Calippusyclus
A cyclus used by the Greeks in their timesystem which was based on the movement of the moon and the sun, it lasts 76 years or 940 lunations, this is 27759 days. The cyclus started 330 B.C. and was used by astronomers for two centuries.
Callisto
Satelite (moon) of the planet Jupiter.
Catastrophetheory
Theory that says that during the geological past of earth, life was periodicaly distroyed by large, global catastrophies (earthquakes, vulcanic eruptions, floods) to return in a different form.
Cepheides
Name for two totally different groups of object:
a. a at 15 november occuring meteorswarm in the sign of the zodiac Cepheus
b. a class of pulsing changing stars named after 5 Cephei, the prototype of the Cepheis.
Ceres
One of the brightest planetoids, the first to be discovered ( by Piazzi at
Palermo at 1 jan. 1801).
Chandler, period of
The period with which the rotation of the earth is counterclockwise around
Earths axis.
Chandrasekharlimit
Named after S. Chandrasekhar, the maximum mass for white dwarfs. When the mass becomes larger then this critical mass (approx. 1,4 solarmasses), the star will colapse into a neutronstar or a black hole due to the fact that there can't be a hydrostatic balance.
Chiron
A object rotating around the sun, discovered at the first of november 1977 by C. Kowal, with an estimated diametre of 500 km.
Chromosphere
One of the layers in the atmosphere of the sun of other stars, lying ontop
of the photosphere.
Cluster
A group of physiologicaly the same stars. A cluster or swarm of galaxies means such a group of extragalactic systems, containing 100-10000 galaxies, for instance the Comacluster and the Virgocluster. A group of clusters form a supercluster.
Coma
The thin gascloud which is located around the core of a comet.
Comacluster
A very large spacious group of extragalactic galaxies in the sign of the zodiac Hoofdhaar van Bernice.
Comet
See : solarsystem
Compton-effect
The difusion of x-rays to free electrons, during which these are submitted
to a revulsion and take over part of te impulse and energy of the radiation.
Conjunction
Scematic representation of both conjunctions of Mercury, the (upper)conjunction of
Mars and the (lower)conjunction of the Moon.
Corona
A vast, thin and hot gasshell around certain types of stars, among which the sun. The suns corona can be seen as a garland of rays during a total solar eclipse.
Cosmic radiation
Radiation that penetrates the atmosphere of the earth as primary radiation,
where it reacts with the atmosphere and forms secundary radiation.
Cosmos
An acronym for 'the universe'
Cosmology
The study of everthing there is to know about the universe
Crab nebula
Luminescent nebula in the sign of the zodiac Bull, made up from remnants of
a supernova, that, according to chinese history, take place in the year 1054.
These remnants have been identified as comming from a supernova
Cygnides
Swarm of meteorites with radiant in the sign of the zodiac Swan (Cygnus).
Cygnus A
The first dotshaped radiosource discovered(1 946), located in the sign of the zodiac Swan.