Arizona’s breathtaking Grand Canyon is the painstaking result of the Colorado River’s persistent flow eroding the Earth’s surface over millions of years.
Earth, however, isn’t the only place in the Solar System with deep canyons and gorges. The Moon has formations comparable to Earth’s Grand Canyon; although, in the absence of liquid water, their formation process has been difficult to explain.
Now, scientists believe they have solved the mystery. Two massive canyons carved into the Moon’s surface were created by a giant impact – and, in a striking and astonishing contrast to the Grand Canyon, their formation may have taken less than 10 minutes.
The two canyons in question, Vallis Schrödinger and Vallis Planck, extend outward from an impact basin called the Schrödinger crater, located on the Moon’s far side near the south pole.
These formations are enormous – stretching 270 kilometers (168 miles) long and 2.7 kilometers deep, and 280 kilometers long and 3.5 kilometers deep, respectively. The Grand Canyon on Earth is longer, at 446 kilometers, but it is shallower, at 1.86 kilometers.
Such formations, known as ejecta rays, occur when vast amounts of material are hurled outward by an impact event. However, a team led by planetary scientist David Kring of the US Lunar and Planetary Institute aimed to refine the understanding of how these immense canyons took shape.
Kring and his colleagues analyzed images of the Moon’s surface to create detailed maps of the direction and spread of the ejecta from the Schrödinger impact. Using this data, they worked backward to reconstruct the impact event and track the spray of material.
Their findings revealed that the impact was asymmetrical, with most of the debris dispersing away from the lunar south pole. And the event was incredibly intense. The material that formed Vallis Schrödinger and Vallis Planck was traveling at speeds between 0.95 and 1.28 kilometers per second.
The energy required to generate this level of ejecta, according to the researchers, is estimated to be around 130 times the total energy contained in all nuclear weapons on Earth.
The upcoming Artemis III lunar mission is set to explore the Moon’s far side, near the south pole, though the exact landing site has yet to be confirmed. The astronauts will not face any significant threat from major impacts, as the Schrödinger event is believed to have occurred 3.8 billion years ago, during a period when large impacts were much more common.
Instead, these findings hold valuable insights for lunar exploration. The team’s models indicate that the impact ejecta was largely propelled away from the proposed Artemis landing sites, meaning the mission’s crew may have better access to the older, underlying minerals they plan to investigate.
The mission is currently scheduled for launch in 2027. When the Artemis crew arrives, their discoveries will undoubtedly provide further insight into how and when this massive impact took place.
The research has been published in Nature Communications.
