What significant scientific theory was published in 1905?

The correct answer is the theory of relativity, which was published by Albert Einstein in 1905. This groundbreaking theory fundamentally changed our understanding of space, time, and gravity. Before this theory, the common understanding of physics was largely based on Newtonian mechanics, which didn't account for the behavior of objects at high velocities or the influence of gravity on light.

Einstein's special theory of relativity introduced the idea that the laws of physics are the same for all observers, regardless of their relative motion. It also established the famous equation E=mc², showing the equivalence of mass and energy. Later, his general theory of relativity, published in 1915, expanded on these ideas, providing a new understanding of gravity and the curvature of spacetime.

This theory has profound implications in various fields, including astrophysics, cosmology, and even technology, influencing GPS systems and our understanding of the universe. Thus, 1905 is marked as a pivotal year in scientific history, mainly due to the introduction of this theory.