Gaia discovers our galaxy’s great wave (edge-on)

The European Space Agency’s (ESA) Gaia space telescope has revealed that our Milky Way galaxy has a giant wave rippling outwards from its centre.

The unexpected galactic ripple is illustrated in this edge-on figure. Here the positions of thousands of bright stars are shown, overlaid on Gaia’s maps of the Milky Way.  

We see across a vertical slice of the galaxy and look at the wave side-on. In this perspective, the Sun is located between the line of sight and the bulge of the galaxy. This perspective also reveals that the ‘left’ side of the galaxy curves upward and the other side curves downward (this is the warp of the disc).

The newly discovered wave is indicated in red and blue: in red areas, the stars lie above, and in blue areas the stars lie below the warped disc of the galaxy.

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[Image description: An edge-on illustration of a spiral galaxy is shown. It reveals the galaxy's thin disc and central bulge from the side. Overlaid is a data visualisation, with colours ranging from blue to red.]