Astronomers Discover Silicate-Rich Rogue Planet Emitting Its Own Light

A planet without a star is not supposed to glow.

But that’s exactly what astronomers are reporting this week after an international team detected a free-floating terrestrial-mass planet—now cataloged as RXJ94-π—emitting an unexpected spectrum of infrared and visible light as it drifts alone in deep interstellar space, 124 light-years from Earth.

“It’s not just reflecting ambient starlight,” said Dr. Navid Hassanpour, lead planetary physicist at the New Leiden Observatory. “This thing is glowing from within.”

🔭 A Planet Without a Sun

RXJ94-π is classified as a rogue planet—a planetary body not bound to any star. These are notoriously hard to find, let alone study. But this one was different: its detection came not from gravitational microlensing or cold background mapping, but from a clear and direct signal in the 1.1–2.3 µm infrared band, picked up by the new OrbitTrace-D array on the Athena Deep Orbit Telescope.

• Distance from Earth: 124 light-years

• Estimated mass: 0.92 Earth masses

• Radius: 1.06 Earth radii

• Surface temp: ~98°C (209°F)

• Rotation period: 31.6 Earth hours

• Albedo: effectively zero—no reflected light detected

The surprising part: it emits a stable, low-wavelength optical glow most commonly associated with volcanic vents.

🪨 A Glowing Crust

Spectral analysis of RXJ94-π’s surface revealed the presence of doped silicates, particularly aluminum-rich pyroxenes and rare magnesium fluorides. These minerals, when exposed to deep geothermal excitation—think mantle-level heat—can release photoluminescent radiation, meaning the planet literally glows from internal stress.

This mechanism has no analog on Earth but bears similarity to phosphorescent compounds used in experimental semiconductors.

“It’s like if a chunk of the Earth’s upper mantle were floating in space—molten, pressure-locked, and surrounded by vacuum,” explained Dr. Hassanpour. “And somehow, it glows like a candle under a dome.”

🔬 Theories and Origins

How did RXJ94-π get here? Some theories point to a violent ejection event, possibly during the early orbital instabilities of its host system. Its escape velocity and current drift trajectory suggest it was cast out between 42–64 million years ago, possibly by a collision or gravitational ricochet.

But one strange feature complicates that story: a persistent halo of loosely bound particulate matter, behaving not like dust, but like ionized glass. This fine material forms a torus around the planet, glowing faintly blue in false-color composites and showing signs of static electromagnetic confinement.

🛰️ Energy, Not Habitability

With a surface temperature just shy of boiling and no solar energy input, RXJ94-π is far from habitable. But its energy signature has opened up new questions in planetary energetics.

• Where does the heat come from?

• Why hasn’t the planet cooled in the vacuum of space?

• Could radioactive or exotic core decay play a role?

Some have even suggested metastable phase transitions—a solid-state phenomenon where mineral lattices under extreme conditions release stored energy over geologic time.

“It may be a planetary battery,” said Dr. Maya Nwoko, materials physicist at the University of Cape Town. “And we’ve just now noticed it flicker.”

🔮 A Strange First

RXJ94-π is the first terrestrial rogue planet known to emit its own light without fusion or external irradiation. Its behavior challenges assumptions about how planets cool, how minerals behave in deep time, and how much we truly know about lonely wanderers between stars.

The planet’s formal naming process is underway, but for now, the nickname among astronomers is simple:

The Ember.