[thedoc (OP)]

Warren Hinchliffe  asked the Naked Scientists:
   
Hi Chris

Love the show, I listen to the podcasts regularly but have never written in.

I was listening to the question about the max mountain height on Earth being around 8,000m whereas on Mars it was around 20,000m.

The geologist from Cambridge explained that even rock can flow (sideways - thus limiting height) under enough weight but then suggested the difference on Mars could be the 'viscosity' of Mars rocks.

To me, the simpler idea would be that the gravity on Mars is 3.7 m/sec/sec versus Earth's 9.8.

Using this ratio on 8,000m gives 21,000m for Mars, which is about right. I know there's probably more to it than that but I would suggest gravity accounts for the lions share of the difference.

Warren Hinchliffe - Perth Western Australia.
What do you think?