Now, new research has doubled the number of known dark comets and grouped them into two distinct populations.
A paper published this week in the Proceedings of the National Academy of Sciences details the discovery of seven dark comets, bringing the total number of known dark comets to 14.
By analyzing their reflectivity and orbits, the researchers identified two distinct populations of dark comets within the solar system.
The outer dark comets, which are similar to Jupiter-family comets, have highly eccentric, or elliptical, orbits and are on the larger side.
Dark comets may have played a crucial role in the origin of life on Earth.
A surprising visitor with a strangely elongated shape flew through the solar system in 2017. Prior to measurements showing it was speeding away from the Sun like a comet, the interstellar object—later named ‘Oumuamua’—was categorized as an asteroid. Because of its hybrid behavior, scientists determined that it was a dark comet, which is an object that resembles an asteroid but behaves more like a comet. According to recent studies, there are now twice as many known dark comets and they are divided into two different populations.
According to a paper this week in the Proceedings of the National Academy of Sciences, seven new dark comets have been discovered, increasing the total to 14. According to their size and orbit, the study also shows that these enigmatic objects can be divided into two different groups. Scientists are learning more about dark comets and their potential to have brought the elements necessary for life to Earth thanks to this most recent discovery.
In 2016, researchers discovered the first dark comet when they saw that the near-Earth asteroid 2003 RM was not following a normal trajectory. Davide Farnocchia, a researcher at NASA’s Jet Propulsion Laboratory and co-author of the new study, said in a statement that “when you see that kind of perturbation on a celestial object, it usually means it’s a comet, with volatile material outgassing from its surface giving it a little thrust.”. Even so, we were unable to locate any indications of a comet’s tail. It appeared as a pinpoint of light, just like any other asteroid. We thus had this one strange celestial object that we were unable to completely understand for a brief period of time. “.”.
When ‘Oumuamua appeared the following year, scientists recognized the correspondence between the two objects right away. “2003 RM was even more interesting because the first object we found from interstellar space showed similar behaviors to 2003 RM,” Farnocchia continued.
By 2023, six additional celestial bodies were recognized as possessing characteristics of both asteroid and comet, leading scientists to formally designate them as dark comets. After seven more dark comets were found, the researchers who conducted the new study decided it was time to start examining these objects’ various features. “We had a large enough number of dark comets that we could start asking if there was anything that would differentiate them,” said Darryl Seligman, the lead author of the new paper and a postdoctoral fellow in Michigan State University’s Physics department.
Two groups of dark comets in the solar system were distinguished by the researchers based on their orbits and reflectivity. Like comets in the Jupiter family, the outer dark comets are larger and have extremely eccentric, or elliptical, orbits. The second category of comets, known as inner dark comets, are smaller and move in almost circular orbits inside the inner solar system.
Researchers have only just begun to explore these odd objects. According to a recent study, dark comets make up almost 60% of all near-Earth objects. These comets may have been a part of larger bodies in the main asteroid belt, which is the area of the solar system between Mars and Jupiter, before being expelled and fragmenting into smaller pieces that now approach Earth.
The origin of life on Earth might have been significantly influenced by dark comets. The materials required for the emergence of life on Earth may have been brought to the planet by dark comets, according to Seligman. The more we know about them, the more we can comprehend how they contributed to the formation of our planet. “.”.
