Scientists have found evidence that the gassy halo of Halley's comet contains tiny chains of formaldehyde molecules that may be older than the solar system. The evidence comes from data collected by the Giotto spacecraft as it flew by the comet in March, 1986, according to two papers in the current issue of Science magazine.
Comets are considered remnants of the gas and dust that condensed to create the sun and its planets. The presence of formaldehyde chains in Halley's comet suggests that they formed before the sun appeared, researchers said. Formaldehyde is made of carbon, hydrogen and oxygen, among the most abundant elements in space.