ESA’s Gaia data release 3 shows us the speed at which more than 30 million Milky Way stars move towards or away from us. This is called ‘radial velocity’ and it is providing the third velocity dimension in the Gaia map of our galaxy. Together with the proper motions of stars (movement across the sky), we can now see how the stars move over a large portion of the Milky Way.
This sky map shows the velocity field of the Milky Way for ~26 million stars. The colours show the radial velocities of stars along the line-of-sight. Blue shows the parts of the sky where the average motion of stars is towards us and red shows the regions where the average motion is away from us. The lines visible in the figure trace out the motion of stars projected on the sky (proper motion). These lines show how the direction of the speed of stars varies by galactic latitude and longitude. The Large and Small Magellanic Clouds (LMC and SMC) are not visible as only stars with well defined distances were selected to make this image.
Credit: ESA/Gaia/DPAC, CC BY-SA 3.0 IGO.
Page last updated: 04 April 2023