Many people think that the whole of the Moon’s far side is entirely hidden from view. This isn’t quite true. There is a region around the boundary between the near and far sides which is sometimes visible due to a phenomenon called libration. Libration causes the Moon to appear to wobble from side to side and… Continue reading How Libration Reveals some of the Moon’s Far Side
A friend of mine recently asked me whether it was possible to have a lunar-stationary orbit. This would be the equivalent of a geostationary orbit, but around the Moon rather than the Earth. To an observer on the Moon, a lunar-stationary satellite would appear fixed in the sky and if a dish were pointed… Continue reading Lunar Stationary Orbits: Why They are Impossible
Revised 18 December 2025 We're all familiar with specifying a location by its latitude and longitude, but I thought it would be interesting to write a post about latitude and longitude on other bodies in the Solar System. Locations on the surface of the Moon are given a latitude and longitude just like they are… Continue reading Latitude and Longitude on the Moon and the Planets
The night of 12/13 August will be the peak of the Perseids, one of the most famous prolific meteor showers. Meteors (also known as shooting stars) are bright streaks of light caused by small lumps of rock or metal called meteoroids hitting the Earth’s atmosphere at very high speed (in the case of the Perseids around 200,000 km/h).… Continue reading The Perseids Meteor Shower 2025
For those of us in the Northern Hemisphere we're in that time of year when there is the most daylight. In this post I’ll talk about the long long summer evenings: not only does the Sun set later at this time of year but the amount of twilight, after Sun has set but it is… Continue reading Twilight and the Long Summer Evenings
Explaining Science 