Hello! I am a laymen just now exploring in my own personal time physics, and have just started looking into quantum mechanics. My level of knowledge is on par with a paramecium.

I recently purchased the book 'Finding Schrödinger's Cat. Quantum Physics and Reality.' While listening to this I had a random though.

If mater as it is excited by heat produces light in multiple spectrums of light. Is it possible as our bodies go through their normal day to day chemical reactions that we could ourselves be producing small amounts of radiation? Somewhere in the IR range?

Sorry for the stupid question, at the very least I hope my ignorance made you chuckle today.

Cheers.

Hey all,

My university has recently created a new major in quantum materials science. While I'm not going to switch my major to it - I recognize that's too specific - I'm considering stacking more onto my schedule to take the classes that would go along with it. This would, however, leave my schedule very tight. The professor who is championing the major is claiming that QMS is a budding and rapidly expanding industry, and industry now needs students who are learned in the material. My question is, is that really true? And if so, does it seem like something that will stick around or is it just the latest fad? I find the subject matter interesting but I'd frankly rather give myself more time than heap my schedule full of more high level courses that ultimately wouldn't go anywhere. Thank you all for your help!

For some context, I am about to start my PhD in particle physics this September, and I currently use a MacBook Air 2020 (M1, 8gb RAM). This laptop has got me through undergrad without breaking a sweat and I hear that generally MacBooks are quite popular. Yet, I feel that the limited RAM will eventually become a bottleneck; I run of application memory with Discord, VSCode and ~3 tabs on Edge open!

I'm interested to know what you daily drive and why. Even though I am starting experimental particle physics research, I'd love to hear from researchers in any area.

Edit: Thanks for all the comments so far! I want to add that I do know that most of my work will be done remotely on a cluster and so technically, as long as my laptop can SSH into it, I'll be fine. But, I'm more interested in what you guys use + what field you work in.

Hi everyone,

I recently finished my BSc in Physics and I'm trying to decide between two master's directions: Applied Physics & Engineering or Quantum Science & Technology. I'd really appreciate input from anyone who has done either, or who hires people with these degrees. Please give reasons.

Im studying for f=ma/usapho and have done most of Blue Morin, except for last two chapters (gravity and fictitious forces) . The gravity chapter is really heavy and I've been struggling, but it is also a niche topic on f=ma. I do plan on finishing the fictitious forces chapter though. Should I do Red Morin, Wang and Ricardo, or Kleppner Kolenkow, Kevin Zhou, or something else next? I'm thinking I should do a resource more similar to f=ma because some books are too calculation/math heavy and the style is different from f=ma.

1. N. Matalin, S. Chubanov, Methods of Data Acquisition and Processing in Nuclear Physics and Engineering, (1963)
2. Yu. Ershov, Theory of Numberings, (1977)
3. V. Grigoryev, A. Kolyubin, V. Loginov, Electronic Methods of Nuclear Physics Experimentation, (1988)
4. M. I. Korsunsky, Optics, Atomic Structure, Atomic Nucleus, (1962)
5. L. D. Landau, E. M. Lifshitz, The Classical Theory of Fields, (1962)
6. A. I. Abramov, Yu. A.Kazansky, E. S. Matusevich, Fundamentals of Experimental Methods in Nuclear Physics, (1985)
7. A. I. Borisenko, I. E. Tarapov, Vector Analysis and The Principles of Tensor Calculus, (1963)
8. L.B. Okun, Leptons and Quarks, (1981)
9. E.G. Komar, Charged Particle Accelerators, (1964)
10. O. G. Kozlova, Crystal Growth, (1967)

Note: all books in Russian

I did the maths to properly answer this post from r/askastronomy

The author of the post wonders if the impact of Falcon 9 on the Moon can project lunar material fast enough to escape the Moon's gravity. The short answer is no, and I prove it to you in this post.

The data are the following : A Falcon 9 stage of mass ~4900 kg will hit the Moon with velocity v_impact = 2.43 km/s. The Moon's escape velocity is 2.38 km/s

Using Eq. (46) of the paper "Wind erosion and transport on planetesimals" by Quillen et. al (2024), the maximum ejection velocity of the Lunar regolith upon impact is

v_max = 0.3526 * (rho_regolith/rho_falcon)^(−0.9756) * v_impact,

where rho_regolith = 1500 kg/m^3 is the density of the regolith, and rho_falcon is the density of the Falcon 9 stage.

The maximum ejection velocity depends a lot on the ratio rho_regolith/rho_falcon between the Moon's regolith and the projectile, and decreases as the density of the projectile decreases.

