Dear colleagues, Welcome to the start of SDG 2021! As the new school year gets underway, I have two orders of business to address. First: This week, Friday, 12 March, Richard Montgomery (University of California Santa Cruz) will give a talk at 2pm (Sydney time) via Zoom. Zoom link: https://uni-sydney.zoom.us/j/87125570381 Meeting ID: 871 2557 0381 Title: Some open questions in the N-body problem Abstract: The classical N-body problem, despite being 333 years old, is alive and well. I will begin with a pictorial survey of a few solution curves. I then state ``the problem’’ and describe between two and four open questions within the problem and survey of recent progress on them. Past talks can be found on the YouTube channel: https://www.youtube.com/channel/UCZqgDJ21wbdzMbeIdealpUg/ Second: As the new year rolls on, often a new cohort of postgraduates, postdocs, and researchers have started at your respective universities. I want to encourage all of you to forward this email to interested parties and to contact me with any names that should be added (or removed â no hard feelings) from the SDG mailing list. I look forward to seeing you all online later this week. Cheers, Sean