Thanks to many hundreds of people making dedicated observations of the sky over many decades, we know that the majority of our Universe is comprised of two substances: dark matter and dark energy. Dark matter is an unknown type of matter, referred to as "dark" because it does not interact electromagnetically, meaning that it doesn't …
Continue reading Thesis off-cuts: how special is our place in the Universe?
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, …
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 …
My early efforts at blog writing were somewhat sporadic, but I did mark some key moments during my PhD, in the posts Year Two and Year Three. In the former, I reflected on the major review that every Portsmouth PhD student must pass in order to progress to their second year. In the latter, I …
Making a daily log of my thoughts and things I tried saved the final year of my PhD.
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
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
This week has been a particularly exciting one, and not just due to the XENON experiment result that has set both the arXiv and cosmology Twitter abuzz. Fate finally smiled on me and the Spanish borders have reopened to non-residents, thereby allowing me a small window of opportunity to return to Madrid to collect the …
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 …
At first I refrained from writing about "the situation we currently find ourselves in", as it has come to be so coyly referred to. I am lucky in that, while I was driven to leave Madrid and return to the UK, the pandemic has not affected my life in any great measure. Only one person …