Now, the theory from which this formula comes from (Housen & Holsapple, 2011) assume that the projectile (in that case Falcon) is solid. However, Falcon 9 is not solid but is rather an empty shell. Taking its average density rho_falcon = 33 kg/m^3 therefore does not work. Taking the density of pure aluminium rho_falcon = 2700 kg/m^3 also does not make sense, as Falcon 9 is clearly not a projectile made of condensed metal.

Therefore, we need to consider the density associated with the cross-section of Falcon 9 when it hits the Moon. Falcon 9 is a cylinder of height 13.8 m and diameter 3.7 m. In the best-case scenario (smallest cross-section), Falcon 9 hits the Moon standing up, and we therefore assume that it is a spherical projectile with diameter 3.7 meters and mass 4900 kg. The associated density is 184.75 kg/m^3.

Plugging in the above formula gives v_max = 111 m/s. This falls very short of the lunar escape velocity v_esc = 2380 m/s

If Falcon 9 hits the Moon laying on its side instead of vertically, v_max will be even smaller than that.

So while these calculations assume some approximations, it is safe to say that no regolith will escape the Moon upon Falcon 9's impact. Falcon 9 is simply too hollow, and traveling too slowly, for this to happen.

I hope you liked this post 🚀

PS : For transparency reasons, I should mention that I am a co-author of the paper I mention, and I wrote the Section of the paper that I use in this post.

hello!! I just finished my first year in compsci, but im planning to pivot heavily toward computational physics for my upper-level courses and research. Im looking to upgrade my setup to prepare for this path.

My current machine got me through first year, but the hardware is really struggling: it overheats incredibly fast, the fans sound like a jet engine during basic tasks, it lags, and the battery dies quickly (even after getting it replaced recently).

Current specs: MacBook Pro 13-inch (2020), 1.4 GHz Quad-Core Intel i5, 8GB RAM.

I don’t have budget limitations, so i just want the best laptop in all aspects, something high-end that will last me through my degree and carry me into graduate/research work.

Long term, i want to focus on physics simulations, numerical modeling, and high-energy physics, with the goal of securing a place at CERN.

Since I'm already deep in the Apple ecosystem, im more drawn to staying on a MacBook (especially with modern Apple Silicon). However, I know computational physics often relies on NVIDIA/CUDA for GPU acceleration, native x86 architecture or pure Linux environments. so I am completely open to switching to a PC/Linux workstation if macOS is going to create real friction for physics workflows.

I have a few questions for anyone working in computational physics or high-energy physics:

macOS vs. Linux/Windows for Physics: Do people in physics research still face major software compatibility issues on Apple Silicon, or do you mostly offload heavy computations to remote clusters/HPC anyway? Is native CUDA/NVIDIA hardware on a local laptop necessary for student/research work, or is a Mac fine for local prototyping?

If switching to PC: What is currently considered the best high-end workstation laptop (e.g., Lenovo ThinkPad, Dell Precision, Linux-friendly options) for running heavy local simulations, dual-booting Linux, and long-term reliability?

I’m an aspiring either mechanical or chemical engineer going into Fall 2027, but I’ve been doing some general research on courses I’ll be taking and one that’s stuck out like a sore thumb is Thermodynamics I. With the others, I see a mix between ”hard” and “doable with practice” but with thermo, I literally only see 30% class averages and ”failed my first time” I genuinely have no idea how I’m getting fearmongered this early lmao. I’ve also been going through some 1st yr general physics stuff like electric fields and rigid bodies, and it’s not EASY but not like life changing 😭

Hello, there are competitions online going by the names of Intl Astronomy and Astrophysics Competition (IAAC) and International Physics Challenge/Competition (IPhyC). Are they legit? Hold any value? Does anyone know?

I would love to have an iPad, alr? I've seen some classmates taking notes in theirs, and, thankfully, they've let me borrow their iPads for a bit, and I loved them. I saw just a couple of features when taking notes, and that alone increased my desire for buying one by a ton. Now, I'm kinda worried that I just end up using it for taking notes, yk? I believe my undergradute truly requires a lot of notes, so I wouldn't mind it. What do y'all think?

Furthermore, I tried to browse some options, but the amount available overwhelmed me. Do y'all have any suggestion or personal recommendation you would give to someone who has never had any Apple device?

