Harvey Lee Ross House

The Harvey Lee Ross House is a two-story frame, side-gabled house built in approximately 1858 on the farm of Harvey Lee Ross near Vermont, Illinois. The house and several outbuildings were added to the National Register of Historic Places (NRHP) in 1996, based on the distinctive characteristics of the architecture and an association with the …

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James Webb Space Telescope

NASA created the James Webb Space Telescope with support from the European Space Agency and the Canadian Space Agency. The telescope is named after James E. Webb, who served as NASA administrator from 1961 to 1968 and was instrumental in the Apollo program. JWST’s primary mirror, the Optical Telescope Element, consists of 18 hexagonal mirror …

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The anion (negatively charged ion) Cl is the anion (chloride ion). It is generated when the element chlorine (a halogen) gets an electron or when a molecule such as hydrogen chloride is dissolved in water or other polar solvents. Chloride compounds like sodium chloride are frequently extremely soluble in water. [4] It is an electrolyte …

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4 velocity is a four-vector whose elements are given by the contravariant expression {\displaystyle U^{\mu }={\frac {dx^{\mu }}{d\tau }}} where {\displaystyle \tau } is the proper time. For special relativity an inertial frame observer finds the proper time from his own coordinate time {\displaystyle t} and the coordinate speed {\displaystyle u} of the thing being observed by {\displaystyle dt={\frac {d\tau }{\sqrt {1-{\frac {u^{2}}{c^{2}}}}}}=\gamma d\tau …

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Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula H2. It is colorless, odorless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all …

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Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is Earth’s most abundant element, and after hydrogen and helium, it is the third-most abundant element in the universe.


An atom is the smallest unit of ordinary matter that forms a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are extremely small, typically around 100 picometers across. They are so small that accurately predicting their behavior using classical physics—as if they were tennis balls, for example—is not possible due to quantum effects.


The Sun is the central star of the Solar System. It is a nearly perfect ball of hot plasma that has been heated to incandescence by nuclear fusion processes in its center and radiates energy mostly as visible light, ultraviolet light, and infrared radiation. It is by far the most essential source of energy for …

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GoldenEye is a 1995 spy film, the seventeenth in the James Bond series produced by Eon Productions, and the first to star Pierce Brosnan as the fictional MI6 agent James Bond. It was directed by Martin Campbell and is the first in the series not to utilize any story elements from the works of novelist Ian Fleming. This is also the first James Bond film not produced by Albert R. Broccoli, following …

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In algebra, the 3x + 1 semigroup is a special subsemigroup of the multiplicative semigroup of all positive rational numbers. The elements of a generating set of this semigroup are related to the sequence of numbers involved in the still open Collatz conjecture or the “3x + 1 problem”. The 3x + 1 semigroup has been used to prove a weaker form of the Collatz conjecture. In fact, it …

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Water vapor

Water vapor, often known as water vapour or aqueous vapor, is the gaseous phase of water. It is a kind of water in the hydrosphere. Water vapor can be formed through the evaporation or boiling of liquid water, or by the sublimation of ice. Water vapor, like the majority of the atmosphere’s elements, is transparent. …

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Euclidean vector

In mathematics, physics and engineering, a Euclidean vector or simply a vector (sometimes called a geometric vector or spatial vector) is a geometric object that has magnitude (or length) and direction. Vectors can be added to other vectors according to vector algebra. A Euclidean vector is frequently represented by a ray (a directed line segment), or graphically as an arrow connecting an initial point A with a terminal point B. A vector is what is needed to “carry” the …

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