As the title says. I'm a 28 year old physicist, working as the lead engineer for a large space and defense manufacturing company. Part of my job is to work directly with all engineering team heads, doing project engineering, project management, and systems engineering. AMA

Original post: https://www.reddit.com/r/AMA/s/ziHdUgtHrt

Here on earth, even if something like GPS didn't exist, we could still orient ourselves using the stars, for they are so far away and the distances we travel on earth are so insignificant in comparison to that that their positions in the night sky are essentially fixed points.

Once we travel distances relevant in comparison to the distances in between stars, obviously, this would no longer work. So, assuming we wanted to get from star A to star B, how would we find our way?

It's exam season so it's probably that but... I'm in a state where idk what I'm doing with myself and I feel like I'm just withering away. For a bit of context I'm a (soon to.br hopefully) third year student and at this point in time I should've already finished my studies but due to my own irresponsibility and a couple of other factors I've dragged it out. Now I'm sitting here trying to study but also having a mini panic attack because of the time I've wasted on nothing. I'm also thinking is any of this worth it (even tho I do want to be a physicist). Due to the time I've wasted and the number of times I've failed and repeated some courses I don't feel that excitement that I've felt for science in the past.

This probably looks like I spewed out a bunch of sentences but try to understand and if you have any advice I'd be happy to receive it ☺

Hi, right now am studying mathematics engineering, and I’m joining in the world of quantum computing, so I’m studying a lot of mathematics and physics to, and I really love the world of quantum mechanics. So my question is that I want to study a PhD in physics but I don’t know how hard is it and how I have to prepare and what I should know for apply in PhD if I have to be a genius or a normal person can apply, and how can I apply to a really top university. Btw I’m in 3th semester

Is it too late by then?

I’ve been reading about the AMPS argument and how it challenges the equivalence principle by suggesting an infalling observer would hit a "firewall" at the horizon. I know there are many proposed resolutions (ER=EPR, complementarity, state-dependence, etc.), but I’m wondering if there’s a widely accepted solution at this point. Has the paradox been resolved in any definitive way, or is it still an open problem in quantum gravity?

For me, it was special relativity when i first learned about it in modern physics as an undergrad.

It’s easy to describe large numbers, but wouldn’t the largest meaningful number (that is, a number that describes either our universe or something within the universe) be the number of cubic Planck lengths in the universe? i.e., the size of the universe expressed in cubic Planck lengths.

Yes, one could easily craft a larger number (e.g., the number of cubic Planck lengths in the universe to the power of the number of cubic Planck lengths in the universe) but that number wouldn’t really represent anything meaningful. Is there a larger meaningful number?

And a side question… As the universe expands, does the number of cubic Planck lengths in the universe increase or do the cubic Planck lengths themselves expand while the number of cubic Planck lengths in the universe remains constant?

Happy Gilmore successfully takes the Coriolis effect into account on his final putt. Say what you want about the rest of the movie, but representation of a somewhat misunderstood physical phenomenon in a goofy Sandler comedy like this is incredible.

The climax of the movie takes place on a flat carosel rotating counter-clockwise with the hole in the center of the circle. Happy is on one side and his caddie (probably my fav character, played by Bad Bunny) is standing directly opposite. For movie drama reasons, they can't move and first must exchange clubs by tossing them to eachother at the same time. They first try this by throwing directly toward eachother from their non-inertial frame which results in them each getting their original club back (at this point the main villain remarks "physics is a b****"). Happy seems to understand what is going in here by now and instead suggests throwing the clubs straight upward, which works (they would actually need to throw the clubs leftward but since the straight vertical toss is what is observed from the rest frame ill give it plausable deniability), but now he needs to make the putt.

At this point I'm having serious doubts that the putt he goes for will be physically reasonable but lo and behold, he aims strongly to the left, much to the caddie's shock, and the ball travels a circular arc curving to the right from Happy's perspective and goes in and the day is saved etc...

TLDR: I have never seen plot relavent and thoughtfully done physics like this in a movie that I can recall, let alone in a throwaway comedy like Happy Gilmore 2. They don't mention Coriolis by name but I was pleasently surprised to see it in action

TL;DR: Torn between HEP Theory (fundamental but very grim job market) and Condensed Matter Theory (safer but less “ultimate”). Curious about relative job prospects and whether CMT is as mathematically rich as HEP.

I recently started my PhD in physics. When I applied, I emphasised that my primary interest was High Energy Theory. But I’ve recently been exploring Condensed Matter Theory. While it doesn’t scratch my itch for “the most fundamental” questions, I’ve been surprised at how much overlap there is (effective field theory, topology, dualities, RG, etc.).

