CETI Astronomy Dictionary, letter C CETI is the acronym that generically indicates extraterrestrial life research programs through radio signals or other appropriate means. It literally means: "Communication with Extra Terrestrial Intellingence" (communication with extraterrestrial intelligence).
Cosmic (Rays) Dictionary of astronomy, letter C Cosmic rays are atomic particles that reach Earth from space and whose origin, although not yet perfectly determined, can be found in the activity of stars and stellar objects. About 90 percent of the cosmic rays are formed by hydrogen nuclei, that is, protons; 9 per 10 of helium nuclei, or alpha particles, as they are usually called helium nuclei; and just 1 percent of cores of other elements.
Einstein, relativity and the nature of light Albert Einstein is probably the best known scientist of the twentieth century. His theories changed physics and, with it, the world. Einstein was an American nationalized German physicist, awarded a Nobel Prize, famous for being the author of general and restricted theories of relativity and for his hypotheses about the corpuscular nature of light.
Cepheids Dictionary of astronomy, letter C Cepheids are a special type of variable stars that change their luminosity cyclically, in times between 1 and 50 days. Its name derives from "delta Cefei", which is the first star of this type, discovered in 1784 by the English amateur astronomer John Goodricke.
Our Sun may seem soft and fluffy, but it is not so. It is a huge ball of boiling gas, mainly hydrogen. The upper image was taken in a single color of light with a hydrogen gas called alpha hydrogen. Infinite granules cover the surface of the solar photosphere like a dusty carpet, sauteed by regions illuminated with dark sunspots.
NASA, through the Goddard Space Flight Center in Greenbelt, Maryland, carries out the Space Technology 5 (ST5) project of the New Millennium Program (NMP). This ST5 project includes the construction of three miniaturized satellites. These small satellites, called nanosatellites or "small-sats," can perform some of the usual functions of a normal satellite.