Cosmic Horizons

Although the Universe may be infinite in extent, in the generally accepted Big Bang cosmology we can only see a small fraction of it. This is known as the observable universe. Field of distant galaxies - Image Credit NASA  There are three widely used definitions of cosmological horizons, which are limits imposed by cosmology to… Continue reading Cosmic Horizons

Easter April 4 2021

This year, for the majority of the world’s Christians, 4 April is Easter Sunday, one of the most important dates in the calendar. Although because of the current restrictions due to the Covid pandemic, celebrations will be a little limited in many places. Although Easter is the festival celebrating the resurrection of Jesus Christ from the dead,… Continue reading Easter April 4 2021

Distances in Cosmology

I recently read an article on the popular astronomy website site Universe Today.   It stated that ‘…the CMB [cosmic microwave background radiation]  is visible at a distance of 13.8 billion light years in all directions from Earth, leading scientists to determine that this is the true age of the Universe. ' This statement isn't… Continue reading Distances in Cosmology

Advancing the Clocks

On the early hours of Sunday 14 March 2021, most of the United States will put their clocks forward an hour and Daylight Saving Time (DST) will commence. Two weeks later on 28 March most countries in Europe (including the UK) will follow, switching to  summer time. In this post I’ll talk about the practice… Continue reading Advancing the Clocks

Solar Sails

Solar sails are the only method of spacecraft propulsion in which no fuel is needed. Until recently spacecraft powered by solar sails were the stuff of science fiction. However,  following the success of the Japanese spacecraft IKAROS which flew close to Venus in 2010, and in 2019 the crowd-funded Light Sail 2 spacecraft it is… Continue reading Solar Sails