An illustrated time line shows you the history of the search for water and life on Mars.

People have looked to Mars with curiosity since the earliest humans began gazing at the night sky. Now, we can do a lot more than just gaze in awe at Mars from the ground. We look with high-powered, space-based telescopes, such as the Hubble Space Telescope—and soon with the Next Generation Space Telescope. We send satellites and rovers to observe up close and look for evidence of ancient liquid water—and past life—on Mars. The data and imagery we get back gets clearer and clearer as our technology gets more and more sophisticated. Pretty soon, we’ll even have Martian rocks and soil to analyze. And someday, we may even voyage to Mars in person!

Delve into the history of the search for water and life on Mars via an illustrated time line.

	View a demonstration of laser altimetry.
	Manipulate NASA Goddard Space Flight Center's interactive topographic map of Mars’s surface.

Looking for Likely Sites
To find the places on Mars that are most likely to have had some form of liquid water in the past, it’s helpful to know everything you can about the planet’s topography. Detailed maps like the one below right that show the height, shape, and texture of Martian landforms help scientists back on Earth figure out how they were formed and whether or not liquid water was involved. Find out how scientists have used laser altimetry to map the topography of the entire planet without ever setting foot on the surface.

NASA Goddard Space Flight Center's interactive topographic map of Mars’s surface was assembled using data from the Mars Orbiter Laser Altimeter (MOLA) on board the Mars Global Surveyor satellite.

The bands of color represent different heights. You can see lots of interesting features, such as volcanoes and canyons, when you look at Mars this way—including the fact that the northern hemisphere is much flatter than the southern hemisphere. Why? That’s one of the things today’s scientists and researchers are trying to find out!

Mars Overview and Basics
For an overview of Mars exploration from the perspective of a Museum scientist, read “Unraveling the Mysteries of Mars (PDF: 2.1MB),” an article by Denver Museum of Nature & Science planetary specialist Dr. Steven Lee. Requires the free PDF viewer to read.