The Sun burst into being 4.6 billion years ago, around 50 million years before the Earth formed. This makes studying its early days incredibly difficult, as physical material remaining from this period is scarce. Now, a team from the University of Chicago has found crystals more than 4.5 billion years old buried deep within meteorites that indicate the Sun had a tumultuous early life.

Prior to the formation of the planets, the Solar System consisted of the Sun surrounded by a massive protoplanetary disc of hot gas and dust that spiralled around it. As this gas and dust cooled down it coalesced into minerals, including the blue hibonite crystals found embedded in meteorites that have landed on Earth.

Upon examining the crystals using a mass spectrometer, the researchers were able to determine that they contained traces of helium and neon, which the team believes would have been created when high energy protons ejected from the young Sun struck the calcium and aluminium atoms within the crystals.

“In addition to finally finding clear evidence in meteorites that disc materials were directly irradiated, our new results indicate that the Solar System’s oldest materials experienced a phase of irradiation that younger materials avoided,” said lead researcher Levke Kööp.

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“We think this means that a major change occurred in the nascent Solar System after the hibonites had formed,” he continued. “Perhaps the Sun’s activity decreased, or maybe later-formed materials were unable to travel to the disc regions in which irradiation was possible.”

This is an extract from issue 326 of BBC Focus magazine.

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Jason Goodyer
Jason GoodyerCommissioning editor, BBC Science Focus

Jason is the commissioning editor for BBC Science Focus. He holds an MSc in physics and was named Section Editor of the Year by the British Society of Magazine Editors in 2019. He has been reporting on science and technology for more than a decade. During this time, he's walked the tunnels of the Large Hadron Collider, watched Stephen Hawking deliver his Reith Lecture on Black Holes and reported on everything from simulation universes to dancing cockatoos. He looks after the magazine’s and website’s news sections and makes regular appearances on the Instant Genius Podcast.