Nicolaus Copernicus challenged the notion proposed by Aristotle, which stated that there were four physical elements: water, fire, earth and air. It also stated that Earth was the centre of the universe, and that the four elements were below the moon and other planets, all moving around the Earth.
Copernicus challenged this with the heliocentric theory, which included assumptions that the Earth was the centre of gravity and its orbiting moon, that the sun is close to the centre of the universe with the planets orbiting it, and that the universe is much larger than the scale that Aristotle suggested.
The structure of the mitochondrion is key to the process of aerobic (in the presence of oxygen) cellular respiration, especially the Krebs cycle and electron transport.
