Was the Earth Created by a Supernova Shockwave?

Explore

WWhen a solar system is born, it is not really a system. Instead, it is simply a protostar surrounded by a swirling disk of gas and dust. Given time, gravity, and various forces, the protostar becomes a star and planets begin to take shape from the matter in this cosmic cloud. The types of planets that form in a given solar system depend on their distance from the star and the elements available.

A new study suggests that in our solar system, the formation of rocky planets, including the one we live on, was also created in part by an external explosive force: supernovae.

For rocky planets to thrive, heat-generating radioactive elements called “short-lived radionuclides,” or SLRs, must be present to boil off excess water from the growing protoplanets. Although these SLRs could come directly from a supernova explosion, a stellar shockwave so close to a fragile baby solar system could disrupt the entire solar system construction project. A new “immersion model” proposed by researchers in Japan and published in Scientific advances suggests an interesting twist.

Read more: »The Cosmic Web and the Destiny of the Universe»

In this model, a supernova about three light years away could have seeded our own protoplanetary disk with SLRs while still being cosmically mild enough to keep the nascent solar system intact. Yet this would not produce the SLR ratio that meteorite analyzes have shown to be present in the infancy of our solar system. To explain the disappearance of SLRs, astrophysicist Ryo Sawada of the University of Tokyo and his team proposed that cosmic rays emanating from a supernova irradiate matter inside the protoplanetary disk to produce additional radioactive elements. In other words, a supernova could cause an initial dose of SLR followed by a sort of “booster shot” of cosmic radiation.

It’s an exciting model, and not just because it could explain how the Earth formed; it also increases the chances of finding other rocky planets capable of supporting life in the Milky Way.

“At least 10 percent, or even 50 percent, of Sun-like stars are likely to host protoplanetary disks with SLR abundances similar to those of the protosolar disk,” Sawada and co-authors wrote. “Our results suggest that water-poor, rocky planets, similar to Earth, may be more widespread in the galaxy than previously thought.”

Enjoy Nautilus? Subscribe for free to our newsletter.

Main image: Merikanto / Wikimedia Commons

• Jake Currie

  Published on December 11, 2025

  Jake Currie is a writer based in Brooklyn, New York.