Saints Spotlight: Rita Tojeiro
In this month’s Saints Spotlight, Professor Rita Tojeiro of the School of Physics and Astronomy discusses her research, which recently helped to make the most extensive map of the Universe ever created.
How did your St Andrews story start?
I first came to the School of Physics and Astronomy at the University of St Andrews in 2014 on an external five-year Science and Technology Facilities Council Ernest Rutherford Fellowship. Towards the end of the Fellowship, I was appointed as a Reader and have worked at the University ever since.
What are your current priorities at the University?
Like many of my colleagues, I wear several hats, including research, teaching and service, each with different priorities. Recent projects I’ve been working on include the development of a new Cosmology module for our MPhys programme, inclusive pedagogy across the University and a national professional development programme for high school Physics teachers in Scotland that brings contemporary astrophysics into the classroom.
What is the focus of your research at St Andrews?
I study how the Universe evolves on a very large scale, through which we can observe matter shaping what we call the cosmic web. This is a collection of voids, stringy filaments and other structures that, together, somewhat resemble a spiderweb, hence the name. I’m fascinated by how the cosmic web evolves over time and how galaxies respond to it.
My work is underpinned by data from sky surveys, which are multi-year, international observational programmes involving several hundred scientists who use telescopes to gather data from distant objects. We then use this data to reconstruct gigantic three-dimensional maps of the Universe that reveal the cosmic web.
Right now, my focus is firmly on one of these surveys – the Dark Energy Spectroscopic Instrument (DESI) survey. DESI is an instrument that takes light from distant objects and allows us to study it in detail. It is mounted on the Nicholas U. Mayall Telescope – a four-metre telescope at the Kitt Peak National Observatory in the Tohono O’odham Nation, Arizona. I hold senior leadership positions in the survey across science and governance.
Over the last five years, DESI has gathered the positions of over 30 million objects, resulting in the largest three-dimensional map of the Universe that humans have ever built – we made the final observations just last night (14 April 2026)! It is a wonderfully detailed map that we will be exploring for decades to come.
Tell us about your proudest achievement.
I don’t have a good answer to this. Sometimes, daily small achievements have a huge impact, and I try to savour those moments as much as I can. But I’ll highlight completing a part-time MA in Inclusive Education with the Open University in 2023 as something that I found extremely challenging yet rewarding. I’m proud of the ways in which it has changed my practice.
Where is your favourite spot in St Andrews?
When I have time and the weather is nice, my feet like to take me away from my office. I step off the trusty 99 at the bus station: first I head towards the bandstand, then up the Scores, past the Castle, down to the pier and East Sands, and then finally towards my office on the North Haugh via South Street. I don’t tire of this little ritual in the mornings, although I don’t get to do it as often as I’d like, especially during teaching weeks, and every time I feel extremely grateful for this town.