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A fireball that hit near Hamburg, Michigan in 2018 could offer new insights into the history of the solar system, the researchers said.
The fireball – a type of very bright meteor that would also be seen in daylight – was spotted in several states as it flew across the sky on the evening of January 16, 2018; the meteor also produced an atmospheric shock wave equivalent to a 2.0 magnitude earthquake.
Walnut-sized fragments were quickly recovered from Strawberry and Bass Lakes by meteorite hunters using information from scientists who had tracked their trajectory using NASA’s weather radar.
“Finding a pebble-sized fragment on a frozen lake or in a blanket of snow is difficult if you don’t know where to look,” said Philipp Heck, co-author of the report and associate professor at the University of Chicago who is also the curator of the report. collection of meteorites, rocks and minerals at the Field Museum of Natural History in Chicago.
Now Heck and colleagues have released an in-depth report examining three of the meteorite pieces housed at the Field Museum.
The results reveal that the space rock is of a type known as chondrite H4, a relatively rare subtype of a class of meteorites common in collections.
“[These] that’s only 4% of all falls today, ”Heck said.
Heck added that initial analysis of the space rock revealed that the meteorite contained 2,600 different organic compounds. Although an even wider range has been found in other meteorites, Heck said the findings add weight to the much-discussed idea that meteorites may have played a role in initiating life on Earth.
“I personally found it astounding how many organic compounds there were still in this meteorite despite its thermal metamorphism,” Heck said.
But there were other insights.
“We found [this meteorite] it was ejected 12 million years ago by its parent asteroid, ”Heck said, noting that this is the first evidence of that particular event.
And the analysis of argon levels in the meteorite, produced by radioactive decay, shed light on the history of the asteroid itself, with Heck observing that the element is released when impacts occur. “We found out that nothing else has happened since [parent asteroid] formed 4.5 billion years ago, “Heck said.” It was pretty much boring on that asteroid. “
Heck he said that when the Hamburg meteorite hit the frozen ice, it was relatively pristine. But to have a truly pristine sample, it is necessary to recover space rocks directly from asteroids: a feat that numerous space missions have set themselves up, including the NASA spacecraft Osiris-Rex which is expected to return to Earth in 2023.
Dr Katharine Joy, a meteorite and lunar science expert at the University of Manchester who was not involved in the report, said space rocks such as the Hamburg meteorite are exciting in that they are fresh extraterrestrial samples.
“Looking at the minerals, the age and the chemistry of [meteorites] we can look back in time to understand how its parent asteroid body relates to other asteroids, and small bodies we know of formed at the same time within the first few million years after the sun was formed, “he said.
Joy added that the UK’s Fireball Network is currently scanning the skies for meteorites and encouraged readers to report the sightings to the network.
“It will be an exciting day when we have the right kind of fireball and we can go out, track down the fallen stone and analyze it to understand where it came from,” he said. “It would be absolutely amazing if it came from a completely unique type of asteroid or from a piece of a large body like the moon or Mars.”
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