How does the solar nebula theory explain the dramatic density difference between the terrestial and Jovian pla?
The general idea is that it is warmer closer to the Sun and colder as you go further out. This means that in the inner solar system molecules like water, ammonia and methane tend to stay as gases and not produce grains and clumps and so on. And because they stay in gas form the radiation pressure from the Sun and the solar wind will push them outwards. Around the orbit of Jupiter is becomes cold enough for ice to form. The gaseous molecules can produce grains and lumps so there’s a lot of this less dense material around to accrete into planets. Jupiter and Saturn grew large enough to pull in great quantities of hydrogen and helium from the solar nebula. The inner planets accreted from grains containing heavier atoms like oxygen and aluminium and silicon as well as iron and nickel and so on. Consequently inside the ice limit at 5 AU only small, dense planets can form, while outside there is matter enough to form the gas giants.
