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Kairos
Kairos (καιρός) is an Ancient Greek word meaning the right, critical, or opportune moment. The ancient Greeks had two words for time: chronos (χρόνος) and kairos. The former refers to chronological or sequential time, while the latter signifies a proper or opportune time for action. While chronos is quantitative, kairos has a qualitative, permanent nature. Kairos also means weather in Modern Greek. The plural, καιροί (kairoi (Ancient and Modern Greek)) means the times. Kairos is a term, idea, and practice that has been applied in several fields including classical rhetoric, modern rhetoric, digital media, Christian theology, and science.
  • 2.4K
  • 07 Oct 2022
Topic Review
Coronal Cloud
A coronal cloud is the cloud of hot plasma gas surrounding a coronal mass ejection. It is usually made up of protons and electrons. When a coronal mass ejection occurs at the Earth's Sun, it is the coronal cloud that usually reaches Earth and causes damage to electrical equipment and space satellites, not the ejection or flare itself. The damage is mostly the result of the high amount of electricity moving through the atmosphere. A coronal cloud is released when a solar flare becomes a coronal mass ejection; the coronal cloud often contains more radioactive particles than the mass ejection itself. A coronal mass ejection occurs when a solar flare becomes so hot that it snaps and breaks in two, becoming a "rope" of heat and magnetism that stretches between two sunspots. The resulting coronal mass ejection can be compared to a horseshoe magnet, the sunspots being the poles and the oscillating magnetic connector the handle. Coronal mass ejections typically do not last very long, because they cool down as the coronal cloud of gas is released and begins to hurtle away from the Sun.
  • 410
  • 07 Oct 2022
Topic Review
Holomovement
The holomovement brings together the holistic principle of "undivided wholeness" with the idea that everything is in a state of process or becoming (David Bohm calls it the "universal flux"). In this interpretation of physics wholeness is not considered static, but as a dynamic interconnected process. The concept is presented most fully in Wholeness and the Implicate Order, published in 1980.
  • 2.7K
  • 06 Oct 2022
Topic Review
Standard Electrode Potential
In electrochemistry, standard electrode potential [math]\displaystyle{ E^\ominus }[/math], or [math]\displaystyle{ E^\ominus_{red} }[/math], is a measure of the reducing power of any element or compound. The IUPAC "Gold Book" defines it as: "the value of the standard emf (electromotive force) of a cell in which molecular hydrogen under standard pressure is oxidized to solvated protons at the left-hand electrode".
  • 553
  • 06 Oct 2022
Topic Review
Astrobiology Science and Technology for Exploring Planets
Astrobiology Science and Technology for Exploring Planets (ASTEP) was a program established by NASA to sponsor research projects that advance the technology and techniques used in planetary exploration. The objective was to enable the study of astrobiology and to aid the planning of extraterrestrial exploration missions while prioritizing science, technology, and field campaigns.
  • 490
  • 06 Oct 2022
Topic Review
List of Exoplanetary Host Stars
The following is a list of exoplanetary host stars. The table contains information about the coordinates, spectral and physical properties, and number of confirmed planets. The two most important stellar properties are mass and metallicity because they determine how these planetary systems form. Stars of higher mass and metallicity tend to have more numerous and more massive planets. Most of the stars below are solar-type, mainly in the spectral classes F, G, and K, because astronomers tend to look for planets around stars similar to the Sun. Others are giants, which have used up all the hydrogen in their cores. Finding planets around giant stars gives clues as to how planetary systems evolve and how the properties of planets change with the evolution of the stars. As of April 2018, there are 2,816 stars with at least one confirmed planet, of which 628 stars have two or more confirmed planets; that is, 22% of all confirmed exoplanetary host stars have two or more confirmed planets. As of 2018, the star with the most confirmed planets is Kepler-90, with eight planets, although HD 10180 may have nine (two are unconfirmed). The most massive exoplanetary host star is Omicron Ursae Majoris (3.09 M☉), while the least massive is 2M J044144 (0.021 M☉). The most metal-rich star is NN Serpentis (1.744, 55.5 × Sun), while the most metal-poor is BD+20°2457 (−0.999, 0.100 × Sun). The nearest exoplanetary host star is Proxima Centauri (4.25 ly), while the most distant is NY Virginis (26940 ly). Visually, the brightest exoplanetary host star seen from Earth is Pollux (1.15), while the faintest is OGLE-2005-BLG-390L (27.98).
  • 344
  • 04 Oct 2022
Topic Review
Deep Underground Neutrino Experiment
The Deep Underground Neutrino Experiment (DUNE) is a neutrino experiment under construction, with a near detector at Fermilab and a far detector at the Sanford Underground Research Facility that will observe neutrinos produced at Fermilab. An intense beam of trillions of neutrinos from the production facility at Fermilab (in Illinois) will be sent over a distance of 1,300 kilometers (810 mi) with the goal of understanding the role of neutrinos in the universe. More than 1,000 collaborators work on the project. The experiment is designed for a 20-year period of data collection. The primary science objectives of DUNE are The science goals are so compelling that the 2014 Particle Physics Project Prioritization Panel (P5) ranked this as "the highest priority project in its timeframe" (recommendation 13).[10] The importance of these goals has led to proposals for competing projects in other countries, particularly the Hyper-Kamiokande experiment in Japan, scheduled to begin data-taking in 2027. The DUNE project, overseen by Fermilab, has suffered delays to its schedule and growth of cost from less than $2B to $3B, leading to articles in the journals Science and Scientific American described the project as "troubled."[11][12] As of 2022, the DUNE experiment has a neutrino-beam start-date in the early-2030's, and the project is now phased.[11][12]
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  • 02 Oct 2022
Topic Review
Conversion of Units of Temperature
This is a collection of temperature conversion formulas and comparisons among eight different temperature scales, several of which have long been obsolete.
  • 253
  • 30 Sep 2022
Topic Review
1769 Transit of Venus Observed from Tahiti
On June 3, 1769, British navigator Captain James Cook, British naturalist Joseph Banks, British astronomer Charles Green and Swedish naturalist Daniel Solander recorded the transit of Venus on the island of Tahiti during Cook's first voyage around the world. During a transit, Venus appears as a small black disc travelling across the Sun. This unusual astronomical phenomenon takes place in a pattern that repeats itself every 243 years. It includes two transits that are eight years apart, separated by breaks of 121.5 and 105.5 years. These men, along with a crew of scientists, were commissioned by the Royal Society of London for the primary purpose of viewing the transit of Venus. Not only would their findings help expand scientific knowledge, it would help with navigation by accurately calculating the observer's longitude. At this time, longitude was difficult to determine and not always precise. A "secret" mission that followed the transit included the exploration of the South Pacific to find the legendary Terra Australis Incognita or "unknown land of the South."
  • 1.3K
  • 30 Sep 2022
Topic Review
Advanced Telescope for High Energy Astrophysics
Advanced Telescope for High-ENergy Astrophysics (Athena) is an X-ray observatory mission selected by European Space Agency (ESA) within its Cosmic Vision program to address the Hot and Energetic Universe scientific theme. Athena will operate in the energy range of 0.2–12 keV and will offer spectroscopic and imaging capabilities exceeding those of currently operating X-ray astronomy satellites – e.g. the Chandra X-ray Observatory and XMM-Newton – by at least one order of magnitude on several parameter spaces simultaneously.
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  • 30 Sep 2022
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