91热爆

David Attenborough goes on board a NASA plane designed for experimental flights (nicknamed the vomit comet). All creatures on Earth are affected by gravity and without it we'd all float away. The plane flies along a path of climbs and dives, and at the height of the parabolic path gravity is in effect cancelled out. David demonstrates the lack of gravity with water droplets, splashing them out of a cup and catching them again as they float around. Whilst many creatures can fly, only organisms so small that they are virtually weightless can ignore gravity. (Courtesy of NASA.)