The Webb telescope detects water in an unusual comet.

Astronomers used the James Webb Space Telescope to observe a rare comet in our solar system, making a long-awaited scientific breakthrough and stumbling across another mystery. The space observatory detected water vapor around Comet Read, suggesting that water ice can be preserved in a warmer part of the solar system. Comets typically exist in the Kuiper Belt and Oort Cloud, icy regions beyond the orbit of Neptune that can preserve some of the frozen materials left over from the formation of the solar system. A rare subclass of comets called main belt comets are objects in the asteroid belt with circular orbits around the sun that periodically exhibit cometlike behavior, such as shedding material that creates a fuzzy appearance and a trailing tail. Rather than shedding icy material through sublimation, the main belt comets only seemed to eject dust.

Main belt comets in the inner solar system were not expected to retain much ice until now. This discovery could add more evidence to the theory of how water became a plentiful resource on Earth early in its history. Comets and water-rich asteroids may have collided with early Earth and delivered water to our planet. Understanding the history of water distribution in the solar system will help us to understand other planetary systems, and if they could be on their way to hosting an Earth-like planet.