Jovian planets did not form in the inner solar system because: A. It was too hot for light-weight but abundant water, ammonia, and methane molecules to accrete into planetesimals that were sufficiently massive to gravitationally pull hydrogen and helium gas out of the solar nebula. B. It was cool enough in the inner solar system to accrete heavier metal and rock molecules into planetesimals, but since metals and rocks are significantly less abundant than water, ammonia, and methane, these planetesimals were small and not sufficiently massive to gravitationally pull hydrogen and helium out of the solar nebula.

The Jovian planets were formed beyond the frost line where hydrogen compounds could condense. Within it, the temperatures were very high and so hydrogen ice could not form. Only solid particles composed of rocks and metal were made. The terrestrial planets were formed from this planetesimals and were too small to capture large amount of hydrogen and helium. Jovian planets were formed farther away from the rocks and ices and grew large enough to pull hydrogen and helium gases.