You can see the polar ice caps in these two pictures of Mars. The ice cap at the North Pole is visible near the top of the upper picture. The ice cap at the South Pole is visible near the bottom of the lower picture. Both of these pictures were taken by the Hubble Space Telescope.
Click on image for full size
Images courtesy Phil James (Univ. Toledo), Todd Clancy (Space Science Inst., Boulder, CO), Steve Lee (Univ. Colorado), and NASA [North Pole image]; and NASA, J. Bell (Cornell U.) and M. Wolff (SSI) [South Pole image].

Mars Polar Regions

The North and South Poles on Mars are a lot like the polar regions on Earth. They are the coldest places on the planet. The temperatures in the winter can drop to -150° C (about -238° F). Both poles have ice caps that are mostly made of water ice. The ice caps get bigger and smaller as the seasons on Mars change.

The polar ice caps on Mars have two kinds of ice. They have lots of water ice, like the ice caps on Earth. They also have "dry ice". Dry ice is made of carbon dioxide. Mars has seasons, like Earth. When it is winter at one pole, some carbon dioxide from the atmosphere of Mars freezes, making dry ice. The polar cap on the winter half of Mars get much bigger as dry ice is added to it. When summer comes to that pole, much of the dry ice goes back into the atmosphere. The ice cap gets much smaller in the summer.

Scientists are very interested in the poles of Mars. Life on Earth needs water. Mars doesn't have any liquid water on the surface. But the poles have lots of ice made from water. Was that ice ever liquid water? The water ice might give us clues about life on Mars. We don't know if Mars has life now, or if it ever did in the past. Maybe learning more about water, and water ice, on Mars will help us learn whether there is (or ever was) life on Mars.

A new space mission will land on Mars in May 2008. It is called the Phoenix Mars Lander. It will land near the North Pole on Mars. Phoenix will search for water ice there. Scientists hope it will help us learn about the history of water, and maybe even life, on Mars!

Last modified July 7, 2008 by Randy Russell.

You might also be interested in:

Cool It! Game

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

The South Pole of Mars

The Mariner 7 spacecraft took the first pictures of the South Pole of Mars. The south polar region is part of the highlands of Mars. The southern highlands of Mars are mostly old, cratered terrain and...more

Glaciers and Ice Sheets

For a glacier to develop, the amount of snow that falls must be more than the amount of snow that melts each year. This means that glaciers are only found in places where a large amount of snow falls each...more

Carbon Dioxide - CO2

Carbon dioxide (CO2) is a kind of gas. There isn't that much carbon dioxide in Earth's atmosphere, but it is still very important. Carbon dioxide is a greenhouse gas. That means it helps trap heat coming...more

What Causes the Seasons?

Let's get rid of some common misconceptions about the seasons. The Earth's orbit is in the shape of an ellipse, so that sometimes the Earth is a little bit closer to the Sun than at other times. Is this...more

Phoenix Mars Lander - Instruments and Mission Objectives

The Phoenix Mars Lander was a robot spacecraft that was sent to Mars. Phoenix landed near the North Pole on Mars. This page tells about the mission of Phoenix. It also describes the instruments on the...more

Mars Global Surveyor Measures Water Clouds

You might think that clouds in the sky have to be made of water like those of Earth, but this is not always so. Clouds might be made of carbon dioxide or ammonia. Just take a peek at the planets Jupiter...more

Isidis Planitia

Isidis Planitia is a flat plain inside a very old crater on Mars. Isidis Planitia is about 1500 km (930 miles) across. It is just north of the equator on Mars on the eastern side of the Red Planet. The...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