Excursion Set is a set of excursions into cosmology, astrophysics, particle physics, and everyday topics as seen through a scientist’s eyes. It’s an eclectic, intermittent outlet for thoughts that (mostly) emerge from my day job.

The name is borrowed from a term of art in my field: an ‘excursion set’ is a mathematical framework used by astrophysicists to describe how galaxies collectively form the cosmic web of our expanding universe.

I post irregularly, every month or so. Subscribe here to receive new articles straight to your inbox.

About me…

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Latest Posts

  • Follow the Money: The Science of Impact
    There is a purely pragmatic issue with targeting the Marsden Fund at economic outcomes: it could hurt more than it helps.
  • The Writing Life: An Update on the Blog
    I have been writing this blog for over ten years. I am not particularly prolific; there are around 100 posts in total – less than once a month and sometimes closer to once a year. Apparently I only write when I have something to say along with the time to say it. For … Continue reading The Writing Life: An Update on the Blog →
  • The Coming of the Comet - illustration of a comet from the Ausberg Book of Miracles
    The Coming of the Comet
    Comets are not unusual. Dozens of them are found every year and a handful – such as Halley’s Comet – are repeat visitors to our skies. But genuinely bright comets must tread a celestial path that takes them close to both the Sun and the Earth, ensuring that they are simultaneously well-lit and easily seen by humans. These are special events and Comet Tsuchinshan-ATLAS is the brightest we have seen in a decade.
  • Keep Looking Up
    I chalked up a personal first yesterday; I saw an aurora with my own eyes and it was every bit as remarkable as I could have hoped for. I was not alone in sharing this special moment – anyone outside before midnight without clouds overhead in New Zealand (and, in fact, much of … Continue reading Keep Looking Up →
  • A Bigger Sky

    Amongst everything else that happened in 2023 a key anniversary for a landmark in our understanding of the Universe passed largely unnoticed – the centenary of the realisation that not only was our Sun one of many stars in the Milky Way galaxy but that our galaxy was one of many galaxies in the Universe.

  • A Hard Rain’s A-Gonna Fall

    There is insight in the stories that numbers can tell, and for some of us that insight offers a sense of calm in turbulent times. Which may be why In the midst of this year’s rains I started making graphs of the accumulated rainfall and how it stacked up against previous years.

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