Much like a toddler throwing a tantrum, the sun was exceptionally explosive early in its life. It kicked and screamed with ferocious flares and rambunctious bursts of radiation that were much more energetic than what we see today.

Astronomers believed the sun went through something like the “terrible twos” based on observations of young stars far away in space. But they lacked physical clues of what our star was like in the early years after it formed some 4.6 billion years ago.

Now, by studying blue crystals trapped inside a meteorite that predates the planets, researchers have collected what they say is the first direct evidence of the sun’s activity during its fiery start. The findings were published Monday in the journal Nature Astronomy.

“This is essentially a real record of the early active sun,” said Philipp Heck, a cosmochemist at the Field Museum in Chicago and the University of Chicago, and an author on the paper.