The Science Geek

As discussed in my previous post, Kepler’s improvement of Copernicus’s heliocentric system led to its more general acceptance, and his three laws describing the way planets move are fundamental laws of astronomy. However, this wasn’t his only contribution to science. He was one of the greatest thinkers of the seventeenth century scientific revolution and in this post I’ll outline some of his other major achievements.

Statue of Kepler in Linz, Austria – image from Wikimedia Commons

The Keplerian telescope

The Italian astronomer Galileo Galilei (1564-1642) was the first person to take observations of celestial objects with a telescope . However, Galileo’s telescope could only magnify objects 30 times before the image became distorted. It also had a narrow field of view

In 1610 Kepler began theoretical and experimental investigations of the way that different combinations of lenses could work together to produce a magnified image. He published his finding in…

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The Science Geek

My latest post is about the work of the German astronomer Johannes Kepler (1571-1630).  He is most famous for his improvement to the earlier model of Copernicus by introducing the idea that the planets move in elliptical, rather than circular, orbits and that their movements in these orbits are governed by a set of laws, which became known as Kepler’s laws of planetary motion. However, as I’ll talk about later, he also made many other major contributions to astronomy and mathematics.

Johannes Kepler – Image from Wikimedia Commons

As readers of a previous post will be aware, in 1543 the Polish astronomer Nicolas Copernicus (1473–1543) published a theory in which the Earth and all the planets orbited the Sun. Prior to Copernicus, the generally accepted view was that the Earth was the centre of the Universe and the Sun, the stars and the planets were all in motion around it. However…

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The Science Geek

In this post I’m going to talk about Nicolas Copernicus (1473 – 1543) and the heliocentric theory.  The move away from the prevailing Earth-centred theory of the Universe to the heliocentric theory represents one of the greatest advances in astronomy ever made.

Nicolas Copernicus – Image from Wikimedia Commons

Background – the need for a better theory

As mentioned in my last post, the geocentric theory was the generally accepted theory of the cosmos until the early 16th century, having been developed by the second century Greek astronomer Claudius Ptolemy.  To make it fit the observations, Ptolemy needed to fine-tune his theory, making it rather complex. Rather than moving directly around the Earth, the Sun, the Moon and the planets moved around small circles called epicycles and the centre of each epicycle moved, at a varying speed, around a larger circle called a deferent. A further complexity was that the…

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New by me for Live Science:

For many ancient cultures, eclipses of the sun and moon were something special — and something to be feared.

Source: Afraid of the Dark? Why Eclipses Frightened Ancient Civilizations

Also: Kepler’s fictional explanation for human fear of eclipses in Somnium is characteristically exotic:



Solar and lunar eclipses have sometimes played quite a remarkable role in human history. From foretelling evil omens to inspiring early works of science fiction, here are 11 of the most curious stories about eclipses.

Source: Christopher Columbus to Thailand’s Kings: 11 Curious Eclipse Stories

Historians discuss astronomer Johannes Kepler in this BBC4 radio broadcast.

Source: BBC Radio 4 – In Our Time, Johannes Kepler