Page 46 - (DK) Eyewitness - Mars

Rivers on Mars

Liquid water is needed for life as we know
it, but Mars is drier than any desert on Earth.
Mars is too cold and its atmosphere is too
thin for water to exist except as ice or vapor.
Yet scientists believe the planet once had a
milder climate, with rivers emptying into
lakes and seas. Some Martian landforms
could be from a watery era 3,500 million
years ago. These landforms include ancient
drainage networks that seem cut by flowing
water. Also, Mars has deposits of soil and
debris normally found at river mouths, and
there are flat regions that could have been
floors of now-vanished lakes or seas. Martian
terrain is often similar to arid regions on RIVERS FLOW IN NOACHIAN MARS
Earth, such as Asian deserts that once had Muddy floods in ancient Mars would have looked like this artist’s
their own rushing rivers and streams. rendering of water-filled river channels at Chryse Planitia. Water from
melting snow and ice is shown flowing through Kasei Vallis in the
background. Layers of sediment would have been deposited and later
exposed when the water evaporated or flowed away.

WATER’S HIGHWAY
Curving landforms may have been shaped by the surging might of a Martian
flood. This artist’s rendering is of a dry riverbed in a mountain valley once
swept with rushing water released from a reservoir of melting ice, perhaps
heated by an erupting volcano. Surrounding the valley floor are rock
formations that have been scoured by wind and dust.

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