When we talk about extremely “old” things on earth, that usually means a few billion years old. After all, the earth itself is only about four and a half billion years old. Scientists now say that they have found something much older on Earth. However, it did not come from the earth. Studying the remains of a meteorite has yielded the oldest known material ever studied at close range.
A team of researchers from the US and Switzerland worked together to analyze the Murchison meteorite (see above), which fell to Earth in the 1960s. This is a carbon-containing chondrite, a common but old type of asteroid. These objects are interesting because they contain the primordial material that merged to form the planets in our solar system. Just like a cosmic breakfast box, it had prices.
The researchers took samples of a fragment of the Murchison meteorite, crushed them and dissolved the remains in acid. They were able to harvest small grains of material with a diameter of a few micrometers. They have different compositions and ages, so categorizing them was a challenge.
To find out how old these hearty little spots were, scientists had to turn to the cosmos itself. Space rocks floating through the void are constantly being bombarded by cosmic rays. These collisions leave subtle isotopic signatures that may indicate the age of the object. This process is known as dating surface exposure. In this analysis, the team found the long-lived Neon-21 isotope particularly useful in determining the age of the beads.
Although most of the material harvested from the Murchison meteorite was no more than a few hundred million years old, some were much, much older. About 8 percent of the sample was around 7.5 billion years old, which is 3 billion years older than the solar system itself.
Scientists are interested in carbon-containing chondrites because they are pristine samples of the material that formed the planets billions of years ago. By studying them, we can learn a lot about how solar systems come together. But there is perhaps even more to learn from these space rocks. The realization that it contains even older materials can help to unravel galactic-scale mysteries. For example, the team believes that the composition of pre-solar samples in the Murchison meteorite supports the idea that the galaxy experienced a period of increased star formation seven billion years ago.