timeline of scientific discoveries

The [timeline] below shows the date of publication of major [scientific] theories and discoveries, along with the discoverer. In many cases, the discovery spanned several years.

BC
- [17th century BC] - [Venus tablet of Ammisaduqa] : first known [Babylonian astronomical observations]
- [8th century BC] - [Aitareya Brahmana] : [heliocentrism]
- [430s BC] - [Thucydides] : [immune system]
::: [Democritus] - Accurate [atomic hypothesis] . Atoms ( [quarks] ) are indivisible, indestructible & between atoms lies empty space.
- [360s BC] - [Eudoxus of Cnidus] : first [Greek planetary models]
- [350s BC] - [Heraclides] : [Earth's rotation]
- [3rd century BC] - [Eratosthenes] : calculated the size of the [earth] and its distance to the [sun] and to the [moon]
- [150s BC] - [Seleucus of Seleucia] : discovery of [tide] s being caused by the moon

[2nd century]
- [150s] [Ptolemy] : produced the [geocentric model] of the solar system

[8th century]
- [Jābir ibn Hayyān] (Geber): beginning of [chemistry] and [experiment] al method; discovery of [hydrochloric] , [sulfuric] , [nitric] and [acetic acid] s; discovery of [soda] , [potash] , [distilled water] and pure [alcohol] ( [ethanol] ); the discovery that [aqua regia] , a mixture of nitric and hydrochloric acids, could dissolve [metal] s such as [gold] ; and discovery of [liquefaction] , [crystallisation] , [purification] , [oxidisation] , [evaporation] , [filtration] and [sublimation]

[9th century]