''We long to see the actual texture of the rings,'' wrote the astronomer and popular author R.S. Ball in 1886 in his best-selling The Story of the Heavens. But how could this ever be achieved? When G.D. Cassini was appointed to the directorship of the Paris Observatory, one enthusiastic optician had proposed developing a 1,000-foot-long arial refractor with which - it was calculated - it should be possible to see the inhabitants of the Moon. Of course, this telescope was never built. It was even more difficult to conceive of a telescope capable of resolving the fine structure of Saturn's rings. However, with the invention of the rocket, some astronomers started to dream of shooting into space in order to inspect the planets for themselves.
''Utter bilge'', scoffed Richard van der Riet Woolley in 1956. As the Astronomer Royal, his voice carried considerable authority. ''Space travel is inevitable,'' insisted Kenneth W. Gatland, a member of the council of the British Interplanetary Society. The United States announced that it would place a satellite into orbit of the Earth as part of the International Geophysical Year, which would actually run for 18 months from mid-1957 through 1958. On 4 October 1957, however, the Soviet Union placed Sputnik into orbit. The Space Age had begun. Within a decade, probes had landed on the Moon, and men were eager to follow them. It was evident from the manner in which the results from the first probes to make fly-bys of Venus and Mars revolutionised our thinking about these planets that the 'robotic explorer' represented a paradigm shift as profound as the invention of the telescope.
Telescopes have come a long way since Galileo's time. Commissioned in 1896, the 40-inch refractor of the Yerkes Observatory is still the most powerful such instrument in the world.
In the Space Age, robotic exploring machines (in this case Mariner 4) carry cameras and a variety of scientific instruments to make in situ observations of the planets.
Was this article helpful?