Extragalactic astronomy is the study of objects and phenomena beyond the Milky Way. Among the most observed deep-space objects is the Whirlpool Galaxy (aka Messier 51). Located 31 million light-years away in the constellation Canes Venatici, it offers a face-on view enabling astronomers to study its magnificent spiral structure comprising huge numbers of stars.

Within its centre and along its swirling arms, dense clouds of gas and dust are being compressed to create clusters of new stars. Not only is the Whirlpool Galaxy a captivating sight, but it also offers researchers an unprecedented opportunity to investigate star-forming processes.

This uniquely patinaed coin portrays a coloured representation of the Whirlpool Galaxy, encircled by the inscriptions ‘EXTRAGALACTIC’, ‘23.58 KPC | 31 MLY’ (its diameter in kiloparsecs and distance from Earth in megalight-years), and its location on the celestial sphere at coordinates ‘RA 13h 29m 53s | Dec +47° 11’ 43’.

Representing stars within the Galaxy’s arms, the reverse is hand set with a pink, golden, and two white diamonds. Also included are the designer’s initials ‘NM’, The Perth Mint’s ‘P’ mintmark, and the 2025 year-date.

These coins have been individually treated to give them a pleasing patina, a surface look normally associated with objects that have grown more beautiful over time. As a result of this treatment, the appearance of each coin in the mintage may vary.