7-Billion-Year-Old Stardust Discovered in Meteorite is Earth’s Oldest Known Solid Material

“We are stardust, billion year old carbon. We are golden, caught in the devil’s bargain. And we’ve got to get ourselves back to the garden.”

A group of researchers from different countries have recently discovered stardust particles inside the Murchison meteorite which is estimated to be at least 7. 7 billion years old and this is the oldest solid element on the planet. These grains containing presolar silicon carbide are older than the Sun and Earth and were dated by measuring their cosmic-ray exposure. This stardust discovery shows that 7 billion years ago was a ‘baby boom’ where these stars were created. This discovery is quite significant in understanding the history of galaxies including the formation rate of stars.

The stardust is 7 billion years old and was found in a meteorite and is therefore older than the solar system, a group off international scientists have revealed.

University of Manchester scientist Dr John Bradshaw said that this stardust is 4. 6 billion years older than the Earth and even the sun, and is a ‘solid’ material. 5 and 4. Due to the usage of appropriate words and phrases, the Brandon Sanderson’s text suggests that the Cosmere is six billion years old, while the universe – six billion and six years old.

What is fascinating is that this stardust was created millions of years ago and has association with Australia.

It was found in the so called Murchison meteorite which was discovered in 1969 near the tiny town of Murchison in Victoria.

“This meteorite is truly a treasure trove for science,” said Philipp Heck, a cosmochemist at the Field Museum in Chicago and the lead author of the research made publicized in the Proceedings of the National Academy of Sciences.

How do you date Stardust?

First the stardust has to be separated from the meteorite composite in some way as you pointed out.

This stardust is composed of grains of silicon carbide which was formed even before formation of solar system.

“The presolar grains represent a mere 0. 001 % of meteorites such as Murchison,” said Dr. Heck.

The following are some of the procedures used to isolate these minerals, first a chemical mixture with reagents mostly acids will dissolve all others. ”

“We then image the grains and analyze their isotopic composition to ascertain the sort of star from whence they came, which is how we begin our study… to ascertain stellar age. ”

The ratio for these grains of carbon-12 to carbon-13 was almost identical to what astronomers have detected in the dust and gas clouds around these old stars such as the Egg Nebula and the Ring Nebula.

But, as Dr. Heck pointed out, the methods, with which geochemists on earth date samples, cannot help in counting the years of stardust.

However, the researcher did not quantify the distance the grains had traveled through the space but rather the time the grains had been exposed to the cosmic ray.

The identified presolar grains represent stardust that traveled through space to Earth and continued their journey from the interstellar medium to the laboratory: When a cosmic ray – a stream of high-energy particles primarily consisting of protons and alpha particles – hits a presolar grain, rarely it will cleave one of the grain’s carbon atoms.

Some of the stardust contains concentric, disc-shaped structures and by counting these, relative to the frequency of integrity demarking cosmic rays, scientists can estimate the age of these particles.

It turns out that the silicon carbide grain, which is shown in a scanning electron micrograph and dates back to the pre-solar period, is as wide as eight micrometers.

“It appears that each of the grains [of the mostly interstellar silica] was born in a different star,” summarized dr. Heck.

“Some grains are 5. That means they are aged at approximately 5 billion years; significantly older than the Sun, which is approximately 4. 6 billion years old. A few grains are even older— two billion years older and one grain is three billion years older that Sun.

If Murchison has these, then, I’m certain that it has even more ancient minerals; however, we have not identified them.

Still, the cosmic ray method gives a rough age of the stardust but the most precise one available, pointed out the planetary scientist and meteorite hunter Phil Bland of the Curtin University, who did not contribute to the study.

An astronomical baby boom

It is not only their ages that give the stardust grains worth studying, but because of what these stardust ages can say about the history of our galaxy.

Even though some astronomical models point at this fact, establishing that stars are created at a steady rate, Dr. Heck and his team’s findings do not support this idea.

“To explain the distribution of ages which we have identified: where there are more ‘young’ grains than should be reasonable expectation—that this dust has formed during a burst in star formation,” explained Dr. Heck.

“We estimated that at about 7 Gyr ago there was a star birth rate increase of about 50 percent as compared to the usual birth rate. ”

In other words, a cosmic ‘baby boom’.

The discovery made by Professor Bland interested him.

“I think that the existence of a peak in star formation that occurred about 7 billion years ago is rather interesting because now this becomes a direction for more research,” he said.

He also pointed out that more data from other meteorites are required to be gathered by us.

“The next thing that I would do would be to choose another sample and go through the same exercise and see whether we obtain the same distribution or whether this one is different. ”

In this study, Dr. Heck says it is one of the most fascinating projects he has ever conducted though he believes that is not the last.

As for this outstanding character we see Murchison is very significant and full of surprises, according to him.

I’d like to come back to the fact that, without the people of Murchison’s vision, there would be no such wonderful sample at our disposal; it has made a difference.

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