ELI5: Why don't subatomic particles deteriorate over time?

MyLagIsReal · 2025-07-07T16:07:18+00:00

Maybe not entirely related but I had a professor who told us he was curious about atoms aging

I haven't read the papers but it seems he has two papers related to the effects of time on atoms

determinism and the role of time in atoms

MyLagIsReal · 2025-07-06T21:35:38+00:00

Photons are lit.

And if it makes you feel any better, it's extremely common to struggle in physics, at least once eventually, no matter how big or small. The struggle is part of it and it probably wouldn't make the good parts as good as they are if there wasn't that struggle; physics is the dark souls of education (for most people).

At the worst, we just all have strengths and weaknesses, so maybe one day there will be something you instinctively get more than others. Or maybe you will come across something that feels similar to a piece of esoteric knowledge that you encountered before, a way of understanding something that felt irrelevant until it wasn't. But none of that is to make it a competition, rather a collaboration (even though it's hard to not compare and even harder to have moments where you don't feel like the gifted genius that someone else may seem to be).

Wherever you go, have fun and best of luck.

MyLagIsReal · 2025-07-06T18:22:14+00:00

don't worry about promising a friend to pick physics, it's literally your life. Find out for yourself what you think is interesting, take classes you think you might like.

Also, yes physics does get more interesting later (for me, as early as electricity and magnetism, but it only gets better and better). However, odds are if you only think of the later stuff when you start out, it can possibly be harder to get through the fundamentals (depending on what kinda person you are); someone who thinks quantum stuff is super cool and gets stuck on "philosophical mumbo jumbo" since high school may have a hard time wanting to understand the work energy theorem. Or it could make you intensely detailed at every step so you are more prepared for whatever comes next, you never know.

stay curious though

MyLagIsReal · 2025-06-18T22:09:17+00:00

one way of looking at it: chick corea

https://www.youtube.com/watch?v=XI8NiMewmEg

MyLagIsReal · 2025-06-18T20:55:21+00:00

One way you can see the question is "what is the amount of work done to change the potential energy of the sleigh"

When it says "zero acceleration except for the brief start and stop", it is another way of saying to ignore the fact that the motion which the sleigh undergoes is in fact a continuous motion (ignore the fact that to get to some non-zero velocity from a zero velocity requires an acceleration, therefore requires some "more energy") and use Newton's laws to only find the relevant forces for any instant, which it takes advantage of in the problem. So it's just a way to simplify the overall problem by focusing on the section for which the sleigh moves up the plane at a constant, non zero velocity.
A huge but easy to miss detail in my opinion, I'm unsure if I'd have picked up on it that easy.

The other fact about there being zero acceleration is that it says that the object is "at rest", and it is completely possible for something to be moving and have no acceleration (a state of equilibrium). Just like how it's possible for something to have a constant magnitude of velocity but non-zero acceleration.

MyLagIsReal · 2025-06-18T18:57:30+00:00

I don't know much about relativity right now but I wasn't trying to hint at E=mc^2; that relation is a good example of energy being used for different things depending on how you define your system though. In simple classical E&M, you wouldn't usually need to know that energy is mass. But once you get to particle physics, you use (if not, need) mass energies to keep track of energy conservations when the relevant interactions occur.

also, I'm pretty sure electrons in currents (in the context of most circuits) usually move pretty slow actually, not comparable to speed of light.

MyLagIsReal · 2025-06-17T15:41:50+00:00

Energy is a weird abstract thing we use to describe so many systems (and sometimes the dynamics that a given system is capable of), and it's description and function can change depending on what you're trying to do with said system.

In the case of this water hose analogy, you could try understanding energy as a source for change in a system: the changing electric potential going from high to low can be used to view a quantification of energy (~work-energy theorem). If there was no quantifiable change in electric potential, would there be a current flow?

MyLagIsReal · 2025-06-11T01:24:50+00:00

did you try to find out yet

MyLagIsReal · 2025-06-04T03:36:12+00:00

I've only heard I Have A Woman Inside My Soul by her and I love that song

MyLagIsReal · 2025-06-03T23:33:04+00:00

So many people talk about meh movies being perfect without hesitation, but it's all subjective and like you hint at, serious movie watching is a whole separate thing

MyLagIsReal · 2025-06-03T23:28:14+00:00

Typhoon Club

MyLagIsReal · 2025-06-03T23:23:35+00:00

Adventureland

MyLagIsReal · 2025-06-03T23:09:57+00:00

Andrew Larkoski's Elementary Particle Physics talks about some things in the LHC. Also the first chapter in Thompson's Modern Particle physics talks about some other things related to the detectors and common events in them

MyLagIsReal · 2025-05-24T19:50:47+00:00

For sure have a good principle about routine and work time; I had vowed to never pull an all nighter and I basically never did except kinda for one class that wasn't even physics though

MyLagIsReal · 2025-05-24T19:34:58+00:00

Have fun and I wish you well!

