In 1972, the astronauts of Apollo 17 brought back a rock, seeking evidence of water on the moon. Nearly 40 years later, scientists have discovered that this rock is rich in graphite, the material used in pencils. This discovery may reveal key information into how life originated on Earth. reports on this first evidence of graphite on the moon.

The moon rock that has scientists so excited was originally studied for phosphate-rich apatite. The presence of apatite would have revealed information about lunar water. However, a second look at the rock showed “whiskers” of graphite. This marks the first time that a pure-carbon material has been found on the moon. As astrobiologist Andrew Steele told, “We came across the graphite by total accident."

It seems that the moon rock was formed when an asteroid struck the moon some 3.8 billion years ago. Scientists think the graphite either came from the asteroid itself or that it was formed from the ensuing carbon-rich impact dust cloud.

This discovery is significant because experts believe this graphite arrived on the moon around the same time the Earth was being pelted with asteroids, too. Around 3.9 billion years ago, the Earth went through what is referred to as the Late Heavy Bombardment. This is when our planet was blasted again and again by a series of meteorites, asteroids and other objects — which many believe carried some essential microbes of life.

While the evidence of this cataclysmic asteroid scarring has since been erased or folded back into the Earth’s crust, this rock was sitting in plain sight on the surface of the moon. Experts hope that this carbon-rich graphite could reveal details on how life may have originated on our planet.

And this has the experts very excited. Francis McCubbin co-authored the study of the lunar rock. As he told, "The most exciting prospect from the discovery is that we now know that the moon holds a record of that period and the materials that contributed to the rise of life on Earth."

For further reading:

Carbon-rich graphite discovered on the moon
Finding the “stuff of pencils” could reveal important insight into the start of life on Earth.