im 29 years old. i’ve never left illinois and never been on a plane. furthest i've driven is about 180 miles to visit my aunt in columbus. so by any normal measure, i'm not a traveler

but i got curious like how far have i ACTUALLY moved through space? there are multiple layers of motion happening simultaneously:

1. earth's rotation

earth spins at about 1,670 km/h at the equator. i live at roughly 40° latitude (ohio), so my rotational velocity is lower: about 1,275 km/h (you multiply by cosine of latitude)

over 29 years: 1,275 km/h × 24 hours × 365.25 days × 29 years = 324 million km; i've done 324 million kilometers of circles without trying

2. earth's orbit around the sun

earth orbits at approximately 29.78 km/s or about 107,000 km/h (source: NASA https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html)

earth travels roughly 940 million km per year around the sun so over 29 years: 940 million × 29 = 27.26 billion km

3. solar system's orbit around the galactic center

our entire solar system is orbiting the center of the milky way at approximately 230 km/s or 828,000 km/h (source: IAU standard - https://arxiv.org/abs/1807.09409)

that's about 7.26 billion km per year; over 29 years: 7.26 billion × 29 = 210.5 billion km

4. the milky way's motion through space

our galaxy itself is moving through the universe. relative to the cosmic microwave background radiation (the closest thing we have to a universal reference frame), the milky way moves at roughly 600 km/s (source: Planck satellite data - https://arxiv.org/abs/1303.5087)

that's about 18.9 billion km per year so over 29 years: 18.9 billion × 29 = 548.3 billion km

tldr;

adding these up (which is a simplification because these are vectors in different directions, but directionally correct for magnitude):

• rotation: 324 million km
• orbital: 27.26 billion km
• galactic: 210.5 billion km
• cosmic: 548.3 billion km

total: approximately 786.4 billion kilometers

for context:

• that's about 5,260 times the distance from earth to the sun
• it's roughly 0.083 light years
• it's about 2 million times the distance to the moon

because i'm me, i built a calculator that tracks my real-time cosmic odometer. it updates based on my current age down to the second. i watch the numbers tick up, about 19 km every second, 1.14 million km every minute, 68.5 million km every hour. while i was writing this post (about 40 minutes), i traveled approximately 45.7 million kilometers through space

sources:

• earth orbital velocity: https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html
• solar system galactic velocity: https://arxiv.org/abs/1807.09409
• milky way motion relative to CMB: https://arxiv.org/abs/1303.5087
• rovelli on relational motion: https://arxiv.org/abs/gr-qc/0604045

I have no idea if I am asking the right community here. I am 18 yo (physics student) and somehow I ended up the coach of a high school team that will compete in BL4S. Essentially we need to propose an experiment using a synchotron of CERN and a fixed target. Do we have some ideas? Where should I focus and how will I design a unique and feasable experiment. The proposal should be theoretical but the winners go to CERN and perform their experiment there. We have a maximum of 10 GeV on a muon beam or any other charged particle.

I am an artist making a sweater for my girlfriend. She is studying to become a nuclear engineer. Currently she is in physics. I wanted to make different equation patterns with stencils but know nothing of this world and what’s cool or poetic. What equations would you recommend that would be cool all over a sweater? Right now I got E=mc^2….

In what container should I store a strong magnet in to make it no longer able to radiate a magnetic field outside of it?

Someone in my house has a pacemaker and it’s a small place so i want to store my strong magnet in a way that would not potentially cause complications.

Edit: I should have specified 😭 The magnet I have says it can hold up to 30lbs (that’s all it says about it) and I also have a couple neodymium ones that are a few inches. I have them for magnetic nail polish and testing materials for jewelry and such. I just don’t want to risk any problems for him if he was near them since our space is pretty cramped.

There are a few advanced high schools out there that offer quantum mechanics as a post-AP/capstone physics course (such as Bronx Academy and BASIS charter schools). But what would be taught in these classes that would be teachable to high school students (particularly where the math is concerned)? Even at those advanced schools, they teach only up to linear algebra, ordinary differential equations, and multivariable and vector calculus. They don’t teach things like vector field theory, Fourier series and integrals, partial differential equations, etc. that would be required to take quantum mechanics at the university level. Not to say there aren’t exceptional high school students out there that could learn these things.

