New research from NASA's Jet Propulsion Laboratory reveals that Jupiter's moon Europa could emit a faint glow in the dark due to the planet's powerful radiation. This phenomenon could unlock insights into its icy surface composition and subsurface ocean.
Europa stands out as a top target in the search for extraterrestrial life. Beneath several kilometers of ice lies a salty subsurface ocean, potentially interacting with the moon's rocky core to drive complex chemical reactions that might foster life. Additionally, Europa's geological activity could periodically eject subsurface material to the surface.
A recent lab experiment highlights a remarkable property: Europa may glow in the dark. The findings are detailed in Nature Astronomy.
Observations indicate Europa's surface is a mix of ice and familiar Earth salts, such as magnesium sulfate (Epsom salt) and sodium chloride (table salt).
Murthy Gudipati and colleagues at NASA's Jet Propulsion Laboratory tested how these materials respond to Jupiter's magnetic field—the strongest in the Solar System after the Sun's.
Jupiter's magnetosphere spans a vast 12 million kilometers, dwarfing Europa's orbit. This environment accelerates charged particles, subjecting the moon to a constant barrage of high-energy electrons lethal to humans in seconds.
The experiments showed that ice embedded with salts, when irradiated, emits visible light—sometimes green, sometimes blue.
Conducted in a lab, these results are preliminary, and it's unclear if Europa truly glows without sunlight. However, if confirmed, the glow's intensity and color could precisely map surface chemistry. For instance, sodium chloride and carbonates produced minimal emission, while Epsom salt (epsomite, magnesium sulfate heptahydrate) amplified it significantly.
The glow is too dim for Earth-based telescopes, but NASA's Europa Clipper mission offers hope. Slated for launch in 2024 and arrival in the Jovian system in the early 2030s, it will orbit Jupiter for four years, conducting 45 flybys of Europa at altitudes from 25 to 2,700 kilometers. Its instruments should detect glows from surface chemicals during close passes.
The researchers note this effect might extend to other Jovian moons like Io and Ganymede, enabling better surface analysis across the system through Jupiter's intense radiation.
