The comet is a visitor from the Oort Cloud, the cloud of frozen debris surrounding the solar system. In January 2015, during its closest approach to the sun, the comet was visible to the naked eye; its unusual brightness made it a good hunting ground for molecules. Planetary scientist Nicolas Bevet of the Paris Observatory in Meudon, France, and his colleagues observed the comet using a radio telescope in the Sierra Nevada Mountains of Spain.

Ethanol and glycolaldehyde have been found in areas where planets are forming around young stars. The discovery of these molecules on comets - "frozen time capsules" from the dawn of the solar system - suggests they have been preserved from the sun's early days. Although comets probably didn't play a big role in delivering water and organic matter to the young Earth, they have a lot in common with the asteroids that did.

A comet called Swift Tuttle enters the Earth's orbit from mid-July to mid-August every year. Astronomers say the meteors seen this year are actually dust emitted by the comet hundreds or even thousands of years ago.