A 3D view of the orbits of four globular clusters (blue) and three dwarf galaxies (red) in motion around our Milky Way Galaxy, based on data from the second release of ESA’s Gaia satellite.

Using Gaia data, astronomers have measured the motion of 75 globular clusters in the halo of the Milky Way and 12 dwarf galaxies orbiting the Galaxy. From measurements of the proper motions – the true motion across the sky – of large numbers of stars in each of these clusters and galaxies, the orbits around the Milky Way could be calculated.

The four globular clusters shown here are NGC 104, NGC 288, NGC 362, NGC 1851; the three dwarf galaxies are Carina, Bootes I and Draco.

The orbits derived from the Gaia data are combined with an artist's impression of the Milky Way.

Acknowledgement: Gaia Data Processing and Analysis Consortium (DPAC); Orbits: Floor van Leeuwen, University of Cambridge, UK / Paul McMillan, Lund Observatory, Sweden / Amina Helmi, Kapteyn Astronomical Institute, University of Groningen, The Netherlands.