Carbon Dioxide Found on Exoplanets: Clues to How Giant Planets Like Jupiter Are Born

In a groundbreaking discovery, scientists have detected carbon dioxide on planets beyond our solar system for the first time. Using the powerful James Webb Space Telescope (JWST), researchers observed this essential gas on four giant exoplanets located 130 light-years away in the HR 8799 system. These findings mark a significant milestone in space exploration and provide key insights into how gas giants like Jupiter and Saturn may have formed.

A New Milestone in Exoplanet Research

The HR 8799 system, home to four massive exoplanets, is relatively young, only 30 million years old compared to our 4.6 billion-year-old solar system. These planets emit intense infrared light, which allowed the JWST to capture direct evidence of carbon dioxide (CO₂) in their atmospheres. This observation was made possible thanks to JWST’s advanced coronagraph technology, which blocks starlight to reveal hidden planetary details.

The discovery suggests that these distant worlds likely formed through core accretion, a gradual build-up of solid material into a dense core that attracted surrounding gas. This same process is believed to have created Jupiter and Saturn.

“By detecting these strong formations of carbon dioxide, we’ve shown that there’s a significant presence of heavier elements like carbon, oxygen, and iron in these atmospheres,” said William Balmer, lead author and astrophysicist at Johns Hopkins University. “This strongly supports the idea that these planets formed by core accretion.”

Why Carbon Dioxide Matters

Carbon dioxide plays a critical role on Earth in supporting life and regulating temperature. In space, its presence tells scientists a great deal about a planet’s history and composition. Because CO₂ can freeze into tiny ice particles in the cold depths of space, finding it on other planets provides clues to their icy beginnings.

Jupiter and Saturn are thought to have formed when icy particles clumped together to create a solid core. Once large enough, the core attracted gas and grew into the massive planets we see today. Detecting CO₂ on exoplanets supports this bottom-up formation theory beyond our solar system.

A Peek Into Planetary Formation and Our Own Origins

Studying these exoplanets helps scientists put our solar system into context. Are the processes that created Jupiter and Saturn unique, or are they part of a universal pattern? The HR 8799 system gives us a rare chance to directly image and study young gas giants in their early stages of development.

“We want to understand how strange or normal our solar system is,” Balmer added. “These kinds of discoveries help us figure that out.”

Understanding how giant planets form is more than a matter of cosmic curiosity. These giants can influence the paths of smaller, rocky planets like Earth by shielding them from asteroids or throwing them off course. Studying gas giants is critical to understanding how life-supporting planets can emerge and survive.

James Webb Space Telescope Proves Its Power

While the JWST was already celebrated for its ability to observe distant galaxies, this discovery shows its value closer to home in our galactic neighborhood. The telescope was able to directly analyze the chemical makeup of atmospheres on planets light-years away, a feat once thought impossible.

“It’s like putting your thumb in front of the sun to block its light,” Balmer explained. “That lets us see the planet’s own light and figure out what gases are in its atmosphere.”

This breakthrough opens the door for future observations that uncover more about how planets form and how life begins.

What This Discovery Means for Future Planet Hunts

The research team plans to continue studying the HR 8799 system and other distant planetary systems. With carbon dioxide as a diagnostic tool, they hope to answer more profound questions: How common are these long-orbit gas giants? Can we find them in other star systems? And how do their atmospheres evolve?

Every new observation pushes us one step closer to understanding our place in the universe.