Universality of physical laws
All parts of the universe are subject to the same simple laws of nature that we find here on Earth.
Planets, stars, and galaxies move according to the same law of gravity that governs the flight of a baseball.
Light from distant galaxies reveals the same atomic and nuclear physics that we observe in our laboratories.
Interstellar clouds contain the same elements as the Sun, Moon, and Earth.
General relativity describes how space is curved by mass. Around high concentrations of mass, the curvature of space becomes strong enough to make space behave like a lens.