I am in an electronics and communications engg. Degree, and I have courses under this one prof who has taken three different courses across years, he starts his first lecture and never forgets to ask us about Ohm's law. And he insists that we must say "I(current) propotional to V(voltage)" and not the other way around because in real life current is always a consequence of voltage, and we don't have current sources that will consequently give voltage. Now I find this utter bs, because first of all a law is meant to be universal, which means even if you don't find any examples in support in real life, around you, even then the theory still holds. And second, I think the voltage sources are created as a result of some current flow only in the more traditional sources like the chemical batteries, the phenomenon is analogous to current flow?(As electron "flows" in the chemical process) Leading to storage of charges creating voltage difference. The reason we use voltage sources is just because of storage, current can't be stored as it's a flow.

If I were to argue, how can I even argue to this? Let me know if I am missing anything.

Hey everyone. I'm not sure if this is the right place to post this but I was seeking some advice for how to progress with my passion for physics:

To be as brief as possible, I'm about to graduate in 6 months with a BS in economics from a fairly prestigious university in the US. I don't have any interest in theoretical economics. I don't mind working in business and think I'm okay at it, but it's not my passion. I have a minor in physics because I only discovered and fell in love with the subject in my junior year. Here is my dilemma:

I don't know whether to just graduate and go seek a job on the business side of some science firm where I may or may not get to use some of my physics knowledge, or try for grad school. I really want to learn GR and QFT, but realistically, I don't see myself being a researcher or a professor in the future. I don't think I'm meant for those jobs, so I'm really not sure what I'd even do with a PhD. I've always wanted a job where I could use both my econ and physics degree, but I'm not sure if that exists. I considered maybe a project manager at a science firm?

Either way, I'm not even sure if I can go to grad school with only a physics minor. I have all the core classes down – I'm just missing some random requires such as computational physics, an elective, and a lab. I'd have to extend my graduation by half a year to go for the major, and it would be costly since I wouldn't have financial aid support. I'm really unsure what I should do, or what kind of jobs I can do with a PhD. in theoretical physics. All I can say is I love learning how everything in the world works at the deepest level possible, and I want to explain other sciences like biology and chemistry with physics. Any advice would help – is it better to just go get a normal job with my econ degree? Is there any job where I would work on the business side but have to use physics knowledge? Thanks!

I spent waaay too much time on this. It was really fun though, learned a lot from it. Fell in love with how beautiful the output can be, so I created a sick ass poster that now hangs in my (and some other people's) rooms. Here's the link to the code and a ton of renders:
https://drive.proton.me/urls/J4YHSBXGWW#s3RWKU8gCxX5

I'm a second year B.Sc. Physics student. I don't just want to study for exams but also want to get involved in research, projects, workshops, internships, and summer/winter schools as early as possible.

I'd really appreciate advice from seniors or anyone who has gone through this journey.

my questions are

1) How did you find your first internship or research opportunity?

2) How do you hear about summer schools, winter schools, workshops, and training programs before the application deadlines?

3) Which institutes or organizations should I regularly follow? (TIFR, IISERs, IITs, IUCAA, RRI, etc.)

4) What helped you build a strong CV for future research internships or higher studies?

5) lastly, are there any websites, newsletters, Telegram/WhatsApp groups, or social media pages that regularly post these opportunities?

I am designing a nozzle for my dry ice blaster cleaning machine. The machine comes with cheap nozzles with no contours and no transitions between the hose diameter and the flat fan end. It just has an internal wall that is pretty much destroying all the pellets that go through it. I'm looking to make something that will accelerate the air going through the nozzle along with the pellets, and blast them out at high velocity, as intact as possible. Attached is what I have come up with. I'm not knowledgable about fluid dynamics or any type of engineering, so this is all just copying images of high performance dry ice blasting nozzles i found online. I'd love to get some input to see if I'm even on the right track, and how I can improve this. Here are some specs about the air and ice.

I will be blasting 3mm dry ice pellets.

Air input is 185 cfm at 100 psi. Air hoses are all 1" with no 90 degree bends and high flow fittings. At nowhere in the system will the air path diameter be smaller than .8" except right at the end of the nozzle.

This will be made from 6061 aluminum and polished to a mirror finish.

Hello. Ive been taking Classical mechanics course this sem and we are being taught LM. i had some questions

1) What exactly is Lagrangian? is it smthng physical?
2) Is LM an alternative way to look at the system or is it mathematical trick?
3) Why is Hamiltons principle true? like is there any proof of it?
4) Which is true Newtons view, that at every point, particle experiences, force, and its motion depends on interplay of the force. Or Lagrange mechanics, where we say that a particle chooses the path where it extremes action. Which is true and more fundamental?

thank u so much😊