wrote:
snipsnipsnip

Imagine the Solar System when it is forming out of the primal nebula,
it formed out of. The cloud that formed the Sun has rotated,
flattended by that rotation into a disc, most of the mass has gathered
into the center forming a young Sun, already burning with fusion
flame. Within the rest of the material of that disc, our familiar
planets have begun to form.

However, the situation is not identical from today. The disc has not
yet dissipated, and it is excerting gentle but constant drag on
Jubiter, causing it to gradually loose orbital energy forcing it to
move closer to the Sun.

Inside it, the familiar rocky planets are forming, but in addition
there is a planet forming outside what is now the orbit of Mars. As
Jubiter moves closer it´s greater gravity ultimatelly perturps the
orbit of that protoplanet, which has achiewed roughly the size and
mass of Mars of today.

Eventually the orbit of that planet is disturbed to such a degree that
it leaves its orbit and is flung towards the Sun. In its path towards
the Sun it encounters the Earth and collites with it, in such a way
that enough material is thrown up from Earth into Earth orbit that the
Moon is eventually formed. The remains of the planet go on and impact
the Sun and are vapourized.

Some time later, a gigant nearby supernova clears away the dust-disc
and Jubiter stops drifting towards the Sun...end of scenario.

Cheers, Einar