Johannes Kepler

Updated 14 December 2025 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… Continue reading Johannes Kepler

Lunar eclipse 21 January 2019

On the night of 20/21 January 2019 there will be a total eclipse of the Moon, which will be viewable from many areas of the world. This will be worth making the effort to see, especially for my readers in the western USA and Canada for whom it will occur at a sociable hour. The… Continue reading Lunar eclipse 21 January 2019

Geocentric Cosmology

Revised March 2026 Today it is generally accepted fact that the Earth is one of eight planets which revolve around the Sun, that the Sun is one of 400 billion or so stars in our Milky Way galaxy and that the Milky Way is one of hundreds of billions of galaxies in the observable Universe.… Continue reading Geocentric Cosmology

The equinox March 20 2017

Now that we are in the month of March, for most of us in the northern hemisphere the worst of the winter is over, and it is only a few days until 21 March, the first day of spring.   There is a commonly held view that March 21 is the spring equinox and that the equinoxes are the two… Continue reading The equinox March 20 2017

Satellite navigation – the next ten years

Satellite navigation is such a vital part of day-to-day life that other countries of the world are planning to build up their own network of navigation satellites and move away from total reliance on the American system, GPS. America As mentioned in my previous post, the GPS system is operated and funded by the US government. The first… Continue reading Satellite navigation – the next ten years