From Martin Austin
A few months ago we were treated to reruns of the BBC Horizon
programme demonstrating the behaviour of rock slides, which mimic water flow
almost exactly under certain circumstances and produce etched gullies and
outflow deltas that are very similar to water erosion.
The enthusiastic excitement of the NASA scientists about the possible
existence of water on Mars, after the discovery of recently formed gullies on
its surface, might be tempered somewhat if they compared the pictures they have
received from the Mars Global Surveyor with the terrestrial rock slides shown so
graphically on the Horizon programme.
Basle, Switzerland
