Couldn't find element LayerAd

Error finding content

The Moon's Geological History - Windows to the Universe

Shop Windows to the Universe

Check out the fun Earth science related bumper stickers in our online store! Express yourself!
An image of the heavily-cratered far side of the Moon.

The Moon's Geological History

Scientists have studied the ages of rocks in regions with craters and determined when in the Moon's past the craters were forming most quickly. By studying the light-colored regions, called highlands, they found that from about 4.6 to 3.8 billion years ago rocky debris rained down on the surface of the young Moon, forming craters very quickly. Then the rocky rain subsided, and fewer craters have formed since then.

Rock samples from very large craters (called basins) showed that about 3.8 to 3.1 billion years ago several huge, asteroid-like objects struck the Moon, just as the rocky rain was ending. This was shortly followed by lava flows which filled in the basins and formed the dark maria. This explains why there are so few craters on the maria, but dense, overlapping craters in the highlands. No lava flows occurred on the highlands to erase the original blanket of craters from the time when the Moon's surface was showered with the debris of the early solar system.

The far side of the Moon has only one small maria. So lunar geologists believe that the far side is very representative of how the Moon looked 4 billion years ago.

Shop Windows to the Universe Science Store!

Our online store includes issues of NESTA's quarterly journal, The Earth Scientist, full of classroom activities on different topics in Earth and space science, as well as books on science education!

Windows to the Universe Community



You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more


This picture of the Earth surface was taken from high above the planet in the International Space Station. In this view from above, we can see that there are lots of different things that cover the Earth....more

Desert Birds

Like the other creatures of the desert, birds come up with interesting ways to survive in the harsh climate. The sandgrouse has special feathers that soak up water. It can then carry the water to its...more

The Desert Biome

Deserts are full of interesting questions. How can anything survive in a place with hardly any water? Why is it so dry to begin with? You can find at least one desert on every continent except Europe....more

Desert Insects and Arachnids

You can find insects almost anywhere in the world. So it should be of no surprise that there are plenty of insects in the desert. One of the most common and destructive pests is the locust. A locust is...more

Desert Mammals

There are several species of mammals in the desert. They range in size from a few inches to several feet in length. Like other desert wildlife, mammals have to find ways to stay cool and drink plenty...more

Biomes and Ecosystems

Biomes are large regions of the world with similar plants, animals, and other living things that are adapted to the climate and other conditions. Explore the links below to learn more about different biomes....more

Temperate Forests

The temperate forest biome is found in regions where winters are cold and summers are warm. Regions with this climate are common in the mid-latitudes, far from both the equator and the poles. Tropical...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF