You’ve heard of dark matter by now, but have you heard of dark comets? Probably not. And you’ll be very surprised to hear that, according to a new study, about 60% of all near-Earth objects are dark comets.

These mysterious celestial bodies, often shrouded in mystery, orbit our sun and could have been an important source of water for our blue planet Earth.

On their journey through the solar system, they bring with them a veritable treasure trove of information about our cosmic history.

These dark comets probably contain or contained ice, which raises some interesting questions about their role in the formation of our planet and the origin of water on Earth.

Studying dark comets

Exciting new findings from a University of Michigan study have bolstered this fascinating theory. The research was led by Aster Taylor, a passionate UMichigan student who is diving deep into the wonders of astronomy.

Taylor’s curiosity drove her to use the cosmos as her playground and explore the chilling mysteries of the asteroid belt, a region full of possibilities.

For those unfamiliar, the asteroid belt is a cool region of the solar system between Jupiter and Mars. It is home to a number of rocky asteroids, each with its own unique history.

Taylor’s groundbreaking discoveries support a suspicion that has existed since the 1980s: these asteroids may have ice beneath their surface.

The implications of these findings are enormous, not only for our understanding of the solar system, but also for exploring potential resources for future space missions.

Are dark comets connected to water on Earth?

While Taylor’s study could not confirm whether these dark comets actually brought water to Earth, he stressed that this could be another way for ice from other parts of the solar system to reach Earth.

“We don’t know if these dark comets brought water to Earth. We can’t say that. But we can say that there is still a debate about how exactly the water got here from Earth,” Taylor said.

“Our work has shown that this is another way to bring ice from anywhere in the rest of the solar system into Earth’s environment.”

Despite dozens of studies, some of them very new, it is unbelievable that scientists have not yet figured out where the water on Earth comes from.

Dark comets vs. normal comets

Dark comets, somewhat enigmatic bodies, combine features of both asteroids and comets. Asteroids are close enough to the Sun to vaporize any ice they carry in a process called sublimation, categorizing them as rocky bodies with no ice.

They tend to have more stable and predictable orbits and lack the coma or tail typical of comets.

Comets, on the other hand, are surrounded by a characteristic, fuzzy cloud called a coma, which is created when the sublimating ice carries dust with it.

This gives them a distinctive glowing appearance when viewed through telescopes or, in some cases, even with the naked eye. They generally have more elongated orbits that can take them far away from the Sun and then approach it again.

Interesting fact: They exhibit slight accelerations that are not due to gravity, but rather to this sublimation process! These non-gravitational forces can cause changes in their orbits over time.

Cracking the code

Taylor’s study examined seven dark comets in detail and estimated that between 0.5 and 60% of all near-Earth objects could be these unique bodies.

They do not exhibit comae (or cometary dust clouds), but are endowed with non-gravitational acceleration, probably due to small amounts of sublimating ice.

According to their findings, these dark comets probably originate from the asteroid belt.

“We believe these objects came from the inner and/or outer asteroid belt, and this suggests that this is another mechanism by which some ice entered the inner solar system,” Taylor said.

“There may be more ice in the inner main belt than we thought. There may be more objects like this out there. This could be a significant portion of the closest population. We don’t really know, but these findings have raised many more questions.”

Cosmic Carousel

Taylor explained that our near-Earth environment is a chaotic place that dynamically evolves in just ten million years. Near-Earth objects do not stay in their orbits for very long and are constantly replenished by a larger external source.

To determine the home of these mysterious dark comets, Taylor’s research team developed dynamic models and tracked their path for a whopping 100,000 years. Most landed exactly where dark comets are today, with the main asteroid belt being their most likely birthplace.

“Near-Earth objects do not stay in their current orbit for very long because the environment near Earth is chaotic,” they said.

“They only stay in the near-Earth environment for about 10 million years. Because the solar system is much older, that means that near-Earth objects come from somewhere – that we are constantly being supplied with near-Earth objects from another, much larger source.”

Origins and fates of dark comets

One of the observed dark comets, 2003 RM, probably originated from Jupiter’s comet family by being pulled inward from its orbit.

The rest may come from the inner band of the asteroid belt, suggesting that ice is likely present in the inner main belt.

But why are these dark comets so tiny and rotating so fast? Taylor explains that when comets collide within the ice line, an acceleration process occurs that releases gases. Combined with the continuous loss of ice, this results in even smaller, rapidly rotating bodies.

“These pieces will also be covered in ice, causing them to spin faster and faster until they break into more pieces,” Taylor said.

“You can just keep doing this until you get smaller and smaller. We suggest that you get these small, rapidly rotating objects by taking a few larger objects and breaking them into pieces.”

How dark comets shape our solar system

There you have it. This exciting detective work by Taylor and her dedicated team has played a major role in shedding light on dark comets, the elusive and mysterious water bringers of our solar system.

Using modern telescopes and cutting-edge technology, they were able to uncover important information about these mysterious objects, their origins, and their impact on our cosmic environment. It’s a reminder that our knowledge of the universe is still growing, just like the universe itself.

So the next time you look up into the night sky, remember: There is always more than meets the eye. Every star, planet and comet holds secrets waiting to be discovered, feeding our eternal curiosity and wonder about the cosmos.

The full study was published in the journal Icarus.

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