Astronomers have spotted seven new examples of the cosmic phenomenon known as dark comets that could help scientists discover whether these celestial bodies helped deliver important elements like water to Earth early in the planet's history.
The latest discovery by astronomers has doubled the known number of these mysterious celestial bodies throughout our solar system that resemble asteroids but travel through space like comets, albeit without the "tail" that comets are known for.
The new research, published in the journal "Proceedings of the National Academy of Sciences", also shows that there are two different populations of these objects, reports CNN.
The discovery of more dark comets has helped astronomers realize that these celestial bodies are not as rare as previously believed.
"One of the most important reasons we study small bodies, like asteroids and comets, is that they tell us about how material is transported through the solar system," lead study author Darryl Seligman, a postdoctoral fellow in physics and astronomy at Michigan State University, said in a statement. .
"Dark comets are a new class of near-Earth objects that may contain water, so they are a new potential source for delivering materials to Earth that were necessary for the development of life. The more we learn about them, the better we can understand their role in the origin of our planets".
Discovery of an interstellar visitor
Astronomers studying what they believed to be an asteroid named 2003 RM two decades ago noticed that the object had shifted slightly from its predicted orbit.
The movement cannot be explained by accelerations that are typical for asteroids, such as the so-called Jarkovski effect, when space rocks absorb heat from the sun and then emit it as infrared radiation, which can cause additional thrust in the asteroid, reports Danas.rs.
Instead, the 2003 RM moved more like a comet. The Sun causes material such as ice inside a comet to turn directly into gas through a process called sublimation. This evaporation provides comets with thrust. Thrust is evident from the tail seen streaming behind the comet, which is made of evaporating material.
"But try as we might, we couldn't find any sign of a comet tail. It looked like any other asteroid - just a point of light. So in a short period of time we had this one strange celestial object that we couldn't fully explain," he said. said study co-author Davide Farnokija, a navigation engineer at NASA's Jet Propulsion Laboratory in Pasadena. "This is a puzzle that challenges the way we've always classified objects as either asteroids or comets."
Then astronomers spotted 'Oumuamua in 2017. It was the first observed object in our solar system that formed outside of it.
Scientists briefly observed 'Oumuamu through telescopes before the interstellar visitor completed its rapid transit through our solar system, sparking a host of hypotheses about its true nature, including even the possibility that it may have been an alien probe.
Telescopic observation showed that 'Oumuamua looked like a point of light, similar to an asteroid, but its trajectory shifted as if it was throwing material, similar to a comet, which makes it difficult to determine which of the objects in question, reports RTS.
"'Oumuamua surprised us in several ways," Farnokija points out. "The fact that the first object we discovered from interstellar space showed similar behavior to 2003 RM made 2003 RM even more intriguing."
In 2023, Farnokia and Seligman published research that described a total of seven objects observed in our solar system with unusual 'Oumuamua-like aspects that blurred the line between asteroids and comets. Scientists have named this new class of objects dark comets.
Now, with the discovery of seven more dark comets, researchers have been able to see differences between their populations.
"We had a large enough number of dark comets that we could start to consider whether there was something that would distinguish them," adds Seligman.
"By analyzing reflectivity and orbits, we discovered that our solar system contains two different types of dark comets."
Inner dark comets can be found in the interior of the Solar System, which includes the planets Earth, Venus, Mars, and Mercury, and move in nearly circular orbits around the Sun. The celestial objects are small, only tens of meters in diameter, and may originate from the main asteroid belt, located between the orbits of Mars and Jupiter.
Meanwhile, outer dark comets, which may have come from the outer regions of our solar system near Jupiter and beyond, have distinct oval-shaped orbits and can be hundreds of meters or more in diameter.
Research on the origin of water
Now that astronomers have found populations of dark comets, they want to determine whether these objects contain ice, what's behind their acceleration, and where they came from.
A better understanding of dark comets could shed light on whether these objects contributed to Earth's early evolution by impacting it as the planet was forming.
"What many people may not think about is that the solar system is a chaotic place," Seligman points out.
"We don't know where the stuff comes from, but with 14 dark comets that we now know are orbiting within our solar system, over the next few years there is an opportunity to collect more data and hopefully uncover answers about the formation of our planet."
Previous research has shown that up to 60 percent of near-Earth objects may be dark comets.
While asteroids are devoid of ice because they orbit closer to the Sun, comets are icy bodies that resemble dirty ice cubes and have a larger orbit. But dark comets, which are near-Earth objects, can be found in the main asteroid belt, between the orbits of Mars and Jupiter, and can contain ice. And if ice is common on small bodies like dark comets in the near-Earth environment, they may have been responsible for bringing water to Earth.
Astronomers are also trying to determine why dark comets are so small and orbit so fast.
Fortunately, the Japan Aerospace Exploration Agency's Hayabusa 2 spacecraft is expected to rendezvous with one of the dark comets, 1998 KI26, in 2031 as part of its extended mission, which could reveal more unique features of these not-so-unusual comets. celestial objects.
Bonus video:
