Wednesday, June 27, 2012

Uncovering the Secrets of the Solar System

The cosmos: ethereal, mysterious, and unfathomable. At least, for a little while. However obscure and mystical the first speculations about the universe were, over time they were no match for astronomers looking through the lenses of empiricism.

Aristotelian "physics" was not physics in the sense we think of now. It was actually a philosophy, one of the most influential theories on the workings of the universe, accepted as the standard work to reference for over 1,000 years. Widely considered one of the greatest thinkers of all time, Aristotle proposed that the universe and the "heavenly lights" were contained in perfect concentric spheres composed of an eternal substance called "aether." However romantically arcane these ideas seem to be, they were obviously not formed from a foundation of deep scientific study. For example, another one of Aristotle’s “truths” was that flies have four legs, which was accepted by scientists for years until someone actually made some basic observations. Similarly, it would require someone to take a good look at the night sky in order to dispel Aristotle’s hypotheses about the universe.

Cue Tycho Brahe, a man as quirky as his nearly unpronounceable name, and yet a brilliant astronomer. Brahe was the first scientist to accurately observe and measure the night sky and its heavenly lights, and thus he refuted much of Aristotle's axioms. In 1572, a supernova that we now know to be 5700 light years away appeared to Brahe as a bright new star in the sky. At the time, it was believed this new star was "in the terrestrial sphere below the moon," meaning it was between the Earth and the moon. Brahe observed that the star had no parallax motion, and thus concluded it must have been past the moon and past all of the planets. Although he was the last and possibly greatest of the naked-eye astronomers, his data was later found to have some observational inaccuracies.  He claimed his measurements were within one arcminute of accuracy, but after his death it was noted that the average error was around two arcminutes, in some cases even three. However, these errors certainly do not overshadow the rest of Brahe’s accomplishments; one of his defining achievements was creating tables that corrected for atmospheric refraction in observation near the horizon. Unfortunately, soon after his remarkable discoveries he suddenly was afflicted by a fatal dose mercury poisoning. It is debated whether this was due to some kind of sinister sabotage from an enemy, or Brahe’s fondness for wearing prosthetic metal noses.

Brahe definitely would have made People magazine's "Sexiest Men Alive" list, if he were alive

After "[living] like a sage and [dying] like a fool" (Brahe's autobiographical epitaph), his data was picked up by his student, Johannes Kepler. In addition to being a mathematics teacher and strong proponent of the Copernican heliocentric system, Kepler was a devout Christian and often related theology and religion to his research on the universe. He used Brahe’s measurements to develop his three famous laws of planetary motion, the most crucial of which to modern planetary science being the third, which states that the square of the orbital period of a planet is directly proportional to the cube of its semi-major axis. His first law states that every orbit of a planet is an ellipse, and these crucial discoveries chipped away at Aristotle’s original theories of perfect heavenly spheres. Brahe and Kepler’s contributions to observational science led the way in the Scientific Revolution, and began to demystify our solar system.

1 comment:

  1. Hi. thanks for sharing such detailed review . will be looking for more updates.