What is that term all about - Ultraviolet light?

In 1801, German physicist Johann Ritter conducted a groundbreaking experiment, aiming to explore the possibility of a wavelength beyond the visible spectrum. Unbeknownst to him, this investigation would lead to the discovery of infrared light, a revelation that would expand our understanding of the electromagnetic spectrum.

Fast forward to today, and we find ourselves delving deeper into the spectrum, investigating the less visible yet equally significant wavelengths. The sun, our celestial beacon, is the source of all types of ultraviolet radiation, including UV-A, UV-B, and UV-C.

UV-A and UV-B rays, though harmful, are the most prevalent types of ultraviolet radiation that reach the Earth's surface. UV-A rays can penetrate the skin more deeply than UV-B, causing long-term effects such as premature ageing and increasing the risk of skin cancer. UV-B rays, on the other hand, are responsible for sunburn and can cause short-term effects like photokeratitis (snow blindness) if the eyes are exposed.

UV-C rays, the most energetic and harmful, are almost entirely absorbed by our atmosphere. However, they play a crucial role in the chemical processes that occur in the upper layers of the atmosphere, affecting the amount of atmospheric ozone, a vital shield that protects us from harmful UV radiation.

Scientists utilise data from satellites orbiting the Earth to study these processes, analysing stellar formation in the microwave range and monitoring the Earth's atmosphere for signs of ozone depletion. Images obtained from the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite show atmospheric ozone levels, with blue and purple areas indicating where the ozone layer is significantly depleted.

Ozone depletion, caused by these chemical processes, is spreading over the South Pole and sometimes extends to high-population areas in South America. This depletion increases the levels of harmful UV radiation, posing a significant risk to human health. Prolonged exposure to sunlight without protection can significantly increase the risk of skin cancer and other cellular disorders.

Protection against these harmful rays is essential. Sunglasses designed to block UV-A and UV-B rays should be worn to protect the eyes, while sunscreen provides a protective layer against these rays on the skin. These protective measures are crucial, as they enable us to enjoy the sun's warmth without the harmful effects of its ultraviolet radiation.

In the realm of astronomy, the study of ultraviolet radiation continues to yield fascinating discoveries. The image above, taken by NASA's Galaxy Evolution Explorer (GALEX), reveals new young stars in the spiral arms of the M81 galaxy, shining brightly in the ultraviolet range. As we continue to explore the electromagnetic spectrum, we uncover the mysteries of the universe, one wavelength at a time.