The "cuspy halo problem" refers to a discrepancy between predictions made by certain cosmological models regarding the distribution of dark matter in galaxies and observations of their rotational curves. The term "cuspy" refers to the expectation that dark matter density should peak sharply (or "cusped" profile) towards the center of a galaxy, as predicted by simulations based on cold dark matter (CDM) cosmology.
Ciro Santilli's hardware / Cell phones by Ciro Santilli 37 Updated +Created
Céline Bœhm by Wikipedia Bot 0
Céline Bœhm is not widely recognized as a public figure in well-documented fields such as entertainment, politics, or science, as of my last knowledge update in October 2023. It's possible that she may be a private individual or an emerging figure in a specific field that has gained attention after my last update.
Daniel McKinsey by Wikipedia Bot 0
As of my last knowledge update in October 2021, "Daniel McKinsey" does not refer to a notable or widely recognized figure, event, or concept. It's possible that it could be a person's name, but without more context, it's difficult to provide relevant information. If this name has gained prominence or significance after October 2021, I wouldn't have that information.
String-sorting algorithm by Ciro Santilli 37 Updated +Created
Dark galaxy by Wikipedia Bot 0
"Dark galaxy" is a term that may refer to a few different concepts in astronomy and cosmology, but it often pertains to regions of space that do not emit light in the visible spectrum, making them difficult to detect and study.
Natural sort order by Ciro Santilli 37 Updated +Created
A dark globular cluster is a type of astrophysical object that is essentially a globular cluster of stars but does not appear to contain significant amounts of luminous matter, particularly stars that can be readily observed. Instead, these dark globular clusters may contain a significant amount of dark matter or may be composed of stars that are dim or obscured from view, often due to dust or gas.
String-search algorithm by Ciro Santilli 37 Updated +Created
Dark radiation by Wikipedia Bot 0
Dark radiation refers to hypothetical particles or forms of energy that may be present in the universe but do not interact with electromagnetic forces, making them invisible and undetectable by conventional means. The term is often used in cosmology and theoretical physics to describe additional forms of energy density that could play a role in the evolution of the universe beyond what is accounted for by ordinary matter (baryonic matter), dark matter, and dark energy.
The term "dark star" can refer to a few different concepts in astrophysics, but it is primarily associated with theoretical stellar objects that are powered by dark matter interactions rather than by nuclear fusion, as normal stars are. ### Key Ideas: 1. **Definition**: A dark star is a hypothetical astronomical object that exists in the early universe, formed when dark matter, which does not interact electromagnetically (i.e.
Darkon, also referred to as "unparticles," is a theoretical concept in particle physics proposed by Howard Georgi in 2007. It suggests the existence of a new type of substance that does not behave like conventional particles. Instead of having a well-defined mass and charge, unparticles are thought to appear as a continuously distributed entity with scaling dimensions that resemble those of a field. The key feature of unparticles is their scale-invariance.
Millennium Prize Problems by Ciro Santilli 37 Updated +Created
Ciro Santilli would like to fully understand the statements and motivations of each the problems!
Easy to understand the motivation:
Hard to understand the motivation!
Vortices by Wikipedia Bot 0
A vortex (plural: vortices) is a flow pattern characterized by a rotating, swirling motion of fluid (which can be gas or liquid) around an axis. Vortices can occur in many different contexts, including in nature, engineering, and physics. Some key characteristics of vortices include: 1. **Rotation**: The fluid moves in a circular or spiral path around a central core or axis. The speed and direction of rotation can vary.
Zermelo-Fraenkel axioms by Ciro Santilli 37 Updated +Created
Feebly Interacting Particles (FIPs) refer to hypothetical particles that interact very weakly with standard model particles, making their detection extremely challenging. These particles are of significant interest in various areas of theoretical physics and cosmology, particularly in the search for solutions to some of the outstanding mysteries in the universe, such as dark matter, neutrino masses, and the matter-antimatter asymmetry.
Hylogenesis by Wikipedia Bot 0
Hylogenesis is a term that is not widely used in mainstream biology, so its meaning can vary depending on the context in which it is used. Generally, it can be understood as a concept related to the evolutionary development of organisms or the origin and diversification of biological forms based on their lineage and evolutionary history.
Indirect detection of dark matter refers to methods used to infer the presence of dark matter by observing its potential interactions with ordinary matter or other particles. Unlike direct detection, which seeks to measure the interactions of dark matter particles with regular matter (such as through elastic scattering), indirect detection looks for evidence of the products resulting from dark matter annihilation or decay.
LArIAT by Wikipedia Bot 0
LArIAT, or Liquid Argon In A Testbeam, is an experimental project designed to study liquid argon as a detection medium for neutrinos. It is part of the broader effort to develop and understand the technology needed for future neutrino detectors, particularly those using liquid argon time projection chambers (LArTPCs).
Oath of the Peach Garden by Ciro Santilli 37 Updated +Created

Pinned article: ourbigbook/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 5. . 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.
  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