a close-up view of mars from orbiting spacecraft what did...

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A close-up view of Mars from orbitingspacecraft

The Mars Reconnaissance Orbiter (MRO) in orbit at Mars

What did we learn from spacecraftvisits from 1971-2000?

But first…Life on Mars?

• Viking biologicallaboratories to searchfor microbes. Threeindependentexperiments

• 2 said no, one said yes• The majority view of

scientists is that theresult was negative(majority, but notunanimous)

Spacecraft finding #1 - the north-southasymmetry

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Finding #2:The

volcanos ofMars:

OlympusMons

Notice smooth,uncrateredSlopes of mountain

The size of Olympus Mons Valles Marineris…Grand Canyon of Mars

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Valles Marineris Valles Marineris…the view of a future astronaut

With modern technology, we can usespacecraft data to generate our ownpersonal tour of the surface of Mars

A trip through Valles Marineris

The most important finding of orbitalstudies of Mars: apparent water

channels

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A startling discovery…the new canals ofMars

Two types of channels: Valley networks

Close-up view

Second type: outflow channels Where are water channels formed?

Does anyone see any patterns?networks found on oldestparts of Mars

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A case ofparticular interest:

Gusev crater

Gusev Crater: the view from thesurface…more next time

A question for the scholarly assembly:

• Last time, said thatthe surfaceconditions of Marsdid not allow liquidwater

• Now we see whatare claimed to bewater flow channels,like dry river beds inthe southwest

• What’s up?