Ask A Scientist

Are there volcanoes on the moon? 

Asked by: Jacob Demer
School: Chenango Bridge Elementary School
Grade: 3
Teacher: Mrs. Shafer
Hobbies/Interests: Xbox, basketball
Career Interest: Veterinarian, scientist

Answer from H. Richard Naslund

Professor of Geological Sciences

Research area: Igneous Rocks, Ore Deposits, Volcanoes Interests/hobbies: Traveling, Scuba Diving, Collecting Masks

As far as we know, there are no active volcanoes on the Moon, but with the naked eye we can look up at the Moon and see the products of ancient volcanoes.

The view of the full Moon shows patches of light and dark areas. Some people look at the pattern of light and dark and see the image of a face, or in some cultures, the image of a rabbit. The light patches are the Lunar Highlands and the dark patches are the Lunar Maria. Early astronomers thought the Highlands were continents and the Maria were oceans (in Latin, Maria = Seas). The Highlands have a powdery surface that reflects lots of sunlight, which is why they look lighter than the Maria, which have smooth surfaces that do not reflect as much light. The Highlands are on average about 3,000 feet higher in elevation than the Maria, hence the name "Highlands."

When the Moon formed about 4.5 billion years ago, there was enough energy from the collisions of all the small planetary objects that came together to form the Moon that the outer surface melted to a depth of approximately 120 miles. This ocean of molten rock slowly cooled to form an initial lunar crust. The early solar system was a dangerous place, however, and this crust was pulverized by multiple meteorite impacts to form the powdered Highland surface we see today. The meteorite impacting dramatically slowed down about 4 billion years ago, and there have been a lot fewer impacts since.

Volcanoes on the Moon were very active during the period from 4 billion to 3 billion years ago, with only a few volcanoes active since then. Lava from these eruptions flowed downhill and collected in the largest and deepest impact craters, filling them with relatively smooth, flat lava flows. These lava-filled craters are the Maria. Their surfaces are marked with much fewer and much smaller impact craters because they formed after the main meteorite bombardment had ended.

The youngest lavas on the moon are thought to be about 1.2 billion years old. As a result of the low lunar gravity, and the very fluid nature of lunar lavas, we don’t find large volcanic peaks on the Moon like we find on Earth, but when you look up at the full Moon, those dark patches that you see are the remains of ancient volcanic eruptions. 

Last Updated: 3/1/17