Concept
Meridian
The great circle through the zenith and the poles.
The imaginary line in the sky passing through the north and south points of the horizon, the zenith and both celestial poles. Objects culminate when crossing it.
Overview
The imaginary line in the sky passing through the north and south points of the horizon, the zenith and both celestial poles. Objects culminate when crossing it.
See also
Warm Ionized Medium
Diffuse ionised gas spread through the galactic disc.
Moving Group
Stars sharing a common motion through the galaxy.
The Big Bang
How everything began, 13.8 billion years ago.
Black Holes
Regions where gravity stops light itself.
Dark Matter
The invisible mass holding galaxies together.
Dark Energy
The mysterious force accelerating the universe.