How does lookback time help resolve Olbers' Paradox regarding the dark night sky?
Light from sufficiently distant stars has not reached us yet
Olbers' Paradox addresses why the night sky appears dark when assuming an infinite, static universe filled uniformly with stars. The resolution involves integrating the finite age of the universe with the finite speed of light, introducing the concept of lookback time. Lookback time establishes that looking farther out into space means looking further back into the universe's history. Because the universe has a finite age, light emitted by stars located beyond a certain distance—and therefore existing in the ancient past—has simply not had enough time, since the Big Bang, to travel across the intervening distance and reach Earth today. This limitation on observable light prevents the entire sky from being saturated with brightness.
