You're welcome. Tides are fun, and that's mostly why I jumped in. Tides are also hard and have occupied a lot of thinking time for gravitational scientists, a

You're welcome. Tides are fun, and that's mostly why I jumped in. Tides are also hard and have occupied a lot of thinking time for gravitational scientists, and naval people with respect to Earth's ocean: https://en.wikipedia.org/wiki/Tide-Predicting_Machine_No._2 https://en.wikipedia.org/wiki/Tide-Predicting_Machine_No._2 (be sure to see the photos). Your comment about the solid earth tide was pretty neat because few people who aren't professionally into geodesy or the study of Earth's gravitation think about that. As I mentioned, there are tides in all sorts of bodies elsewhere in our solar system (and beyond). The ones people think about are atmospheric tides and ocean tides (within e.g. Europa), or how it couples to volcanism (e.g. Io's magma and Enceladus's ice). However, scattered about our solar system there are "asteroids" in pairs, where one is what amounts to a blob of kitty litter to large gravel, and the other is a more solid body. The rubble-pile is especially interesting in a tidal context. I just submitted https://news.ycombinator.com/item?id=39561656 https://news.ycombinator.com/item?id=39561656 which the Royal Astronomical Society announced yesterday in various places including <https://twitter.com/RAS_Journals/status/1763219322732786054 https://twitter.com/RAS_Journals/status/1763219322732786054> (the image is worth a click, but also appears as Fig. 1 in the full article at the HN submission; if you hate X and/or extra clicks, this is a direct link: <https://academic.oup.com/view-large/figure/441211342/stae325fig1.jpg https://academic.oup.com/view-large/figure/441211342/stae325...>). When general relativity students learn about decompositions of the Riemann curvature tensor they are sometimes taken to the idea of a sort of cloud of coffee-grounds (with the special provision that they pass through each other, always have gaps between them, or are otherwise non-collisional and therefore non-clumping; and they have no internal pressure) to see a variety of ways in which one can find "tidal forces" encoded in e.g. the Weyl curvature tensor (which is extracted from the Riemann curvature tensor). Baez is an example of this <https://math.ucr.edu/home/baez/gr/outline2.html https://math.ucr.edu/home/baez/gr/outline2.html> and <https://math.ucr.edu/home/baez/gr/ricci.weyl.html https://math.ucr.edu/home/baez/gr/ricci.weyl.html>, although textbooks generally stick to "test particles". Rubble pile asteroids, while essentially not needing any post-Newtonian gravitational corrections at all, are a neat step up in difficulty because they do clump. But unlike larger bodies, they aren't fused by e.g. melting; the rubble can shift around unlike a fused rock or icy concretion; and internal pressures and shear stresses are low. So the rubble (how it shifts around, what shape it tends to adopt) will be affected by tides induced by the sun and possibly other solar system bodies closer to them. Personally I like the idea of depositing a crash test dummy loaded with sensors onto the surface of (probable) rubble-pile 101955 Bennu. Is it like a ball pit, or like a bean-bag chair? Does the dummy sink or get buried in landslides or fountains of material? (We already know we can send things there (and return them): <https://www.nasa.gov/news-release/nasas-bennu-asteroid-sam https://www.nasa.gov/news-release/nasas-bennu-asteroid-sam>).