[madbadgalaxyman (Robert)]

This list gives the years when very major advances in human understanding of the physical world occurred. It excludes technological advances, and it leaves out advances in mathematics. So here are the most important scientific discoveries and the most revolutionary steps forward in human understanding. Included as scientific discoveries are important milestones in cartography & cosmography & astrometry & human anatomy, because the absolute prerequisite for scientific understanding is the accurate observation & description & drawing & measurement of the physical world.

This list is far from being comprehensive. Many discoveries in the exponentially expanding sciences of astronomy and biology were left out due to space limitations (I would like to have included the many discoveries regarding our own Galaxy and its various components!). And my apologies for the lack of chemistry advances, and for leaving out the long & complex history of work on the wave-particle duality. In reality, some of the important scientific discoveries are so new that their 20th Century History has only started to be investigated and recorded.

Some important discoveries aren't suitable for this timeline, as they were made through a very long history of fundamental advances made by many scientists. An example of this sort of scientific advance that is not suitable for a "General Science" timeline is the theory of stellar interiors and stellar evolution; this field was started 160 years ago by Helmholtz (1854) & Kelvin (1861) with a plausible physical theory of the energy source and the age of the Sun..... but stellar astrophysics is still very much under development as of today. The landmark papers on stellar physics and stellar evolution & nucleosynthesis are so numerous that they need their own Very Long timeline!

The discovery dates that are given here are, where possible, the year (or years) of the publication(s) of a major conceptual advance as a connected whole, in the form that eventually convinced the skeptics, rather than the dates when earlier scientists (or even the scientist who published the completed discovery) may have discovered parts of the final information content of a discovery.
I have aimed for accuracy in the the attribution of credit for each discovery, but attribution is quite often a source of ongoing heated controversy; please refer to the notes.