Stars Also Have Life Cycles



Do you know that stars also have life cycles? Also they're born when the bits of dust and gas floated through space and found each other and they collapsed in on each other and heated up. Stars have been burning for millions to billions of years, and after that they die and when they die, they pitch the particles that are formed in their winds and out into space, and those little bits of stardust eventually will form new stars, along with some new planets and moons and meteorites. And in a meteorite which fell fifty years ago in Australia, recently scientists have now discovered the stardust that formed 5 to 7 billion years ago -- the oldest solid material ever found on Earth.
"This is one of the most exciting studies I've worked on," says Philipp Heck, a curator at the Field Museum, associate professor at the University of Chicago, and lead author of a paper describing the findings in the Proceedings of the National Academy of Sciences. "These are the oldest solid materials ever found, and they tell us about how stars formed in our galaxy."
The materials Heck and his colleagues examined are called presolar grains-minerals formed before the Sun was born. "They're solid samples of stars, real stardust," says Heck. These bits of stardust became trapped in meteorites where they remained unchanged for billions of years, making them time capsules of the time before the solar system..
But presolar grains are hard to come by. They're rare, found only in about five percent of meteorites that have fallen to Earth, and they're tiny-a hundred of the biggest ones would fit on the period at the end of this sentence. But the Field Museum has the largest portion of the Murchison meteorite, a treasure trove of presolar grains that fell in Australia in 1969 and that the people of Murchison, Victoria, made available to science. Presolar grains for this study were isolated from the Murchison meteorite for this study about 30 years ago at the University of Chicago.
"It starts with crushing fragments of the meteorite down into a powder ," explains Jennika Greer, a graduate student at the Field Museum and the University of Chicago and co-author of the study. "Once all the pieces are segregated, it's a kind of paste, and it has a pungent characteristic-it smells like rotten peanut butter."

By: Prerana Sharma
Content: https://www.sciencedaily.com/releases/2020/01/200113153306.htm


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