Day and night


It takes 90 minutes for an astronaut on the International Space Station to circle Earth completely, passing from daytime to nighttime and back again. This video taken by ESA astronaut Alexander Gerst shows the view from space in under one minute. Each orbit the Station moves around 2200 km to the West in relation to 90 minutes before.

Astronauts often use normal consumer digital cameras to take pictures of Earth through Europe’s observatory module Cupola in their spare time. Setting the camera to take an image every few seconds and then playing the images back quickly create this timelapse effect.

Alexander worked as a geophysicist and volcanologist before he was chosen as an ESA astronaut in 2009. His Blue Dot mission includes an extensive scientific programme of experiments in physical science, biology, and human physiology as well as radiation research and technology demonstrations. All experiments chosen make use of the out-of-this-world laboratory to improve life on Earth or prepare for further human exploration of our Solar System.

Read more about his mission at

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  1. I understand this is ISS, but i was wondering if satellites stay 'fixed' at their position relative to earth's surface / coordinates. If satellites do not stay exactly above a single point of earth's reference, how will they give a GPS position on the ground…while moving 'away'?

    I understand there's this 'traingulation' concept but all 3 satellites would be constantly moving 'away' from a single point of reference on earth.

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