Thanks to today’s modern technology, science can answer the question: How old is this matter?
Science has successfully confirmed which is the oldest hard matter on Earth, but the surprise does not stop there: it is even “older” than our Solar System, about a few hundred years older. million years. New research shows that this microscopic bit of cosmic dust formed in some distant star some 5 to 7 billion years ago; Our Sun is “only” 4.6 billion years old.
Then a certain meteorite brought this dust to Earth, so we have a new discovery and today’s article.
” This is one of the most interesting studies I’ve ever been involved with ,” said space chemist Philipp Heck at the Museum of Natural History and the University of Chicago. ” These are the oldest solids ever discovered, and they tell us a lot about how stars form in our galaxy .”
Although there are precedents of meteorites containing some matter older than the Solar System, they are still very rare and very difficult to determine their existence, because these particles are very small, hidden deep inside. the stone “falling from the sky”. The Murchison meteorite is one such example: it weighed more than 100 kg, ejected from a meteor explosion over the Murchison region, Australia, in September 1969.
The Natural History Museum retrieved 52 kg of meteorites and put a lot of effort into studying them. They discovered a large amount of the mineral silicon carbide – confirmed to come from another star. The time it takes it to get from another star to here is longer than the age of the Solar System, so scientists know that this matter is very old, but they have not yet measured its exact age. .
Since the 1990s, researchers have been extracting silicon carbide powder from meteorites, by crushing the stone and removing unwanted silicates with acid. At that time, the silicon carbide powder analysis tool was not as modern as it is now, and it took until science was advanced enough to answer the questions that researchers agonized over for so long.
They use scanning electron microscopes, secondary ion mass spectrometry and noble gas spectrometry, looking for the effects of cosmic radiation, which can penetrate solid matter (such as meteorites), and affect silicon carbide.
“ Cosmic rays can interact with matter to form new elements. And the longer they are exposed to radiation, the more elements are formed ,” explains Heck. “ I often use the example of putting a bucket out in a storm. Assuming continuous rain, the amount of water contained in the bucket will reflect the amount of time the bucket has been outdoors .”
By detecting the existence of two isotopes helium-3 and neon-21 in silicon carbide powder, the scientists determined their lifespan. Some samples are 5.5 billion years old, but most silicon carbide specimens are only between 4.6 and 4.9 billion years old.
It is the “younger” silicon carbide powders that fascinate scientists: they tell the historical story of the Milky Way.
“ Our hypothesis is that most of this powder, which is between 4.6 and 4.9 billion years old, occurred during a star’s formation. At the time before the birth of the Solar System, the number of stars born was more than usual ,” explains Professor Heck.
This sequence of star-forming events took place about 7 billion years ago. Then as the star ages, these silicon carbide matter will flow out into streams and into the Universe; Over time, they will coalesce with other matter to form meteorites, as happened with the Murchison meteorite.
According to Professor Heck, the discovery of this ancient matter encapsulated in the meteorite shows that the process of star formation in the Universe is very volatile.
“ Many people assume that the rate at which stars form in galaxies is a constant. But thanks to the existence of this matter, we have direct evidence that about 7 billion years ago, there was a time when stars formed at a much faster rate than usual. This is the key finding of our study ,” said Heck.
Maybe the feeling of holding the dough in the hand is older than our Solar System, it’s so wonderful.