Rather exciting. Here is a link to Science Daily and news that the proper motion of various stars have been observe in another galaxy..In Sculptor. https://www.sciencedaily.com/releases/2017/11/171127124737.htm Alex
From Astronomy Daily and all credit to them...their article says... First proper motions measured of stars in a small galaxy outside the Milky Way Findings question models of dark matter halos Date: November 27, 2017 Source: University of Groningen Summary: By combining data from the Hubble Space Telescope and the Gaia mission, astronomers have been able to measure the proper motion of 15 stars in the Sculptor Galaxy, the first such measurement outside the Milky Way. Analysis shows an unexpected preference in the direction of movement, which suggests that the standard theoretical models used to describe the motion of stars and dark matter halos in other galaxies might be invalid. End.
Also, A second major result is a more precise measurement of the orbit of the Sculptor Galaxy around the Milky Way. 'This orbit is much wider than expected. Previously, it was believed that the current spheroidal shape of Sculptor was in part the result of some close passages, but our measurements show that this is not the case.'
Pity to add this as without more seems speculative and for me detracts from what has apparently been done. Alex