Fourteenth recorded perihelion passage of Halley’s Comet.

Halley’s Comet is one of the most famous and well-documented comets, primarily because it’s visible to the naked eye from Earth and returns roughly every 76 years—making it a “short-period” comet. Named after the English astronomer Edmond Halley, who accurately predicted its return in 1758, this comet has been observed since at least 240 BCE, with records found in ancient Chinese, Babylonian, and medieval European texts. What makes Halley’s Comet especially interesting is that it’s the only short-period comet visible without a telescope and that it was the first comet recognized as periodic. Its nucleus is about 15 kilometers long and composed mainly of ice, dust, and gas. When it nears the Sun, solar radiation causes its icy surface to sublimate, creating a bright coma and a long, luminous tail that can stretch for millions of kilometers. The next time it’s expected to visit Earth’s vicinity is in 2061, so mark your calendar—it’s a once-in-a-lifetime sky show worth waiting for.