General relativity by Ciro Santilli 40 Updated 2025-07-16
Unifies both special relativity and gravity.
Not compatible with the Standard Model, and the 2020 unification attempts are called theory of everything.
One of the main motivations for it was likely having forces not be instantaneous, but rather mediated by field to maintain the principle of locality, just like electromagnetism did earlier.
Fast travel is a gameplay mechanic commonly found in video games, particularly in open-world and role-playing games (RPGs). It allows players to quickly move between locations on the game map without needing to travel the distance in real-time. This feature is often implemented to save time and enhance the gaming experience by allowing players to focus on other aspects of the game, such as quests or exploration.
"Ship load" typically refers to the quantity of goods, cargo, or materials that a ship is designed to carry. It can relate to various measurements, including: 1. **Deadweight Tonnage (DWT)**: This is the maximum weight a ship can safely carry, including cargo, fuel, crew, provisions, and any other items. 2. **Cargo Capacity**: This specifically refers to the volume or weight of goods that can be loaded onto the ship for transport.
Video 1.
Replicating the Fizeau Apparatus by AlphaPhoenix (2018)
Source. Modern reconstruction with a laser and digital camera.
Video 2.
Visualizing video at the speed of light - one trillion frames per second by MIT (2011)
Source. Fast cameras. OK, this takes it to the next level.
Body Mass Index (BMI) is a numerical value derived from a person's weight and height, used as a screening tool to categorize individuals into different weight status categories.
The Encyclopedia of Triangle Centers is a comprehensive resource dedicated to the study of various notable points associated with triangles, known as triangle centers. These include well-known centers such as the centroid, orthocenter, circumcenter, and incenter, among many others. The encyclopedia aims to catalog these centers, providing their mathematical properties, relationships, formulas, and sometimes historical contexts. The work typically includes both theoretical aspects and practical applications, offering insights that could be beneficial for mathematicians, educators, and students.
Inspec is an open-source testing framework primarily used for infrastructure as code (IaC) compliance and security auditing. Developed by the company Chef, Inspec allows users to write automated tests for their applications and infrastructure, validating that they meet specific compliance and security requirements. Key features of Inspec include: 1. **Human-Readable DSL**: Inspec uses a domain-specific language (DSL) that is easy for both developers and non-developers to understand, enabling clear and concise test definitions.
Computational economics is an interdisciplinary field that utilizes computational methods and techniques to analyze economic models, conduct simulations, and solve complex economic problems. It combines elements from economics, computer science, mathematics, and statistics to better understand economic systems and behavior. Key features of computational economics include: 1. **Modeling Complexity**: Economic systems are often complex, involving multiple agents with diverse behaviors and interactions.
Contract theory is a field of study in economics and legal studies that examines how individuals and organizations formulate contracts and agreements in the presence of uncertainty and varying information. It focuses on the design, enforcement, and implications of contracts in various contexts, considering factors such as incentives, moral hazards, and the allocation of risks among contracting parties.
Ergodicity economics is an approach to understanding economic systems that emphasizes the difference between time averages and ensemble averages in the context of decision-making under uncertainty. The term "ergodicity" comes from statistical mechanics, where it refers to systems that exhibit the same statistical properties over time as they do across different states or configurations.
Mean-field game theory (MFG) is a mathematical framework used to analyze strategic interactions among a large number of agents, each of whom makes decisions based on their own objectives while considering the collective impact of all agents on the system. The essential idea of MFG is that as the number of players becomes very large, the effect of any individual player on the overall dynamics becomes negligible. Instead, each player interacts with the statistical distribution of all other players.

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 2.
    You can publish local OurBigBook lightweight markup files to either https://OurBigBook.com or as a static website
    .
    Figure 3.
    Visual Studio Code extension installation
    .
    Figure 4.
    Visual Studio Code extension tree navigation
    .
    Figure 5.
    Web editor
    . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
    Video 4.
    OurBigBook Visual Studio Code extension editing and navigation demo
    . Source.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact