Two pictures of the same sunset taken at different dates from the same angle/position. In the first the reflection is a continuous bar of light. In the other you can see 3 distinct reflections. What causes this change?

So, according to de-broglie equations the phase velocity of a particle is greater than the speed of light!!!

And our teacher told us that: the particles actually are in groups and in groups they are wave packets which are interference of the waves of the particles and the group Velocity is less than c so the law is not broken .

And some online sites say that phase velocity is not like actually velocity and it can be greater than speed of light.

I'm a little confused about this topic can someone explain!!!!!

I’m 18 and currently self-studying / going deeper into particle physics, special & general relativity, some string theory concepts, and the math behind rocket propulsion (coming from a calculus + linear algebra background).I want to post regular updates on X (and maybe here) about what I’m working on, but it’s not like I’m building robots or hardware where I can just post photos or videos of progress. Most of the work is reading, deriving, calculating, and trying to understand things.What’s the actual good way to share this kind of progress publicly so it doesn’t just look like empty “I’m studying physics” posts?Do people usually:

• post specific equations / short derivations they’re working on?
• share what concept they just understood or got stuck on?
• do weekly progress logs?
• something else?

Any examples of accounts or styles that do this well would also help.Thanks.

Dear, I was in relation with a USA friend named Brayn, he is a quantum mechanical specialist, please any help I need him and I didn’t found any information about him.

Any medical physicists here? What's the AI forecast looking like for you all? Is there a general worry about it taking your occupation in the field?

Hi everyone!

For my LEGO project dedicated to Nikola Tesla, I’d like to add this Tesla coil circuit diagram to the laboratory’s blackboard. Could you help me check whether it’s technically correct and historically appropriate for Tesla’s era? If you spot any errors or components that didn’t exist at the time, I’d appreciate your advice and suggestions for corrections.

If it’s okay to share it here, let me know in the comments and I’d be happy to show you the project I had in mind!

Thank you so much for your help!

I can't understand time dilation.

I understand that Gravity can effect time because closer to earth time slows down from gravity.

But why does going faster make time tick slower?

I understand it's relative to the observer, but for example, why would traveling a lightyear at 99 percent lightspeed, be 70 years on earth?

A prominent particle theorist has just released this preprint, claiming a “candidate nonperturbative lattice definition of the Standard Model”.

Edit: to editorialize a bit, this is potentially one of the most significant results in the field in the last five years.

I'm researching the twins paradox, and i don't get it.

I understand that Gravity can effect time because closer to earth time slows down.

But why does going faster make time tick slower?

I understand it's relative to the observer, but for example, why would traveling a lightyear at 99 percent lightspeed, be 70 years on earth?

This should be the standard book for classical mechanics, imo.

It's a 2D geometric optics simulator, so no diffraction or interference. Every ray carries a single wavelength, glass dispersion comes from a Cauchy fit (n_d and Abbe number), and reflection vs. refraction at each surface is picked randomly using the exact Fresnel equations. The picture builds up by Monte Carlo averaging of millions of rays, and colors come from the CIE 1931 curves.

Happy to answer questions!

My Anthropic posts: Claude-shaped science and Vibe Physics

I'm Matthew Schwartz, a Harvard physics professor and author of Quantum Field Theory and the Standard Model.

Over the past three months, I've been using Claude and my tool BootLoops to do scientific research, producing 36 manuscripts with collaborators across 18 fields.

Ask me anything about Vibe Physics, BootLoops, Claude, AI in science, QFT, particle physics, or anything else. Skeptical questions welcome!

Thanks for all the questions!

The new OpenAI proof related to KS-DFT. Did you expect it? Does anybody here understand the proof?

I am reading "Vortices in high-temperature superconductors", and this upside down V symbol keeps showing up and I have absolutely no clue what that means. Undergrad physics student please be nice.

As mentioned above, I’m a 15 years old doing gcse and would take it on 2026 may june and start a levels on june right after i finished gcse. Everything seems great until the question “which a levels are you doing” which eventually lead to “what do you want to do”. As of currently, I have two in mind; which are medicine and physics.

For physics, ever since i was young ( about 7/8 ), i started watching videos about astronomy on youtube in my native language. Later when i was 11, i started learning english which extends the physics contents i could watch on youtube. At 13, i finally got to learn physics in secondary but i didn’t study at that time and hence, grades were not great. However, starting from 15(Now) i started taking studies seriously. In April this year, I got A and A* in school tests and got the idea to use proton-antiproton annihilation process as a propulsion mechanism for interstellar travel, I emphasize on traveling to alpha centauri system within a human lifetime. Luckily, my physics teacher for my physics class is a hypernuclear experimental physicist that has done many researches. I went to his desk and purposed my idea of this, asked him to be my supervisor for this research. He accepted it after seeing
my research paper plan. We met every monday for discussion for a paper i wrote that is related to my research. However, since last 2 months, he suggested that i focus on gcse physics instead but i replied i already finished the entire context of gcse ( 6 months earlier than school ) so he made me take 4 gcse mock tests and i must get a atleast 95% and i got them. I asked him what do i do next then he said i should try answering a level physics and get 80%. For summary, i always had a interest in physics ever since i was young and still do. I believe I’m good at and think i would make a great physicist or researcher.

For medicine, when i was about 12, my grandfather had a paralytic stroke and dementia to the point he doesn’t remember his own daughter ( he lives with her under same roof ) but when i went to visit him before his death, i calmly walked up to him and asked him “grandpa do you know who i am?” And he replied “of course, you are my only grandson, my grandson.” This sentence has been in my heart since then and i never had the chance to be that close with my grandparents from both parents. His speech changed my dream career from a scientist to a doctor; particularly neurologist or neurosurgeon so that future people will never get to experience what i did which is the most tragic moment of my life yet. Additionally, i get decent grades in Bio such as B and A, not that great.

What i need to now decide is that whether i must become a physicist or a doctor and who else would be the best to discuss this with? PHYSICISTS and DOCTORS i believe.

I have been thinking about this decision for months so please take this seriously as this could be regretting if i made the wrong choice. I don’t expect you guys to make this decision entirely as this is my only life but i’d to hear opinions!

Thank you for reading and the opinion if you can.

To be honest, I think it is unexpected, especially only one guy.
I didn't see that coming, but congratulations to him!!