Shop Windows to the Universe

Young Voices for the Planet DVD in our online store includes 8 films where students speak out and take action on climate change.
The two basic types of regions on the Moon: a smooth, dark mare on the left and a heavily-cratered, light-colored highland region on the upper right.

Lunar Geology

Looking up at the Moon, you can see that there are dark regions and light regions. With binoculars, you can even see that the dark regions are smooth compared to the light regions which have many craters.

Dark areas on the Moon are called maria, which means "seas" in latin. Astronauts discovered that these regions are smooth and shallow. Maria have few craters and are covered with a type of rock (called basalts) which are similar to lava rocks formed by volcanoes here on Earth. Tests showed that these lunar rocks are between 3.1 and 3.8 billion years old.

Light-colored areas are more hilly and covered with lots of craters. This is the "land", or terrae on the Moon. The color of these areas comes from a type of light-colored rock called anorthosite. This type of rock is found only in the oldest mountain ranges on the Earth. Geologists have found that these lunar rocks are over 4 billion years old. That's nearly as old as the solar system itself!

Once it was known that the light areas were old and the dark maria younger, scientists could piece together the Moon's history.

Shop Windows to the Universe Science Store!

Learn about Earth and space science, and have fun while doing it! The games section of our online store includes a climate change card game and the Traveling Nitrogen game!

Windows to the Universe Community



You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

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

What are the flat surfaces on the Moon called? What is maria? What are lunar highlands?

What phase was the Moon in on December, 22 1962? How long does it take the Moon to travel from one phase to the next? Suppose that the Moon spun twice on its axis during each orbit around the Earth. How...more


This picture was taken from high above our planet. Looking at the Earth from very far away like this we can see that some parts of our planet look light in color, and some parts look dark. The color of...more

Desert Birds

Did you know that many species of birds live in the desert? You have probably heard of the roadrunner or seen the cartoon. The roadrunner is a real bird that lives in the desert! It prefers to run rather...more

The Desert Biome

Deserts are very hot and dry places. Deserts get very little rain each year. So how do plants and animals live here? This section on the desert ecosystem will explain how! Do you know what a desert looks...more

Desert Insects and Arachnids

There are all kinds of insects in the desert! Some of them cause a lot of problems. The locusts fly from place to place, eating all the plants they see. But not all desert bugs are bad. There isn't a...more

Desert Mammals

There are many species of mammals in the desert! Many of them dig holes in the ground to live in. These holes are called burrows. Rats and hamsters live in burrows. Bigger mammals, like the wild horse,...more

Biomes and Ecosystems

Biomes are large areas of the world where there are similar plants, animals, and other living things. The living things are adapted to the climate. Explore the links below to learn more about different...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA