The Copernican Revolution


Nicolaus Copernicus lived from 1473-1543, a time when rebellion against the Church was at its height. And unfortunately for the astronomy of the time, it had gotten inextricably tied up with Christian teachings.

In that time, heaven and hell weren’t just parts of our personal religions and beliefs—the Church held some of the highest authority over the land, and questioning heaven and hell just wasn’t done.

The way astronomers of the time pictured the universe fell right in sync with the heaven and hell geometry—Earth was the imperfect center of the universe, with hell nested deep below. Heaven was a place of perfection, and it was where all the heavenly bodies—the moon, sun, planets and stars—all moved.

Problem was, the Ptolemaic model of the universe really couldn’t explain detailed observations. It used epicycles to explain why the planets moved backwards sometimes. And no matter what people tried, they couldn’t get it to be accurate…

But then along came Copernicus, who would be the first to challenge the Ptolemaic universe and be believed. Continue reading

The Ptolemaic Universe

Ptolemy Retrograde Motion.jpg

Claudius Ptolemy lived about five centuries after the Greek philosopher Aristotle’s time. Aristotle’s model for the universe—the first geocentric model, with Earth at the center—was still widely accepted, and Ptolemy sought to improve it.

Ptolemy was one of the first of the ancient Greeks to be a true astronomer and mathematician, rather than a philosopher.

Where Aristotle, Plato, Thales, and Pythagoras before him had tried to use “pure thought” to understand the nature of the heavens, Ptolemy set about to perfect the geocentric model mathematically.

This was a huge step forward for science as a whole, as science today relies heavily on mathematics.

In Ptolemy’s time, science didn’t really exist yet. The Greeks preferred to just think through problems logically and reasonably, and if the logic they used was based on untrue assumptions…well, no one was the wiser.

But Ptolemy came up with the wonderful idea to line up observations of the sky with mathematics. And even though Aristotle’s view of the universe shackled him, he moved science forward with great strides. Continue reading

Stars: Naming and Brightness


Meet Pegasus, and the constellations surrounding it. As I said in my last post, constellations are just regions of space.

Yes, they are named after mythical beasts and ancient queens, but for scientific purposes, all that matters are the regions they denote.This way, astronomers can easily find obscure, faint objects in the sky.

And telescopes can be easily programmed to find the same objects for those with less experience.

Keep in mind, though, that constellations only appear to fall in the same horizontal plane over Earth’s surface. Some of these stars, even in the same constellation, are light-years apart from one another.

So, in that case, the brighter stars must be closer to us and the dimmer stars farther away, right?

Wrong. Continue reading