SI and gauss in cgs units). Note (since magnetism is not talked about a lot...) The gauss is itself defined as one maxwell/cm 2 ( gauss http://en.wikipedia.org/wiki/Gauss_(unit)). The earth's magnetic field is 0.3-0.6gauss (about 1 gauss for a back of the envelope calculation) (30-60μteslas). An MRI machine has a magnetic field