"Sunbeam" can refer to several different things depending on the context. Here are a few common usages: 1. **Natural Phenomenon**: A sunbeam is a ray of sunlight that appears to shine through clouds or is visible in the atmosphere, often creating beautiful visual effects. 2. **Brand**: Sunbeam is also the name of a well-known brand primarily associated with household appliances, such as toasters, slow cookers, and other kitchen gadgets.
"Water sky" typically refers to a phenomenon that occurs when the surface of a body of water reflects the sky above, creating an illusion of a seamless transition between the water and the sky. This can happen under specific conditions, such as during calm weather when the water is still, or at dawn and dusk when light conditions enhance the colors and reflections. The term might also relate to visual art or photography, where artists and photographers capture these reflections to create stunning and surreal images.
A polynya is an area of open water that is surrounded by sea ice, typically found in polar regions. These areas can form in ice-covered seas due to various factors such as ocean currents, wind, and differences in water temperature. Polynya can be important for ecological reasons, as they provide vital habitats for marine life, including seals, birds, and other species. They also play a significant role in regulating climate and ocean circulation by influencing heat exchange between the ocean and the atmosphere.
Ballistic conduction in single-walled carbon nanotubes (SWCNTs) refers to a transport phenomenon where charge carriers (such as electrons) move through the nanotube without scattering or losing energy over relatively long distances. This occurs in materials where the dimensions are on the order of the mean free path of the charge carriers, allowing them to maintain their coherent quantum state. In the case of SWCNTs, their unique one-dimensional structure and high degree of purity contribute to the effectiveness of ballistic conduction.
Drift velocity refers to the average velocity that charged particles, such as electrons, attain due to an electric field in a conductor. When an electric field is applied across a conductor, it causes the free electrons (or charge carriers) to move in a specific direction. However, these electrons are also subject to random thermal motion, which causes them to collide with atoms in the material.
Burns temperature, also known as the "Burns temperature," refers to a specific temperature, often used in the context of engineering and materials science, that indicates the onset of chemical reactions or degradation of materials, particularly polymers or organic compounds. It is critical in various applications, including fire safety, material selection, and understanding combustion processes.
Heat lightning is a term used to describe a phenomenon where lightning is observed from a distance but does not produce audible thunder. It typically occurs during warm weather conditions, especially on summer nights when thunderstorms are present in the area but not directly overhead. The phenomenon is not a distinct type of lightning; rather, it refers to the lightning flashes from distant storms that are too far away for the sound of thunder to reach the observer.
A narrow bipolar pulse is a type of electrical signal characterized by its short duration and bipolar nature, meaning that it alternates between positive and negative voltages. These pulses are typically used in various applications, such as in communication systems, digital signal processing, or biomedical devices like nerve stimulators. ### Key Characteristics: 1. **Narrow Pulse Width**: The "narrow" aspect refers to the short duration of the pulse, which can be measured in microseconds or nanoseconds.
Self-ionization of water, also known as autoionization, is a process in which water molecules dissociate into ions. In this process, two water (H₂O) molecules interact, resulting in the formation of a hydroxide ion (OH⁻) and a hydronium ion (H₃O⁺).
Adularescence is a phenomenon observed in certain gemstones, particularly moonstone, where a soft, floating light appears to glow from within the stone. This effect is created by the scattering of light as it interacts with the internal structure of the mineral, specifically due to the presence of thin layers of different minerals within the stone. The most commonly recognized adularescent effect displays a bluish-white sheen that can appear to move as the stone is rotated in light.
The "black drop effect" is an optical phenomenon that occurs during the transit of a planet across the face of the Sun, typically observed during transits of Venus or Mercury. It manifests as a distortion of the planet's silhouette, where the edges appear to be blunted or "dropped" against the Sun's bright disk. This effect makes it seem as if the planet is connected to the Sun by a dark "tail" or that it has a larger apparent size than it actually does.
The term "black hole electron" is not a standard or widely recognized term in physics. It seems to combine two distinct concepts: "black holes" and "electrons," each of which have their own well-defined meanings: 1. **Black Holes**: These are regions in space where the gravitational pull is so strong that nothing, not even light, can escape from them.
Stellar black holes are a type of black hole that forms from the gravitational collapse of massive stars. When a star with sufficient mass (typically more than about three times the mass of the Sun) exhausts its nuclear fuel, it can no longer support itself against the force of gravity. Consequently, it collapses under its own weight, and if the residual core's mass is sufficient, it can form a black hole.
The Carter constant, often denoted as \( C \), is a key parameter in the study of black hole physics, particularly in relation to the Kerr black hole solution of Einstein's field equations in general relativity. The Carter constant arises in the context of the geodesic motion of particles and tests the symmetry of the Kerr metric.
The Immirzi parameter is a constant that arises in the context of loop quantum gravity, a theoretical framework aimed at unifying general relativity and quantum mechanics. It is named after the physicist Barbero-Immirzi, who introduced it in the context of loop quantum gravity to address issues related to black hole entropy. In loop quantum gravity, the geometry of space is quantized, and the Immirzi parameter plays a significant role in the definition of the quantum states of the gravitational field.
MAXI J1659-152 is a binary system identified as a microquasar located in the constellation of Scorpius. It was discovered in 2010 by the MAXI (Monitor of All-sky X-ray Image) experiment aboard the International Space Station. The system consists of a black hole and a companion star, which is likely a red giant or a main-sequence star, transferring material to the black hole.
The Fanning friction factor is a dimensionless quantity used in fluid mechanics to characterize the frictional resistance to flow in a pipe or duct. It is defined as the ratio of the wall shear stress to the dynamic pressure of the fluid. The Fanning friction factor (\(f\)) is commonly used in the analysis of laminar and turbulent flow regimes and plays a crucial role in the calculation of pressure losses due to friction in piping systems.
A "sonic black hole," also known as a "sonic horizon," is a concept in theoretical physics that pertains to the behavior of sound waves in a medium moving at supersonic speeds. It is an analog to the event horizon of a gravitational black hole but involves the dynamics of fluid mechanics rather than gravity. In a sonic black hole, a fluid can flow faster than the speed of sound within that medium.
A "virtual black hole" is not a standard term in astrophysics, but it can refer to a couple of different concepts depending on the context: 1. **Quantum Physics Context**: In the realm of quantum mechanics, virtual particles are temporary fluctuations that occur in a vacuum. Some theoretical frameworks suggest the existence of "virtual black holes" as a way to understand certain aspects of quantum gravity, where the properties of black holes may emerge from more fundamental quantum states.
Asteroseismology is the study of oscillations and vibrations in stars, which allows scientists to probe the internal structure and dynamics of these celestial bodies. Just as seismologists study earthquakes to learn about the Earth's interior, asteroseismologists analyze the pulsations of stars to gather information about their internal layers, composition, age, and evolutionary state.

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