THE COSMIC ENERGY PROBLEM

We here on Earth are constantly reminded by experts that with advancing technology our energy needs are growing, and that we need to worry about stocks of oil, coal, nuclear fuel, etc. that are needed to generate energy to meet these demands all over the world. How long will the supplies last? Can we extend that period by conserving energy? If so, how? These questions are being debated by experts and lay people alike.

Astronomers face the ‘energy problem’ in their investigations of cosmic sources of radiation. The age-old problem, where the Sun gets its energy to shine so brightly and steadily, has been solved. In Chapter 4 we saw that the key to solar energy lies in the nuclear fusion going on in the central core of the Sun.

But in the 1950s new problems with far greater magnitude began to confront the astronomers. The radio astronomers began to find sources of radio emission whose total energy reservoir exceeded that of the Sun by several billion. Where did the source of this energy lie? The problem was exacerbated in the early 1960s with the discovery of quasi-stellar sources, commonly called quasars. Initially mistaken for stars, quasars turned out to be far more energetic, and far more dramatic in spending their energy.

A typical quasar radiates in visible light as much as a galaxy of hundred billion stars. It also radiates in X-rays and possibly other wavebands.