A mosaic of the 2,000-kilometer-long Valles Marineris canyon. The image is composed of 102 Viking Orbiter images, at a distance of 2500 kilometers from the surface.
A mosaic of the 2,000-kilometer-long Valles Marineris canyon. The image is composed of 102 Viking Orbiter images, at a distance of 2500 kilometers from the surface.
NASA/JPL-Caltech
A mosaic of the Schiaparelli Hemisphere of Mars, showing the Schiaparelli Crater, circa 1980.
A mosaic of the Schiaparelli Hemisphere of Mars, showing the Schiaparelli Crater, circa 1980.
Space Frontiers/Archive Photos/Getty Images
This artist impression from the ESA shows Mars Express in orbit around Mars.
This artist impression from the ESA shows Mars Express in orbit around Mars.
AFP/Getty Images/AFP/AFP/Getty Images
An artist's impression of the ExoMars 2020 rover exploring the surface of Mars.
An artist's impression of the ExoMars 2020 rover exploring the surface of Mars.
Courtesy European Space Agency
A crater on Mars, estimated to be about 1 kilometer wide.
A crater on Mars, estimated to be about 1 kilometer wide.
NASA/JPL-Caltech/Univ. of Arizona
The European Space Agency (ESA) captures the Echus Chasma, one of the largest water source regions on Mars from ESA's Mars Express. It is still debated whether the valleys originate from precipitation, groundwater springs or liquid or magma flows on the surface.
The European Space Agency (ESA) captures the Echus Chasma, one of the largest water source regions on Mars from ESA's Mars Express. It is still debated whether the valleys originate from precipitation, groundwater springs or liquid or magma flows on the surface.
ESA/Getty Images Europe/Getty Images
Another angle of the Echus Chasma, from the ESA's Mars Express. The dark material shows a network of light-colored valleys that look similar to drainage networks known on Earth.
Another angle of the Echus Chasma, from the ESA's Mars Express. The dark material shows a network of light-colored valleys that look similar to drainage networks known on Earth.
ESA/Getty Images Europe/Getty Images
The Echus Chasma, one of the largest water source regions on Mars, as pictured from ESA's Mars Express. Scientists report that gigantic water falls may once have plunged over these cliffs on to the valley floor.
The Echus Chasma, one of the largest water source regions on Mars, as pictured from ESA's Mars Express. Scientists report that gigantic water falls may once have plunged over these cliffs on to the valley floor.
ESA/Getty Images Europe/Getty Images
Taken from NASA's Mars Odyssey spacecraft, this composite image shows Mars' own Grand Canyon, Valles Marineris, on the surface of the planet. The Valles Marineris is 10 times longer, five times deeper and 20 times wider than Earth's Grand Canyon.
Taken from NASA's Mars Odyssey spacecraft, this composite image shows Mars' own Grand Canyon, Valles Marineris, on the surface of the planet. The Valles Marineris is 10 times longer, five times deeper and 20 times wider than Earth's Grand Canyon.
Handout/Getty Images North America/Getty Images
NASA's Mars Reconnaissance Orbiter captures the Garni Crater. The dark, narrow streaks are said to be formed by a flow of water on the surface of present-day Mars.
NASA's Mars Reconnaissance Orbiter captures the Garni Crater. The dark, narrow streaks are said to be formed by a flow of water on the surface of present-day Mars.
NASA/Getty Images