Sedna: a dwarf planet with a chaotic past

Dwarf planet candidates like Sedna, discovered in 2003, have incredibly stretched-out orbits, hinting they might be captured comets from the solar system's distant Oort cloud. Sedna, about 995 kilometers wide, takes 11,400 years to orbit the Sun, traveling from 76 to nearly 937 astronomical units away. Its path is so unstable that even small nudges from Neptune could drastically change it over billions of years.