Sunrise, Sunset. Repeat.

On July 26, 2017 an ISS crew member captured this image of one of 15 sunsets they would experience on that day. Why this embarrassment of riches?

The International Space Station zips around the earth at an exhilarating 17,500 mph - not because it wants to, but because it has to. Any slower and it would be drawn gradually back toward earth, which wouldn’t end well. Any faster and it would break out of its orbit, which wouldn’t end much better if you think about it.

At that velocity the ISS completes one orbit around the earth every 90 minutes. ‘Night’ and ‘day’ are a mere 45 minutes each, and when you add up all those transitions you end up with 16 sunrises and 15 sunsets in a 24-hour period.

Makes you wonder if the idea of sending a rooster into space has ever been seriously discussed.

Image link: https://www.windowsonearth.org/Featured-Galleries/Best-New-Images/i-P75QJVd/A
Science link: https://eol.jsc.nasa.gov/Tools/orbitTutorial.htm