Friday, 07 August, 2020

Stardust billions of years older than Earth found on meteorite

Seven-billion-year-old stardust in meteorite ‘oldest solid material found The Oldest Known Material on Earth Is Officially Older Than The Solar System
Sandy Nunez | 14 January, 2020, 16:12

Presolar grains are formed when material made in stars is shed and thrown off from dying stars, where they go on to mix and mingle with interstellar material.

Ever since researchers began finding presolar grains in meteorites in 1987, they've studied these ancient relics to find out how old they are and where they came from. The star dust found on the meteorite is called presolars because they formed before our sun. Those particles, or space dust, eventually form new stars, planets, moons and meteorites. This in turn helps the new star will be born, creating a daisy chain space. Meteorites, if they don't collide with too much, can act as time capsules of trapped materials, like star dust.

"We use a chemical recipe of different chemical reagents, mainly acids, to dissolve away everything else, and then we extract those minerals".

The grains are small, measuring from two to 30 micrometres in size.

The Australian town of Murchison rose from obscurity to global (astronomical) fame after a large meteorite landed nearby on 28 September 1969.

One meteorite that is known to contain presolar grains is the Murchison meteorite, a large, over 100 kilogram (220 pound) chunk of space rock that exploded in the sky over Murchison, Australia in September 1969, scattering its fragments all over the place.

"These are the oldest solid materials ever found, and they tell us how the stars formed in our galaxy".

"These are solid samples of stars, real star dust", said Professor Heck.

Scientists have found in a bit of meteorite the earliest product previously entirely on earth. A new study on the presolars of the Murchison meteorite recovered in Australia published Monday in Proceedings of the journal of the National Academy of Sciences.

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And, Heck said, the discovery of a furious starburst in microscopic grains wrapped up in a meteorite confirms that star formation ebbs and flows. Some people think the star formation rate in the galaxy is constant, "said Heck".

"We already knew that they were older than the solar system, hence older than 4.6 billion years", Heck told Newsweek. "This is one of the most exciting studies I have worked on", said Philipp Heck, lead author of the study and curator at the Field Museum.

The stardust was formed before the sun and is known as presolar grains. "This is one of the key findings of our study". Stardust is the remnant material left behind after the death of a star in a supernova.

The process involves crushing the powdered meteorite fragments. So the longer a sample is exposed, the more secondary elements are formed.

Forty silicon carbide presolar grains were checked for traces of the particular elements in question - helium-3 and neon-21; these revealed the ages of the grains. As long as the rain falls at a steady rate, you could calculate how long the bucket had been outside based on the amount of rain that it collects, Heck explained.

"Thanks to these grains, now we hold yell evidence for a interval of enhanced big title formation in our galaxy seven billion years within the past with samples from meteorites".

Scientists have also discovered that presolars often float in space, stuck together in large clusters like "granola", something that had not been thought of on this scale before. For context, the Sun is 4.6 billion years old and Earth is 4.5 billion.

"I'm still excited about just the idea of having a rock, taking a rock out of a cabinet, extracting minerals and learning something about the history of our galaxy", he said.