Looking back: The Sky at Night
31 May 1981
On 31 May 1981, The Sky at Night took a look at the most distant major planet of our Solar System, Neptune. Though the gas giant had been discovered over a century before in 1846, it had remained something of an enigma. Neptune is some four and a half billion kilometres from Earth, making observations challenging. Even by 1981 little was known about the planet, though astronomers had managed to measure the planet’s rotation – once every 16 hours – and discovered at least one large moon, named Triton.
This would soon change, however, as interplanetary spacecraft Voyager 2 was due to fly past the planet in 1989. On the episode, presenter Patrick Moore spoke with Garry Hunt, a member of the spacecraft’s imaging team, about what the
future flyby
hoped to achieve. When Voyager 2
eventually flew
past the planet on 25 August 1989, it revealed a surprisingly lively world. Despite being far away from the heat of the Sun, the planet was home to the fastest winds in the known Solar System, which reached over 2,000 km/h.
Moore and Hunt teamed up over Neptune once again in 1994, when the pair wrote a summary of all we knew about the planet up until that point, called Atlas of Neptune.