Will Triton finally answer the question ‘are we alone?’

We lately examined how and why Saturn’s icy moon, Enceladus, may reply the longstanding query: Are we alone? With its inside ocean and geysers of water ice that shoot out tens of kilometers into space that allegedly incorporates the substances for all times, this small moon may very well be a first-rate goal for future astrobiology missions.

However Enceladus is not the one location in our solar system with energetic geysers, as one other small moon close to the sting of the solar system shares comparable traits, as nicely. That is Neptune’s largest moon, Triton, which has been visited solely as soon as by NASA’s Voyager 2 in 1989. However are Triton’s geysers the one traits that make it goal for astrobiology and discovering life past Earth?

“Triton could also be an ‘ocean world,’ a moon that has a strong ice crust over a liquid water subsurface ocean,” mentioned Dr. Candice Hansen-Koharchek, who’s a planetary scientist and was a Voyager Imaging Group Assistant Experiment Consultant through the Voyager missions.

“If that’s the case, and if we’re in a position sometime to achieve that ocean and discover life, that might lengthen the habitable zone to the Kuiper Belt, not simply the internal solar system. That has profound implications, each in our solar system and at exoplanets.”

As a consequence of its geysers, which Voyager 2 recognized as darkish streaks, Triton is barely the third recognized planetary physique within the solar system to be volcanically energetic, apart from Earth and Jupiter’s innermost Galilean moon, Io. In contrast to the geysers of Enceladus, which is believed to be brought on by means of tidal heating, Triton’s geysers are the results of solar heating, the place the dim daylight that reaches the moon causes the frozen nitrogen on the floor to slowly soften and finally erupt. The energetic geology additionally explains the shortage of craters on its floor, as nicely, and it seems that Triton holds one other characteristic just like Earth.

“Triton has a nitrogen environment that freezes into polar caps seasonally,” mentioned Dr. Hansen-Koharchek. “The Earth additionally has a primarily nitrogen environment—are you able to think about if our environment froze onto the bottom within the winter? Though Triton’s environment is skinny, winds blow and scatter particulates throughout the floor.”

As said, Voyager 2 is the one spacecraft to have visited Triton, however one other NASA mission often known as TRIDENT was chosen as a finalist in 2020 to discover Triton up shut for the primary time since 1989, however was in the end handed over within the last choice spherical by NASA in 2021.

“Trident would have established the existence of a subsurface ocean—step one in reconnaissance of an ocean world,” mentioned Dr. Hansen-Koharchek. “Trident carried a near-infrared spectrometer, which might have allowed us for the primary time to map the distribution of ices (N₂, CH₄, CO, CO₂, and H₂O) throughout its floor (Voyager didn’t carry a near-IR spectrometer so all we all know concerning the composition is what we are able to glean from Earth).”

For now, Triton orbits Neptune close to the sting of the solar system with its energetic geysers, nitrogen environment, and potential inside ocean. When will we go to it once more, and does this energetic moon harbor life as we all know it as a consequence of its distinctive options?

And with this, we marvel if Triton will lastly reply the query “are we alone?”