Mentors' note: thread spun off from https://www.physicsforums.com/threads/equivalence-principle-and-rindler-horizons.1007879/] [Disclaimer] Definitely not B Level, but possibly of interest: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.100.084029 discusses the Rindler horizons of an...

Robert Lawrence Kuhn: It seems that special relativity suggests time is like gravity and electromagnetism, not built into the absolute fabric of reality like logic and causation. David J Gross: Yes, time is dynamical. The phenomena are dynamical and are labeled by what we call time. Including...

I am a student at high school who just finished a paper about nuclear energy and I really learned a lot from it. I found the topic interesting and really enjoyed learning about it. I now am searching out more people who know about it and as much information as I can fins while having good...

just something i think about, maybe it difficult to answer. i know, from study, that any observer moving along his world-line - in any state of motion - will not himself notice any difference to the rate which time passes for him. example: his heart-rate will feel normal (well, so long as he...

I want to work on a personal project, a web application similar to PhysicsForums just to understand how everything works. I have some basic questions. 1. What kind of database is ideal for a discussion forum like this ? SQL or NoSQL ? 2. Which frontend and backend technologies are used to...

At the base isn't education just imposing prof's beliefs and way of acting to learners ? So it lasts only if learners copy, but everyone knows that the system is kidding and contradictory, so isn't education fragile ? That's why the profs control and eventually punish discrepancies between what...

Summary:: Covid 19: How effective would a two week worldwide lockdown be? How effective would a two week worldwide lockdown be against Covid 19? In March when the news first hit, the US went swiftly into a hard lockdown. But things have mostly let up since then with mostly just masks, and...

Ok, so I have long been fascinated with magnetic fields and their mysterious nature. I've been wondering what would happen when the magnetic field of Earth gets bent/disturbed/rippled by some extraneous force. I am aware the extent of effects that magnetic fields have on a planet is great, but I...

Overview of thread: 1. Quick derivation of bragg scattering 2. Discussion of modern xray experiments as they relate to bragg/fraunhofer 3. Summary of points. Bragg/von Lau Scattering: (I will be following Ashcroft if you want to sing along, pg 98-99) Imagine you have light incident on some...

https://www.feynmanlectures.caltech.edu/I_19.html "Suppose we have an object, and we want to find its moment of inertia around some axis. That means we want the inertia needed to carry it by rotation about that axis. Now if we support the object on pivots at the center of mass, so that the...

Archimedes Riemann integral is one of the most elegant achievements in mathematics, I have a great admiration for it. Mr. Patrick Fitzpatrick commented on it as Archimedes first devised and implemented the strategy to compute the area of nonpolygonal geometric objects by constructing outer...

a.) 4 critical values b.) there are no points of inflection c.) 2 local maxes and mins d.)

It is expected from civilised folks to use respectful terms for others. I personally find “kicked out” a very derogatory and insulting remark :-) . How do you see that? (Especially if it is from someone who is classified as civil and meant for someone who is also civil).

Hello everyone! I was surprised to find Mr. Mike Berke has changed his avatar. Earlier there used to be a very high CC motorbike in his avatar and that caused me to believe that our mod used to drive that bike (at high speed, like some racer) but now seeing his avatar I found he is a very calm...

Hi, I am the leader of a University of the Third Age discussion group which has just been suspended due to the ongoing Coronavirus situation. I am hoping to be able to continue our discussions online in some way. All group members are tech savvy enough to use email, and search the internet...

I'm splitting this off the proton radius thread. The first measurements of the neutron lifetime worked as follows: you get a nuclear reactor as a neutron source and open a port in it to get a beam of neutrons. You count the number of neutrons in the beam and the number of protons (from neutron...

Imagine a massless (or very light-weight) charge that is glued to a rod undergoing sinusoidal motion along an axis. The acceleration of this charge produces electromagnetic waves, which can be harvested for energy, and this energy can be used to power the continued sinusoidal motion as well as...

I have always wondered about the ethical aspect of engineering in general. Considering engineers of all kind are responsible for the creation of some of the worlds most useful and innovative technology and some of the most destructive, do engineers feel that they may hold responsibility in what...

What I understand is, I have written something like this myself. What is a Static Proxy and a Dynamic Proxy then? Also, What is a Transient Proxy and a Persistent Proxy?

https://www.cnn.com/2019/03/10/africa/ethiopia-airline-crash-nairobi-intl/index.html There is now a lot of speculation about whether something is seriously wrong with the 737 MAX. https://www.cnn.com/2019/03/10/africa/ethiopian-airlines-crash-boeing-max-8-intl/index.html

Hi, for those who don't know, Landau (Lev Davidovitch Landau) had a famous exam called "The theoretical minimum". That exam had to be passed by any future grad-student of his. That test was extremely extensive and difficult, and the student was supposed to be knowledgeable about many fields of...

I'd like to start a thread of thoughts and opinions of a topic that I am considering spending time and money on. Unfortunately, I do not have a very broad knowledge of the engineering intricacies of the topic. I'm really curious if there has been a proposal or workings of a vehicle that uses an...

When you look at a bird in a tree with binoculars, that is not the bird as it exists at the moment but the bird that was there before the light traveled to the scope, which for practical purposes is the bird. You can shoot the bird of before, and it will fall to the ground. However, when you...

I just finished watching Xmen:Apocalypse and have several ideas about Peter Maximoff i.e,quicksliver. Minor spoilers ahead:(I will try my best at saying the minimum amount of plot itself, only when nessasary:smile:) First to declaim:The Xmen series are basicly around a group of people that can...

Forking a subject that was in risk of hi-jacking anther thread here. If the hypothetical TNO "planet 9" is detected , it would not fit the IAU's current criteria of being a planet. What would it be ? For the sake of discussion let's assume 10 Me and estimated likely distance and orbital...

How can we make a search just focusing on forum sites? Is there any discussion search options in search engines? https://www.makeuseof.com/tag/3-forum-search-engines-to-search-40-000-message-boards/...

This thread is for us to discuss the text The Drunkard's Walk: How Randomness Rules Our Lives by Leonard Mlodinow, and by that I mean for me to ask questions of you, those of you who will suffer me, my experts in probability, the PhysicsForums readers, on things I'm interested in from the text...

Hi everyone. As you may know, I had previously started a discussion regarding poverty rates among Millennial households in the US (see the link here for those who may not be familiar). https://www.physicsforums.com/threads/more-millennial-households-in-the-us-are-in-poverty.936087/ After...

WARNING! This thread contains spoilers for Star Wars: The Last Jedi. If you have not yet seen the movie, we strongly encourage you to turn around and return once you have. Please use this thread for discussions about The Last Jedi, including spoilers. :smile: I have not seen the movie yet, so I...

Given the evidence available as of today, is it reasonable to believe there is even a miniscule chance that the Oumuamua asteroid was built by aliens? Or is this just sensationalist journalism?

Here's a math question I've been thinking about lately. We have a stick of length one which is broken in one spot (with that spot chosen randomly and uniformly). Of the two broken pieces we take the one on the right and break it into two pieces in the same manner as before. With our three...

Hello, May I ask, are there any Arduino lovers here? I would like to know, because I have just started with Arduino and wish to know who I could ask if I have a problem or interesting project idea... Thank you. P.S. I have the Arduino starter kit.

Do receivers only receive signals or they emit emf?

Einstein said, "The distinction between past, present and future is only an illusion, even if a stubborn one." That's my problem--that illusion is so vivid and stubborn. Paul Davies said in his book "About Time": There is only one rational conclusion to draw from the relative nature of...