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Studies have been performed on the use of shortwave radiation for cancer therapy and promoting wound healing, with some success. However, at a sufficiently high energy level, shortwave energy can be harmful to human health, potentially causing damage to biological tissues, for example by overheating or inducing electrical currents. [28]
The dark side of the Moon illuminated by the Sun. The dark (far) side of the Moon receives about the same amount of light from the Sun as the near side. It is called "dark" not because it never receives light but because it had never been seen until humans sent spacecraft around the Moon, since the same side of the Moon always faces the Earth ...
Blue light, a type of high-energy light, is part of the visible light spectrum. High-energy visible light (HEV light) is short-wave light in the violet/blue band from 400 to 450 nm in the visible spectrum, which has a number of purported negative biological effects, namely on circadian rhythm and retinal health (blue-light hazard), which can lead to age-related macular degeneration.
It emits more blue light than traditional incandescent bulbs, potentially impacting the quality of sleep and eye health if used excessively at night. [2] [8] A person using a smartphone at night. Blue light is emitted by digital screens such as computers, tablets, smartphones, and televisions, which can lead to extended exposure in modern lives ...
This is four times the worldwide average artificial radiation exposure, which in 2008 amounted to about 0.6 millisieverts (60 mrem) per year. In some developed countries, like the US and Japan, artificial exposure is, on average, greater than the natural exposure, due to greater access to medical imaging. In Europe, average natural background ...
For instance, a NASA design study for an ambitious large space station envisioned 4 metric tons per square meter of shielding to drop radiation exposure to 2.5 mSv annually (± a factor of 2 uncertainty), less than the tens of millisieverts or more in some populated high natural background radiation areas on Earth, but the sheer mass for that ...
Natural exposure to gamma rays is about 1 to 2 mSv per year, and the average total amount of radiation received in one year per inhabitant in the USA is 3.6 mSv. [23] There is a small increase in the dose, due to naturally occurring gamma radiation, around small particles of high atomic number materials in the human body caused by the ...
The Sun is much larger than the Moon, but it is the vastly greater distance that gives it the same apparent size as the much closer and much smaller Moon from the perspective of Earth. The variations in apparent size, due to the non-circular orbits, are nearly the same as well, though occurring in different cycles.