Formation and evolution of the Solar System

There is evidence that the formation of the <a href="/facts/Solar_System/QIcLSazQ">Solar System</a> began about 4.6 <a href="/facts/Bya/5E7foypY">billion years ago</a> with the <a href="/facts/Gravitational_collapse/7f4zQs8Y">gravitational collapse</a> of a small part of a giant <a href="/facts/Molecular_cloud/5jEwCJxs">molecular cloud</a>. Most of the collapsing mass collected in the center, forming the <a href="/facts/Sun/CadPCVHh">Sun</a>, while the rest flattened into a <a href="/facts/Protoplanetary_disk/FtfSbP61">protoplanetary disk</a> out of which the <a href="/facts/Planet/rbPjE6Bx">planets</a>, <a href="/facts/Natural_satellite/AE4KQKbq">moons</a>, <a href="/facts/Asteroid/g7Ulr1VB">asteroids</a>, and other <a href="/facts/Small_Solar_System_bodies/Vrnr9n3M">small Solar System bodies</a> formed.
This model, known as the <a href="/facts/Nebular_hypothesis/IT3D6MpE">nebular hypothesis</a>, was first developed in the 18th century by <a href="/facts/Emanuel_Swedenborg/QE3Pcl8U">Emanuel Swedenborg</a>, <a href="/facts/Immanuel_Kant/vIxjdy6I">Immanuel Kant</a>, and <a href="/facts/Pierre-Simon_Laplace/6ktp0txb">Pierre-Simon Laplace</a>. Its subsequent development has interwoven a variety of scientific disciplines including <a href="/facts/Astronomy/0ArJVM1p">astronomy</a>, <a href="/facts/Chemistry/SrNqkGVm">chemistry</a>, <a href="/facts/Geology/WGvVRIYF">geology</a>, <a href="/facts/Physics/a7aH2y08">physics</a>, and <a href="/facts/Planetary_science/ocX6rp0d">planetary science</a>. Since the dawn of the <a href="/facts/Space_Age/48vLk51b">Space Age</a> in the 1950s and the discovery of <a href="/facts/Exoplanet/zjfmqfUf">exoplanets</a> in the 1990s, the model has been both challenged and refined to account for new observations.
The <a href="/facts/Solar_System/QIcLSazQ">Solar System</a> has evolved considerably since its initial formation. Many moons have formed from circling discs of gas and dust around their parent planets, while other moons are thought to have formed independently and later to have been captured by their planets. Still others, such as Earth's <a href="/facts/Moon/zKHqEMPb">Moon</a>, may be the result of <a href="/facts/Giant-impact_hypothesis/x2cw2Xxn">giant collisions</a>. Collisions between bodies have occurred continually up to the present day and have been central to the evolution of the Solar System. Beyond <a href="/facts/Neptune/1eucwHIC">Neptune</a>, many sub-planet sized objects formed. Several thousand <a href="/facts/Trans-Neptunian_object/oF5vsbz9">trans-Neptunian objects</a> have been observed. Unlike the planets, these trans-Neptunian objects mostly move on <a href="/facts/Orbital_eccentricity/WGlB4NBn">eccentric orbits</a>, inclined to the plane of the planets. The positions of the planets might have shifted due to gravitational interactions. The process of <a href="/facts/Planetary_migration/rH6cEwNR">planetary migration</a> explains parts of the Solar System's current structure.
In roughly 5 billion years, the Sun will cool and expand outward to many times its current diameter, becoming a <a href="/facts/Red_giant/lla6Bsvy">red giant</a>, before casting off its outer layers as a <a href="/facts/Planetary_nebula/5Vy84cPq">planetary nebula</a> and leaving behind a stellar remnant known as a <a href="/facts/White_dwarf/gIYlTtrC">white dwarf</a>. In the distant future, the gravity of passing stars will gradually reduce the Sun's retinue of planets. Some planets will be destroyed, and others ejected into <a href="/facts/Interstellar_space/R3LRKyFs">interstellar space</a>. Ultimately, over the course of <a href="/facts/Timeline_of_the_far_future/0AYlHLon">tens of billions</a> of years, it is likely that the Sun will be left with none of the original bodies in orbit around it.

Formation and evolution of the Solar System open-in-new

Formation and evolution of the Solar System