From U Minnesota:
About 4.6 billion years ago, a cloud of gas and dust that eventually formed our solar system was disturbed. The ensuing gravitational collapse formed the proto-Sun with a surrounding disc where the planets were born. A supernova—a star exploding at the end of its life-cycle—would have enough energy to compress such a gas cloud. Yet there was no conclusive evidence to support this theory. In addition, the nature of the triggering supernova remained elusive.
Qian and his collaborators decided to focus on short-lived nuclei present in the early solar system. Due to their short lifetimes, these nuclei could only have come from the triggering supernova. Their abundances in the early solar system have been inferred from their decay products in meteorites. As the debris from the formation of the solar system, meteorites are comparable to the leftover bricks and mortar in a construction site. They tell us what the solar system is made of and in particular, what short-lived nuclei the triggering supernova provided.
“This is the forensic evidence we need to help us explain how the solar system was formed,” Qian said. “It points to a low-mass supernova as the trigger.” More.
On the other hand, maybe our solar system formed from “poorly mixed elemental soup.” It’s amazing what a big explosion or a big mess can do by way of organization.
See also: HeKs is on a roll
Cosmologist Luke Barnes on fine-tuning of the universe
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