This is a fun paper. It uses the dynamics of orbiting galaxies to show that Antlia 2 (a dwarf galaxy orbiting our own) must have crossed through the galactic pl

This is a fun paper. It uses the dynamics of orbiting galaxies to show that Antlia 2 (a dwarf galaxy orbiting our own) must have crossed through the galactic plane. It uses the ripples in the hydrogen cloud around the galaxy as the marker for the previous transit. The authors suggest this happened within the last 100 Myears or so (you just have to run the various proposed orbits backward in time.) These sorts of things would presumably result in increased levels of debris flying through solar systems such as our own and possibly lead to increased impact activity.