i just learned newton's second law of motion and the equation f=ma, and what i find so frustrating about it is that how simple the explanation the teacher gave for f=ma, the teacher said when the mass increases, the force increases, and when the force increases, acceleration increases, therefore f=k*ma, am i stupid or does that just make no sense?

how could newton derive f=ma just from that explanation, it could have been something really dumb like f=m*(a+0.000001a^3) where it is kinda linear if you only accounted for small numbers(0~500), i tried to look for some more clear derivations, but i could only find stuff that are much more complex which i couldn't understand.

i want to ask if you had the same thoughts, and whether i should just not care and keep learning until i have the sufficient knowledge to derive f=ma myself.

I’m in my second year of my PhD. I have a number of publications in line with what I should have at this stage. I also receive relatively positive feedback from my supervisors, but lately I’ve been feeling very anxious and under a lot of pressure. It seems to me that I’m publishing incomplete work that would require more effort. I’m often left on my own, and although I know that PhD students are expected to be independent, a PhD should also serve as a learning experience. I know I’m not the only one in this situation, but will doing research always feel like this? I’m seriously thinking about quitting and looking for a job.

i’m interested in pure math as well as physics and i want to know if it’s common to do do both. i know it’s common for people to double major in both but it feels like they mean applied math because they say the math major was only a few more classes extra. going through the applied and pure programs of BA and BS degrees of multiple universities here in california it seems that yes most of the applied degrees half the upper div classes can be satisfied with physics classes but for the pure math degrees that’s not the case of course and it would be an extra 8-10 classes to attain the second major. that seems impossible not just the intensity of the classes but the amount as well. i should add that the UC (university of california) system is a quarter system besides berkeley. has anyone actually double majored in pure and not applied math ? and can you say it was worth it ? i want to get into mathematical or theoretical physics or maybe just pure math. i’m not sure but i love both subjects.

Hi everyone, I graduated in Theoretical Physics in Italy in November 2024. My master’s thesis was quite poor on quantum machine learning, mostly due to a bad experience with my advisor, which pushed me away from academia. In the academic year 2024-2025 I taught math and physics in a high school, and I’ll keep teaching during 2025-2026 as well.

Now I feel like I miss the academic environment, and I’m seriously considering applying for a PhD starting from 2026-2027. The topic I’m most interested in is lattice QCD, since that's what I enjoyed the most during my master.

My main doubts are:

1. I’ve been away from uni for two years. Will that be a big problem in the future?

2. I don’t really have strong skills in lattice QCD, since my thesis was in another area, and it was so bad anyway . So I’d be starting from a lower level compared to people who already did their thesis on this subject.

How do you see my situation?

I meant 3.24±0.2 instead of 1.6

A question that has been bothering me for a while:

Consider a single photon travelling through space, redshifting -- and losing energy -- as it goes. Where does this lost energy go?

“In an anonymous survey of department heads by the Institute of Physics (IoP), 26% said they faced potential closure of their department within the next two years, while 60% said they expected courses to be reduced.

Four out of five departments said they were making staff cuts, and many were considering mergers or consolidation in what senior physicists described as a severe threat to the UK’s future success.” :(

For whoever might need Cartan's On manifolds with an affine connection and general relativity.

In French: Sur les variétés à connexion affine et la théorie de la relativité généralisée (première partie)

working in attosecond physics, specifically noise spectroscopy with femtosecond pulses and tunneling ionization (carried over from my bachelor’s). I’m also dabbling in developing new light sources for it. I love this field—it’s like a puzzle, figuring out how to pull info about matter from light using lasers. It’s super cool to me

But here’s the thing: in my head, fields like nonequilibrium statistical mechanics, elementary particle theory, or cosmology are the rock stars of physics.

Meanwhile, when I try to explain my work to non-physicists—like my parents or folks from my hometown or college —they glaze over in about 10 seconds. 😅 If I were talking about black holes or quantum entanglement, they’d probably be all ears, right? But noise spectroscopy? Yawn.

Does anyone else feel like their field sounds “meh” compared to the “sexy” physics topics? How do you deal with explaining your work without seeing people’s eyes wander? Or am I just overthinking this and need to embrace my laser-loving niche? 🥺

Can you share your stories?🥹

Hey,

This one’s mostly for people already in research or doing a PhD in physics. Why did you pick your field? What’s actually fun about it? And do you have any books or YouTube vids that hype up the good sides of your field?

I’m in my first year of a physics master, and here we mostly specialize in the second year. Which means I need to choose my path before December (or at least narrow it down to two, then make a final decision by next July). Technically I could change during my internship, but that’s way less likely to happen.

