What paradox explains why the night sky is dark?

Olbers' Paradox addresses the question of why, despite the vast number of stars in the universe, the night sky is predominantly dark. If the universe were infinite, eternal, and uniformly populated with stars, one would expect that every line of sight from Earth would eventually land on a star, resulting in a sky that is completely bright at night. However, this is not observed; the night sky is largely dark.

The reason behind this paradox involves several key factors: the finite age of the universe means that we can only see light from stars and galaxies that has had time to reach us. Moreover, the expansion of the universe leads to redshift, which stretches the wavelength of light from distant stars, making them less visible. Additionally, stars are not uniformly distributed, and many of them are obscured by dust and gas.

The correct identification of Olbers' Paradox highlights a significant aspect of cosmology and our understanding of the universe, illustrating the complex interplay between distance, light travel time, and cosmic expansion that explains the darkness of the night sky.