Exploratour - Life in the Solar System

In the past, Mars was much different than it is today. There is much evidence that liquid water once flowed on the surface of Mars. Although calculations show that both the Earth and Mars should have been frozen in their early history due to the weak luminosity of the sun, both planets show ample evidence of flowing water very early in their histories, which suggests that they both must have had thick atmospheres with a significant greenhouse effect in place to keep the surface warm. With a liquid water habitat and a thicker atmosphere, life may have once thrived.

The atmospheres came from volcanoes which belched gases forth from the interior. Even today on Earth, volcanic eruptions produce a great deal of water vapor. The water vapor eventually condenses into the oceans. Mars was sufficiently cool for water vapor to eventually be absorbed into the ground and freeze like tundra in the Canadian northwest. Today scientists estimate that a large amount of water is frozen into the surface of Mars. They estimate this happened by 2.8 billion years ago. By comparison, check the geologic record for where the Earth was at that time.

Mars is small, and so cooled off very rapidly. There was not much plate tectonics on Mars, and not much volcanism either. (This compares to the Earth where volcanism continues today). Today, unlike the Earth where the surface plates still move around and create earthquakes, Mars' surface is fixed. This means no new releases of gas. It also means that carbon dioxide, which is absorbed into the ground and ocean on earth, is absorbed into the ground of Mars and is never released.

Compare this environment with Earth of the past, or read about NASA's attempts to understand the environment of Mars by leaving this tour and linking to the Exporatour: NASA's Exploration for Life at the bottom of this page.

This is page 7 of 20

You might also be interested in:

Cool It! Game

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

ExploraTour - Looking at the World in a Different Light

Even though the sleeping man is no longer on the bed, you can still see where he was lying down. The heat from his body warmed up the bed sheets which are now radiating infrared light toward your eyes....more

ExploraTour - Looking at the World in a Different Light

All warm objects radiate in the infrared. The warmer the object, the higher the frequency and intensity of the radiation. Very hot objects give off other types of radiation in addition to infrared. Click...more

ExploraTour - Looking at the World in a Different Light

Your eye is a wonderful detector of visible light. Different frequencies of light produce different sensations in the eye which we interpret as colors. Our eyes detect light by using light sensitive components...more

ExploraTour - Looking at the World in a Different Light

Imagine you found a pair of special glasses that not only gave you telescopic vision but gave you the ability to see all forms of radiant energy. The universe in visible light contains all the familiar...more

ExploraTour - Looking at the World in a Different Light

This is a volcano on the island of Miyake in Japan. It has erupted, sending hot lava and ash into the air, a total of ten times. The time after one eruption until the next occurred was about twenty years...more

ExploraTour - Looking at the World in a Different Light

The awesome power of a giant black hole was revealed by looking at this galaxy in three different types of light. The picture that you see is of Centaurus A, a very peculiar galaxy. A galaxy is just a...more

ExploraTour - Looking at the World in a Different Light

This is a plant in Gary, Indiana where power is made. We use power to run things like television sets, radios, lights, and microwave ovens. The picture looks very strange because it was taken in infrared....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