Albert Einstein was a giant in the scientific community, and his Theory of General Relativity was probably his greatest work. Ten years earlier, in 1905, he published a paper linking space and time, called Special Relativity. General Relativity expanded on it by incorporating gravity, saying the observed gravitational effect between masses is the result of their warping of spacetime. Einstein wasn’t fallible, and this was cutting edge science, so the challenge became how to prove its viability.

On September 21, 1922, there was a total eclipse of the sun, and two expeditions set out to use it to prove General Relativity. One of them, in Wallal, Western Australia, successfully used photographs of the eclipse to precisely measure the positions of the bodies, indicating that indeed, Einstein was right. It was called the Wallal Expedition, and the RAM’s new coin celebrates its centenary.

The RAM has a fairly long association with domed coins, arguably popularising the format with its Southern Sky, and subsequent series of astronomy themed issues. After a quiet spell, they’re back with this one-ounce proof silver coin, depicting a stylised Earth and Moon sitting in the centre of a gravitational warp, with the Sun in the background.  Simple, yet very effective, it does a great job of giving us a hint of this complex theory on a single coin. The concave nature of the reverse face enhances the effect. The convex obverse depicts the effigy of Queen Elizabeth II. It comes boxed with a COA, and is available now for $130.00 AUD

LINK: Royal Australian Mint product page