The solar system was once engulfed by a vast wave of gas and dust

The stars as seen from Earth would have looked dimmer 14 million years ago, as the solar system was in the middle of passing through clouds of dust and gas

By Alex Wilkins

5 March 2025

A visualisation of the Radcliffe wave, a series of dust and gas clouds (marked here in red) across the Milky Way. It is about 400 light years from our sun, marked in yellow

Alyssa A. Goodman/Harvard University

Our solar system passed through a vast wave of gas and dust around 14 million years ago, dimming Earth’s view of the night sky. The wave may even have left traces in our planet’s geological record.

Astronomers have previously discovered large ocean-like waves of stars, gas and dust in the Milky Way that undulate up and down over millions of years. One of the closest and best-studied of these is the Radcliffe wave, which is nearly 9000 light years in width and sits only about 400 light years from our solar system.

Read more

Dozens of stars show signs of hosting advanced alien civilisations

Advertisement

Now, Efrem Maconi at the University of Vienna and his colleagues have found that the Radcliffe wave used to be much closer to us, crossing our solar system between 11 million and 18 million years ago.

Maconi and his team used data from the Gaia space telescope, which has tracked billions of stars in the Milky Way, to identify recently formed groups of stars within the Radcliffe wave, along with the dust and gas clouds from which they formed.

Using these stars to indicate how the wave as a whole is moving, they tracked the orbits of the clouds back in time to reveal their historic location. They also calculated the past path of the solar system, winding the clock back 30 million years, and found that the wave and our sun made a close approach between around 15 million and 12 million years ago. Estimating exactly when the crossing began and ended is difficult, but the team thinks the solar system was within the wave around 14 million years ago.