The Electromagnetic Spectrum is remembered fondly in our hearts as being one of the few useful things to come out of the countless GCSEs we had to endure. The spectrum is made up of a several sections. Visible light (Blue (0.4-0.5 μm), Green (0.5-0.6 μm) and Red (0.6-0.7 μm)) is the only electromagnetic radiation that can be seen by the human eye, but there are also other sections invisible to us that can be used in remote sensing.
One of the most useful sections of the spectrum regarding remote sensing is Infrared Radiation. It has a broad range (0.7 μm- 1mm) and therefore includes radiation with differing properties e.g. Near-Infrared, Mid-Infrared, and Far-Infrared.
All objects (unless at absolute zero) emit electromagnetic radiation. By monitoring the amount of electromagnetic radiation that an object emits or reflects, analysts are able to deduce the type of land cover on the Earth’s surface. This has all sorts of real-world applications that are invaluable in both Geography, and other fields of study.
Fun Fact: All electromagnetic waves travel at 300,000km per second!
Natural resources Canada, (2015), The Electromagnetic Spectrum, Available at: http://www.nrcan.gc.ca/node/14623, (Accessed on: 20th May, 2017)