Microwave Radiation Exposure from Satellites

Physics is fine, but most of us are happier if we can relate unfamiliar situations to every day life. So lets look at a more familiar source of radiation as a parallel to what we can expect to experience from RADARSAT.

As the primary effect of microwave exposure on the human body is heating, let us look at the thermal radiation exposure that we experience from an ordinary 100 Watt incandescent lamp and try to match it to radiation from a RADARSAT overpass.

If the lamp is reasonably well worn (like the front porch light at home) we can expect that only about 10% of the power supplied to it is radiated as electromagnetic energy in the form of heat and light. If we assume that this radiation is isotropic (radiated uniformly in all directions) then our radiation exposure is just the radiated power times the solid angle defined by us and our distance from the light.

How far from the light bulb must we be to have a radiation exposure equivalent to our exposure from RADARSAT? This distance is just the square root of the radiated lamp power times our surface area divided by 4 pi and divided by the power that we intercept from RADARSAT. This would be approximately 300m.

In order to experience the full thermal effect of the light bulb "equivalent", you would have to coat your naked body in soot (to help absorb the radiation). Then, expose yourself to the light bulb, positioned 300 metres away, for three quarters of a second!

• you will not notice the heat
• you will impress the neighbours
• you may have trouble explaining your actions.

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