From a long time ago and a galaxy far away... 7billion-year-old space dust
IMAGINE a time before the existence of Earth, the Sun or any planet in the solar system.
Incredibly, we now have a souvenir from that time, in the form of star dust which is up to 7billion years old.
Scientists extracted the dust from the Murchison meteorite, which hit Victoria, Australia, in 1969.
Only now do researchers have the tools to calculate the age of the materials in the meteorite. They found that the star dust is more than 2billion years older than the most ancient material on Earth – the ‘Jack Hills zircons’ in western Australia, which formed only a few hundred million years after the planet was born.
The researchers, led by the Field Museum in Chicago, calculated the age of the dust – which is made from carbon and silicon – by seeing how many atoms it contained. Every time dust is hit by a cosmic ray, it breaks apart, making it possible to work out how old it is by counting the pieces.
Lead author Dr Philipp Heck 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. We are all made of star dust, because the elements in our bodies were all forged in the stars, but they have been changed over time.
‘Seeing this material means we can see the ingredients of the solar system, because the dust flung from stars also formed the planets around us.’
When the Murchison meteorite hit Earth, the roar as it exploded close to the ground was described as sounding like an ‘express train’, and people ran out of their homes to collect fragments, which looked like coal.