On a dark night, you could even see a candle flame flickering up to 30 miles (48 km) away. How far the human eye can see depends on how many particles of light, or photons, a distant object emits.

CU Aerospace: Developing Next Gen Space Tech 10:20. Astronomers have, for the first time, witnessed the death of a distant galaxy, which they describe as a "truly extreme event." ...