Tag: Surface brightness

• Why Is the Night Sky Dark? Olbers' Paradox and the Finite Age of the UniverseIf the universe were infinite and eternal, the night sky would shine as brightly as the Sun's surface. We quantify the contradiction with solid angles and the inverse-square law, refute the absorbing-dust escape, and arrive at finite light speed, finite age, and a shortage of energy.PhysicsCosmologyHigh school / generalOlbers' paradoxCosmic microwave backgroundRedshiftInverse-square lawSurface brightness~30 min