What long wave-shaped gas structure near the Sun was announced in 2020?

The Radcliffe Wave is the long, wave-shaped gas structure near the Sun announced in 2020.

Astronomers identified it as a roughly 2.7-kiloparsec chain of nearby molecular clouds and star-forming regions. The structure runs through several familiar features of the local Milky Way, including the Orion and Perseus regions, but its clouds are arranged in a coherent three-dimensional pattern rather than lying in the flat plane suggested by older maps.

The discovery was reported in Nature in January 2020 by researchers associated with the Harvard–Smithsonian Center for Astrophysics and the Radcliffe Institute. It became a striking reminder that the Milky Way’s nearby interstellar medium is not a simple, smooth disk. The wave’s physical origin remains an active research question; proposed explanations include gravitational effects and instabilities involving the Galactic disk and halo.

The Radcliffe Wave is easily confused with the Gould Belt, an older, tilted ring-like arrangement of nearby young stars and clouds. The Orion Spur, by contrast, is a broader Galactic arm segment, not this newly mapped wave.