Thesis off-cuts: how special is our place in the Universe?

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

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

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

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