‘Dark comets’ could reveal how Earth got its oceans

Dec 28, 2024

Dark comets offer clues to the origin of Earth's water, potentially revealing its oceans' history.

‘Dark comets’ could reveal how Earth got its oceans

: Comets and asteroids are thought to have delivered water to Earth, with dark comets being a potential source. Identified by Darryl Z. Seligman's research, 14 dark comets have been categorized into two types: larger outer dark comets and smaller inner dark comets. Outgassing without visible tails explains their non-gravitational acceleration. Future telescopes, including the Vera C. Rubin Observatory, may discover more, enhancing understanding of Earth's oceans.

Water is crucial to the development of life on Earth, yet its origin remains uncertain. Darryl Z. Seligman's study on dark comets, a mix of comet and asteroid characteristics, provides potential insights. These objects exhibit non-gravitational acceleration due to outgassing, but lack the dusty tails of traditional comets.

Seligman and his colleagues have identified 14 dark comets, categorized into outer and inner groups based on size and orbit. Although not fully understood, these comets may outgas water, potentially contributing to Earth's early water sources. Future technologies like the Vera C. Rubin Observatory's powerful survey capabilities aim to uncover more such objects.

The Rubin Observatory, operational in 2025, promises nearly unprecedented sensitivity in tracking night sky motion. This research's foundation was supported by an NSF Astronomy and Astrophysics Fellowship and contributions from Charles Simonyi. The findings could illuminate the composition and delivery methods of Earth's water, impacting theories on the planet's development and life genesis.