Distant icy worlds are unlocking secrets of the solar system

Exploration of the outer solar system is offering critical clues about its history. Scientists have uncovered new details about the formation of distant icy worlds beyond Neptune. The findings are painting a richer picture of how our solar system formed and evolved over time.

The research was led by scientists from the University of Central Florida (UCF) and their collaborators. The team relied on the advanced capabilities of the James Webb Space Telescope (JWST) to achieve their findings.

Clues from distant icy worlds

Using the telescope, the researchers studied distant Trans-Neptunian Objects (TNOs) – remote, frozen worlds – and discovered surprising patterns of methanol on their surfaces. Their work highlights how chemical reactions in deep-space could link to the origins of life itself.

The team’s findings revealed that TNOs fall into two main groups based on methanol ice presence.

Some bodies showed strong traces of methanol hidden beneath their surfaces. Others, farther from the sun, exhibited a weaker overall methanol signature.

The differences suggest that cosmic radiation over billions of years may have changed the surface chemistry of these distant objects.

For the TNOs closer to the sun, methanol seems to survive better beneath the surface, protected from harsh space weather. But the outermost TNOs still pose new questions with their fainter chemical fingerprints.

Icy worlds hold solar system secrets

TNOs are like ancient time capsules. They are some of the best-preserved pieces of the early protoplanetary disk – the cloud of gas and dust that surrounded the newborn sun. By studying these distant icy worlds, scientists can peer back into a time before planets formed.

Professor Noemí Pinilla-Alonso, formerly of the UCF Department of Physics and now based at the University of Oviedo in Spain, helped lead the project. It is part of the Discovering the Surface Compositions of Trans-Neptunian Objects (DiSCo) program.

“Methanol, a simple alcohol, has been found on comets and distant TNOs, hinting that it may be a primitive ingredient inherited from the early days of our solar system – or even from interstellar space,” noted Pinilla-Alonso.

“But methanol is more than just a leftover from the past. When exposed to radiation, it transforms into new compounds, acting as a chemical time capsule that reveals how these icy worlds have evolved over billions of years.”

Frozen methanol tells a story

Methanol is an important building block. It can form organic molecules like sugars, linking frozen space chemistry to the building blocks of life.

According to Pinilla-Alonso, these new spectral differences suggest that not all distant TNOs were formed from the same set of ingredients.

“What excited me the most was realizing that these differences were linked to the behavior of methanol – a key ingredient that had long been elusive on TNOs from Earth-based observations,” she said.

“Our findings suggest that methanol is being destroyed on the surface of TNOs by irradiation, but remains more abundant in the subsurface, protected from this exposure.”

Bringing the chemistry to life

To better understand what was happening, UCF Florida Space Institute researcher Ana Carolina de Souza-Feliciano played a key role. She used laboratory data combined with modeling to recreate the behavior of methanol in space.

“One of the biggest surprises came from the methanol behavior,” said de Souza-Feliciano. “From laboratory data, its signatures at shorter wavelengths differ from the fundamental ones in longer wavelengths.”

This hands-on modeling helped the team connect what they saw through JWST to the actual chemistry of these remote bodies.

Tracing solar system origins

De Souza-Feliciano also collaborated on previous DiSCo projects using JWST, helping to characterize binary objects and other distant TNOs.

“The main DiSCo paper addressed the main characteristics of the three groups of TNOs. This paper goes into detail about one of them, known as the cliff group, which is the nickname for the spectral group where the reflectance did not increase after approximately 3.3 microns,” explained de Souza-Feliciano.

The “cliff group” TNOs are valuable because they include cold-classical TNOs, the oldest and least altered solar system objects.

This group is key to understanding the outer solar system because it contains all the cold-classical TNOs. “The cold-classical TNOs are the only dynamic group that probably stayed in the place where they formed from the formation of the solar system to today,” noted de Souza-Feliciano.

Methanol sparks new space journeys

The research effort was led by astronomer Rosario Brunetto at Université Paris-Saclay, working alongside Elsa Hénault and Sasha Cryan. The team believes that these findings will not only change how we view TNOs but also guide future missions into deep space.

“This discovery not only reshapes our understanding of TNOs but also provides a crucial reference for interpreting JWST’s observations of other distant objects, such as Neptune Trojans, Centaurs and asteroids, as well as for future missions exploring the outer solar system,” said Brunetto.

“Beyond its scientific significance, the search for methanol in the solar system also fuels curiosity and inspires new generations to explore the cosmos and understand the chemical evolutions in space.”

The full study was published in the journal The Astrophysical Journal Letters.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–