The thing that’s making me hesitate is career prospects. I didn’t realise when applying how bad the funding/job situation is in HEP theory. None of the advisors in my undergrad were kind enough to explain the over saturation and competition in the field, and now that I am talking to profs in my grad program, I becoming more and more aware of it, like how I'd have to TA for the entirety of my PhD. CMT seems a bit safer — more funding, stronger links to experiment, and a broader appeal to departments — but I can’t find solid info on the theory side specifically (everything I see is about experiment).

Is the academic job market in Condensed Matter Theory noticeably better than in HEP Theory, or just slightly less impossible? How does the mathematical sophistication/abstraction in cutting-edge CMT compare to HEP Theory? I enjoy using abstract mathematical concepts like differential geometry, algebraic topology, abstract QFT tools, etc., and I don’t want to give that up. Would doing a PhD at a place strong in HEP but only solid (not elite) in CMT hurt my prospects if I switch tracks?

I don't want to move to Condensed Matter if my chances of getting an academia position later don't increase at all. I also have no experience in CMT research, but I'm willing to learn on an accelerated pace.

This question may have been asked on this subreddit a lot already but I really need advice regarding this. I'm a student in IBDP and will apply for universities next year.

I absolutely love physics, I enjoy almost everything about physics (except electric stuff because it wasn't really taught with that much information in my curriculum.) the derivations, unknowns, finding stuff and looking at stuff that makes absolutely no sense without staring at it blankly for an hour. I also really enjoy maths, not as much as physics definitely but I do like it a lot. I'm quite decent and coding, I know python and a little bit of C and Java. I also used to daily drive linux for 2 years so I'm quite decent at it too (left it because my laptop decided it doesn't want to run linux anymore for some reason. Yes I tried to read documentation and fix it. It didn't work.)

Since grade 9th (the time I started to finally become serious with life and started to have interest in studies), I have really enjoyed physics and planning to apply for B.Sc physics in future and study to become a physicist. I researched more regarding it and found out that the study for becoming a physicist is quite long. Which doesn't demotivate me at all to be honest but, it feels like whoever I try to talk to about wanting to be a physicist just discourages me into doing it. When it was just a few classmates it wasn't an issue, but then my teacher (not my physics teacher) and for some reason even my principal started lecturing me about why I should do engineering instead of physics because I won't find a job and the pay is bad. It more discouraging because the principal himself holds a PhD in physics so it seems like he's saying with experience.

I do know by studying physics I probably will not earn as much as an engineer. But that doesn't really seem like an issue to me as long as I will be able to earn enough to live without worrying about making ends meet. If I get to do something I am interested in then it seems quite good. The only thing worrying me about my choice with physics is if I don't end up in a STEM field. Physics has very high unemployment rate.

And engineering does seem quite interesting too. But one of the reasons I do not want to do engineering is because of the image engineering has in my country. India. Literally most of the people who did engineering have either ended up unemployed or underemployed or payed an extremely shitty salary and have a boss constantly yelling at them and overworking them (a relative of mine told me, someone who did engineering from the top University here).

I just don't know what I'm supposed to do. Whether to do engineering or physics. It's only an year until I have to apply. I'm planning to apply to Oxford but if that fails then I will do Studienkolleg and apply to German universities. I'm still really lost when it comes to select between physics and engineering. Any advice will be appreciated. Thank you

I've been somewhat in the public as a physicist and/or student for some time now. I was an active member of the student body with a public facing email address and now, as a member of a working group, I am listed on the university website. Oh boy, the quality of the schizophrenia I am exposed to.

In the student council it was a fairly common occurrence to have people send us crackpot theories either thinking we were some kind of scientific council or asking us to pass along their barely comprehensible write ups. I've been listed on my groups website for about a week (Hooray to university bureaucracy and its speed) and now people think they want me to listen to their insane trains of thought.

