Related by context. Frequent words. (Click for all words.) 52 Sir Ernest Shackleton 50 Lake Vostok 50 Ernest Shackleton 48 Weddell Sea 48 Ross Ice Shelf 45 Antarctica 45 Wilkins Ice Shelf 45 Petermann Glacier 45 Antarctic explorer 45 Vinson Massif 45 oceanic crust 44 marine sediments 44 Snowball Earth 44 Siberian permafrost 43 Arctic permafrost 43 volcanic vents 43 Catlin Arctic 43 Galileo spacecraft 43 Antarctic ice 43 Opportunity rover 43 polar explorer 43 lithosphere 42 Earth ozone layer 42 Carol Rymer Davis 42 Antarctic Expedition 42 Saturn moon Enceladus 42 Rover Spirit 42 Antarctic Territory 42 glacier 42 Antarctic expedition 42 continental crust 42 Arctic explorer 42 Antarctic ozone 42 Antarctic Peninsula 41 stratospheric ozone 41 NASA Mars rover 41 Mars rover Opportunity 41 Fastest fingers 41 sediment cores 41 Phoenix lander 41 equatorial Pacific Ocean 41 Roald Amundsen 41 Adventurer Steve 41 icecaps 41 magma chamber 41 moon Europa 41 #.#C [004] 41 Pen Hadow 40 hydrothermal activity 40 Antarctic 40 icecap 40 Spitsbergen 40 Robert Peary 40 Beringia 40 Martian landscape 40 basalts 40 Melting glaciers 40 Canoeist 40 Sir Ranulph Fiennes 40 Martian surface 40 interglacial 40 Antartica 40 polar vortex 40 interglacial period 39 Arctic seabed 39 Sir Ranulph 39 glacial ice 39 famed aviator 39 conquered Everest 39 Martian rocks 39 HMS Beagle 39 Messenger spacecraft 39 mesosphere 39 underwater volcanoes 39 Arctic Ocean 39 deglaciation 39 IODP 39 Sandwich Islands 39 seabed 39 Aland Islands 39 supercontinent 39 Mars Odyssey orbiter 39 Martian arctic 38 Gusev Crater 38 Carboniferous 38 clathrates 38 Antarctic peninsula 38 crustal 38 Greenland Ice 38 Permafrost 38 floe 38 Burgess Shale 38 lunar soil 38 expedition 38 protective ozone layer 38 Endurance Crater 38 polar explorers 38 gas hydrates 38 Polar Regions 38 Ellesmere Island 38 Namib Desert