
Antlia2's role in driving the ripples in the outer gas disk of the Galaxy - bookofjoe
https://arxiv.org/abs/1906.04203
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ChuckMcM
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.

