Is the Night Sky Really Dark?

In 1823 German astronomer Henrich Wilhelm Olbers formulated a theoretical question regarding the darkness of the night sky. Assuming an infinite universe, permeated by infinite stars, Olbers pondered on how could the night sky be dark. Modernly this question is known as the Olbers Paradox. Multiple explanations have been offered since its formulation, and some of the explanations are no longer valid or are incomplete. Only in the light of the most recent theories and astronomical observations of the 20th century can this apparent paradox be resolved. The objective of this article is to list the most relevant observational evidence that helps to clarify Olbers’ Paradox. By addressing the latest discoveries in astronomy and theoretical physics, we seek to provide a comprehensive overview of the reasons why the night sky is brighter and richer in radiation than initially supposed.

Keywords:
Astrophysics; Sky; Expansion of the universe; Olbers’ paradox