Eris is about 9 billion miles (15 billion kilometers) from the sun at its farthest orbital point, making it about twice as distant as Pluto.

Due to the near-circular orbits of Earth and Jupiter, as Earth has a faster orbital period than Jupiter, from our point of view we will appear to "overtake" the gas giant.

And the other thing to point out is that the energy that an anti-bonding orbital is raised by, is the same amount as a bonding orbital is lowered by.