Our sun’s beginnings are a mystery. It burst into being 4.6 billion years ago, about 50 million years before the Earth formed. Since the sun is older than the Earth, it’s hard to find physical objects that were around in the sun’s earliest days that bear chemical records. But in a new study in Nature Astronomy by scientists with the University of Chicago, the Field Museum and ETH Zurich, ancient blue crystals trapped in meteorites reveal what the early sun was like.
And apparently, it had a pretty rowdy start.
“The sun was very active in its early life—it had more eruptions and gave off a more intense stream of charged particles. I think of my son: He’s three; he’s very active too,” said study co-author Philipp Heck, associate curator at the Field Museum and part-time associate professor at the University of Chicago. “Almost nothing in the solar system is old enough to really confirm the early sun’s activity, but these minerals from meteorites in the Field Museum’s collections are old enough. They’re probably the first minerals that formed in the solar system.”
The study examined microscopic ice-blue crystals called hibonite. Their composition bears earmarks of nuclear reactions that only would have occurred if the early sun was spitting lots of energetic particles.
“These crystals formed over 4.5 billion years ago and preserve a record of some of the first events that took place in our solar system,” said first author Levke Kööp, a UChicago postdoctoral scholar. “And even though they are so small—many are less than 100 microns across—they are able to retain highly volatile noble gases that were produced through irradiation from the young sun such a long time ago.”