Electromagnetic radiation
Electromagnetic radiation are composed of photons, linked waves of electric and magnetic fields. These include, radio waves, heat waves (infrared), visible light, x-rays, etc.
A list of the electromagnetic spectrum (note these boundaries are approximate, they blend into each other:
- Radio waves. \t10 cm to 1 km or longer.
- Micro waves. \t1 mm to 10 cm.
- Infrared light. \t 700 nano-meters to 1mm. Around 1 cm these waves are thermal IR.
- Visible light. \t400 nano-meters for blue light, to 700 nm for red light.
- Ultraviolet light. \t5 nm to 700 nm. UV light can damage surface tissue, and has sterilized the surface of Mars.
- X-rays. \t\t 1 Angstrom to 5 nm. These rays can damage deep tissue.
- Gamma-rays. \t shorter than 1 Angstrom and shorter. These can damage deep tissue and can penetrate deep thru many materials.
The lowest energy waves are radio waves. They act like waves. As the energy increases, the wave length shortens, and the photons act more and more like powerful particles that can damage tissue.
Light levels on Mars
Mars gets a little less than half the light from the Sun, as Earth. (Mars is 1.524 AU from the sun. Solar Flux = 1 / (1.524 * 1.524) = 0.4306 or 43% of the light from the sun as Earth.)
This is enough to grow crops, and our eyes (which adapt wonderfully to varying light levels) won't perceive Mars as dim.
