The Milky Way's plane of satellites: consistent with $\Lambda$CDM
  The "plane of satellites problem" describes the arrangement of the Milky
Way's 11 brightest satellite galaxies in a remarkably thin plane, possibly
supported by rotation. This is in apparent contradiction to the standard
cosmological model, wherein the Galaxy is surrounded by a dispersion-supported
dark matter halo. Here, we show that the reported exceptional anisotropy of the
satellite system is strongly contingent on a lopsided radial distribution,
which earlier simulations have failed to reproduce, combined with the close but
fleeting conjunction of the two most distant satellites, Leo I and Leo II.
Using Gaia proper motions, we show that the orbital pole alignment is much more
common than previously reported, and reveal the plane of satellites to be
transient rather than rotationally supported. Comparing to new simulations,
where such short-lived planes are common, we find the Milky Way satellites to
be compatible with standard model expectations.
