According to the 4-inch-wide arthropod, the entire planet-once nothing more than a large, tedious mass of molten rock-has really taken shape recently.

What does matter a lot is Eris' surprisingly large mass, which means it has considerably more rock underneath its icy surface than Pluto.

When a large mass of dirt and rock falls into a body of water very quickly the water is displaced and starts racing away from the slide.