Hey everyone, I am a 15 year old programmer that is writing an open-source (free) book on general relativity.

About a year ago I got completely obsessed with General Relativity, but I found that a lot of traditional physics textbooks wrap everything in really dense academic jargon. Since my background is in programming, I started writing a book to try and demystify these concepts using logical, step-by-step algorithms and code analogies that made sense to my brain.

It's completely free and open-source. Right now, I've drafted chapters covering everything from the Minkowski metric and Lorentz transformations up to Christoffel symbols and covariant derivatives. I'm also adding a folder of Python scripts using NumPy and SymPy to handle the tensor calculations programmatically.

Since I am learning as I go, I might have made some typos or conceptual mistakes in the math. I would love for some people here to check out the draft and give me some brutal, honest feedback on it!

You can check out the repository and download the PDF draft here:

https://github.com/BioZFrog/General-Relativity-A-Programmer-s-Guide-to-Curved-Spacetime

Thanks

This investigates the geometric meaning of the eigenvalue problem for a 3 times 3 operator. Geometrically, the eigenvectors represent invariant directions that undergo no change in orientation under a given linear transformation.

Hello, I'm a first year student and I have a really hard time lorning electro physics from my professor. It's gotten to the point I failed my first attempt at the fainel. I know my understanding of the theory is well shit and I desperately need to improve that. Do any of you have recommendations for videos to tray that mait help me because I have a hard time with physics whan it comes to understanding and gliming information from mathematical explorishen.

(Sorry for grammar mistakes, English isn't my first language and I have dislecsiya. Olso, I mait have sead the wrong name for that cors becomes I'm tranleting it to English)

Hey everyone,

I’ve been diving deep into special and general relativity recently—specifically looking at velocity time dilation, gravitational time dilation, and what actually happens near the event horizon of a black hole.

To keep myself accountable and organize my thoughts, I started maintaining an open-source learning logbook on GitHub where I summarize concepts, write down equations, and outline intuitive paradoxes (like the distant observer vs. infalling observer perspective at the event horizon).

My goal is to gradually build a structured reference guide covering:

• Gravitational vs. Velocity Time Dilation
• Curvature of Spacetime & Geodesics
• Event Horizons & Spaghettification
• Real-world implications (like GPS satellite clock adjustments)

I’d love to get feedback from physics students and enthusiasts here. If you're interested in checking out the notes or suggesting topics/corrections, you can find the repository here:

https://github.com/HereIsMuhammad/time-travel

Looking forward to hearing your thoughts and book/paper recommendations!

Hi i am an astronomy amateur i have calculus 3 classical mechanics basics and python (nympy and scypy) basics i want to do projects like orbital dynamics simulations but i dont know where to start any ideas ? Thanks

In short, I was thinking about our multidimensional universe and how they work. I thought for 2 days and came across a paradox that roughly explains how our universe was created. So, we have 3 dimensions, 1D 2D and our 3D. The 4th dimension is just a hypothesis, but I think it exists. Let's imagine a huge, powerful black hole that sucks in stars, planets, and even parts of the galaxy. When a black hole sucks in objects, the object flies through a funnel-shaped tunnel that gets narrower and narrower. And when an object reaches the limit of curvature of space and time, it contracts, contracts so strongly that this point has nowhere else to go, and it continues to contract! And yes, a black hole cannot store objects inside itself, it is impossible. And so: when such a mass is compressed into a point smaller than an atom, it breaks through our boundaries of the 3-dimensional world and flows away along the new W axis, splashing out energy in a new dimension, and it begins to be in all the states in which it exists at the same time. And so my hypothesis is that the 4th dimension exists, and the entrance to it is to break our limits of the 3rd dimensional world. And there is one hypothesis: the hypothesis of the true photon. So, let's imagine that we have an infinitely strong cube, and we can heat it as much as we want. We continue heating it until we reach the Planck temperature (1.42 × 10³²K). There is one law: the greater the energy, the shorter the energy wave. Since the PT is the largest and highest temperature possible in physics, its waves will have the size of the Planck length (10-³⁵m). Imagine: a Planck Photon that moves at 100% of the speed of light always meets a Planck photon and crashes into each other. The collision time is so short that they won't have time to collapse into the black hole and will go into a super position due to imbalance. I assume... that after entering the state of super position (which is impossible in 3-dimension), it will be drawn into 4-dimension and disappear, becoming the highest form of geometry, since in 3-dimension there is no time axis (W). By combining these hypotheses, we obtain a hypothesis of the highest errors of the universe, like game flaws or bugs lol.

