NASA Discovers Earth's Moon and Asteroid Vesta Share Bombardment History

Earth's moon may have more in common with a large asteroid than once thought. NASA scientists have discovered that the two have a shared history--both were once bombarded by high-speed space missiles about four billion years ago.

The asteroid in question is named Vesta. Located far from the moon in the main asteroid belt between the orbits of Mars and Jupiter, it has helped provide researchers with a new means for studying the early bombardment history of terrestrial planets.

Moon rocks brought back by NASA Apollo astronauts have long been used to study the bombardment history of the moon. Yet at the same time, these samples limited scientists in what they could learn. In order to expand their studies, researchers derived the ages from howardist and eucrite meteorite samples in order to study the collisional history of main belt asteroids--in particular, the asteroid Vesta. With the aid of computer simulations, the researchers then determined that meteorites from Vesta recorded high-speed impacts. They then linked the two datasets and found that the same population of projectiles responsible for making craters and basins on the moon were also hitting Vesta at very high velocities--enough to leave behind telltale, impact-related ages.

In order to confirm their findings, the researchers then used recent observations of Vesta's surface conducted by NASA's Dawn spacecraft. They also used dynamical models of early main belt evolution in order to discover the source of these cosmic missiles. They eventually found that the projectiles that hit Vesta had orbits that also enabled them to strike the moon.

The findings support the theory that the repositioning of gas giants, such as Jupiter and Saturn, from their original orbits to their current locations actually destabilized portions of the asteroid belt. This then triggered a solar system-wide bombardment of asteroids, called the lunar cataclysm.

"It's always intriguing when interdisciplinary research changes the way we understand the history of our solar system," said Yvonne Pendleton, NLSI director, in a press release.

The recent findings are published in the journal Nature Geoscience.