In pieces of a meteorite, scientists have found tiny mineral grains that are older than the sun and the solar system, which formed about 4.6 billion years ago. Some of these “presolar grains,” the researchers found, are between 5 billion and 7 billion years old, making them the oldest known materials on Earth.
The grains initially formed in interstellar space out of material ejected from mature stars that then condensed into dust. The researchers who identified the grains think many of them likely were created following a boom in star formation the Milky Way experienced some 7 billion years ago. If confirmed, the new finding demonstrates that researchers can study meteorites to better understand the history of star formation in our galaxy.
