Rocky Planets May Have Formed Just 100 Million Years After the Big Bang

Researchers from the University of Portsmouth say the raw ingredients for building rocky planets may have existed as early as 100 million years after the Big Bang, far sooner than scientists had assumed. The findings, published in The Astrophysical Letters Journal, would place the origins of planet formation close to the dawn of the universe, which is about 13.8 billion years old, even before the first galaxies had fully formed. Scientists had generally thought significant planet formation began billions of years into cosmic history.

The team traced the ingredients to "Pop III" supernovae -- explosions that ended the lives of some of the earliest, most massive stars, scattering elements such as carbon, oxygen and iron into surrounding gas. One especially energetic type, called a pair-instability supernova, can eject more than 100 times the mass of the Sun in heavy elements in a single blast. "Our new paper shows that the precursors of terrestrial planets can form around low-mass, long-lived stars in the debris of the first cosmic explosions 100 million years after the Big Bang," said Dr. Daniel Whalen of the University of Portsmouth's Institute of Cosmology and Gravitation, whose PhD student Chris Jessop ran the first part of the simulation.

In the team's simulations, gravity pulled element-enriched gas clouds together to form a rotating disc around a young star about 70% as massive as the Sun. Enough solid material accumulated within that disc to create several Earth-masses' worth of planetary building blocks, at roughly the same distance from the star as Earth is from the Sun.

The disc also held a substantial supply of water -- only a few times less than what was available when the solar system formed, the researchers found. Since Earth is thought to have gained much of its water from material left over during planet formation, the team said any planets forming in such a disc could have received water in a similar way.