Solar system's oldest rocks
In 1969, a two-ton meteor broke up in the atmosphere above the Mexican village of Allende. The stony Allende meteorite is peppered with white particles of aluminum oxide and calcium oxide. Except for hydrogen and helium, they are about the same composition as the Sun, and are believed to be remnants of the first solid grains that formed in the solar system. Dated to 4.566 billion years ago, they are its oldest known objects.
Keywords: Meteorites, Astronomy, Solar System--Origin, Oxide minerals