Light is not the only source of pollution to guard against. A lot of the elaborate arrangements at Paranal made sure that very little heat escaped from the human habitation at the residency. Humans and their infrastructure generate heat, which normally escapes into the atmosphere setting up air currents. Any such disturbances in the vicinity of the telescope make the images of the heavenly bodies flicker. To avoid this phenomenon and to get as steady and clear images as possible, every attempt is made to reduce air currents.

While these problems bring headaches to the optical astronomers who use visible light for their observations, their radio counterparts are no more fortunate. In radio astronomy, the radio waves bring information about cosmic sources far and near. These radio signals are basically very faint and demand sophisticated devices in the radio telescopes to catch and store them. However, these efforts are negated if the background in which the radio telescope operates is noisy, having a profusion of man-made radio waves.

Imagine a school classroom with many students. One naughty boy lets out a shrill whistle. If the overall class is quiet, the teacher can easily identify the culprit. In a noisy classroom, however, this may not be so easy. In the same way, a radio astronomer will not function efficiently in detecting and observing faint sources in a noisy environment. For this reason, radio astronomers the world over have to engage in vigorous lobbying and elaborate international protocols to ensure that the radio wavelengths they use are safe from incursions by the advancing technology. The spread of cell phones is thus a potential threat to radio astronomy.

... contd.