When you're in this business long enough, you eventually go down enough rabbit-holes to accumulate a smörgåsbord page like this of random topics that do not have much relevance to your primary research. Here's a selection...

  • Color Perception. Astronomy is all about colors. M-type stars are red, O-type stars are blue, and so on. However, we often quantify the spectral energy distributions in ways that diverge from the simple ways that a human eye would perceive those colors. Thus, I've been exploring ways to compute those eye-perceived colors and display them on computer screens. A brief paper (Cranmer 2021) described some of this. It's been interesting to explore earlier suggestions that "brown dwarfs" would actually appear violet or magneta to the unaided human eye.

    Since that paper, I've uploaded several bundles of data and code to assist others in reproducing and extending this work:

  • Infinite Mathematics. I was enticed down the garden path by some interesting ways to solve transcendental equations (see, e.g., Cranmer 2004). But where was I led? Seemingly, down a road that some have called "mathematical nonsense," but others have called a "paradise." Inspired by other attempts from, say, Rucker and Conway & Guy (and also Vsauce!), I've undertaken to write an intuitive review of infinite number theory that attempts to convey the beauty and wonder without all the rigorous proofs. A first draft has been posted on arXiv, and I'm open to discussing, improving, and updating it over time.

  • Active Asteroids. In the inner solar system, there are "Mercury-crossing" asteroids that get so close to the Sun that their surface temperatures can exceed 1000 K. When that happens, some rocky materials on their surfaces can start to sublimate into gaseous form, thus creating comet-like comas. Cranmer (2016) investigated whether these cometary clouds could be big enough for the WISPR instrument on Parker Solar Probe to be able to image them. Since the launch of PSP in 2018, WISPR has indeed seen cloudy emission around at least one of these active asteroids, but it's still not clear to what extent sublimation may be responsible.