|NASA, ESA, AND G. BACON (STSCI)|
An artist's impression of an object in the Kuiper belt at the outer edge of the solar system.
A cluster of icy bodies in the same region as Pluto could be proof that our early solar system was home to a fifth giant planet, according to new research. That planet may have “bumped” Neptune during its migration away from the sun 4 billion years ago, causing the ice giant to jump into its current orbit and scattering a cluster of its satellites into the Kuiper belt in the outer solar system.
The cluster—a grouping of about a thousand icy rocks called the “kernel”—has long been a mystery to astronomers. The rocks stick close together and never veer from the same orbital plane as the planets, unlike the other icy bodies that inhabit the belt. Previous studies proposed that the tightly bound objects formed from violent collisions of larger parent bodies, but that hypothesis fell apart as soon as scientists realized these collisional families would have to be stretched across the Kuiper belt.
Our early solar system may have been home to a fifth giant planet, Nola Taylor Redd