Atmosphere
layer of gases surrounding a planet
Lunar
relating to the moon
Eclipse
when one object blocks the light from another object from being visible
Solstice
when the sun reaches its highest or lowest point in the sky at noon (longest & shortest days)
Satellite
an object in space that orbits another object
Equinox
the time or date at which the sun crosses the celestial equator (day and night are of equal length)
Milky Way
the galaxy that contains our solar system and 100's of billions of stars
Luminosity
the rate at which a star emits energy
magnitude
brightness of a star
nova
a star that flares from obscurity to great brilliance, then back to obscurity
Neutron star
the smallest and densest type of star known, composed solely of neutrons packed very closely
Spectroscopy
the scientific study of how matter interacts light & certain other forms of energy
Apparent magnitude
a star's brightness as viewed from earth
MK luminosity classification
a system of classifying stars according to their brightness
Supernova
an exceptionally bright nova (the explosion of a star at its final stage)
black hole
a region of space whose gravitational force is so strong that nothing can escape from it
