The Arctic at night. Satellite image of the Earth at night, set against a background of stars, centred on the Arctic. The North Pole is at centre. City lights (yellow) show areas of dense population. The Arctic is largely uninhabited, with small population centres in Alaska (lower left), Siberia (across upper centre), Scandinavia and Iceland (centre right), Greenland (lower right) and northern Canada (lower centre). Outside the Arctic, the main population centres of the Northern Hemisphere are seen in North America (bottom centre), Japan (top left), and Europe (top right). The deserts of central Asia are seen across top. Image data obtained in 2001 by the Defense Meteorological Satellite Program (DMSP).