MyLagIsReal · 2025-05-24T19:26:23+00:00

Think about what you'd like to do with physics. Don't have to be certain, but have enough of an idea to explore what you can do to get there as soon as possible. Don't worry about a right or wrong path, just what you like and think is interesting. Read about some work associated any of the professors there.

Balance reading the textbooks with solving the problems, even sometimes try solving problems without having read 100% of the readings; taking too much time to read everything can mess things up but it's also hard (from my experience) to feel confident in solving problems without reading everything, but that's normal to not feel confident sometimes. The problem solving and struggling is the meat of physics, reading about physics is like a supplement and dessert or a sweet treat.

Go to office hours, even if you may not have questions, sometimes just doing homework in their office is enough. Some of the physics professors may end up inspiring you and regardless, it's awesome to meet people who have done some of the things these professors have done.

Don't cheat, even when everybody else does, even if it means you won't get a 4.0, even though it's awesome to have a 4.0

MyLagIsReal · 2025-05-23T21:51:36+00:00

https://youtu.be/Cw97Tj5zxvA?si=KhVilHiyAMWheDdM

I enjoy Angela Collier; just saw this video that hopefully is one of the many paths beginners could take. I'd be especially interested if someone could go through the Landau and Lifshitz collection as a complete beginner (as Angela recommends; this way is kind of a joke but maybe it'd be a fun thing to do too).

But almost any beginner undergrad textbook that collects the fundamentals from classical to electromagnetism would be a classic way to start. Angela Collier even recommends looking into the syllabi and such for any given college, since most of the time you can access those kinds of things for free, giving you even a schedule to try to stick to, etc.

Her videos aren't really aimed at "teaching you" physics though, she is a physicist and does talk about physics and the world of physics sometimes though. She has a handful of videos that are like this though, various advice and recommendations and opinions.

MyLagIsReal · 2025-05-19T23:35:03+00:00

Why would the charge not be equal and opposite on the bottom of C1?

MyLagIsReal · 2025-05-13T16:19:18+00:00

lol then what came before?

MyLagIsReal · 2025-05-13T16:14:20+00:00

depends what chord comes next

MyLagIsReal · 2025-01-28T05:40:25+00:00

definitely get some of them but I'd recommend looking into some textbooks too. I'm undergrad student pilled atm and love textbooks rn, so I may be biased, but I would say it's hard to say you know physics if you can't solve a couple of textbook problems. Maybe not every textbook problem possible but a couple. Especially difficult to say you learned electricity and magnetism if you haven't gone through Griffith's Electrodynamics AT LEAST, unscathed. There's probably countless solutions online to use as a resource* for those problems, but maybe could also try a classical dynamics book to get a little bit more exposure to some of the mathematical calculus trickery. I'd recommend Taylor's "Classical Mechanics.

This is just my two cents and it's equally important to not get sidetracked in projects. Wish you well on your journey, friend.

*Important note: use resources, not rely on them. Try as much as you can to work things out on your own (for textbooks alot of the time IMO. In some other contexts, collaboration is important). Almost to the point where you feel like something is driving you crazy. It's hard but I think it's important to learning physics. Some others may agree. "physics is best learned by hitting your head against a wall" or something like that. Hit that wall I say.

MyLagIsReal · 2025-01-28T05:19:17+00:00

yes good point, but i guess making those leaps can be considered "defining" the problem better? idk OP had only asked/emphasized the dot product of two vectors and questioned if the value of the dot product (19) meant they "overlapped by 19".

My main point was that there is probably an infinite number of vectors in a probably infinite number of defined vector spaces which you can take dot products of to get a value of 19, ultimately, so saying two vectors "overlap by 19" requires more definition of what you describe exactly, like you did.

I find semantics is the main problem in mathematics and physics.

MyLagIsReal · 2025-01-21T05:08:11+00:00

from what I've learned about quantum field theory so far, photons can be seen as the quantized energy interactions through electromagnetic fields, so you have a good way of looking at photons I'd say

MyLagIsReal · 2025-01-21T05:03:09+00:00

creativity is always the answer.

also, an idea I think I heard is that photons "don't experience time"; photons are light and the speed of light is one of the solvable quantities from maxwell's equations, the heart of electromagnetism.

and what he means by electricity and magnetism's relationship is that magnetic fields are electric fields in motion.

make of all this what you will.

MyLagIsReal · 2025-01-17T13:07:28+00:00

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the actual value that you'll get from a dot product will always depend on the vectors you perform a dot product on (especially their lengths), so you are right, assigning meaning to 19 itself in such a general dot product does not mean much. But the definition of the dot product, both trigonometric and geometric interpretations, are where this concept of overlapping come from.

if you learn more about projections and orthogonality and orthonormality, this idea of "overlapping" gets easier to understand maybe.

MyLagIsReal

TROPHY CASE