A pair of planetary scientists simulated how our solar system might have evolved if it had a super-Earth orbiting where the asteroid belt is today. The results are enough to make you grateful that we only have eight planets.

A super-Earth beyond Mars would have made Earth nearly uninhabitable

Source: space
Source Link: https://www.space.com/the-universe/solar-system/a-super-earth-beyond-mars-would-have-made-earth-nearly-uninhabitable