The biggest questions about our Universe remain unanswered. What is it? How did it get here? We don’t know. We’ll likely never know. But we find comfort in what we do know. We understand the basics, like the fact that planets live in solar systems and orbit stars.
Except a paper published this year in the Astrophysical Journal points out, that’s not entirely true.
There’s a rogue planet out there.
When astronomers first saw it in 2004, they didn’t realize what they were looking at. The detection was made by NASA’s Spitzer Space Telescope, which used infrared light to find stars and planets hidden by dust clouds, missed by Earth-bound telescopes that rely on visible light. On this particular night, the team saw an object 8 times as massive as Jupiter flying through an area of our Galaxy where new stars formed, about 600 light years away. Astronomers figured it was a brown dwarf, something on its way to being a star but not big enough to shine on its own yet.
They gave it the label “Cha 110913-773444”. I guess there are so many objects out there, astronomers have given up on clever names.
Turns out, this particular object might deserve a better name. Because it is changing in unexpected ways.
Four years later they observed their brown dwarf again, expecting it to be glowing hotter and brighter as nuclear fusion began and a star, well — no other way to say it — was born. But that is not what they found at all. By 2008, “Cha” was not brightening. In fact, it looked more like a cold, low-mass body, not an igniting star. Astronomers detected a disk of gas and dust around it, like you’d expect in the early stage of planet formation.
The mystery object was put in a category of objects that had only recently been created: it was identified as a free-floating planetary mass, or FFPMO.
There was something odd they noticed about this free-floating planet. It was engaging in low-level accretion, meaning it was slowly pulling in material from its surrounding disk of gas and dust. Imagine the rings of Saturn being slowly absorbed by the planet. Apparently this object, more massive than Jupiter, was still hungry.
This slow and steady accretion went on for decades. Scientists figured that’s just how it was going to be. Until it changed again.
This year, “Cha” got even hungrier. In fact, it went from its normal casual snacking to a full-on feeding frenzy.
In June of 2025, the Very Large Telescope (VLT) in Chile set its sights on the slow forming mystery planet. Astronomers used an instrument on the VLT called the XShooter that can see light across a range of wavelengths, from ultraviolet to near-infrared. The XShooter lets Astronomers study the spectra around objects, which gives back data on an object’s temperature, composition and, in the case of our mystery planet, its appetite for the gas and dust around it (accretion).
What they found was astounding. “Cha” ****suddenly started pulling in material from its disk much faster, eating 8 times more material than before. And this big feeding burst wasn’t a single event. It lasted two months. It is nothing less than the strongest burst of its kind ever seen in an object of that mass.
Astronomers can “see” the accretion through changes in the light readings, or bands of the spectrum. For example, they saw a peak in the “H-alpha line” and were able to tell material was being pulled in along the object’s magnetic field.
Prompted by the unusual burst, researchers looked back at past readings of the mystery planet — had this ever happened before? Turns out, the answer was yes. Studying infra red readings from 2016, they found similar high feeding rates. Scientists realized this increase in accretion happened every few years. This was no sudden change, but some ongoing process. And the most disturbing aspect? They have no idea what triggers the bursts.
Is this rogue, growing planet somehow alive, eating the gas and dust it collects as it flies 1,200 miles an hour through the Milky Way? Of course not.
Although — during the accretion burst, certain elements necessary for life were actually detected. There was one element in particular not visible during the quieter phases that was suddenly there during the feeding frenzy: water vapor. The water is likely a result of the planet’s rising heat as it feeds, transforming the disk of dust around it.
But there is more. The cloud around the object is carbon rich. These are the building blocks for life — chains of hydrocarbons are inside essential biological molecules like fats, lipids and some amino acids. A carbon’s ability to form stable chains allows for complex molecules and, well, life. Hydrocarbons like methane or oil store energy used by life. Or in this case, eaten by a growing mass bigger than Jupiter.
The thing is, these elements of life are not commonly found out there. Their detection is the first time water vapor or hydrocarbons caused by accretion — or feeding — have ever been observed in a substellar object.
It’s far fetched, sure. The idea that some version of a living entity looks like a growing planetoid to our eyes. But there is much we don’t know about the Universe.
We keep searching for life that lives on the surface of planets, and even looks a bit like us. But it could be that life is hidden in plain sight, disguised as just another planet forming, devouring everything it finds.
When it turns in our direction, it might just make headlines.