Comets that have hit Earth have been a mixed bag. Early in Earth's history, during the solar system's chaotic beginning, they ...

Comets are notoriously unpredictable. Some of the most spectacular of these icy visitors pop up unexpectedly, careening ...

Pluto resembles the icy, comet-like objects orbiting the Sun outside of Neptune's orbit, rather than either the rocky terrestrial planets or the Jovian planets. Factors that distinguish Pluto from ...