Enceladus, a frigid moon of Saturn measuring approximately 500 kilometers across, has been a magnet for scientific scrutiny for many years. This enigmatic world is famous for its powerful geysers erupting from fissures located in its south polar region. Back in 2005, the Cassini probe detected water, ice, and—most intriguingly—organic compounds within these plumes. Analysis of the plume composition suggested the presence of a global ocean beneath the icy shell, featuring a rocky seabed where active chemical reactions, akin to those observed at Earth’s hydrothermal vents, are likely occurring.
To decipher the source of these organics, an international consortium, spearheaded by researchers from the Tokyo Institute of Technology, conducted a novel experiment. They replicated the presumed environmental conditions within Enceladus’s interior. A specialized solution simulating the chemical makeup of the plumes (a mixture involving water, ammonia, methane, and various other substances) was sealed within capsules and heated to 150 degrees Celsius under intense pressure. Subsequently, the samples underwent cooling and freezing cycles, mimicking the natural processes within the moon’s icy crust. The outcomes were remarkable: numerous organic molecules, including amino acids such as alanine and serine, were successfully synthesized under laboratory conditions. Furthermore, the simplest amino acid, glycine, was generated even without heating, simply through prolonged periods of freezing. These findings were then cross-referenced with the telemetry provided by the Cassini spacecraft, confirming the similarity between the lab-created substances and those actually present in Enceladus’s jets.
Scientists have explained where Mars’s water went and why it turned into a desert. The researchers attribute the absence of amino acids in direct samples collected by the probe either to their scarcity or the possibility that they are sequestered within saline ice particles. As for larger, more intricate molecules, their reproduction in the lab has so far proven unsuccessful. It is probable that these formed under even higher temperatures at the ocean floor, or perhaps they date back to the moon’s initial formation. The study, featured in the journal Icarus, implies that the chemical evolution on Enceladus follows a trajectory similar to that of early Earth. The hot water inside this icy satellite is effectively “cooking” the building blocks of life. This discovery positions Enceladus, alongside other similar bodies like Europa and Titan, as prime candidates for the detection of extraterrestrial life within our Solar System.
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