These are some of my cosmology posts
-
Creating Videos
I started my Explaining Science blog nearly 11 years ago in April 2014. Back then I wasn’t sure how long I’d want to keep it going. But now in 2025 I still find that I enjoy blogging very much. In July 2020, the year of the first covid-19 lockdowns in the UK, I started the…
-
eBooks from Explaining Science 2024
Update 30 August 2025 I have extensively expanded and rewritten all three “A Short Guide to…” e-books. I will make these books available on Kindle for a competitive price. However, in future I won’t do any deals where I offer free or discounted prices on these books for a limited time period. I believe the…
-
Understanding the Magnitude Scale in Astronomy
Astronomers use the magnitude scale to measure the brightness of celestial objects, originally developed by Greek astronomers. Standardized by Norman Pogson in 1856, the scale uses whole and fractional values. Today, it encompasses all luminous objects, with both apparent and absolute magnitudes.… Continue reading Understanding the Magnitude Scale in Astronomy →
-
Twice Yearly Clock Changes
At 0100 UTC (2 AM local time) on Sunday 27 October, the UK like most of Europe will put it clocks back by one hour at is comes to an end of Daylight Saving Time. Most of the USA will follow a week later. In this post I’ll give an overview of DST and why…
-
Gliese 710: The Closest Future Star Encounter
Updated 21 November 2025 In 1.3 million years’ time the star Gliese 710 is forecast to pass within 0.166 light years of the Solar System, 25 times closer than Proxima Centauri which is our current nearest star (excluding the Sun of course). The close approach of Gliese 710 will be the strongest disrupting encounter known…
-
September 22 2024 – the equinox
In 2024 September 22 is the date of the September equinox and is also the first day of autumn (or the first day of spring if you’re one of my readers in the Southern Hemisphere). In this post I’ll talk about the equinoxes and discus the commonly held, but not quite correct, view that they…
-
Guide to Observing the Perseids Meteor Shower 2024
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).…
-
Understanding Solar Day Length Variation
Revised and updated 12 February 2026 July 25, is one of the four days a year in which the length of the apparent solar day, the natural day measured by the rising and setting of the Sun, is 24 hours. I have written about this in previous posts but I thought it be worth mentioning…
-
Starlink and other Large Satellite Constellations
Back in 2019, the year before the pandemic, many of you will have seen images of long ‘trains’ composed of up to sixty SpaceX Starlink satellites crossing the sky in a straight line. These pictures hit the headlines not only because of the number of satellites, but because of their brightness. A ‘train’ of…
-
Sirius: The Dog Star and Its History
Updated Marck 2026 As most people with an interest in astronomy know, Sirius is the brightest star in the night sky. On the magnitude scale used by astronomers it has a magnitude of -1.46, easily outshining all other stars. The apparent brightness of a star depends on two factors: how luminous it is (its intrinsic…
Explaining Science 