Light-years
A distance, not a time: how far light travels in a year — about 9.46 trillion km.
Planets, stars, galaxies and the deep history of the cosmos.
A distance, not a time: how far light travels in a year — about 9.46 trillion km.
Stars fuse hydrogen, swell into giants, then end as white dwarfs, neutron stars or black holes.
Light from receding galaxies stretches toward red — the evidence the universe is expanding.
v = H₀ · dThe CD's grooves split light into a spectrum — the same technique that reveals what stars are made of.