JWST detects the largest water plume observed so far emanating from one of Saturn's moon Enceladus

 

 

A simulation shows the hypothesized curtains of water leaking from cracks in Enceladus's icy surface. (NASA/JPL-Caltech/SSI/PSI) / 2015

 

The James Webb Space Telescope (JWST) has made a remarkable discovery, capturing the sighting of a massive water vapor plume emanating from Saturn's moon Enceladus. This newfound plume surpasses any previous observations in terms of size, raising intriguing possibilities that it could harbor the chemical building blocks of life, escaping from beneath the moon's icy surface.

Back in 2005, NASA's Cassini spacecraft had initially detected icy particles being expelled from the subsurface ocean of Enceladus through fractures in its surface. However, the recent findings from JWST demonstrate that the material is being ejected much farther into space than previously known, extending well beyond the moon's own dimensions.

During a conference at the Space Telescope Science Institute in Baltimore, Maryland, planetary astronomer Sara Faggi, from NASA's Goddard Space Flight Center, described the plume as "immense." Further details were not disclosed, as they are reserved for an upcoming scientific paper.

Enceladus holds immense significance for astrobiologists due to its classification as one of the few "ocean worlds" within our solar system, making it a promising target in the search for extraterrestrial life. The salty ocean beneath the moon's icy exterior presents a potential environment capable of sustaining living organisms, possibly fueled by chemical energy from hydrothermal vents on the ocean floor.

The material spewing from Enceladus, primarily through fractures known as tiger stripes near the moon's south pole, provides a direct connection to this potential extraterrestrial ecosystem. Cassini's observations of the plumes unveiled silica particles likely transported from the sea floor by turbulent fluids. Cassini extensively studied the plumes, measuring ice grains and detecting life-friendly chemicals like methane, carbon dioxide, and ammonia.

However, JWST, positioned 1.5 million kilometers from Earth, has now uncovered what Cassini couldn't observe from its close proximity. While Cassini mainly spotted ice grains close to the surface, JWST's wider perspective and sensitive instruments have allowed it to capture faint gas signals surrounding Enceladus.

In a brief observation on November 9, 2022, JWST detected an immense plume of very cold water vapor, although it is expected to have low density, resembling a diffuse, cold cloud rather than a dense spray. This poses challenges for researchers hoping to detect signs of life in the plume, as the sparse nature of potential life indicators may make them difficult to identify. In contrast, ice grains observed by Cassini in closer proximity to Enceladus are more likely to contain higher concentrations of organic particles.

JWST's analysis of the sunlight reflecting off Enceladus has also revealed evidence of various chemicals, including water and potentially other compounds hinting at geological or biological activity within the moon's ocean. These findings hint at more surprises to come, according to Sara Faggi.

Researchers are already devising plans to follow up on this discovery. The JWST's second round of operations will include an extended study of Enceladus, examining the moon for an extended period to search for habitability indicators such as organic compounds and hydrogen peroxide. Additionally, there are proposals for future NASA missions to Enceladus, including an "orbilander" mission that would orbit the moon before landing at its south pole and an autonomous snake robot mission to explore the moon's ocean by maneuvering beneath its icy surface.

JWST's revelations provide substantial support for the possibility of a NASA mission to Enceladus, dedicated to investigating potential signs of life. Proposed missions include an "orbilander" concept, wherein the spacecraft would orbit the moon for an extended period before landing at its south pole. Another proposal involves the development of an autonomous snake robot capable of maneuvering beneath Enceladus's icy crust to explore the hidden ocean depths.

JWST's observations are not limited to Enceladus alone; other icy moons within our solar system have also garnered attention. During the conference, planetary scientist Geronimo Villanueva from Goddard reported JWST's detection of carbon dioxide on Jupiter's moon Europa. This discovery is particularly exciting as carbon and oxygen are fundamental components for life as we know it. In the coming years, NASA is launching a mission to Europa to explore this ocean world in greater detail, signaling a new era in the exploration of our solar system.

The findings from JWST not only emphasize the significance of Enceladus as a potential harbor for life but also raise intriguing possibilities for the existence of life on other icy moons. As our understanding of these intriguing celestial bodies deepens, scientists are motivated to uncover the mysteries that lie within their enigmatic oceans. The James Webb Space Telescope's capabilities and future missions hold great promise for unraveling the secrets of these distant worlds and shedding light on the prospects of extraterrestrial life.

Source: Nature