History of Solar System in Timeline

By Popular Timelines Editorial Team · Updated: July 8, 2025

The Solar System, named after the Sun, originated approximately 4.6 billion years ago from the collapse of a molecular cloud, resulting in the formation of the Sun and a protoplanetary disc. The Sun, at its center, is a typical G-type main-sequence star. It sustains equilibrium through hydrogen fusion into helium, releasing energy from its photosphere.

1915: Einstein's Theory of General Relativity Quashes Vulcan Searches

In 1915, Albert Einstein's theory of general relativity effectively ended the search for Vulcan, a hypothetical planet located interior to Mercury, explaining Mercury's orbital anomalies without requiring another planet.

1989: Visiting All Eight Planets by Space Probes

By 1989, all eight planets in the Solar System had been visited by space probes, marking a significant milestone in space exploration.

1992: Discovery of the first cubewano, 1992 QB1 (Albion)

In 1992, the first classical Kuiper belt object, originally designated 1992 QB1 and later named Albion, was discovered. These objects are called "cubewanos" and have near primordial, low-eccentricity orbits.

2006: Redefinition of Planet and Demotion of Pluto

In 2006, the term "planet" was redefined, resulting in the demotion of Pluto to a dwarf planet and sparking further interest in trans-Neptunian objects.

2016: Discovery of Proxima Centauri b

In 2016, the exoplanet Proxima Centauri b, a potentially habitable planet, was discovered orbiting Proxima Centauri. This is the closest confirmed exoplanet to the Sun.

2017: IAU Definition of Meteoroids

In 2017, the IAU designated solid objects with diameters between ~30 micrometers and 1 meter as meteoroids, replacing the micrometeoroid category and referring to smaller particles as 'dust particles'.

2060: Discovery of 2060 Chiron as a comet

In 2060, the first centaur, 2060 Chiron, was discovered and later classified as a comet (95P) because it develops a coma, similar to comets when approaching the Sun.