We’ve all seen sunsets, but most people never see a sunset like this one, with its last rays filtered through the solar panels of the International Space Station. ISS astronauts, of course, see sunsets like this regularly — several times a day, in fact.
ISS commander Scott Kelly posted this image on his Twitter account yesterday evening, on Day 204 of his year in space.
Here on Earth, we see a sunset once every 24 hours — every 23 hours, 56 minutes, and 4 seconds, to be precise — when the planet rotates so that our area of the surface is turned away from the Sun. Because ISS is orbiting Earth at about 5 miles per second, Kelly and his crewmates see a new sunrise and sunset every 92 minutes.
That means that Kelly, who set a new record on Friday as the American astronaut who has spent the most time in space, will see about as many sunrises and sunsets during his year-long ISS mission as most of us see in 16 years.