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
Oberon (operating system) powerful. A steep ascent in the early learning curve makes it a little bit difficult in the beginning. No questions are asked: this is a deliberate design decision, which needs getting used to. Most editors ask the user when closing a modified text: this is not the case in the Oberon System. The usage of the TUI and programming interface is fully documented in Martin Reiser's book "The Oberon System". A short introduction to the user interface can be found on Niklaus Wirth's home page. The later Versions of System Oberon, "Oberon V4" (or V4 in short, sometimes also referred