Polish scientists have created a prototype of light which can replace the sun. This breakthrough discovery will be of assistance in space missions and depression treatment.

Human biological rhythm depends on the light, including serotonin secretion, which conditions the quality of sleep and activity during the day. Thanks to a cocktail of light developed by Polish scientists, which consists of various wavelengths, it is possible to create conditions in space similar to those on Earth. A prototype already exists, and can be implemented after the tests. It will also find its use in greenhouses, hydroponic systems, bioreactors and even in depression treatment.

“Light is the key parameter for survival in space. Every spacecraft, as well as future habitats, will be isolated from starlight. We, as creatures, as well as plants and the majority of organisms adapted to sunlight, must provide people and organisms in space a source simulating sunlight or starlight in a way which does not damage cells. This is why we have developed a prototype of this kind of lighting which simulates sunlight,” dr Agata Kołodziejczyk from Space Garden underlined in a conversation with the Newseria Innowacje agency.

Light has the greatest impact on human biological rhythm, on hormonal balance, metabolism and blood circulation. Light synchronises our internal clocks, allowing us to operate based on a circadian rhythm. The sun influences the synthesis of proteins, including serotonin, which is responsible for controlling sleep and maintaining alertness. The lack of serotonin might lead to aggression, irritation and even depression. Every space mission becomes harder under such conditions. Cosmonauts closed in habitats, without sunlight, lose the sense of time already after the first day. Creating an artificial sun, light consisting of specific waves, can prevent this.

The Advanced Concepts Team of the European Space Agency designed such a prototype based on special LEDs. It operates in a different way than light in homes or offices, because it has a direct impact on the organism, replacing the real sun. These are physiological lamps which emit UV radiation with an appropriate frequency, stimulating serotonin receptors.

“This light is intended to trigger the synthesis of serotonin in the brain. We will be more active during the day, it will regulate our biological clocks, sleep and such psychological states as depression, exhaustion and the lack of motivation. It is of crucial importance as regards space missions, but can also prove useful if we can get it to actually work,” dr Agata Kołodziejczyk stated.

This artificial light will help to correctly perceive time, which flows slower in the dark. Thanks to the perception of time it is possible to determine location, which is important in space. This can speed up space missions as well as tourist space flights.

If further tests are positive, the use of the artificial sun can be much wider, e.g. in the treatment of depression, which is greatly affected by the lack of sunshine. Nowadays, according to the WHO, depression is among the most common diseases. It will be the second most common in 2020 and most common in 2030. As many as 350 m people suffer from depression worldwide.

“Artificial sunlight will be of key importance to the correct synthesis of proteins, Vitamin D, urocanic acid and serotonin, responsible for sleep, aggression and the state of activity in general. It will be used in greenhouses, hydroponic systems, bioreactors, and, of course, for the benefit of people,” the expert said.

First tests of such light have already been conducted on animals. Tests on people were carried out in Piła, where the Lunares space base is located. Volunteers were closed in the habitat, which perfectly mimics the conditions at a space station.

“We already have a prototype, three two-week missions have been completed and research involving eighteen people is under way. This is still not enough to say anything, but after we receive data corroborating that it actually works, we want to commence production right away and establish cooperation with Philips,” dr Agata Kołodziejczyk said.