The newfound structure — named ‘Radcliffe Wave’ to pay tribute to the Radcliffe Institute for Advanced Study — is around 9,000 light-years long and 400 light-years wide.

It contains around 3,000,000 solar masses of gas and involves most of the close by star-forming regions.

Some of these excellent nurseries were previously thought to form some portion of ‘Gould’s Belt,’ a band of star-forming regions accepted to be situated around the Sun in a ring.

“No astronomer expected that we live next to a giant, wave-like collection of gas — or that it forms the Local Arm of the Milky Way,” said Professor Alyssa Goodman, an astronomer at Harvard University, the Smithsonian Institution, and the Radcliffe Institute of Advanced Study.

“We were completely shocked when we first realized how long and straight the Radcliffe Wave is, looking down on it from above in 3D — but how sinusoidal it is when viewed from Earth.”

“The Wave’s very existence is forcing us to rethink our understanding of the Milky Way’s 3D structure.”

The research group consolidated Gaia information from different measurements to construct a detailed, 3D map of interstellar matter in the Milky Way and saw the wave-shaped structure in the spiral arm nearest to the Earth.

“Gould and Herschel both observed bright stars forming in an arc projected on the sky, so for a long time, people have been trying to figure out if these molecular clouds form a ring in 3D,” said Professor João Alves, an astrophysicist at the University of Vienna.

“Instead, what we’ve observed is the largest coherent gas structure we know of in the Galaxy, organized not in a ring but a massive, undulating filament.”

“The Sun lies only 500 light-years from the Wave at its closest point. It’s been right in front of our eyes all the time, but we couldn’t see it until now.”

“We don’t know what causes this shape but it could be like a ripple in a pond, as if something extraordinarily massive landed in our Galaxy,” Professor Alves added.

“What we do know is that our Sun interacts with this structure. It passed by a festival of supernovae as it crossed Orion 13 million years ago, and in another 13 million years it will cross the structure again, sort of like we are ‘surfing the wave’,” he said.