Molten rock within the crust of a planet that is capable of intrusion
into adjacent crustal rocks or extrusion onto the surface.
Igneous rocks are derived from magma through
solidification and related processes or through eruption of the magma
at the surface.
The degree of brightness of a celestial body designated on a
numerical scale, on which the brightest star has magnitude -1.4
and the faintest visible star has magnitude 6, with the scale
rule such that a decrease of one unit represents an increase in
apparent brightness by a factor of 2.512; also called apparent magnitude.
Latin word for "sea." Galileo thought the dark featureless
areas on the Moon were bodies of water, even though the Moon is
essentially devoid of liquid water. The term is still applied to the basalt-filled
impact basins common on the face of the Moon visible from Earth.
(Aka Mayr) German astronomer. Marius gave Jupiter's "Galilean" moons their names. He and Galileo both claimed to have discovered them in 1610 and likely did so independently. They became involved in a dispute over priority. Marius was also the first to observe the Andromeda Nebula with a telescope and one of the first to observe sunspots.
