It was the duty of Earth, as the nearest of the Circle planets to Zirda, to find out what had happened. With this aim in view the expedition’s ship had taken on board a large number of instruments and several prominent scientists, those whose nerves, after lengthy testing, had proved capable of standing up to confinement in a spaceship for several years. The ship was fuelled with anameson; only the barely necessary amount had been taken, not because of its weight but because of the tremendous size of the containers in which it was stored. It was expected that supplies could be renewed on Zirda. In case something serious had happened to Zirda, Second Class Spaceship Algrab was to have met Tantra with fuel supplies on the orbit of planet K2-2N 88.

Nisa’s attuned ear caught the changed tone in the hum of the artificial gravitational field. The discs of three instruments on the right began to wink irregularly as the starboard electron feeler came into action. An angular mass flashed on to the screen, brightening it up. It flew straight at Tantra like a shell which meant that it was a long way away — a huge fragment of material such as is seldom met with in cosmic space, and Nisa hurried to determine its volume, mass, velocity and direction. She did not return to her meditations until the spool of the automatic log gave a click to show that the entries were finished.

Her most vivid memory was that of a blood-red sun that had been steadily growing in their field of vision during the last months of their fourth space-borne year. It had been the fourth year for the inhabitants of the spaceship as it travelled with a speed of 5/6ths of the absolute unit, the speed of light, but on Earth seven of the years known as independent years had passed.

The filters on the screens were kind to human eyes; they reduced the composition of the rays of any celestial body to what they would have been had they been seen through the thick terrestrial atmosphere with its protective screens of ozone and water vapours.