A rebel genius

The year 2015 also happens to be the birth centenary year of Fred Hoyle, arguably the most imaginative astrophysicist of the 20th century. Hoyle was born in the small town of Bingley in Yorkshire, on June 24, 1915. To mark his centenary, there have been lectures and symposia related to his work. That, in itself, does not do justice to his numerous contributions to astronomy and astrophysics which practically cover the whole range of topics from comets to cosmology. But apart from the wide span of his work, the main aspect that should be appreciated is its highly original nature, whose significance his peers often failed to grasp. As a result, he often stood as an isolated rebel.

His rebellious nature was also visible during his school years, as seen from an episode he describes in his autobiography. Once his primary school teacher asked the class to collect samples of a certain type of flower that had begun to bloom with the arrival of springtime. She pointed out to the class that such flowers have five petals each. As the class dispersed and went in search of these flowers, Hoyle was able to find one with six petals. He was puzzled by this discrepancy: he could have explained four petals if one had fallen off but how to explain the extra one So he brought his anomalous sample to the attention of the teacher. Could she explain the extra petal The teacher was dismayed by this “counter-example” and rather than admit it to be so, she took it as an affront to her authority and punished the offender with a smack on his head.

This shocked the young Hoyle who left class, went home and told his mother that he would not return to school unless the teacher admits that her behaviour was wrong. His mother could see that his claim was just and backed him up so that the school authorities allowed Hoyle to study at home till the spring term was over, after which he was allowed to change school.

Science is all about man’s efforts to unravel how nature functions. Observations and experimentation lead to theories which provide the answer to the “how” aspect of a problem. If the theory works, well and good. But if there are instances where it fails, such anomalies call for further investigation.

Discovering something new from such problems requires an original approach, which was Hoyle’s landmark. Consider the following example. Why does a star like the Sun shine According to astrophysicists the answer was that a thermonuclear reactor in the core of the star makes nuclei of helium from fusion of hydrogen nuclei and in this process it releases energy. This opened up the possibility of going higher along the nuclear ladder, making carbon from helium, then oxygen, then neon, and so on. This appeared to resolve another mystery: how did the universe acquire all the chemical elements Alas! A giant stumbling block appeared to rule out this route to a solution.

It did not seem possible to make carbon from helium, as the process was not stable enough to work, like climbing a ladder whose rungs are weak. Hoyle, however, found a clever solution namely that the carbon nucleus had a state of high energy which could be directly reached by the fusion of three helium nuclei. Such a state is called “resonance” andit makes the reaction go fast.

Hoyle took this suggestion to the nuclear physicists at California Institute of Technology. They thought it to be incredulous at first, but finally Ward Whaling and Willie Fowler at the Kellogg Radiation Laboratory decided to conduct the experiment. Lo and behold! They found the excited state of carbon, with energy exactly as Hoyle had predicted. Hoyle later recalled that his reason for finding carbon in the excited state was based on the evidence that there is life on Earth. Life, as we know it, has carbon as an important part and so some way of making it had to exist.

In the mid-1950s, Hoyle was caught in another controversy. He wrote a paper advocating the existence of vast clouds of molecules, both organic and inorganic, spread over thousands of light years in the galaxy. He felt this was needed if life were a common phenomenon outside our Earth. His paper was rejected by several journals both in physics and astronomy. Frustrated, he wrote a science fiction novel in which he featured this idea. The novel called The Black Cloud became a bestseller and the idea of molecular clouds became well-known. A decade later astronomers could design and use millimetre wavelength telescopes which revealed the existence of molecular clouds just as Hoyle had predicted.

Perhaps the bitterest controversy surrounding Hoyle relates to his ideas on the origin of life. Together with his former student Chandra Wickramasinghe, now retired from a chair at Cardiff, Hoyle proposed what amounted to a revival of the panspermia hypothesis. This idea centres round tiny spores of bacteria and viruses encased in frozen ice travelling vast distances in the interstellar space. Such units may get into a comet and as its tail forms near the Sun the bacterial units will spread out along it. If the tail brushes the Earth’s atmosphere, these units would enter it and eventually fall on the surface of the Earth. Hoyle and Mr Wickramasinghe have argued that such showers of panspermia may have started life on the Earth. They have also argued that showers of viruses from the sky may bring occasional epidemics.

Biologists who are normally of the view that life is only known to exist on the Earth vehemently oppose this idea. While arguments for and against have been going back and forth, an experiment conducted in India may hold the clue to the actual answer. In this experiment, sponsored by Indian Space Research Organisation, air samples were collected from heights ranging from 25 to 41 km and examined in biological labs under sterile conditions. These showed bacteria of different kinds, some known and some new. Are they raining from above or climbing up from the Earth Further tests are needed to solve this riddle, which will show us whether Hoyle was, once again, right.

The writer, a renowned astrophysicist, is professor emeritus at Inter-University Centre for Astronomy and Astrophysics, Pune University Campus. He was Cambridge University’s Senior Wrangler in Maths in 1959.