I recently read an article from a popular astronomy website called 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 quite correct.… Continue reading Understanding Cosmic Distances
Updated 28 November 2025 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… Continue reading The Observable Universe and Its Horizons
This post has now been superseded by a more detailed post Measuring Distances in Cosmology ---------------------------------------------------------------------------------------------- I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… Continue reading Distances in Cosmology
I offered recently to write an article for my local astronomy society on the discovery of dark energy. It is an expanded version of the blog post I wrote on the topic last year and, at over 3000 words, it is longer than my usual posts. I thought it would be of interest to many… Continue reading Dark energy an unexpected finding
In a previous post I talked about the Large Synoptic Survey Telescope (LSST), a large telescope being built in Chile which will spend 90% of its time surveying most of the sky a total of 1000 times over a 10 year period (in the remaining 10% it will revisit areas of specific interest). In this… Continue reading Surveying the Cosmos – Part II
Explaining Science 