A familiar-looking messenger from another solar system – Renfrewshire Astronomical Society

The visit of the interstellar interloper 1I/2017 U1, recently spotted streaking through the solar system, gives the people of Earth their first chance to study up close an object from another planetary system. In a study carried out with the WIYN telescope at Kitt Peak National Observatory and the Nordic Optical Telescope in the Canary Islands, astronomers find that despite its foreign origins, U1 is familiar in appearance—its size, rotation, and color are similar to that of asteroids in our solar system. Its familiar appearance supports the long-held view that our solar system once ejected its own flotilla of such messengers out into interstellar space.