Timeline Of Discovery Of Solar System Planets And Their Natural Satellites

For comparison, discovery dates of the first fifteen Asteroid s are also included, down to the end of 1851. Beginning in 1852, in light of the fact that new asteroids were being discovered every year (eight were discovered in 1852 alone) and that it was becoming difficult to find appropriate symbols for all of them, the asteroids were placed in a new section in astronomical almanacs and given a new notation to replace the old symbols . For several decades, however, at least Ceres, Pallas, Juno and Vesta were considered full-fledged planets.

Historically the Naming Of Natural Satellites did not always match the times of their discovery.

In the following tables, planetary satellites are indicated in bold type (e.g. Moon) while planets, major or minor, which directly circle the Sun are in italic type (e.g. ''Earth''). The tables are sorted by publication/announcement date. When two dates are given, the first is publication, the second is the discovery observation's date. If a third date appears, it is the actual date of discovery (the date on which the discoverer first realised what he was looking at).

Note: Marked moons had complicated discoveries. Several moons took several years to be confirmed, and in several cases were actually lost and rediscovered. Others were found in Voyager photographs years after they were taken.''

Color code

The planets and their natural satellites are marked in the following colors:

PREHISTORY

17TH CENTURY

18TH CENTURY

19TH CENTURY

20TH CENTURY

21ST CENTURY

SPURIOUS SATELLITES

EXTERNAL LINKS

City of Hudson's Natural Satellite Page

Gazetteer of Planetary Nomenclature

Scott Sheppard's Giant Planet Satellite Page

JPL Natural Satellite Discovery Data

When Did the asteroids Become Minor Planets?

Information About

Timeline Of Discovery Of Solar System Planets And Their Natural Satellites