This is an image of the Martian dunefields.
Click on image for full size

What causes a Planet's surface to change?

Over the course of time there are many things which can cause the surface of a planet to change its appearance.

  • winds can slowly wear erode a planet's surface.
    • The surface of Mars is affected by wind.
    • Monument Valley on Earth is an example
  • weather & water cause more dramatic erosion.
  • volcanism, which pours out a new surface
    • The maria on the Moon are examples.
  • plate tectonics, or continental drift
  • slow forces of uplift & deformation similar to those which cause mountains to form.
  • relaxation of craters, mountains and volcanoes.
In their earliest histories, every planet & moon was bombarded with the remains of the material which formed them. If a planet's surface does not show many craters, it means that the surface is new, and the planet has been resurfaced, perhaps by one of the processes above. If the planet's surface still shows the many craters left over from it's formation, then that same surface was present during the ancient bombardment, and has not been changed by any activity.

Last modified April 26, 2001 by Jennifer Bergman.

You might also be interested in:

Ready, Set, SCIENCE!: Putting Research to Work in K-8 Science Classrooms

What types of instructional experiences help K-8 students learn science with understanding? What do science educators teachers, teacher leaders, science specialists, professional development staff, curriculum designers, school administrators need to know to create and support such experiences?...more

Step 1: Weathering (Destroying Rock!)

Rocks are broken apart by two types of weathering. By chemical weathering, the minerals in rocks are dissolved into rainwater or changed from one type of mineral into another. Climate is an important factor...more


Volcanism is part of the process of bringing material up from the deep interior of a planet and spilling it forth on the surface. Eruptions also deliver fresh gases to the surface from the melted material...more

Lunar Volcanism

This picture of the lunar maria shows the difference betwen the highlands, which are heavily cratered, and the dark maria which are relatively smooth with few craters. The absence of craters indicates...more

Regional Metamorphism

A large amount of metamorphism over a broad geographic area is called regional metamorphism. Movements of the Earth's tectonic plates are the primary cause of regional metamorphism. As continental plates...more

Exploratour - The Archean Age

In addition to being hot, the surface of the Earth was being cratered. Even though the solar system was finished forming, there were still probably a lot of smaller planetesimals and debris around, too....more

Exploratour - Evolution of the Solar System

For many planets, such as Mercury, shown here, pictures show that there are lots of craters. The craters were formed early in the history of the planet. Because there are so many craters, scientists can...more

The Formation of the Moon

Any successful theory must account for everything we know about the Moon now, as well as make predictions about future observations. There are three theories about how the moon came to be in place: that...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