Published: Tue, January 14, 2020
Sci-tech | By Patricia Wade

Scientists identify oldest material on Earth in meteorite

Scientists identify oldest material on Earth in meteorite

Scientists recently identified the oldest material on Earth: stardust that's 7 billion years old, tucked away in a massive, rocky meteorite that struck our planet half a century ago.

They are made of silicon carbide, the first mineral formed when a star cools. These high-energy particles flit around space and can pass through solid matter, creating new elements inside the existing minerals as they interact with them.

It's been also revealed that a team of experts from the United States and Switzerland as well analyzed 40 such pre-solar grains that were contained in a piece of the meteorite that we mentioned above that fell in Australia back in 1969.

Heck and an global team of cosmochemists published the new study Monday in the Proceedings of the National Academy of Sciences.

"This is one of the most interesting studies I worked", said Philipp Heck, the study's lead author and a curator at the Field Museum.

"Once all the pieces are segregated, it's a kind of paste, and it has a pungent characteristic - it smells like rotten peanut butter", said Greer.

"It's like burning the haystack to find the needle", says Heck.

Once the presolar grains were isolated, the researchers figured out from what types of stars they came and how old they were.

Presolar grains are more abundant in what we would call these primitive meteorites, Professor Bland said.

The researchers learned that some of the presolar grains in their sample were the oldest ever discovered on Earth. Most of these grains were on the younger side, though ⁠- just four million to 300 million years older than the sun.

The presolar grains Dr.

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The ages of these grains of stardust isn't only important in themselves, but also because of what they tell us about the evolution of our galaxy.

The researchers suggest that seven billion years ago, there was a bumper crop of new stars forming.

The researchers reckon parts of the grains started off in a star that formed seven billion years ago, during a time when part of the Milky Way was experiencing higher levels of star formation than today. "There was a time before the solar system started when more stars formed than normal".

Image used for illustrative purposes only: This handout received from the Beijing Planetarium via the China Academy of Sciences on November 26, 2019 shows a rendering by artist Yu Jingchuan of the accretion of gas onto a stellar black hole from its blue companion star, through a truncated accretion disk.

The ratios of carbon-12 to carbon-13 isotopes in these grains were a ideal match to what astronomers have observed in the clouds of dust and gas around ageing stars like the Egg Nebula and the Ring Nebula.

However, the oldest yielded a date of around 7.5 billion years old.

Understanding the grains has shed light not only on stars and how long their stardust can last but also more on galaxies and their timelines.

Those bits of stardust eventually form new stars, along with new planets and moons and meteorites. "With this study, we have directly determined the lifetimes of stardust". For context, the Sun is 4.6 billion years old and Earth is 4.5 billion. We hope that it will be taken up again and studied so that people can use it as input for models of the whole galactic life cycle "said Heck".

When small to medium stars (from about 0.5 to 5 times the mass of the Sun) approach the ends of their lives, they expand into red giant stars and blow off their outer layers.

"It's so exciting to look at the history of our galaxy", he continued.

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