tag:bbc.co.uk,2008:cps:playlist:mediaAsset:20695595 Lake Ellsworth: Why drill a cavity? Engineer Chris Hill explains why an Antarctic research team is drilling a cavity in the ice before they drill down to Lake Ellsworth to hunt for signs of life. 2012-12-14T10:39:17Z en News 20695595 99110 true tag:bbc.co.uk,2008:cps:advert:mediaAsset:20695595 tag:bbc.co.uk,2008:cps:ident:news:video:640x360 tag:bbc.co.uk,2008:cps:mediaAsset:20695595