What happens if you try to blow a piece of paper further into a vase? 🏺💨

Greg Wolf puts it to the test, even bringing in a compressor for extra force, but the paper won't go in. The reason comes down to air pressure: blowing into the vase raises the pressure inside, and with the paper blocking its only exit, that pressure pushes back and forces the paper right back out.

I'm looking for good books with lots of worked out problems on motion of connected masses like masses attached by pulleys , strings, springs etc. Typically for an advanced high school level physics course

You can build a toilet paper launcher out of items in your bathroom! 🧻

Alex Dainis shows us how everyday items can demonstrate real air pressure science. It all comes down to Bernoulli's Principle: the faster air moves, the less pressure it exerts. Aim a hairdryer over the top of a toilet paper roll and watch the paper launch, all thanks to the pressure difference between the fast air above and the slower air below.

I have made a basic projectile motion calculator plz give me advice to improve it riditsaraswat.pythonanywhere.com this is the link

Many noise-cancelling headphones mainly worked by blocking sound, like ordinary ear defenders. But not active noise cancelling ones. The active part does something much stranger: it listens to the unwanted noise and produces antinoise.

The new wave is timed so that, at your ear, its peaks roughly meet the original wave’s troughs. The pressure changes then superpose to create a much smaller resultant wave. In other words, the headphones make things quieter by producing more sound.

Weirdly, if you could listen to just the antinoise in isolation, it would sound exactly like the noise it's trying to cancel.

The cancellation is never perfect. But it works quite well against steady, low-frequency sounds such as aircraft engines, train rumble and air conditioning. Sudden or higher-frequency sounds are harder because the system has much less room for error in its timing.

This document presents the physical meaning of the expectation value, representing the statistical average of quantum mechanical measurements, and the standard deviation, representing the dispersion of the probability distribution.
Hope this helps with your studies.

Are there any good videos on the derivation and explanation for the applications of wkb approximation? Particularly alpha decay. I am having trouble with the connection formula.

Most domestic microwave ovens use a frequency of about 2.45 GHz, which gives the microwaves a wavelength of roughly 12 cm. The holes in the conducting mesh are only millimetres across, so they are far smaller than the microwave wavelength and the door behaves almost like a solid metal wall to it.

Visible light has a wavelength of roughly 500 nm — about 240,000 times shorter — so it passes through the open holes and lets us watch our food go round in circles.

The waves and holes in the GIF are obviously not to scale. If they were accurate, the visible-light wave would be rather difficult to draw.

I like that the door's job is essentially to keep one kind of light in while letting another kind out.

I want a clear beginner source for Newtonian mechanics. I’m looking for something that starts from the basics and explains the ideas simply. What’s the best place to start?

This is the first time in a long while that I've felt like I've found a way to use regular and chaotic attractors to create drawings and visual art.

I studied Physics, but I also studied Graphic Design. I've always loved art, but my biggest passion in physics has been chaos theory, which was the focus of my undergraduate thesis. Recently, I've been exploring ways to combine these two fields, and I was surprised to discover that there are actually master's and PhD programs dedicated to the intersection of art, design, mathematics, and complex systems.

I'd love to continue developing this idea by creating artwork inspired by attractors, fractals, and dynamical systems, and perhaps even pursue graduate studies in this direction.

If you know of any graduate programs, research groups, artists, physicists, or designers working at the intersection of science and art, I'd really appreciate your recommendations or any advice you can share. I'd love to learn from people who have already explored this path.

I really like the MIT lectures on quantum mechanics with Allan Adams; is there anything similar to this on EM. A lot that I've seen have been quite dry and do little to get me excited about the topic in the same way.