Incredible reason why astronauts in space experience 16 sunrises and sunsets in a day

On Earth, a day and night is defined by what people call “sunrise” and “sunset.” But in actuality, it’s not the Sun that rises or sets, it’s the rotation of Earth that causes the planet’s residents to experience days and nights. So, when it comes to space, the mathematical timekeeping of sunrises and sunsets falls apart. In the vacuum of space, clocks tick quicker and astronauts on the Space Station do a full circle of Earth every 90 minutes, experiencing 16 sunsets and sunrises every day, as reported by the European Space Agency (ESA).

Sunrise and sunset are spectacular phenomena and such an intelligent demonstration of nature’s timekeeping. Depending on the wavelength of the colors, light gets scattered in the sky, shifting its colors from red at sunset to blue at sunrise, per The School Observatory.

Since Earth is spherical, about half of the planet is illuminated by the sun at any given time. But the Sun always stays at its position, at the center of the solar system. It appears to rise and set because Earth rotates on its axis, with one rotation completed in 24 hours. But outside Earth, the International Space Station (ISS) travels at a speed of 17,100 miles per hour, according to The Atlantic. This implies, that it completes an orbit around the Earth every 90 minutes, resulting in a total of 16 sunrises and sunsets the astronauts and cosmonauts abroad get to witness.

In a September 2021 tweet, when someone asked whether astronauts feel any temperature difference in their schedule, NASA explained that the temperature difference in space is huge since there is no atmosphere to maintain a comfortable temperature. At sunrise, the temperature is 250 degrees Fahrenheit, and at sunset, it is -250 Fahrenheit. This is why their spacesuits are designed in such a way that their insides remain cool so they can comfortably conduct spacewalks and carry out mission experiments.

According to ESA, the Space Station follows Greenwich Mean Time (GMT), which helps astronauts maintain a consistent schedule, along with regular wake-up and bedtime routines. However, since light exposure is a primary factor that determines the circadian rhythm of a human body, the sleep-and-wake cycle of astronauts is prone to getting disturbed as their bodies can’t maintain a regular circadian rhythm in the environment of microgravity.

To curb this problem, ESA’s team created “The Circadian Light experiment,” which is basically a lamp designed to support the circadian rhythm of astronauts in space. The lamp is supposed to emit a red glow to simulate a sunset, and blue light to emulate a morning sky. Plus, they also get an in-ear measuring device to keep up with their bodily rhythms. Given that all these factors are taken care of, the witnessing of dozens of sunrises and sunsets becomes a breathtaking phenomenon.

 Watch the gorgeous timelapse footage of a sunrise captured by ESA astronaut Alexander Gerst, and later reposted in this YouTube video.