The original motivation for choosing the degree as a unit of rotations and angles is unknown. One theory states that it is related to the fact that 360 is approximately the number of days in a year. A ...
Main article: Figure of the EarthEarth's rotation, internal density variations, and external tidal forces cause it to deviate systematically from a perfect sphere. Local topography increases the varia ...
Geodesy of the Earth's Equator The latitude of the Earth's Equator is by definition 0° (zero degrees). The Equator is one of the five notable circles of latitude on Earth, with the others being the t ...
The orbital plane of an object orbiting another is the geometrical plane in which the orbit lies. The orbital plane is defined by two parameters, Inclination (i) and Longitude of the ascending node ( ...
The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit. It is the angular distance of the orbital plane from the plane of reference (usually the ...
Main article: Magnetosphere chronologyStudy of Earth's magnetosphere began in 1600, when William Gilbert discovered that the magnetic field on the surface of Earth resembled that on a terrella, a smal ...
The satellite's functional versatility is imbedded within its technical components and its operations characteristics. Looking at the "anatomy" of a typical satellite, one discovers two modules. Note ...
"Newton's cannonball", presented as a "thought experiment" in A Treatise of the System of the World, was the first published mathematical study of the possibility of an artificial satellite.The first ...
There are two aspects to the harmful effects of plutonium: the radioactivity and the heavy metal poison effects.Isotopes and compounds of plutonium are radioactive and accumulate in bone marrow. Conta ...
Plutonium, like most metals, has a bright silvery appearance at first, much like nickel, but it oxidizes very quickly to a dull gray, although yellow and olive green are also reported. At room tempera ...
Neptunium nitride (NpN) was first prepared in 1953 by reacting neptunium hydride and ammonia gas at around 750 °C in a quartz capillary tube. Later, it was produced by reacting different mixtures of ...
Neptunium is a hard, silvery, ductile, radioactive actinide metal. In the periodic table, it is located to the right of the actinide uranium, to the left of the actinide plutonium and below the lantha ...
Natural uranium consists of three major isotopes: uranium-238 (99.28% natural abundance), uranium-235 (0.71%), and uranium-234 (0.0054%). All three are radioactive, emitting alpha particles, with the ...
When refined, uranium is a silvery white, weakly radioactive metal, which is harder than most elements. It is malleable, ductile, slightly paramagnetic, strongly electropositive and is a poor electric ...
In 1871, Dmitri Mendeleev predicted the existence of an element between thorium and uranium. The actinide element group was unknown at the time. Therefore, uranium was positioned below tungsten, and t ...
