Comets are small pieces of rock and ice that start to evaporate when they enter the inner solar system, due to their proximity to the sun, but their spectacular appearance in our skies in the past has led to them being associated with completely unrelated events occurring on Earth. This is, of course, a myth, but comets can indeed pose some risk to Earth.

In 1994, Comet Shoemaker-Levy 9 collided with Jupiter, heating the gas giant’s atmosphere to thousands of degrees on impact. Such collisions with a small terrestrial planet like Earth would indeed be catastrophic for life, although chances of such an occurrence are indeed extremely remote.

Periodic meteor showers, however, are nearly all attributed to the passage of comets intersecting with Earth’s orbit in the past, with the shooting stars we observe being caused by the atmospheric entry of small pieces of dust that the comet would have left in its wake as it crossed Earth’s path.