The oldest material on the planet has been discovered inside a meteorite, according to Proceedings of the National Academy of Sciences magazine.
The magazine published the results of a study on Murchison meteorite that fell to Earth in 1969 in Australia.
Research on the mineral particles in the meteorite were found to be even older than the sun and solar system which date back roughly 4.6 billion years.
American and Swedish experts determined some 40 particles to 5 to 7 billion years old, making them the oldest substances in the world.
The leader of the research team, Philipp Heck from Chicago University, said: "They're solid samples of stars, real stardust."
When small and medium stars approach the end of their lives, they turn into red giants and their outer layers expand.
Over time, materials in the solar nebula cool, solidify and form dust and mineral particles. Some end up in meteorites that fall to planets such as Earth.