Although the Australian town of Murchison in Victoria has a population of less than 1000, it is one of the most important sites in the history of astronomy,media reported. In 1969, a huge meteorite fell on Earth, shattered in the atmosphere and eventually scattered in the southern part of the town. Decades later, researchers found that the debris had tiny particles of stardust inside, the oldest known to reach Earth.
Researchers have discovered particles that may be 5 to 7 billion years old — older than our solar system, which formed 4.6 billion years ago.
“This is one of the most exciting studies I’ve ever done,” said Geophysicist Philipp Heck of the Field Museum of Natural History in Chicago in a statement Monday. “
The latest paper, published in Proceedings of the National Academy of Sciences, details how Heck and his colleagues detected 40 particles of stardust collected from the Murchison meteorite 30 years ago. To determine the age of these particles, they studied the isotopes of the argon element, which interacts with cosmic rays in space. Cosmic rays are high-energy particles that pass through the universe at high speed, producing isotopes of thorium when exposed to cosmic rays.
When the Murchison meteorite crossed into space and eventually collided with Earth, the particles of stardust were pulled into its meteorite. Most of these dust particles formed before the sun was born 4.6 billion years ago, and some were even more than 5 billion years old.
Because stardust is so old, it can tell us more about space before the formation of the solar system.
Understanding the life cycle of interstellar dust is an important task because it is a key part of the universe and can be incorporated into asteroids as well as star and planetary systems.