Before Vulcan became the birthplace of Mr Spock and a British bomber aircraft, but after it was the Roman god of fire and volcanoes, it was a non-existent planet.
The Hunt for Vulcan by Thomas Levenson is a great little book telling the story of how Newton’s theory led to its discovery and Einstein’s general theory of relativity led to its destruction.
Newton’s amazing work led to the discovery of a whole host of celestial objects as theorists looked at the trajectories of the existing planets and realised that to explain their paths through the sky there must be other bodies whose gravitational force was affecting them. The most famous example at the time was Neptune theorised by Urbain Le Verrier and then observed by astronomer Johann Gottfried Galle.
The progression of the planet Mercury made everybody at the time think that it too must have a hidden body affecting its orbit and many people claimed to have seen it. For over a hundred years astronomers searched for Vulcan — even naming the shy planet before they’d truly found it.
Ultimately though, it took Einstein to realise that Vulcan wasn’t just hiding, it didn’t exist. Newton’s theory only told us so much about the universe. The slight discrepancy in the progression of Mercury from Newton’s laws was actually a result of relativity not a hidden planet. The Hunt for Vulcan tells the story of how Einstein developed his theory and you can’t help but marvel at just how much of a one-off he was. In a few short years, Einstein completely changed science and our understanding of the universe and in so doing proved that Vulcan just didn’t exist.