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The Planetary Data System (PDS) is a distributed data system that NASA uses to archive data collected by Solar System missions. The PDS is an active archive that makes available well documented, peer reviewed planetary data to the research community. [1] The data comes from orbital, landed and robotic missions and ground-based support data ...
A fundamental ephemeris is the basis from which apparent ephemerides, phenomena, and orbital elements are computed for astronomical, nautical, and surveyors' almanacs. Apparent ephemerides give positions and motions of Solar System bodies as seen by observers from the surface of Earth, and are useful for astronomers, navigators, and surveyors ...
In planetary science, planetary differentiation is the process by which the chemical elements of a planetary body accumulate in different areas of that body, due to their physical or chemical behavior (e.g. density and chemical affinities). The process of planetary differentiation is mediated by partial melting with heat from radioactive ...
Solar cycles are nearly periodic 11-year changes in the Sun 's activity that are based on the number of sunspots present on the Sun's surface. The first solar cycle conventionally is said to have started in 1755. The source data are the revised International Sunspot Numbers (ISN v2.0), as available at SILSO. [1]
Planetary science. A geological map of the Sputnik Planitia basin on the dwarf planet Pluto. Analysis of planetary surfaces and surface features is a major component of planetary science. Planetary science (or more rarely, planetology) is the scientific study of planets (including Earth), celestial bodies (such as moons, asteroids, comets) and ...
The inner Solar System is the region comprising the terrestrial planets and the asteroids. [ 89 ] Composed mainly of silicates and metals, [ 90 ] the objects of the inner Solar System are relatively close to the Sun; the radius of this entire region is less than the distance between the orbits of Jupiter and Saturn.
K-U ratio. The K/U Ratio is the ratio of a slightly volatile element, potassium (K), to a highly refractory element, uranium (U). It is a useful way to measure the presence of volatile elements on planetary surfaces. The K/U ratio helps explain the evolution of the planetary system and the origin of Earth's moon.
The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows (" periods ") and columns (" groups "). It is an icon of chemistry and is widely used in physics and other sciences. It is a depiction of the periodic law, which states that when the elements are arranged in order ...