The langley is a unit of measurement used to quantify the amount of solar radiation energy received on a surface. Specifically, it represents the amount of solar energy in terms of irradiance over time. One langley is defined as one calorie per square centimeter (1 cal/cm²) of energy received. This unit is commonly used in fields such as meteorology, environmental science, and solar energy studies to assess solar radiation exposure and its effects on various materials and biological processes.
The list of unusual units of measurement includes a variety of unconventional and whimsical units used to quantify different things. Some of these units may have historical significance, while others are used in specific contexts or as a form of humor. Here are some examples: 1. **Smoot**: A unit of length based on the height of Oliver R. Smoot, who was measured as 5 feet 7 inches (1.70 m) long by MIT students in 1958.
A micromort is a unit of measurement used to quantify the risk of death associated with a particular activity or exposure. One micromort represents a one in a million chance of dying. The term is often used in discussions of risk analysis and decision-making to help people understand the relative dangers of various activities, such as flying, driving, or engaging in extreme sports.
PCO2, or partial pressure of carbon dioxide, refers to the measure of carbon dioxide (CO2) pressure within a particular environment, typically in the blood or within the lungs. It is an important parameter in assessing respiratory function and metabolic processes in the body. In clinical settings, PCO2 is often measured to evaluate a person's respiratory status and to help diagnose or manage conditions such as respiratory failure, chronic obstructive pulmonary disease (COPD), and metabolic disorders.
A percentage point (often abbreviated as "pp") is a unit of measurement used to express the difference between two percentages. It represents an absolute difference rather than a relative difference. For example: - If the interest rate increases from 5% to 7%, it has increased by 2 percentage points (7% - 5% = 2 percentage points).
In general relativity, mass plays a crucial role in the way matter and energy interact with the curvature of spacetime. However, the concept of mass in general relativity is more complex than in Newtonian physics. Here are the key points to understand about mass in the context of general relativity: 1. **Mass-Energy Equivalence**: According to Einstein's famous equation \(E = mc^2\), mass and energy are interchangeable.
The O'Connell effect refers to a phenomenon in the field of geophysics, specifically related to the behavior of electromagnetic waves in the presence of a magnetic field. It describes the way in which the polarization of electromagnetic waves can be altered due to interactions with charged particles in a plasma or magnetized environment. This effect is particularly significant in the study of space weather and can have implications for understanding the behavior of solar particles in the Earth's magnetosphere.
The Windisch–Kolbach unit is a unit of measurement used in the field of medicine, specifically to quantify the activity of certain enzymes, such as lipases. It is named after the researchers Franz Windisch and G. Kolbach, who contributed to the understanding of enzyme activity and its measurement. In the context of clinical biochemistry, the Windisch–Kolbach unit may be used to express the concentration of an enzyme in a solution or the enzyme activity in a given sample.
In mathematics, particularly in abstract algebra, a **group** is a set equipped with a binary operation that satisfies four fundamental properties: closure, associativity, identity, and inverses. When we say "group with operators," we typically refer to a group that has a specific operation defined on its elements.
Lunar swirls are unique, enigmatic features found on the surface of the Moon, characterized by their bright, wavy patterns that can be several kilometers long. They are generally thought to be caused by ancient volcanic processes or the interaction of the lunar surface with the solar wind and magnetic fields. Lunar swirls are often associated with areas of the Moon that have a stronger magnetic field compared to their surroundings.
The Balmer jump refers to a specific phenomenon observed in the spectra of hydrogen or hydrogen-like atoms, where there is a significant discontinuity in the intensity of the spectral lines in the Balmer series. The Balmer series consists of the spectral lines corresponding to electron transitions from higher energy levels (n3) down to the second energy level (n = 2) in hydrogen.
In the context of astronomy, the "Baldwin effect" refers to a correlation observed in the properties of quasars, particularly the relationship between the luminosity of a quasar and the equivalent width of certain emission lines, such as the magnesium II line. This effect suggests that more luminous quasars tend to have weaker emission lines, which can be interpreted as a result of different physical processes occurring in these high-energy environments. The phenomenon is named after the astronomer James A.
Fast Blue Optical Transients (FBOTs) are a type of astronomical phenomenon characterized by a rapid rise and decline in brightness, typically occurring in the optical wavelengths. These events are often linked to cataclysmic occurrences such as supernovae, neutron star mergers, or the collapse of massive stars. FBOTs are distinguished by their exceptionally fast light curves, which reach their peak brightness within just a few days and then fade away quickly, often within weeks.
The Galactic Center GeV excess refers to an observed excess of gamma-ray radiation in the vicinity of the center of our galaxy, the Milky Way, particularly in the GeV (giga-electronvolt) energy range. This excess was first noted in gamma-ray data collected by the Fermi Gamma-ray Space Telescope and has become a subject of significant interest in astrophysics and particle physics.
Fast Radio Bursts (FRBs) are brief, intense bursts of radio waves originating from outside our galaxy. They are typically only a few milliseconds long and carry massive amounts of energy. The exact sources of FRBs are still not completely understood, but they have intrigued astronomers since they were first discovered in 2007. The list of FRBs includes both repeating and non-repeating bursts.
The field of astronomy contains numerous unsolved problems and mysteries that continue to intrigue scientists and researchers. Here are some notable examples: 1. **Dark Matter**: While it is known that dark matter makes up a significant portion of the universe's mass, its exact nature remains unknown. What is dark matter made of? Various candidates like WIMPs (Weakly Interacting Massive Particles) and axions have been proposed, but none have been confirmed.
The stellar corona refers to the outermost layer of a star's atmosphere. In the case of our Sun, the corona is the layer that extends millions of kilometers into space and is characterized by its high temperatures and low densities. It is visible during a total solar eclipse as a halo of plasma surrounding the Sun.
Odd Radio Circles (ORCs) are a relatively recent discovery in astrophysics, first identified in 2020. They are large, circular, and faint radio-emitting structures in the sky, characterized by their unusual shapes and the absence of visible counterparts in other wavelengths, such as optical or infrared light. These enigmatic features have sparked considerable interest and research, as their exact nature and origins remain unclear.
SCP-06F6 is a fictional entity from the SCP Foundation, a collaborative writing project that features a collection of horror-themed stories surrounding anomalous objects, entities, or phenomena. Each SCP entry is assigned a unique number and typically includes a description, containment procedures, and documentation about the SCP.
The Bombieri–Lang conjecture is a concept in number theory that relates to the distribution of rational points on certain types of algebraic varieties. Specifically, it deals with the behavior of rational points on algebraic varieties defined over number fields and has implications for understanding the ranks of abelian varieties and the distribution of solutions to Diophantine equations. The conjecture can be stated in a few steps for certain types of varieties, particularly for curves and higher-dimensional varieties.

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