Our venerable 4.6-billion-years-old sun was quite rowdy in its youth, reveals a new study just published in the journal Nature Astronomy. The research bases its conclusions on the analysis of ancient blue crystals that still bear the marks of the sun’s smoldering activity during the early stages of its life, reports Phys.org.
According to study co-author Philipp Heck, a professor at the University of Chicago and curator at the Field Museum, these ice-blue crystals, found trapped inside meteorites in the museum’s collection, may be the first minerals to form in our solar.
“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,” Heck said in a statement.
Known as hibonite, these blue crystals date back to almost right after the sun sparked into existence and still contain traces of chemical reactions that only took place in the sun’s early days, when “it had more eruptions and gave off a more intense stream of charged particles,” Heck explained.
Led by Levke Kööp, a postdoctoral fellow at the university and an affiliate of the museum, the team examined microscopic hibonite samples — the largest of which are only a few times wider than a human hair — recovered from ancient meteorites.
Commenting on the work, study co-author Andy Davis, also affiliated with both the Field Museum and the University of Chicago, described the hibonite crystals as “quite beautiful.”
“When we look at a pile of these grains under a microscope, the hibonite grains stand out as little light blue crystals — they’re quite beautiful.”
The investigation uncovered that these ancient and fascinating blue crystals contain calcium and aluminum, as well as neon and helium — “highly volatile noble gases that were produced through irradiation from the young sun such a long time ago,” explained Kööp.
As she pointed out, these blue crystals were shaped more than 4.5 billion years ago and still keep “a record of some of the first events that took place in our solar system” as shown by the noble gases in their composition.
“Given their volatile nature, we infer that the noble gases were produced by irradiation in a relatively cold region at a considerable distance from the sun (not at the inner disk edge), requiring high particle fluxes and thus high early solar activity,” Kööp’s team wrote in their paper.
A Blast From The Sun’s Past
In the sun’s early days, before the planets were churned up from the massive disk of dust and gas encircling our biggest star, the disk was still piping hot, reaching overwhelming temperatures of more than 1,500 degrees Celsius, or 2,700 degrees Fahrenheit.
Once this incandescent disk of material began to cool down, the earliest calcium and aluminum minerals in the solar system started to take shape in the form of blue hibonite crystals.
As the young, impetuous sun continued to spew charged particles into space, some of these molecules blasted the blue crystals, producing helium and neon atoms that remained encased in the hibonite for billions of years — until they were released for the very first time in a laser experiment conducted by Kööp’s team.
Retrieved from space rocks that fell on our planet as meteorites, the hibonite was examined with a cutting-edge mass spectrometer in Switzerland, which melted one of the minuscule crystal grains to release the noble gases trapped inside it.
“We got a surprisingly large signal, clearly showing the presence of helium and neon — it was amazing,” said Kööp.
While astronomers have long speculated that the sun was extremely active in its early days, this is the first piece of evidence to back up their claims.