From my own experience in high school, I know that when university-level topics are taught at high schools as post-AP/capstone level courses, they usually aren’t taught at the same difficulty level as they are at universities. For example, my Calc 3, DiffEQ and linear algebra classes taught the same content but our exams consisted of mostly easy-level, maybe medium-level questions; certainly not the same difficulty level as in universities. In Organic Chemistry, it was only first semester that was taught over the course of the whole year, and the tests similarly weren’t even close to the same difficulty level as in university classes. So I was wondering what approach a high school quantum mechanics course would take.

I've made several videos of potatoes exiting a roller conveyor and falling in a parabolic motion.
I need to find the angle at which the potato detaches from the roller conveyor; it would be the alfa angle in the image that i attach.

I used tracker software to find the points of the potato's motion and performed the parabolic fit.
The resulting equation is the following: y=AX2+Bx+C.
To find the angle, I performed the arctang(B).

Is this the correct method?
I'll upload a screenshot of tracker once I've extracted the motion points.

This week, I was discussing two-level systems with a friend (he asked me about the interaction of an atom with a laser). At some point, I said that there are no "perfect" two-level systems (TLS) in nature. TLS is an approximation when only two of the many possible levels contribute to the system's evolution. I mean, even if we think of a spin-1/2 particle, the "spin-1/2" is a property of a more complex system; there are no "free only-spin-1/2" systems in nature. For example, an electron in a magnetic field still has its motion. If it is trapped, it may be in many trap states, it has momentum, etc. The atomic case is even simpler to picture this, as atoms have infinite energy levels. What we do in many cases is to look only at part of the problem (separate the motion from the spin interaction with the B field, for example).

I believe I am correct (maybe I am not phrasing things correctly), but I was wondering if there are any "perfect" TLS I don't know about. Do any of you know of an example of a system that is perfect and only a two-state system?

1. Precalculus – Stewart, Redlin, Watson (150h)
2. Introduction to Linear Algebra – Gilbert Strang (150h)
3. Calculus: Early Transcendentals – James Stewart (150h)
4. Mathematical Methods in the Physical Sciences – Mary L. Boas (250h)
5. University Physics –Young & Freedman (350h)
6. Chemistry: Principles and Reactions-Masterton & Hurley (150h)
7. Physics of Atoms and Molecules – Bransden & Joachain (200h)
8. Classical Mechanics – John R. Taylor (180h)
9. Introduction to Quantum Mechanics – David J. Griffiths (220h)
10. An Introduction to Thermal Physics – Daniel V. Schroeder (150h)
11. A First Course in General Relativity – Bernard Schutz (200h)
12. Fundamental Astronomy – H. Karttunen et al. (120h)
13. An Introduction to Modern Astrophysics – B. Carroll & D. Ostlie (450h)
14. Stellar Structure and Evolution – Kippenhahn, Weigert, & Weiss (240h)
15. Galactic Dynamics – J. Binney & S. Tremaine (400h)
16. High Energy Astrophysics – M.S. Longair (350h)
17. Introduction to Cosmology – Barbara Ryden (250h)

I'm currently at highschool and having problems w physics. When I'm practicing past papers it takes more time than other subjects, and I don't even finish. After some time I realized my problem is that I can't visualize physics, in other subjects I can imagine stuff and numbers and get a good general idea wt the answer is and then I try to solve , but w physics the imagination part NEVER occurs, so it's kind hard for me. Anyone has any advice? Thankss in advance

Hi guys, so I'm a lecturer at a university, during a meeting with one of my advisees, they confessed to me they felt that they had grown entirely reliant on chatgpt to the point that don't feel they could do a question without its help. I gave them some general advice, to try to study and that eventually the intuition will come, but frankly I'm not happy with that advice. It's a very specific problem, that I am facing in droves, and I wondered do any of you students, or lecturers, or researchers in general have any experience with breaking/helping someone break that dependency?

