Resumen de Not set in stone (or ice).
The article discusses a model for comet production that revises the theory of their origins. Chunks of ice and dust that reside in the Oort cloud, beyond the orbit of the dwarf planet Pluto, become dislodged and enter the solar system as streaking comets. Topics include an overview of how the planets Jupiter and Saturn influence comet dynamics, a computer simulation by researchers Nathan Kaib and Thomas Quinn hypothesizing comet production, and the role of comets in major extinctions on Earth.
