Solar System
Includes the Sun, planets, moons, asteroids, and comets within our system.
Binary Star
Two stars orbiting a common center.
Dark Matter
Cold, non-radiating matter inferred from physics.
Main Sequence Star
A normal star undergoing hydrogen fusion to become helium.
Lightyear
Distance light travels in a year in space vacuum, approximately 9.461 × 10^12 kilometers.
Stellar Parallax
Measures space distances using Earth's orbit.
Luminosity
Total power radiated by a star in all directions, measured in watts.
Inverse Square Law
States a physical quantity is inversely proportional to the square of the distance from the source.
Hertzsprung–Russell (HR) Diagram
Relates absolute magnitude, luminosity, classification, and temperature of stars.
Chandrasekhar Limit
Maximum mass for a white dwarf, about 1.4 solar masses.