<P> The various planets are thought to have formed from the solar nebula , the disc - shaped cloud of gas and dust left over from the Sun 's formation . The currently accepted method by which the planets formed is accretion , in which the planets began as dust grains in orbit around the central protostar . Through direct contact , these grains formed into clumps up to 200 metres in diameter , which in turn collided to form larger bodies ( planetesimals ) of ~ 10 kilometres ( km ) in size . These gradually increased through further collisions , growing at the rate of centimetres per year over the course of the next few million years . </P>
<P> The various planets are thought to have formed from the solar nebula , the disc - shaped cloud of gas and dust left over from the Sun 's formation . The currently accepted method by which the planets formed is accretion , in which the planets began as dust grains in orbit around the central protostar . Through direct contact , these grains formed into clumps up to 200 metres in diameter , which in turn collided to form larger bodies ( planetesimals ) of ~ 10 kilometres ( km ) in size . These gradually increased through further collisions , growing at the rate of centimetres per year over the course of the next few million years . </P>
where did the elements that formed planets come from
where did the elements that formed planets come from
from the solar nebula , the disc - shaped cloud of gas and dust left over from the Sun 's formation
from the solar nebula , the disc - shaped cloud of gas and dust left over from the Sun 's formation