The International Space Station orbits about 354 kilometers
(220 miles) above the Earth and travels at approximately 27,700 km/hr (17,211 mph), so it takes about
92 minutes to circle the Earth once. For this reason, every 45 minutes the
astronauts on-board see a sunrise or a sunset, with a total of 15 – 16 of each
every 24 hours.
Moreover, a space sunset is said to be a spectacular sight that shows in
vivid detail the many layers of the Earth’s thin atmosphere. The first layer
displays the dark part of the Earth experiencing night. Above that, in deep
orange and yellow is the Earth’s troposphere, which contains almost all of the
clouds in the sky. Then the pink to white region above the clouds which
gradually turn to a light blue band, essentially the stratosphere, which is
that part of the Earth’s atmosphere where airplanes fly. The layer above the stratosphere appears
as a darker blue band that gradually
fades away into the cold dark vacuum of outer space.
