Philips Atlas of the Universe

THE SOLAR SYSTEM

certain only when we can examine Martian material in our

laboratories, and this should be possible before long; an

automatic probe should be able to land there and return to

Earth with specimens for analysis.

It now seems that there is much more ice below the

Martian surface than used to be thought. The Odyssey

probe, launched on 7 April 2001, has confirmed that ice-

rich soil covers much of the planet, and that the southern

polar cap is composed mainly of water ice, with only an

upper coating of carbon dioxide ice. It has been estimated

that if all the frozen water were released at once, the entire

surface would be covered ankle deep in water.

It has been claimed that some meteorites found in

Antarctica have come from Mars, blasted away from the

Red Planet by a giant impact, and that they contain traces

of past primitive organisms. This is an interesting possibil-

ity, but the evidence is far from conclusive. We do not

know for certain that the meteorites are of Martian origin,

or that the features contained in them are indeed indicative

of past life.

Gullies cut by water?

Newton is a large crater,

287 km (178 miles) across, at

latitude 41.1ºS, longitude

159.8ºW. Inside it is a 7 km

(4.4 mile) crater, imaged by

Mars Global Surveyor in

2000. Debris carried with the

water created lobed deposits

at the base of the crater wall.

If there is liquid water not far

below the surface, these

gullies may be fairly recent.

Launch of Mars Odyssey

on 7 April 2001.

Valles Marineris (Mars

Global Surveyor). A vast

canyon system, dwarfing

anything found on Earth.

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