We recently looked at how and why Saturn’s icy moon Enceladus might answer the long-standing question: Are we alone? With its internal ocean and geysers of water ice that shoot tens of kilometers into space that is said to contain the ingredients for life, this small moon could be a prime target for future astrobiological missions. But Enceladus isn’t the only location in our solar system with active geysers, as another small moon near the edge of the solar system also shares similar features. This is Neptune’s largest moon, Triton, which was visited only once by NASA’s Voyager 2 in 1989. But Triton’s geysers are the only features that make it a good target for astrobiology and finding life beyond. the earth; “Triton may be an ‘ocean world,’ a moon that has a solid crust of ice over an ocean of liquid water,” said Dr. Candice Hansen-Koharchek, who is a planetary scientist and was the Voyager Imaging Team’s Assistant Experiment Representative at during Voyager Missions. “If that’s the case, and if we can someday get to that ocean and find life, that would extend the habitable zone to the Kuiper belt, not just the inner solar system. This has profound implications, both for our solar system and for exoplanets.” Because of its geysers, which Voyager 2 recognized as dark streaks, Triton is only the third known planetary body in the solar system to be volcanically active, besides Earth and Jupiter’s innermost Galilean moon, Io. Unlike Enceladus’ geysers, which are thought to be caused by tidal heating, Triton’s geysers are the result of solar heating, where the faint sunlight reaching the moon causes frozen nitrogen on the surface to slowly melt and eventually explode . Active geology also explains the lack of craters on its surface, and it turns out that Triton has another feature similar to Earth. “Triton has a nitrogen atmosphere that freezes at the polar caps seasonally,” Dr Hansen-Koharchek said. “Earth also has a mostly nitrogen atmosphere – can you imagine if our atmosphere froze to the ground in winter? Although Triton’s atmosphere is thin, winds blow and scatter particles across the surface.” As mentioned, Voyager 2 is the only spacecraft to visit Triton, but another NASA mission known as TRIDENT was selected as a finalist in 2020 to explore Triton up close for the first time since 1989, but ultimately passed on to the final selection round by NASA in 2021. “Trident would have demonstrated the existence of an ocean on the surface – the first step in identifying an oceanic world,” said Dr Hansen-Koharchek. “Trident carried a near-infrared spectrometer, which would allow us for the first time to map the distribution of ice (N2, CH4, CO, CO2 and H2O) across its surface (Voyager did not carry a near-infrared spectrometer) . all we know about the composition is what we can gather from Earth). Currently, Triton orbits Neptune near the edge of the solar system with its active geysers, nitrogen atmosphere and possible internal ocean. When will we visit again and does this active moon host life as we know it due to its unique features? And with that, we wonder if Triton will finally answer the question “are we alone?” Provided by Universe Today Quote: Will Triton finally answer the question “are we alone?” (2022, November 14) retrieved November 14, 2022 by This document is subject to copyright. Except for any fair dealing for purposes of private study or research, no part may be reproduced without written permission. Content is provided for informational purposes only.
