Viswanathan K's Thoughts

Tycho Brahe and Johann Kepler are one of the great pairs of science. The former collected immaculate data from his observations of the skies; which the latter then analyzed to come up with his famous laws of planetary motion. Very fairy tale like, right? Except that reality was far more complicated, as Kitty Ferguson describes in Tycho and Kepler , her awesome biography of the two men, their personal lives and their science. This blog, the first in a four-part series, explains the prevailing astronomical views before Brahe and Kepler changed our understanding forever. There was Ptolemy’s model, with the Earth at the center, and everything else orbiting the Earth. In this model, planets seemed to slow down and accelerate at times and even reverse direction: this is because we on Earth are moving in a circle while observing the other planets. Hence the concept of epicycles (circles within circles) was added to the model: How did the epicycles help describe the observed m...

Everyone’s heard of Galileo and how the Church persecuted him. But what I didn’t know was why . Sure, Christianity considered the earth to be the center of the universe, but was that such a central belief of Christianity that they’d kill a guy over it? I always felt like there was something more to it. Like everything else in the Western world, the story starts in ancient Greece. Pythagoras believed the earth was at the center of the universe. The sun, moon, planets and stars revolved around the earth, with each pinned inside a sphere. How far did these spheres within spheres extend? To infinity? Or did they stop at some point? If they stopped, what lay beyond the last sphere? Aristotle denied the existence of both the void and the infinite. As far he was concerned, both the void and the infinite were just constructs of the mind: and he felt there’s nothing in the real world (universe) that was infinite. So Aristotle’s answer was that there were only a finite number of spheres and that...