Originally shared by Ethan Siegel
“On November 15th, it will make its closest approach to the Sun — perihelion — passing interior to the orbit of Earth and reaching a minimum distance of 123 million km (76.5 million miles) from the Sun. After that, it will make its closest approach to Earth, where it may well become a naked-eye comet, and will certainly be visible through even a cheap pair of binoculars.”
Originating from the Kuiper belt and the Oort cloud, comets are generally thought of as periodic objects, with their initial trajectories having been perturbed by either Neptune, another distant object or a passing star or rogue planet. But most comets aren’t periodic; they’re transient instead, where a trip into the inner Solar System gives them additional gravitational perturbations, causing them to either fly into the Sun or gain enough kinetic energy to escape entirely. This latter fate is the case for Comet Catalina, which reaches perihelion on November 15th and then heads out of the Solar System after putting on one final show for observers on Earth.