Earth and solar system may have been shaped by nearby exploding star

Earth may owe some of its properties to a nearby star that exploded just as the solar system was forming. This sample that I saw supernova bubble envelops the Sun and showers it with cosmic rays, may be ubiquitous throughout the galaxy, meaning there may be many more Earth-like planets than previously thought.

We know thanks to the ancients meteorite samplesthat the solar system was once filled with heat-generating radioactive elements that quickly decayed. The heat from these elements drove away large amounts of water from the space rocks and comets that came together to form the Earth, ensuring that the planet had enough water for life to continue to develop.

However, it is unclear how these elements entered the solar system. Many of these are commonly found in supernova explosions, but simulations of nearby supernovae have failed to obtain accurate ratios of radioactive elements derived from meteorite samples that were present in the early Solar System. One problem is that these nearby explosions could have been so powerful that they would have destroyed the fragile early solar system before any planets formed.

Now, Ryo Sawada from the University of Tokyo in Japan and his colleagues found that a supernova could have provided Earth with the necessary radioactive ingredients without disrupting the planet's formation if it had been a little further away.

In their model, a supernova located about 3 light years from the solar system could produce the necessary radioactive elements in a two-step process. Some, such as radioactive aluminum and manganese, would be produced directly in the supernova and then travel on shock waves from the exploding star to reach the solar system.

High-energy particles called cosmic rays from the supernova will then follow these shock waves and strike other atoms in the still-forming disk of gas, dust and rock in the solar system. This process will produce the remaining necessary radioactive elements such as beryllium and calcium. “Previous models of the formation of the solar system focused only on the injection of matter. I realized that we were ignoring high-energy particles,” says Sawada. “I thought, 'What if the young solar system was just swallowed up by this bath of particles?'

Because this process works with a supernova that is farther away than previous studies, Sawada and his team estimate that 10 to 50 percent of Sun-like stars and planetary systems may have been seeded with radioactive elements in this way, forming planets with Earth's abundance of water. For previous models with close supernovae, failure was “like winning the lottery,” Sawada said. But moving the supernova further means that “the recipe for Earth is most likely not a rare fluke, but a universal process occurring throughout the galaxy,” he says.

“It's completely new because it's a beautiful balance between destruction and creation,” says Cosimo is closed at Cardiff University, UK. “You need the right elements and the right spacing.”

If this mechanism is correct, it could help in future searches for terrestrial planets using planned telescopes such as NASA Habitable Worlds Observatoryby looking for traces of ancient supernovae and discovering star systems that were close to them at the time, Inserra says.