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1) ядро формира от процеса на α (q.v.) (виж още дори ядра) 2) частици открит за първи път в радиоактивни α гниене и по-късно идентифициран като хелий ядра (две протони и два неутрона, свързани помежду си.) 3 ядро на 4He атом, състояща се от два протони и два неутрона. Маса на α-частица 4.00260 АМУ.
Industry:Astronomy
1) Unit of electric current. "The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2 × 10-7 newton per meter of length" CIPM 1946, Resolution 2, approved by the 9th CGPM 1948). A current of 1 A is equivalent to the passage along the filament of a light bulb of about 6 × 1018 electronic charges per second.
2) constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2 × 10-7 newton per meter of length
Industry:Astronomy
Античастица на неутрон. Неутрон и antineutron и двамата имат една и съща маса и zero електрически заряд, но могат да бъдат разграничени от техните взаимодействия: неутрон и antineutron може да унищожи в гама-лъчи, докато два неутрона не могат.
Industry:Astronomy
1) An elementary particle of opposite charge but otherwise identical to its partner. Most of the observable universe consists of particles and matter, as opposed to antiparticles and antimatter.
2) Atomic particles that have the same mass as, but opposite charge and orbital direction to, an ordinary particle. Thus, instead of negatively charged electrons, atoms of antimatter have positrons. A quantity of antimatter coming into contact with matter would "cancel out" - annihilate, with total conversion of mass to energy - an exact proportion of matter corresponding to the original quantity of antimatter, provided that the elements in the matter also corresponded with the "elements" in the antimatter, i.e., that the atoms were equivalent but opposite.
3) For every known type of particle, there exists an antiparticle with exactly the same mass, but with the opposite electric charge. When a particle and its antiparticle come together, they can always annihilate to form gamma rays. The antiparticle of an electrically neutral particle is sometimes the same as the original particle (e.g., photons) and sometimes it is distinct (e.g., neutrons.)
4) Particles predicted by combining the theories of special relativity and quantum mechanics. For each particle, there must exist an antiparticle with the opposite charge, magnetic moment and other internal quantum numbers (e.g., lepton number, baryon number, strangeness, charm, etc.), but with the same mass, spin and lifetime. Note that certain neutral particles (such as the photon and π0) are their own antiparticles.
5) Particles with identical mass and spin as those of ordinary matter, but with opposite charge. Antimatter has been produced experimentally, but little of it is found in nature. Why this should be so is one of the questions that must be answered by any adequate theory of the early universe.
Industry:Astronomy
Също така AR покритие. Слой от материал с по-нисък индекс на рефракция само правилната дебелина (1/4 вълна) се нанася върху оптичната повърхност, за да бъдат покрити. По-сложни покрития са възможни, което покрива голям диапазон.
Industry:Astronomy
Точката, в която орган в орбита около Земята достига своя най-отдалечената разстояние от земята.
Industry:Astronomy
Също така наречен planetoids или малки планети, астероиди са малки планети-голямата част от които орбита слънцето между Марс и Юпитер. Най-големият - и първите открити - е Церера, с диаметър от 1003 км. Изчислено е, че общо може да има не по-малко от 40000. Някои са много елиптични орбити и пресичат орбитите на няколко други планети, (основна). Една или две дори имат свои собствени спътници (луни).
Industry:Astronomy
