|The gist of how the Egyptian gods, in the Jewish recension, became Judaic prophets (see: religious prophets); about which, Galileo (1614) was queried to explain how Copernican cosmology, with its "moving earth", could explain Joshua 10:13, based on the model that it is the sun (Ra) and moon (Thoth) that "move" about a stationary earth (Geb), according to Heliopolis cosmology (Heliopolis creation myth). |
In 1881, Gerald Massey, in his A Book of Beginnings (pg. 285), decoded the Joshua equals "god Shu" etymology as follows:
“Now as the name of Joshua was altered in order that the name of the male god Jah, made known by Moses, might be compounded with that of Shu or Shva ; and as Jah-Adonai is the sun-god Ra who adopted Shu as his son in the solar regime, it follows that Jah-Shua is the Hebrew equivalent Shu-si-Ra, and the original Oshea becomes the son of Adonai-Jah, just as the pre-solar god Shu in the creation by Ra becomes the son of Ra, whereas previously he was, like Joshua, the sun of Nun.”
In 1907, Massey, in his Ancient Egypt: the Light of the Modern World (Ѻ), elaborated on the above in more detail. Others to do the Joshua equals Shu etymology include: Andre Austin (c.2015) (Ѻ) and Libb Thims (2016), the latter, independently, while reading the story of the Sorrows of Isis in Muata Ashby (1997) and later Wallis Budge (1904).
The most cited mention, in secular literature, of Joshua is the story, as told in Joshua 10:13, of Joshua commanding both the sun and the moon stood still for an entire day; the physically-impossible descriptions, which has troubled geniuses (Maimonides, Gersonides, Galileo, Spinoza, Herder, Paine, Napoleon, etc.) for centuries, is a monotheistic rescript of the Egyptian mythology story of the Sorrows of Isis (line 205), wherein Isis finds her son Horus foaming at the mouth after being bitten by a scorpion and summons Ra the “sun” god and Thoth the “moon” god to her aid, to stop time and to heal her son; the god Shu, originally the grandfather of Isis, according to Heliopolis creation myth, becomes the man Joshua, from Jo- meaning “god” + -Shua meaning “Shu”. 
1. Thims, Libb. (2016). Smart Atheism: For Kids (pdf | 309-pgs). Publisher.
● Joshua – Wikipedia.