894 Erda (prov. designation: or ) is a bright background asteroid from the outer regions of the asteroid belt. It was discovered on 4 June 1918, by German astronomer Max Wolf at the Heidelberg-Königstuhl State Observatory. The X-type asteroid has a short rotation period of 4.7 hours and measures approximately in diameter. It was likely named after a character in Wagner's Der Ring des Nibelungen, "Erda", who is the goddess of wisdom, fate and Earth, borrowed from the Norse sagas, and referring to both Urðr and Jörð in Norse mythology. Orbit and classification Erda is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements. It orbits the Sun in the outer main-belt at a distance of 2.8–3.5 AU once every 5 years and 6 months (2,013 days; semi-major axis of 3.12 AU). Its orbit has an eccentricity of 0.11 and an inclination of 13° with respect to the ecliptic. On 14 May 1907, the body's observation arc begins as () at Heidelberg; just two nights after its first observation, and more than 11 years prior to its official discovery observation. Naming According to The Names of the Minor Planets by Paul Herget in 1955, and adopted by Lutz Schmadel in the Dictionary of Minor Planet Names, this minor planet was named after the Norse goddess described as the "incarnation of the nature", and as "a seer who knows the origin and the destination of all things" (). The discoverer, Max Wolf, likely adopted the name from Wagner's opera cycle Der Ring des Nibelungen, which is loosely based on figures from the Norse sagas. In Wagner's Ring, the character , named after the Old High German word for "Earth", is the goddess of wisdom, fate and Earth. She is the world's wisest woman, the mother of the three Norns and of the valkyrie (shieldmaid) Brunhild, whose father is the norse chief god Odin (Wotan). Wagner, in turn, adopted the name from the treatise Deutsche Mythologie by Jacob Grimm (1785–1863) and other sources. Erda combines attributes of both, Urðr (wisdom and fate) and Jörð (the personification of Earth). Physical characteristics In both the Tholen- and SMASS-like taxonomy of the Small Solar System Objects Spectroscopic Survey (S3OS2), Erda is an X-type asteroid. Rotation period In June 2006, a rotational lightcurve of Erda was obtained from photometric observations by David Higgins at Hunters