I've been getting emails with PDFs, letters asking for help with their nonsense maths, one guy came into my office, last week I got this email which I have yet to decipher:

Can you tell left from right? The object is flying from the left to the right! With the cloud away from the Sun, it is heading directly towards Earth and will reach us in September! Not only can you not calculate the probability of an object of 20km in size moving 60km/s towards us (extremely improbable, yet TRUE!) But you also believe that it moves into the TAIL!??It is moving 5 million + km per day, which means in 24 hours, everything will change!WHERE DO YOU DRAW THE LINE OF BEING ABSURD!??? REVELATION, chapter 8, offers a scientific description of an asteroid hitting the Earth! Should we prepare for an emergency?? Stock up on oil and gas, as there will be 33% less solar energy. This is all **because you can not comprehend Newton's law of gravity. At 99% escape velocity, you reach only 310 000 km distance from the EARTH, which means to get to the Moon, you need to have a SPECIFIC INITIAL VELOCITY between 99-100% of 11.2km/s-Gravity well is real. How do you jump out of a well? Other than having a SPECIFIC initial VELOCITY, or you are in the well forever!ALSO, can you do simple high school math? ORBITAL VELOCITY of an object at a height of 420 km (ISS location) must be like 120,000 km/h, or 30km/s, or half the speed of this asteroid!You believe in FARYTAILS! In MYTHS!!  There is an object hanging up in the air called IS(I)S for 25 years, rotating around the Earth at 120,000 km/h.CONGRATS!! One has to have a HUGE Imagination to think that is possible! Continuous human LUNACY! for 25 years Hubble telescope IS A LIE, it does not exist, and of course, this is the source of the claim that it moves INTO THE TAIL!?? Or it is moving from right to the left on the screen (logically) or in the direction of Earth, not Mars!Read more on Substack under hrabmv--more articles that explain what it means to be created in God's image: we have Mind, Soul, and Heart (true psychology! not Id, Ego and Super Ego nonsense!)
3 Denn es kommt eine Zeit, da werden die Menschen der gesunden Lehre ´des Evangeliums` kein Gehör mehr schenken. Stattdessen werden sie sich Lehrer aussuchen, die ihren eigenen Vorstellungen entsprechen und die ihnen das sagen, was sie hören möchten. 4 Sie werden die Ohren vor der Wahrheit verschließen und sich Legenden und Spekulationen zuwenden BRAUNSCHWEIG SHAME ON YOU!!! The town where HITLER STARTED his march!

I do experimental hadron physics, why am I your target audience??? I have no idea what this woman is trying to tell me and I love it. (As long as they don't physically come looking for me) There is not a single coherent thought in there. (Note: in the original email all of this text is written in title font. This is a four page email) The things crazy people tell me is my guilty pleasure. I never respond because this is psych-ward level crazy and I don't want to encourage it but receiving these brings me so much joy and so much bliss. I love collecting them. I can't be the only one who feels this way. It there a public repository of these or does anyone else collect these?

Dm me.

The loop is placed in a uniform magnetic field pointing into the page, and the field is increasing over time. Which way would the induced current flow?(The answer should be in the direction I showed in the image). What confuses me is, a smaller loop creates a stronger magnetic field per amp, so why does the current flow along the outer circumference to oppose the change, while the inner circumference ends up reinforcing the increasing field instead of opposing it?

A neat video by my graduate school classmate back in the day, totally not biased, working through Heisenberg’s original paper on quantum mechanics. If you ever wanted to see how the paper was structured and don’t want to learn German and old fashioned notation, now’s your chance.

I’m currently taking an quantum information theory class and was wondering if information theory in general could/is used in theoretical biophysics. Any ideas?

From the beginning of my BSc I was really interested in high-energy physics, especially in theoretical particle physics, so I took related courses on advanced math and mathematical physics, went to conferences, talked with professors working in HEP, and (tried) to read papers from the field. But I realized that pure theoretical stuff was not the right field for me.

I enjoy the hard math and I respect people who are working in very technical areas like strings, BSM theories, dark matter, orbifolds, etc., but I don’t picture myself doing this type of work in the future. I feel the necessity of working closer to experimental data (I don’t see myself becoming an experimental physicist either). Maybe phenomenology is closer to what I'm looking for.

• Have you ever changed your field of interest in physics?
• Do you have any suggestions on how to go about this?
• How did you know it was the “right” field for you?
• How much did “being employable” influence your choice?

I’m trying (if it is possible) to find an intersection between working on a field that I find interesting and something that gives me transferable skills in case I can’t succeed in the academic path. (Is it too early to think about this?)

Since I was convinced that theoretical particle physics was for me, I didn’t pay much attention to other areas, but I took interest in gravitational-wave detection (interferometers are pretty cool devices) and plasma physics (fusion in tokamaks). I’m exploring other areas, so I would really appreciate it if you could share some of the things you find cool in your field.

Hey, everyone.
I thought about studying a textbook called "An Infinite Descent into Pure Mathematics by Clive Newstead" as I'm really into abstract math and thinking about learning coding as a skill for the future. But I think I'm wasting my time because it seems really hard to follow and requires a lot of discipline.

What do you think?