Paper Roundup December 2025: computing billiards, an impossible atmosphere, and Roman constructions

Papers on big questions at the frontiers of science, curated by hand each month

Paper Roundup December 2025: computing billiards,  an impossible atmosphere, and Roman constructions
Magpies are notorious thieves, but I like to think they see themselves as curators. Art: American Magpie by Robert Havell after John James Audubon (1837) in the National Gallery of Art
I'm back from a much-needed holiday break! And I have some news: paper roundups are changing.

From now on, paper roundups will be weekly — and they get their own newsletter! Instead of one big list of papers with commentary each month, starting later this month I will send out leaner lists of papers without commentary every week. You can choose whether to receive only main newsletter posts, weekly roundups using your account portal.

Free subscribers will be able to see my top 3 picks for the week, but the full list of papers is an exclusive perk for paid supporters.

So if you don't already support R2, now's a great time to change that: to thank you for being with me this far, I'm offering 25% off of a monthly subscription for the next 6 months to anyone who signs up by the end of January.