91Èȱ¬

STUDENT SPACE PROJECTS
Quentin Cooper learns about student contributions to front-line space projects. He meets undergraduates from the University of Leicester who are building their own satellite to study space dust, detecting nano-meteoroids in orbit around the Earth.

At the Open University at Milton Keynes, PhD students are building an experiment that will orbit the Moon as part of the European Student Moon Orbiter (ESMO), which is being designed and built by students from 29 universities in 12 countries.

DID THE EARTH FREEZE OVER?
Something strange was happening to the Earth around 700 million years ago. There’s evidence of deposits left by ice on every continent, including regions that were then near the equator. The implication that has become widely accepted over the last decade, is that the Earth froze over.

Such a ‘snowball earth’ scenario would have almost wiped out the primitive marine life of the time. There would have been no marine algae to remove volcanic carbon dioxide from the air. When the greenhouse gas had built up, about 635 million years ago, it caused rapid warming and a sudden thaw that plunged our planet into a hothouse.

The climate change is marked by a global layer of limestone as marine algae took advantage of the CO2 and warm seas. Soon afterwards the first assemblage of diverse, multicellular life forms evolved. But now, in a review article, Professor Phillip Allen of Imperial College London has called the global glaciation into doubt.

He discusses the evidence with Gabrielle Walker, author of ‘Snowball Earth’.