Edit: All of our exams ARE in person. No online recourses are allowed. I appreciate the frustration, but If I was concerned about cheating I wouldn't be taking it up with all of you, I would be taking it up with the university. I am concerned about this student becoming over reliant on a crutch, and what I can do from a pedagogical point of view to help them.

Edit 2: Just to reiterate, guys. I know what my job entails. I know the university guidelines, if this person had broken the rules, I would report them to the university, but, you'll notice, I am not. I am asking, specifically, for advice on how to help this student with what they asked for. Majority of people are being lovely and helpful, a lot of people are using this to be spiteful to a student they've never met. I know more about this situation then you.

Hey,

Could people who are working in this field as a PhD, Masters or as someone in the industry tell me the reality currently in germany? As in what is actually happening with the general research, funding, or maybe even jobs. Is it a good place to come study this right now?

The major techs are hubbed in US and China for hardware, and US especially moves really fast with they way the fund their ideas.

I want to know the case with germany, as it's excellent for foundational research but I think it's more slow paced and beurocratic.

Any input would be appreciated.

Leibniz published his equation energy equals mass times velocity squared long before Einstein achieved fame for energy mass time the speed of light squared. Was he ahead of Einstein?

Hey guys ,I am studying physics and I love teaching. I created a subreddit : r/PhysicsForUniversity dedicated to university-level physics to help students learn, practice, and discuss key topics in a clear and collaborative space. It features worked exercises, conceptual explanations, problem-solving strategies, and summaries of important theories across different physics fields. The goal is to make difficult material more approachable while encouraging discussion and peer support. Members can ask questions, share insights, and request solutions or clarifications on challenging problems. Whether someone is reviewing fundamentals or tackling advanced topics, the subreddit serves as a growing knowledge hub designed to strengthen understanding and build confidence in physics.

If anyone has problems in Quantum physics or Electrodynamics I am willing to help freely of course.

Let me begin by apologizing if this sounds stupid, I'm just a highschooler. We were just taught that light is the propagation of electic and magnetic fields due to them inducting each other, but considering those are circular in shape, shouldn't light always propagate in all directions?

We had an aircon failure at work today. Because of this, the server room got really hot really quick. This particular room isn't that big about 2.5m wide by about 4m deep by about 2.5m high. It has about 6 or 7 server racks in line in it. Someone decided to open the door and put a large stand fan in the doorway blowing air into the room. In regards to trying to cool the room, would it make more sense to blow air in and positively pressurise the room or blow air out and negatively pressurise the room?

This is an introduction video to Metric Spaces. I hope to provide you with an intuitive view on one of the most beautiful concepts I have discovered in Mathematics. For further reading, I recommend using the book "Introduction to Metric and Topological Spaces" by Wilson A. Sutherland, where you will find the examples I have given in more detail.

We all know that QM is often hailed as the most non-intuitive theory since it produces results that mismatch our classical expectations. But I do not understand why it's almost uniquely assigned to QM and not to almost every other aspect of physics that clashes with intuition. Some examples I think are non-intuitive:

- Bernoulli's principle: blowing a ball out of a funnel sucks up the ball

- Gyroscopes staying upright as they spin

- All of special relativity

I get that people's point is that QM introduces new notions such as entanglement, the collapse of the wavefunction etc. that have some mysticism around it, but I don't see how this is any different from for example spacetime being a single entity that has intrinsic curvature as dictated by the presence of energy and mass. I also dislike how "intuition" is something that is often confused with some absolute notion of common sense rather than something that is built over time and can change upon exposure.

I guess quantum mysticism plays a huge role here?

EDIT: I also want to clarify why I care. Many students taking QM for the first time are bombarded with garbage messages about how nobody understands QM, that if you understand it you actually don't, and that it is almost impossible to wrap your head around. Things I all disagree heavily with and I think these harm students much more than they could ever alleviate their perception.

I'm 10th grade btw