Remote sensing

Many objects and phenomena that we wish to investigate cannot be examined face to face. For very obvious reasons a direct examination of the Sun is not possible, so we are forced to use solar telescopes and an examination of the radiation of the Sun to draw conclusions about its characteristics. We are remote from the object of investigation and we are using various instruments to ‘sense’ its character. Another example rather closer to home is the use of an echosounder to tell us the depth of water under a vessel’s hull or perhaps of the existence of a shoal of fish. In the environmental sciences the term remote sensing is reserved for an examination of the Earth and its atmosphere using information gathered from the Earth’s surface or various altitudes above it.