Timeline of discovery of Solar System planets and their moons



The timeline of discovery of Solar System planets and their natural satellites charts the progress of the discovery of new bodies over history. Each object is listed in chronological order of its discovery, identified through its various designations, and the discoverer listed.
Historically the naming of moons did not always match the times of their discovery. Traditionally, the discoverer enjoys the privilege of naming the new object; however, some neglected to do so or actively declined. The issue arose nearly as soon as planetary satellites were discovered: Galileo referred to the four main satellites of Jupiter using numbers while the names suggested by his rival Simon Marius gradually gained universal acceptance. The International Astronomical Union eventually started officially approving names in the late 1970s.

Key info

In the following tables, planetary satellites are indicated in bold type while planets and dwarf planets, which directly circle the Sun, are in italic type. The Sun itself is indicated in roman type. The tables are sorted by publication/announcement date. Dates are annotated with the following symbols:
In a few cases, the date is uncertain and is then marked "".
* Note: Moons marked by an asterisk had complicated discoveries. Some took 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 legend
The planets and their natural satellites are marked in the following colors:
;Planets
;Dwarf planets
;Designations

17th century

18th century

19th century

20th century

1901–1950

1951–2000

21st century

2000s

2010s