It is much, much older than the dust of your older PC
This is not an illustration of the artist for this story, just wishful thinking on our part
Boffin think they have found the oldest known substance on Earth, the specks of dust that formed about 5-7 billion years ago – before the Solar System even formed.
“This is one of the most interesting studies I have worked on,” said Philipp Heck, lead author of the article published in the Proceedings of the National Academy of Sciences on Monday and associate professor of geophysical sciences at the University of Chicago. “These are the oldest solid materials ever found and tell us how stars formed in our galaxy.”
The tiny specks of dust were found in the Murchison meteorite, which landed in Australia over 50 years ago. The research team analyzed meteorite samples by grinding it into a fine powder to create a chemical paste that can be dissolved with acid to leave the “presolar” grains behind.
“It begins with the crushing of meteorite fragments into a dust,” said Jennika Greer, a graduate student from the University of Chicago and co-author of the study. “Once all the pieces are separated, it is a kind of pasta and has a pungent characteristic: it smells like rotten peanut butter.”
These presolar particles were forged before the Sun formed in environments with completely different chemical compositions. After placing the samples in a mass spectrometer, the researchers were able to study the concentrations of several isotopes.
Isotopes such as neon-21 are created when the meteorite was bombarded with galactic cosmic rays. The concentration of some isotopes provides an estimate of how long ago the rock was torn by rays.
“Some of these cosmic rays interact with matter and form new elements. And the longer they are exposed, the more these elements form, ”explained Heck. “By measuring how many of these new elements produced by cosmic rays are present in a preschool grain, we can tell how long it has been exposed to cosmic rays, which tells us how old it is.”
Boffins finds proof that yes, Carl Sagan and Joni Mitchell were right, we are all really made of star things
Enough neon-21 had accumulated in the Murchison meteorite that the oldest parts were found to be more than 5.5 billion years old. Most cereals, however, were around 4.6 to 4.9 billion years old, a time before the Sun formed 4.6 billion years ago.
Preschool grains are formed when the material made in the stars is scattered and thrown away by the dying stars, where they continue to mix and mix with interstellar material. The oldest grains of the Murchison meteorite, therefore, were created in an ancient star that precedes 5.5 billion years ago.
The researchers believe parts of the grains started in a star that formed seven billion years ago, at a time when part of the Milky Way was experiencing higher levels of star formation than today.
“Some people think the galaxy’s star formation rate is constant,” said Heck. “But thanks to these grains, we now have direct evidence for a period of greater star formation in our galaxy seven billion years ago with meteorite samples. This is one of the key results of our study. “®
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