Stellar motion
![](https://cdn.sci.esa.int/documents/33580/35361/1567216664853-Proper_motion_625x509.jpg)
Date: 28 November 2013
Satellite: Gaia
Copyright: ESA/ATG medialab
As stars move through our Galaxy, the Milky Way, their positions in our sky change over time.
The movement of a star across the sky is termed 'proper motion'. This provides two of the three components of a star's true velocity. The third component is 'radial velocity' – the movement towards or away from us – can be inferred from the red- or blueshift of its light spectrum.
Last Update: 1 September 2019