A four-dimensional concept is now presented in a three-dimensional format.

A 2015 $2 coin in the name of Cook Islands visibly explains the relationship between space and time, as created by scientist Hermann Minkowski. Building on Albert Einstein’s 1905 Special Theory of Relativity, Minkowski suspected the existence of a fourth dimension (time, in addition to height, width and length), in which space and time are connected geometrically, and he created a diagram illustrating the connection.

The Prooflike half-ounce .999 fine silver $2 Space–Time Continuum coin was issued by Coin Invest Trust. It was struck by B. H. Mayer‘s Kunstprägeanstalt Mint in Munich, Germany. 

The reverse of the coin depicts the Minkowski diagram, a geometric illustration of the formula of special relativity, which is engraved in one of the diagram’s columns together with the inscription SPACE–TIME CONTINUUM. The center of the high-relief coin is marked with a magnetic sphere, which can be removed.

The obverse, whose shape is a mirror or inversion of the reverse, displays the Ian Rank-Broadley portrait of Queen Elizabeth II, the issuing nation and the face value.

Einstein incorporated Minkowski’s ideas into his general theory of relativity in 1915, six years after Minkowski died.

The coin measures 35 millimeters in diameter and has a mintage limit of 1,500 pieces. 

U.S.-based distributor Coin & Currency Institute is offering the coin, for $95 each. Shipping and handling is $5.75 per order.

To order, visit the distributor's website.