Heliocentric universe. This diagram of a heliocentric universe was published by the English astronomer Thomas Digges (1546-1595) in A prognostication everlastinge (1576 edition). The heliocentric theory of Copernicus had been published in 1543, and Digges was one of the first people to publish it in English. He added this diagram in an appendix to the original book by his father, which had featured the older Ptolemaic theory of a geocentric universe. In this diagram, the Sun is at center, with the six known planets in successive spheres, followed by an outer sphere of stars.