Antarctic Ground Ice
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You could say that ice defines Antarctica. Most of the continent is covered by it and even the few areas of bare ground in Antarctica have been shaped by ice. Hi, I'm Dave Thurlow and this is the Weather Notebook. In one of the ice-free valleys, high in the mountains of Antarctica, you can find a strange and beautiful feature-- cracked ground that is shaped like polygons and scientists believe was formed by the expansion and contraction of ice. Correspondent Allan Coukell files this report.

You can tell largely where ground ice is by the pattern ground on the surface. And it is essentially polygons on the surface. And you look at the surface and it looks like a honeycomb surface. And these honeybcombs add a rare dimension of beauty to a landscape, where you can look up one of these large U-shaped glaciated valleys, so it almost looks like large bees could live in the bottom of the Valleys. But instead what you've got is ice underneath the surface, which expands and contracts, forming these polygons.

Warren Dickinson is with Victoria University in Wellington, New Zealand. He says honeycomb ground is also found in the Arctic, where it is formed by the daily summertime freezing and thawing, when daytime temperatures can be as high as ten degrees celcius. But in Antarctica, something different must be happening.

Well in the Antarctic, we do not have this daily freeze-thaw mechanism which we have in the Arctic. But instead what we do have in the Antarctic is this high temperature difference between summer and winter. In the summer we can get up to near zero, and in the winter of course we gets down to minus 50, minus 60. So we have a temperaure differential of 50 degrees centigrade there, which we never have in the Arctic. So we have this incredible temperature differential, which we think is enough to expand and contract and actually form these polygons.

Antarctica is remote, but studies of ground ice there may help scientists understand the formation of a landscape even further away the polygons that have been observed on the surface of Mars!