Six Minutes English From B B C Learning English

navigation at sea is easy compared to finding your way in outer space. For astronauts who are floating in zero gravity in space, is there a true north like here on earth? And how is everything complicated by the fact that all the stars and planets are moving,. some big questions thereof. Listen to astro physicist ethan segal as he explains why a compass always points north to b b c world service programm crowd science.