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 March 2026 Although the Universe may be infinite in extent, in the generally accepted Big Bang cosmology we are only able to see a small fraction of it. We call this small fraction we can see the observable universe. Outside the boundary of the observable universe lies a much larger region the unobservable universe… Continue reading The Observable Universe and Its Horizons
Discusses the nuances of distance measurement in cosmology., focusing on the cosmic microwave background (CMB) and its proper distance of 46 billion light years from Earth. It clarifies concepts such as light travel distance, proper distance, comoving distance, and various astronomical distance metrics, emphasizing the expansion of the Universe
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 