The Saturnians, the Uranians, the Jovians, cannot have had very serious difficulty in effecting some communication with their satellites.
Jupiter's four moons, for instance, though on an average actually 2-1/2 times farther from their planet's centre than the Moon is from us, are comparatively four times nearer to him on account of his radius being eleven times greater than the Earth's.

With Saturn's eight moons, the case is almost precisely similar.

Their average distance is nearly three times greater than that of our Moon; but as Saturn's diameter is about 9 times greater than the Earth's, his bodyguards are really between 3 and 4 times nearer to their principal than ours is to us.

As to Uranus, his first satellite, _Ariel_, half as far from him as our Moon is from the Earth, is comparatively, though not actually, eight times nearer." "Therefore," said Barbican, now taking up the subject, "an experiment analogous to ours, starting from either of these three planets, would have encountered fewer difficulties.

But the whole question resolves itself into this.