One of the earliest questions asked by thinkers over the centuries, concerning the “plurality of worlds,” the commonness or rarity of other worlds like our own, was answered convincingly only during the past few decades, with the help of several orbiting telescopes designed to detect planets orbiting other stars. The result is that planets form naturally in the process of star formation. We are fortunate to have nearby a huge complex of gas and dust, the Orion Region, in which every stage of star formation is taking place and can be readily observed. Close observation of the accretion discs at the center of which stars are born shows very distinctly the formation of planets, and even moons of planets, within the disc... as gravity clears the orbits of the forming bodies. Gravity is always the great creator here, amplifying the slightest initial variations in density to form the structures we are familiar with, structures which in many cases make life itself possible. As of 14 March 2024, there are 5,599 confirmed exoplanets in 4,158 planetary systems, with 947 systems having more than one planet. Most of these were discovered by the Kepler space telescope.

Stars in the (sometimes violent) process of formation

Planetary systems forming, as the planets gradually clear their orbits.

A system with seven rocky planets!

Most stars are members of multiple star systems, so any planets in those systems may have complicated orbits. The nearest stars to us are the triple star system Alpha Centauri.

There is at least one known planet of a triple-star system which orbits the most massive of the stars.   [The planets in the Alpha Centauri system, by contrast,  orbit only the dim red Proxima, not the two sunlike stars.]