- calcium K
- A narrow wavelength of blue light which is emitted
and absorbed by ions of the element calcium.
- A large, basin-shaped volcanic depression that is more or less
circular in form. Most volcanic calderas are produced by collapse of the
roof of a magma chamber due to removal of magma by voluminous eruptions or
subterranean withdrawal of the magma, although some calderas may be formed
by explosive removal of the upper part of a volcano.
- A compound containing carbon and oxygen; an example is calcium carbonate (limestone).
Cassini, Giovanni Domenico 1625-1712
- (Aka Jean Dominique) Italian-born French astronomer. Cassini was the first
director of the Royal Observatory in Paris. He discovered four of
Saturn's moons (Tethys,
and Iapetus) and the major gap in its rings.
- A texture found in metamorphic rocks in which brittle minerals
have been broken, crushed and flattened during shearing.
- A chain of craters.
- Hollows, irregular depressions.
- The exposed core of uplifted rocks in complex meteorite impact
craters; the central peak material typically shows evidence of intense
fracturing, faulting and shock metamorphism.
- A distinctive area of broken terrain.
- A canyon.
- The lower level of the solar atmosphere between the photosphere and the corona.
- Loose, vesicular volcanic ejecta 4 to 32 millimeters (.16 to 1.28 inches) in diameter.
- A conical hill formed by the accumulation of
pyroclastic fragments that
fall to the ground in an essentially solid condition.
- A fragment of rock that has been transported, either by volcanic or
- A small hill or knob.
- The dust and gas surrounding an active comet's nucleus.
- A volcano composed of interbedded lava and pyroclastic material
commonly with steep slopes.
- Fluid circulation driven by large temperature gradients;
the transfer of heat by this automatic circulation (see also
Educator's Guide to Convection).
Copernicus, Nicolaus 1473-1543
- Polish astronomer who advanced the
heliocentric theory that the earth
and other planets revolve around the Sun. This was highly controversial
at the time; the Ptolemaic view of the
universe, which was the prevailing theory for more than 1000 years,
was deeply ingrained in the prevailing philosophy and religion.
- 1) The upper level of the solar atmosphere,
characterized by low densities and high temperatures (> 1.0E+06 K);
it is not visible from the Earth except during a total eclipse of the
sun or by use of special telescopes called coronagraphs.
2) An ovoid-shaped feature.
- A special telescope which blocks light from the
disk of the Sun in order to study the faint solar atmosphere.
- Electromagnetic rays of extremely high frequency and energy;
cosmic rays usually interact with the atoms of the atmosphere before
reaching the surface of the Earth. Some cosmic rays come from outside the
solar system while others are emitted from the Sun and pass through
holes in the corona.
- 1) A depression formed by the impact of a meteorite. 2) A depression
around the orifice of a volcano.
- The relatively stable portions of continents composed of shield
areas and platform sediments; typically, cratons are bounded by tectonically
active regions characterized by uplift, faulting and volcanic activity.
- A geological term denoting the interval of Earth history
beginning around 144 million years ago and ending 66 million years ago.
- A major stratigraphic boundry on Earth marking the end of the
Mesozoic Era, best known as the age of the dinosaurs. The boundary
is defined by a global extinction event that caused the abrupt demise
of the majority of all life on Earth.
- Rock types made up of crystals or crystal fragments, such as
metamorphic rocks that recrystallized in high temperature or pressure
environments, or igneous rocks that formed from cooling of a melt.