Solid Matter

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Some of the pre-solar grains in the Murchison meteorite (inset) could have come from evolved stars, similar to The Egg -to have a fog (in the photo)

scientists in the analysis of a meteorite discovered, with the oldest material known to exist on the earth.

they found dust grains in the space Rock - which fell to earth in the 1960S , and as much as 7. 5 billion years Old .

the oldest of The dust grains in stars, our sun was born roaring to life, long before the system was formed.

A team of researchers has described the result in the journal Proceedings of The National Academy of Sciences.

When stars die, the formed particles in space are far in the world. This "pre-solar grains" then get incorporated into new stars, planets, moons, and meteorites.

"you are the solid samples of stars, real stardust," said author Philipp Heck, curator at the Chicago Field Museum and associate professor at the University of Chicago lead.

A team of researchers from the USA and Switzerland, analyzed 40 pre-solar grains contained in a portion of the Murchison meteorite in Australia in 1969.

"It starts with crushing the fragments of the meteorites down into a powder," said co-author Jennika Greer, from The Field Museum and the University of Chicago.

"Once all the pieces are separated, it is a kind of paste, and it has a pungent characteristic - it smells like rotten Peanut Butter . "

This whiffy paste was then dissolved in acid so That only the stardust.

"It is like the burning of the haystack, the needle," said Philipp Heck.

To find out how Old the grains were measured by the researchers, how long they were exposed to the cosmic radiation in space. These rays are highly energetic particles That travel through our galaxy and penetrate Solid Matter .

Scanning electron micrograph of a pre-solar grain. This example is about 8 micro-meters long

interact with The Matter they encounter, and form new elements. The longer you are exposed to, the more these elements form. The researchers used a special form (isotope) of the element Neon - Ne-21 - to date the grains.

"I compare this to where you put a bucket in a rain shower. Provided That the precipitation is constant, the amount of water in the bucket tells you how long it has been exposed to," Dr. stern.

measure how many of the new elements are present, tells the scientists how long The Grain has been exposed to cosmic rays. This in turn informed you how Old it is.

Some of the pre-solar grains, it turned out That the elders were ever discovered.

on the basis of how many cosmic rays inter had interacts with the grains, most of them had to 4. 6-4. 9 billion years Old . For comparison, The Sun is 4. 6 billion years Old and the earth is 4. 5 billion.

But the oldest showed a date of around 7. 5 billion years Old .

Murchison meteorite fell to earth in 1969, and More

Dr. stern can be found Bbc News said: "Only 10% of the grains, which are older than 5. 5 billion years, 60% of the grains are "young" (at) 4. 6 to 4. 9 billion years Old , and the rest is In Between the oldest and youngest.

"I'm sure there are older pre-solar minerals in Murchison and other meteorites, we haven't found her just yet. "

Previously, the oldest pre-solar grain dated, with the Neon isotopes was about 5. 5 billion years Old .

The results shed light on a debate about whether or not new stars form at a constant rate, or whether there are UPS and downs in The Number of new stars in the course of time.

"with these grains, we now have direct evidence for a period of increased star formation in our galaxy seven billion years ago, with samples of meteorites. This is one of the Central results of our study," said Dr. stern.

The researchers also learned That pre-solar grains often float through the room stuck together in large clusters, such as cereal. "No One thought this was possible, That the scale" Philipp stern explains.

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Source of news: bbc.com