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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 (multiple dates occur when the moments of imaging, observation, and publication differ), identified through its various designations (including temporary and permanent schemes), and the ...
There is evidence that the formation of the Solar System began about 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular cloud. [ 1 ] Most of the collapsing mass collected in the center, forming the Sun, while the rest flattened into a protoplanetary disk out of which the planets, moons, asteroids, and ...
1609 – Johannes Kepler states his first two empirical laws of planetary motion, stating that the orbits of the planets around the Sun are elliptical rather than circular, and thus resolving many ancient problems with planetary models, without the need of any epicycle. [79]
At that time, Uranus, Neptune, nor the asteroid belts had been discovered yet. Discovery and exploration of the Solar System is observation, visitation, and increase in knowledge and understanding of Earth 's "cosmic neighborhood". [ 1 ] This includes the Sun, Earth and the Moon, the major planets Mercury, Venus, Mars, Jupiter, Saturn, Uranus ...
All planets orbit the Sun in elliptical orbits (image on the right) and not perfectly circular orbits. [72] The radius vector joining the planet and the Sun has an equal area in equal periods. [73] The square of the period of the planet (one revolution around the Sun) is proportional to the cube of the average distance from the Sun. [74]
The most widely accepted model of planetary formation is known as the nebular hypothesis. This model posits that, 4.6 billion years ago, the Solar System was formed by the gravitational collapse of a giant molecular cloud spanning several light-years. Many stars, including the Sun, were formed within this collapsing cloud.
720,000 km/h (450,000 mi/h) [10] Orbital period. ~230 million years [10] The Solar System[d] is the gravitationally bound system of the Sun and the objects that orbit it. [11] It was formed about 4.6 billion years ago when a dense region of a molecular cloud collapsed, forming the Sun and a protoplanetary disc.
This is a timeline of Solar System exploration ordering events in the exploration of the Solar System by date of spacecraft launch. It includes: All spacecraft that have left Earth orbit for the purposes of Solar System exploration (or were launched with that intention but failed), including lunar probes. A small number of pioneering or notable ...