The distance duality relation

The distance duality relation tells us how, assuming that photons propagate on null geodesics in a pseudo-Riemannian spacetime and that their number is conserved, luminosity and angular diameter distances are related, via where dL is the luminosity distance, dA the angular diameter distance and z the redshift. This relation was introduced by Etherington in 1933,…… Continue reading The distance duality relation

Tribalism in science

Last week, a tweet by Roberto Trotta drew my attention to a recent paper by Simon Portegies Zwart that studied the amount of carbon dioxide emitted by running N-body simulations in different programming languages. The figure that caught my attention was Figure 3, copied below from the version of the paper published in Nature…… Continue reading Tribalism in science

How asking a question on Stack Exchange kick started my career in research

I did my undergraduate degree at Aberystwyth University in Wales. I took the astrophysics course, which ran in parallel to the plain physics degree for the first two years, covering all the basics such as mathematical methods, classical mechanics, waves, optics, thermodynamics and so on. In the third year the astrophysics became the main focus,…… Continue reading How asking a question on Stack Exchange kick started my career in research

Thesis off-cuts: the ancient history of general relativity

Chocolate frosted donuts with sprinkles are ready to be served during the grand opening of Dunkin' Donuts in Fremont, California, on Wednesday, Sept. 27, 2017. This is the first Dunkin' Donuts shop to open in Alameda County. (Gary Reyes/ Bay Area News Group)

I have recently been thinking a lot about what introductory and background material I want to include in my PhD thesis, as my self-imposed December deadline continues to hurtle towards me at an alarming speed. Concurrent with this thinking, I’ve also recently been enjoying a fantastic book called The Poincaré Conjecture by Donal O’Shea, all…… Continue reading Thesis off-cuts: the ancient history of general relativity

The joy of journal clubs

Presenting papers in journal clubs is one of my least favourite things to do. While I enjoy reading in general, I find reading academic papers a chore, especially if the writing is uninspired or the results obscured by reams of unfamiliar theory. However, papers are the currency of academia and, to stretch the analogy, journal…… Continue reading The joy of journal clubs

Paper day! Madrid week seven

Today my first paper as first author came out on the arXiv! You can check it out here: In this work, we reconstruct a coupling function between dark matter and vacuum energy. Such models are generally motivated as solution to problems such as the Hubble tension, so we were keen to update our previous…… Continue reading Paper day! Madrid week seven

Standard sirens, Cobaya and Beethoven’s 9th: Madrid week two

As of tomorrow, I’ll have been in Madrid for two weeks! Time really does fly. The weather is still freezing and there’s fresh snow on the hills behind campus (as you can hopefully see in the header image, which I took on my commute this morning). This week I made a proper start on the…… Continue reading Standard sirens, Cobaya and Beethoven’s 9th: Madrid week two

COSMO19 in Aachen

This week I travelled to Aachen on the western border of Germany for the COSMO19 conference hosted by TTK, the theoretical physics department of RWTH. The conference, which occurs yearly in different locations around the world, has a very broad scope ranging from particle astrophysics to theoretical cosmology. Conferences are an important and fun part…… Continue reading COSMO19 in Aachen