What scientific discoveries challenged traditional views of the cosmos?

The discoveries of Copernicus, Galileo, Hubble, and Einstein significantly challenged traditional views of the cosmos.

Nicolaus Copernicus, a Polish astronomer in the 16th century, was the first to propose a heliocentric model of the universe, which placed the Sun, not the Earth, at the centre. This was a radical departure from the geocentric model that had been accepted since the time of Aristotle and Ptolemy. Copernicus' theory was controversial because it contradicted the teachings of the Church, which held that the Earth was the centre of the universe. However, his work laid the foundation for future astronomers and sparked a scientific revolution.

Galileo Galilei, an Italian astronomer, further challenged traditional views in the 17th century. He improved the telescope and used it to make observations that supported Copernicus' heliocentric model. Galileo discovered that the Moon had craters and mountains, Venus had phases like the Moon, and Jupiter had moons orbiting it. These findings contradicted the Aristotelian belief that celestial bodies were perfect and unchanging. Galileo's support for heliocentrism led to his trial and house arrest by the Inquisition.

In the 20th century, American astronomer Edwin Hubble made discoveries that expanded our understanding of the universe beyond the Milky Way. He observed that galaxies were moving away from us in all directions, leading to the conclusion that the universe was expanding. This contradicted the traditional view that the universe was static and unchanging. Hubble's discovery was the first observational evidence for the Big Bang theory.

Albert Einstein's theory of relativity also revolutionised our understanding of the cosmos. His theory proposed that space and time were interwoven into a single continuum known as spacetime. It also suggested that gravity was not a force, as Newton had proposed, but a curvature of spacetime caused by mass and energy. Einstein's theory predicted the existence of black holes and gravitational waves, phenomena that were later observed. His work has had profound implications for our understanding of the universe and has challenged traditional views of space, time, and gravity.