Shulou(Shulou.com)11/24 Report--

According to the news on the morning of September 1, Beijing time, it is reported that when we were young, day and night meant nothing more than "how long before the next holiday". As we grow up, day and night become endless cycles of work goals, deadlines, and repayment dates. Some people can feel the beauty and mystery of the day-night cycle, while for others, it is just the result of the earth's rotation.

No matter what you think of day and night, for all living things on earth, day and night is a light and dark cycle repeated every 24 hours.

However, once you leave our planet, these definitions no longer apply. For example, the astronauts on the International Space Station, have you ever wondered what they feel like day and night?

Why is there a difference between day and night?

The rotation of the earth produces day and night.

In addition to revolving around the sun in an oval orbit, the earth rotates around its axis. In the process of rotation, the side facing the sun is "day" and the side that is not exposed to the sun is "night". The earth rotates very fast, about 1670 kilometers per hour, but even so, it takes 24 hours for the earth to rotate around. So we spend 24 hours a day, of which about 12 hours are bathed in the sun and 12 hours hidden in the dark.

What is the day and night like on the International Space Station?

The orbit of the ▲ International Space Station is very close to the surface, so it is visible to the naked eye.

The International Space Station usually carries five to seven astronauts. Will they also experience diurnal changes on the International Space Station? If so, is it similar to day and night on earth?

Day and night on the International Space Station, the International Space Station travels at speeds of up to 27600 kilometers per hour, about once every 90 minutes. During this period, the space station spends about half its time in the sun and the other half in the shadow of the earth. So each turn of the space station will experience about 45 minutes of light and 45 minutes of darkness.

The sunrise was photographed on the ▲ International Space Station. Photographed by German astronaut Alexander Gerst

Sunset seen on the ▲ International Space Station

Within 24 hours, the International Space Station will revolve around the Earth 16 times. So every past day on Earth, astronauts on the International Space Station witness 16 sunrises and sunsets.

Why frequent switching between day and night causes problems watching 16 sunrises a day from space may sound cool at first, but it can cause a serious problem in the long run.

▲ 's night view of the earth from the International Space Station

The human body operates according to a 24-hour cycle, and light plays a key role in the regulation of the cycle. Our circadian rhythm follows the laws of light on the earth, working at sunrise and resting at sunset. Therefore, the rapid day-to-night switching will adversely affect the biological clock of astronauts.

But we can't let these astronauts who undertake one of the most important tasks in the world be in a state of "jet lag", so we must create a "normal" day and night environment on the International Space Station.

How to simulate the normal day and night environment of the International Space Station 1. Fix a time zone

The International Space Station uses coordinated Universal time. This is a set of global time standards, determined by two factors: one is the international atomic time calculated by a high-precision atomic clock, and the other is the universal time based on the rotation of the earth. All global time zones are adjusted according to coordinated Universal time.

▲ 's World clock in Berlin

Why use coordinated Universal time?

As mentioned earlier, the International Space Station is a multinational cooperation project with the participation of five major space agencies from all over the world, so coordinated Universal time is undoubtedly the best choice to promote effective cooperation among agencies.

two。 Control the lighting on the International Space Station

In the early days of the mission to the International Space Station, it was found that even though astronauts were assigned 8.5 hours of sleep a day, their sleep was still poor. So the scientists decided to adjust the light on the space station.

In fact, "the effect of light on the human body" is one of the experiments carried out by NASA on the International Space Station.

The International Space Station initially used the General Lighting Assembly system, which uses fluorescent lights to provide lighting. In 2016, these modules were replaced by "solid-state LED modules", which are more durable, cheaper and brighter. LED lights can also change the intensity and wavelength of illumination, making it very suitable for simulating the real day and night environment in the space station.

Astronauts' Day on the International Space Station on the International Space Station, the astronaut's working day begins at 6 a.m. and ends at 9 p.m. UTC.

In the first few hours, the light was set brighter to simulate daytime lighting levels. When astronauts need to perform more challenging tasks, the wavelength of light will be adjusted to a band closer to blue light, thus improving the astronauts' alertness and alertness. At the end of the day, the light is warmed to help astronauts sleep better.

▲ sleeping bag

From 09:30 in the evening to 6 o'clock in the morning, the light will be dimmed to simulate the night environment. In this way, after the astronauts have finished a day's work, they can lie down comfortably in their sleeping bags and have a good night's rest. Follow-up studies have found that such lighting patterns help to improve the work efficiency of astronauts. These findings have also promoted the commercial promotion of LED products such as emotional Lights.

Relax. The International Space Station has taken a variety of measures to ensure that astronauts maintain a normal routine. However, if astronauts want to enjoy the strange view of space, they only need to stay in the dome for a while, and they can spend a complete "day" in just 90 minutes.

The dome module of the ▲ International Space Station

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