Scientists may have discovered the oldest Earth rock ever—on the Moon. A lunar sample returned by the Apollo 14 astronauts may contain a bit of Earth from about 4 billion years ago. The research about this possible relic from the Hadean Earth is published in the journal Earth and Planetary Science Letters. https://doi.org/10.1016/j.epsl.2019.01.010
An international team of scientists associated with the Center for Lunar Science and Exploration (CLSE), part of NASA’s Solar System Exploration Research Virtual Institute, found evidence that the rock was launched from Earth by a large impacting asteroid or comet. This impact jettisoned material through Earth’s primitive atmosphere, into space, where it collided with the surface of the Moon (which was three times closer to Earth than it is now) about 4 billion years ago. The rock was subsequently mixed with other lunar surface materials into one sample. RSES's Prof. Marc Norman was also involved in the study.