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PSR B1620-26 B
PSR B1620-26 b is an extrasolar planet located approximately 12,400 light-years away from Earth in the constellation of Scorpius. It bears the unofficial nicknames "Methuselah" and "the Genesis planet" due to its extreme age and a few popular sources refer to this object as "PSR B1620-26 c" (see below for discussion). The planet is in a circumbinary orbit around the two stars of PSR B1620-26 (which are a pulsar (PSR B1620-26 A) and a white dwarf (WD B1620-26)) and is the first circumbinary planet ever confirmed. It is also the first planet found in a globular cluster. The planet is one of the oldest known extrasolar planets, believed to be about 12.7 billion years old.
  • 865
  • 28 Nov 2022
Topic Review
Soyuz TM-23
Soyuz TM-23 was a Soyuz spaceflight which launched on February 21, 1996, to Mir. The spacecraft launched from Baikonur Cosmodrome, and after two days of flight, Yuri Onufrienko and Yury Usachov docked with Mir and became the 21st resident crew of the Station. On September 2, 1996, after 191 days docked with Mir, the ship undocked with the launch crew and Claudie André-Deshays onboard, before eventually landing 107 km (66 mi) south west of Akmola, Kazakhstan.
  • 313
  • 28 Nov 2022
Topic Review
Chemical Ionization
Chemical ionization (CI) is a soft ionization technique used in mass spectrometry. This was first introduced by Burnaby Munson and Frank H. Field in 1966. This technique is a branch of gaseous ion-molecule chemistry. Reagent gas molecules (often methane or ammonia) are ionized by electron ionization to form reagent ions, which subsequently react with analyte molecules in the gas phase to create analyte ions for analysis by mass spectrometry. Negative chemical ionization (NCI), charge-exchange chemical ionization, atmospheric-pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) are some of the common variants of the technique. CI mass spectrometry finds general application in the identification, structure elucidation and quantitation of organic compounds as well as some utility in biochemical analysis. Samples to be analyzed must be in vapour form, or else (in the case of liquids or solids), must be vapourized before introduction into the source.
  • 693
  • 28 Nov 2022
Topic Review
Plasma
Plasma (from grc πλάσμα (plásma) 'moldable substance') is one of the four fundamental states of matter. It contains a significant portion of charged particles – ions and/or electrons. The presence of these charged particles is what primarily sets plasma apart from the other fundamental states of matter. It is the most abundant form of ordinary matter in the universe, being mostly associated with stars, including the Sun. It extends to the rarefied intracluster medium and possibly to intergalactic regions. Plasma can be artificially generated by heating a neutral gas or subjecting it to a strong electromagnetic field. The presence of charged particles makes plasma electrically conductive, with the dynamics of individual particles and macroscopic plasma motion governed by collective electromagnetic fields and very sensitive to externally applied fields. The response of plasma to electromagnetic fields is used in many modern technological devices, such as plasma televisions or plasma etching. Depending on temperature and density, a certain amount of neutral particles may also be present, in which case plasma is called partially ionized. Neon signs and lightning are examples of partially ionized plasmas. Unlike the phase transitions between the other three states of matter, the transition to plasma is not well defined and is a matter of interpretation and context. Whether a given degree of ionization suffices to call a substance 'plasma' depends on the specific phenomenon being considered.
  • 2.7K
  • 25 Nov 2022
Topic Review
Simulation Argument (Planck Scale)
Programming deep universe (Programmer God) Simulation Hypothesis models at the Planck scale The simulation hypothesis or simulation argument is the argument that proposes all current existence, including the Earth and the rest of the universe, could be an artificial simulation, such as a computer simulation. The ancestor simulation approach, which Nick Bostrom called "the simulation argument", argues for "high-fidelity" simulations of ancestral life that would be indistinguishable from reality to the simulated ancestor. However this simulation variant can be traced back to an 'organic base reality' (the original programmer ancestors). The Programmer God approach conversely states that the universe simulation began with the big bang (the deep universe simulation) and was programmed by an external intelligence (external to the universe), the Programmer by definition a God in the creator of the universe context. As the universe in its entirety, down to the smallest detail, is within the simulation, coding will occur at the lowest level. In Big Bang cosmology, the Planck epoch or Planck era is the earliest stage of the Big Bang, where cosmic time was equal to Planck time. In analyzing the feasibility of a Programmer God simulation, Planck time therefore becomes the reference for the simulation clock-rate, with the simulation operating at or below the Planck scale, and with the Planck units as (top-level) candidates for the base (mass, length, time, charge) units.
  • 726
  • 25 Nov 2022
Topic Review
2020 AV2
2020 AV2 is a near-Earth asteroid discovered by the Zwicky Transient Facility on 4 January 2020. It is the first asteroid discovered to have an orbit completely within Venus's orbit, and is thus the first and only known member of the inner-Venusian Vatira population of Atira-class asteroids. 2020 AV2 has the smallest known aphelion and third-smallest known semi-major axis among all asteroids. With an absolute magnitude around 16.4, the asteroid is expected to be larger than 1 km in diameter.
  • 409
  • 25 Nov 2022
Topic Review
Shock Capturing Method
In computational fluid dynamics, shock-capturing methods are a class of techniques for computing inviscid flows with shock waves. The computation of flow containing shock waves is an extremely difficult task because such flows result in sharp, discontinuous changes in flow variables such as pressure, temperature, density, and velocity across the shock.
  • 607
  • 25 Nov 2022
Topic Review
Action
In physics, action is a numerical value describing how a physical system has changed over time. Action is significant because the equations of motion of the system can be derived through the principle of stationary action. In the simple case of a single particle moving with a specified velocity, the action is the momentum of the particle times the distance it moves, added up along its path, or equivalently, twice its kinetic energy times the length of time for which it has that amount of energy, added up over the period of time under consideration. For more complicated systems, all such quantities are added together. More formally, action is a mathematical functional which takes the trajectory, also called path or history, of the system as its argument and has a real number as its result. Generally, the action takes different values for different paths. Action has dimensions of energy × time or momentum × length, and its SI unit is joule-second (like the Planck constant h).
  • 2.2K
  • 25 Nov 2022
Topic Review
Mir EO-28
Soyuz TM-30 (Russian: Союз ТМ-30, Union TM-30), also known as Mir EO-28, was a Soyuz mission, the 39th and final human spaceflight to the Mir space station. The crew of the mission was sent by MirCorp, a privately funded company, to reactivate and repair the station. The crew also resupplied the station and boosted the station to an orbit with a low point (perigee) of 360 and a high point (apogee) of 378 kilometers (223 and 235 miles, respectively); the boost in the station's orbit was done by utilizing the engines of the Progress M1-1 and M1-2 spacecraft. At that time a transit between Mir and the International Space Station was already impossible - such a transfer was deemed undesired by NASA - and the orbital plane of ISS had been chosen some time before to be around 120 degrees away from that of Mir. The mission was the first privately funded mission to a space station. The mission was part of an effort by MirCorp to refurbish and privatize the aging Mir space station, which was nearing the end of its operational life. Further commercially funded missions beyond Soyuz TM-30 were originally planned to continue the restoration efforts of the then 14-year-old space station, but insufficient funding and investment ultimately led to the de-orbit of the station in early 2001.
  • 507
  • 25 Nov 2022
Topic Review
Drinking Bird
Drinking birds, also known as insatiable birdies, dunking birds, drinky birds, water birds, dipping birds, and “Sippy Chickens” are toy heat engines that mimic the motions of a bird drinking from a water source. They are sometimes incorrectly considered examples of a perpetual motion device.
  • 2.1K
  • 25 Nov 2022
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