History of Solar System formation and evolution hypotheses with Uranus having a 98° tilt. The Moon being relatively large with respect to the Earth and other moons which are in irregular orbits with respect to their planet is yet another issue. It is now believed these observations are explained by events which happened after the initial formation of the Solar System. Attempts to isolate the physical source of the Sun's energy, and thus determine when and how it might ultimately run out, began in the 19th century. At that time, the prevailing scientific view on the source of the Sun's heat was that it was generated by gravitational
History of Solar System formation and evolution hypotheses stars and clusters and the star-clouds of the Milky Way", which proposed that the planets formed in the outer Solar System and were captured by the Sun; the moons were formed in thus manner and were captured by the planets. This caused a feud with Forest Moulton, who co-developed the planetesimal hypothesis. A preview was presented in 1909 at a meeting of the ASP (Astronomical Society of the Pacific) at the Chabot Observatory in Oakland, Cal., and newspaper headlines blared "Prof. See's Paper Causes Sensation" (San Francisco Call) and "Scientists in Furore Over Nebulae" (San Francisco Examiner). Our current knowledge