Ten new dark comets were discovered recently by the Dark Energy Camera (DECam) instrument placed on a large telescope in Chile.

About Dark Comets

• A Dark Comet is a celestial object that looks like an asteroid (devoid of the bright coma characteristic of traditional comet)  but moves through space like a comet(such as sudden accelerations)
• First Discovery: The first dark comet, identified in 2016, was asteroid 2003 RM and was nicknamed “The Asteroid that Wanted to be a Comet.”
  • NASA in 2017 discovered (‘Oumuamua’), the first ever documented celestial object that originated outside the solar system which appeared like an asteroid but behaved like a comet.
• Categories: There are 2 main categories of Dark Comets,
  • Inner Dark Comets: They reside in the inner solar system and travel in nearly circular orbits, and are on the smaller side (tens of meters or less).
  • Outer Dark Comets: They have similar characteristics to Jupiter-family comets ie. They have highly eccentric (or elliptical) orbits and are on the larger side (100m or more).
• Characteristics: 
  • Elusive: Dark comets lacks the characteristic feature of a comet ie. a glowing tails and instead appear as a faint point of light in space resembling an asteroid.
  • Orbit: Dark comets follow elongated, elliptical paths and can go beyond Pluto, some even making it out to the Oort Cloud,
  • Size: Dark comets are often small objects, just a few metres to a few hundred metres wide leaving less surface area for material to escape and form into the beautiful tails as seen on typical comets. 
  • Spin: They often spin quite rapidly and disperse escaping gas and dust in all directions, making them less visible.
  • Composition or Age: Their composition and age may result in weaker or no gas loss, as the materials that go into the tails of bright comets are depleted over time.
• Significance: 
  • Planet Formation: Studying Dark Comets assumes significance as it could hold clues about the formation of Earth, the origins of Earth’s water, and even the beginning of life 
  • Abundance: A 2023 study suggested that between 0.5% and 60% of all NEO might be dark comets originating from the asteroid belt between Mars and Jupiter.

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