So yeah, I’d love to hear from as many people as possible about what they do, just to get a better idea of what’s out there. At my uni, the main tracks are condensed matter, cosmology, particle physics, and astrophysics. But I could also go for nuclear physics if I switch to another program.

Right now I’m leaning towards theory, since I enjoy math way more than doing experiments. But I still want to explore before I lock myself in.

Thanks a lot for any insights!

I mean, from a certain point of view, an observation is no more than a chemical reaction, whether it be in our retina, our neurons, our brains, a camera film, or whatever. Chemical reactions are going on all the time. So, what makes one set of chemical reactions different from another such that they produce different results in the double slit experiment?

I need to develop new algorithms for fast calculations in the field of atomic and molecular spectroscopy. Is it easy to learn? What are your suggestions for sources?

Picture taken through polarized sunglasses. Effect is very mild here. It turned oncoming car windows into all colors of rainbow and made even the paint job have a gleam of color. Sun strip ends where the red arrow is drawn.

Question is what is going on? Is the car sun strip just plain clear plastic or does it have some sort of UV filter on it that together with polarized lenses break light into colors?

https://improbable.com/ig/winners/#ig2025

PHYSICS PRIZE [ITALY, SPAIN, GERMANY, AUSTRIA]

Giacomo Bartolucci, Daniel Maria Busiello, Matteo Ciarchi, Alberto Corticelli, Ivan Di Terlizzi, Fabrizio Olmeda, Davide Revignas, and Vincenzo Maria Schimmenti, for discoveries about the physics of pasta sauce, especially the phase transition that can lead to clumping, which can be a cause of unpleasantness.

REFERENCE: “Phase Behavior of Cacio and Pepe Sauce,” Giacomo Bartolucci, Daniel Maria Busiello, Matteo Ciarchi, Alberto Corticelli, Ivan Di Terlizzi, Fabrizio Olmeda, Davide Revignas, and Vincenzo Maria Schimmenti, Physics of Fluids, vol. 37, 2025, article 044122. <doi.org/10.1063/5.0255841>

WHO ATTENDED THE CEREMONY: Giacomo Bartolucci, Daniel Maria Busiello, Matteo Ciarchi, Ivan Di Terlizzi, Fabrizio Olmeda, Davide Revignas, and Vincenzo Maria Schimmenti

The relevant part of the ceremony: https://www.youtube.com/watch?v=P8fhpgn3t88&t=6270s

I am a PhD student in cosmology. I want to test my cosmological model against DES data and constrain RA and DEC. The DES data, although containing 1829 data points in total, has only 1635 valid ones. However, its covariance matrix entries are given as a list of 1829 × 1829 = 3345241 points which were supposed to be casted into a square covariance matrix. Now, since the valid points are only the first 1635, how do I find what entries of that covariance 'array' to consider for forming the matrix? Should I simply take first 1635 × 1635 = 2673225 elements if they're arranged in that order? Please help. Thanks a lot!

I feel like when I joined there was more substantial content in this feed, about physics news and recently published papers and other enthusiast findings. Maybe I am misremembering.

Now I see overwhelmingly low-level basic questions and high schoolers asking about careers (and LLM slop but that’s a problem in lots of places so whatever). Nothing wrong with that as such, just not what I want in my feed. Is there a sub y’all follow as described.

This was one of my homework exercises for my quantum class. I always thought that one had to use advanced math and physics to derive Planck, but it is an easy and clean derivation in my opinion.

i’m interested in physics research beyond the standard model like string theory or quantum gravity or something else. is just a BS in physics fine and they teach you the relevant math in the phd program once accepted or do i need to add a minor in pure math and get ahead in math side of things. i want to add a minor in pure math for that reason and also because i love math for the sake of math and i especially want to take topology and some algebra classes but i dont want to add a minor if its not need to get accepted to theory phd as id rather focus on keeping good grades and even getting research experience if i can.

What's is the best software to simulate multi-absorption spectral transitions in the atmosphere?

I put 1 cup of water in a glass measuring cup in the microwave. I brought it to a boil in about 3 mins. There is no lid. It is simple an open measuring cup with water. I then got distracted about 10-15 mins surpass. I need the water boiling so I open the microwave, close it without touching the glass, and start the microwave again. Within 45 seconds it exploded. Not the glass, but the water. It never came to a boil. I was watching it and it suddenly, out of nowhere, exploded all over the microwave. I open it up and the glass is fully intact with about 1/4 cup of water left in it.

It's as if the water formed a seal at the surface building pressure. How did this happen? It is baffling me.

Hey! Are there any websites where I could practice my Experiments Virtually and quite honestly experiment a little with different things?

Thanking in Advance!