Comets Are Low-Key Metals; Here's What Scientists Found in an Interstellar Discovery

Astronomers found iron and nickel vapor in the atmospheres of comets from our Solar System and beyond for the first time. Scientists are now baffled by such a discovery.

The recent finding seems to be an unusual activity for comets. However, as other research suggests, comets can spew atomic metals regularly, whether they're close by or from across the Milky Way.

Comet 2I/Borisov Paved the Way to New Discovery

Two recent articles in Nature update astronomers about comets, both in terms of their origins and the circumstances under which they evolved.

The first paper is titled "Gaseous Atomic Nickel in the Coma of Interstellar Comet 2i/Borisov." The second paper is titled "Iron and Nickel Atoms in Cometary Atmospheres Even Far From the Sun."

Astronomers did an unparalleled comparative study when the papers are combined. Both studies compared local comets to comets that originated far, far away.

We're talking about comet 2I/Borisov, an alien visitor to our solar system in January 2020. Because of its unusual orbit, astronomers were able to determine that it was interstellar.

According to recent studies, Borisov is thought to be a remnant of a Pluto-like object that originated in its home star system's Kuiper belt. Borisov is often overshadowed by Oumuamua, the first observed interstellar object to enter our solar system in 2017. However, the fireball is equally worthy of recognition, owing to its similarity to native comets.

Chile's VLT Helped Scientists Discover Metallic Comets

SciTechDaily said a team of researchers used observations from the European Southern Observatory's Very Large Telescope (VLT) in Chile to find nickel and iron sputtering on the surfaces of 20 different comets dating back to 2002. These comets are usually found in the Solar System's far reaches.

Scientists discovered the comets passing by the inner Solar System in their incredibly long-term orbits. They found the most distant one at around 480 million kilometers from the Sun, close to Mars' orbit.

All comets seem to lose the improbable metals with a rate of up to a gram of material per second, as detailed in the first paper. This is a small amount relative to the 100 kilograms of water per second that most comets spit out when they bask in the Sun's sunlight. Still, comets are also made up of icy water and other ices.

The second of the two articles is for comet 2I/Borisov, a frozen object found in 2019 that came from outside our Solar System. It, too, seems to have nickel vapor spurting from its surface, contributing to the mystery surrounding this interstellar mystery.

What is Causing the Metals to Leak?

Steven Bromley, a postdoc at Auburn University and co-author with Bodewits, told Inverse that the cause of the leak remains a mystery. Experts, however, also proposed several hypotheses.

One theory is that the comets' tiny dust grains are boiling up to 725 degrees Celsius. However, the precise circumstances that would lead to this remain unknown.

Another theory is that the metals are incorporated into metal carbonyls formed when four to five carbon monoxide molecules bind to nickel or iron atoms.

The final theory proposes that the metals have been trapped within large complex molecules known as polycyclic aromatic hydrocarbons, a kind of comet content that is often observed. However, how those compounds may have shaped and then been emitted from the comets' surfaces is a mystery as well.

However, the fact that comparable leakage seems to be occurring on 2I/Borisov means that whatever chemical processes occur in our local neck of the universe are also taking place elsewhere, according to Bodewits.

Comets Seem To Evolve In Similar Conditions, Locations

The two articles, taken together, point to a common cometary mechanism. Since native comets and Borisov have similar chemical properties, they likely evolved under similar conditions and in similar locations within their respective star systems.

Gizmodo said if scientists may unravel the roots of iron and nickel in normal comets and this interstellar rock, they will be able to uncover a tale of organic chemistry shared by various planetary systems.

It's not surprising that other star systems go through identical mechanisms to our own since the laws of physics are the same anywhere in the universe.

As these experiments demonstrate, it is now possible to investigate the chemical composition of other star systems without having to go to outer space.

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