Ancient meteorites provide ‘ground-breaking insight’ on formation of Jupiter

Rare ancient meteorites have provided “ground-breaking insight” on how Jupiter formed and settled in its position as the fifth planet from the sun billions of years ago, according to scientists.

The researchers said that angrite meteorites hold clues about the chaotic way the gas giant came into existence during “a huge solar system event”.

Ben Rider-Stokes, a PhD student at the Open University, said: “The formation and migration of giant gas planets such as Jupiter are crucial to the evolution of planetary systems, and yet the timing of these events in our solar system remains largely unconstrained.

“Angrite meteorites represent some of the oldest materials in the inner solar system, and therefore provide an exclusive window into the processes that occurred during this period.”

It is thought that over millions of years, Jupiter roamed towards the centre of the solar system and back out again, at one point moving in about as close as Mars is now.

The planet’s journey is believed to have profoundly influenced the solar system.

Mr Rider-Stokes said: “One of the most popular models for Jupiter’s formation is known as the ‘Grand Tack’.

“This model suggests that upon Jupiter’s initial formation it was pulled towards the sun due to gravitational attraction.

“However, when Saturn formed, it pulled Jupiter back to its current position in the Solar System.

“This movement of in-and-out is thought to have caused gravitational disruptions to asteroids and other bodies that formed close to Jupiter, causing these bodies to smash into one another.”

The researchers examined Angrite meteorites collected by a joint Japanese and Belgian Antarctic research expedition as well as others found in north-west Africa.

Mr Rider-Stokes said: “Angrite meteorites are ancient meteorites that formed at a similar time period to the proposed formation and migration of Jupiter around 4.5 billion years ago.

“Due to their ancient ages, these meteorites are extremely important in testing this model.”

An international team of scientists analysed the chemical composition of the meteorites focusing on oxygen isotopes – different forms of the same element.

The researchers said that, for the first time, they found two oxygen isotopic signatures, which indicates two differing planetary origins within a single sample.

Mr Rider-Stokes said: “This study indicates these meteorites are a result of asteroids and bodies colliding together and possibly due to the gravitational disruptions of Jupiter’s formation and movement.

“This, therefore, provides the first empirical evidence for this event, which has only been previously modelled.”

As part of the next steps, the researchers are investigating the hydrogen content of the samples to understand more about how water was delivered to the inner solar system.

The findings are published in the journal Nature Astronomy.