Jupiter's icy moons—Europa, Ganymede, and Callisto—hide oceans beneath their surfaces. Could they harbor conditions for life? The key is whether complex organic molecules (COMs), the precursors to biomolecules, are present. Scientists simulated COM formation in the protoplanetary disk of Jupiter from which the moons were born. It turns out the main mechanism is heating of ices made of ammonia and carbon dioxide, not ultraviolet light. During Europa's cold formation, organics could have been preserved. It's as if a cosmic 'oven' baked the building blocks of life and then froze them. These findings will help interpret data from the JUICE and Europa Clipper missions.
Life may be hiding in the oceans beneath the ice of Europa, Ganymede, and Callisto. Its carbon-based building blocks perhaps baked before the moons were born — in a disk of gas and dust around a young Jupiter. This giant cosmic oven ran on slow frictional heating, not harsh ultraviolet light. Icy grains of ammonia and carbon dioxide, like dough, circulated in the warmth for months, turning into amino acids and sugars. The heating gently assembled molecules, without tearing them apart like UV light does.
When the disk cooled, the moons were born. Europa ended up in a cool spot, like on the bottom shelf of a fridge, while Ganymede and Callisto went into the freezer. The temperature kept the complex organics almost untouched. Soon, the JUICE and Europa Clipper probes will scan liquid water beneath the crust using spectrographs and check how well these cosmic loaves have baked.
🎯 Icy crumbs of ammonia and carbon dioxide turn into sugars and amino acids in warmth, just as easily as regular sugar becomes caramel.
🎬 The search for organic molecules on icy moons echoes the plot of the film 'Europa' (2013) — but in reality, probes are already on their way.