Writing my PhD thesis

How do you write a PhD thesis? This question sounds like the start of the old joke: “How do you eat an elephant? One piece at a time”. A PhD thesis is a document which must explain, summarise and defend three or more years of research in your chosen field, often running to 40,000 words…… Continue reading Writing my PhD thesis

Thesis off-cuts: the reproducibility crisis in cosmology

As we frequently hear1, we’re now in the precision era of cosmology. What this really means is that we’re in the era of measuring things really well, and we’re getting really good at measuring things because we keep building ever more enormous and powerful telescopes. I remember attending the STFC Introductory Summer School on Astronomy…… Continue reading Thesis off-cuts: the reproducibility crisis in cosmology

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. https://twitter.com/R_Trotta/status/1309457430267523072 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

Applying for a PhD in physics

Almost exactly one year ago, I sent my final two applications off for PhD places in cosmology. One year on, as my department prepares to interview the candidates for October 2018 entry, I wanted to reflect on the application process. In total, I sent off nine applications and had three interviews. I was fortunate in…… Continue reading Applying for a PhD in physics