Meteorite contains 7billion-year-old stardust that predates the SUN and is oldest matter on Earth
THE oldest material ever found on Earth has been discovered lurking in a meteorite that fell to our planet.
Ancient stardust dating back seven billion years was identified by scientists, making the mysterious matter a good deal older than both Earth and the Sun.
The tiny spec of dust – no thicker than a human hair – made its way to our planet in a meteorite that fell in Australia 50 years ago, scientists wrote in a new study.
Lead author Dr Philipp Heck, a curator at the Field Museum, and researcher at the University of Chicago, said: “This is one of the most exciting studies I’ve worked on.
“These are the oldest solid materials ever found, and they tell us about how stars formed in our galaxy.”
Stars are born when dust and gas floating through space find each other, collapse in on each other and heat up.
After burning for millions of years they die and throw particles that formed in their winds out in to space.
Those bits of stardust eventually form new stars, along with new planets and moons and meteorites.
The materials examined in the new study are called presolar grains-minerals formed before the Sun was born.
“They’re solid samples of stars, real stardust,” said Dr Heck.
However, presolar grains are tiny and rare, only found in about five per cent of meteorites that have fallen to Earth.
But the Field Museum has the largest portion of the Murchison meteorite, a treasure trove of presolar grains that fell in Victoria, Australia, in 1969.
Presolar grains for this study were isolated from the Murchison meteorite about 30 years ago at the University of Chicago.
The process involves crushing the fragments of meteorite into a powder.
Co-author Jennika Greer, a graduate student at the Field Museum and the University of Chicago, said: “Once all the pieces are segregated, it’s a kind of paste, and it has a pungent characteristic – it smells like rotten peanut butter.”
This “rotten-peanut-butter-meteorite paste” was then dissolved with acid, until only the presolar grains remained.
Researchers compared the process to burning down a haystack to find the needle.
Once the presolar grains were isolated, the researchers figured out from what types of stars they came and how old they were.
Exposure age data allowed the researchers to measure their exposure to cosmic rays.
By measuring how many of the new cosmic-ray produced elements are present in a pre-solar grain, scientists can tell how long it was exposed to cosmic rays, telling them how old it is.
The researchers learned that some of the presolar grains in their sample were the oldest ever discovered on Earth.
What's the difference between an asteroid, meteor and comet?
Here's what you need to know, according to Nasa...
- Asteroid: An asteroid is a small rocky body that orbits the Sun. Most are found in the asteroid belt (between Mars and Jupiter) but they can be found anywhere (including in a path that can impact Earth)
- Meteoroid: When two asteroids hit each other, the small chunks that break off are called meteoroids
- Meteor: If a meteoroid enters the Earth’s atmosphere, it begins to vapourise and then becomes a meteor. On Earth, it’ll look like a streak of light in the sky, because the rock is burning up
- Meteorite: If a meteoroid doesn’t vapourise completely and survives the trip through Earth’s atmosphere, it can land on the Earth. At that point, it becomes a meteorite
- Comet: Like asteroids, a comet orbits the Sun. However rather than being made mostly of rock, a comet contains lots of ice and gas, which can result in amazing tails forming behind them (thanks to the ice and dust vapourising)
Based on how many cosmic rays they had soaked up, most of the grains had to be 4.6 to 4.9 billion years old, and some grains were as old as 7billion years.
For context, our Sun is 4.6billion years old, and the Earth is 4.5billion.
But the age of the presolar grains was not the end of the discovery.
As presolar grains are formed when a star dies, they reveal the star’s history.
The researchers suggest that seven billion years ago, there was a bumper crop of new stars forming.
“We have more young grains that we expected,” said Prof Heck.
“Our hypothesis is that the majority of those grains, which are 4.6 to 4.9 billion years old, formed in an episode of enhanced star formation.
“There was a time before the start of the Solar System when more stars formed than normal.”
Scientists also found that presolar grains often float through space stuck together in large clusters like “granola”, something that had not previously been thought possible on that scale.
The research was published in Proceedings of the National Academy of Sciences.
TOP STORIES IN SCIENCE
In other news, it recently emerged that an asteroid obliterated early human civilisations in a catastrophic collision with Earth 13,000 years ago.
Scientists recently discovered a “Super-Earth” 31 light-years away that humans could one day colonise.
And, distant planets may host even more life than we have here on Earth, according to one shock study.
What secrets do you think the ancient stardust holds? Let us know in the comments!
We pay for your stories! Do you have a story for The Sun Online Tech & Science team? Email us at tech@the-sun.co.uk