Recent imagery from NASA's solar-powered Juno spacecraft has offered a detailed look at Jupiter's moon Europa, revealing significant details about its icy surface.
NASA Juno Captures HD Images of Jupiter's Europa
The images taken by the JunoCam visible-light camera support the idea that Europa's polar ice crust has shifted over time. Additionally, a high-resolution image from Juno's Stellar Reference Unit (SRU) indicates potential plume activity and areas where brine might have recently emerged through the ice shell.
NASA's Juno spacecraft achieved its closest flyby of Jupiter's moon Europa on September 29, 2022, getting within 220 miles (355 kilometers) of the moon's icy surface. This close encounter allowed Juno to capture detailed images with its JunoCam and Stellar Reference Unit (SRU), providing the highest-resolution views of Europa since the Galileo mission's flyby in 2000.
During this close approach, Juno's path enabled the capture of images near Europa's equator. These images revealed familiar features such as ice blocks, ridges, scarps, and troughs.
Additionally, the camera detected irregularly distributed steep-walled depressions, measuring between 12 to 31 miles (20 to 50 kilometers) wide. These depressions are similar to large ovoid pits observed in earlier images of Europa.
A Vast Ocean in Europa?
Scientists believe that beneath Europa's icy crust lies a vast ocean. The observed surface features lend support to the theory of "true polar wander," which posits that Europa's outer ice shell moves independently of its rocky interior, resulting in significant stress and predictable fracture patterns.
This recent mapping in the southern hemisphere indicates that the effects of true polar wander on Europa's surface are more extensive than previously understood.
The high-resolution images captured by JunoCam have also led to the reclassification of a previously significant surface feature. What was once identified as a 13-mile-wide impact crater, known as Crater Gwern, has been revealed through JunoCam data to be a set of intersecting ridges forming an oval shadow, according to Candy Hansen, a Juno co-investigator.
The Platypus
One particularly intriguing feature, spanning 23 miles by 42 miles (37 by 67 kilometers), has been named"the Platypus" due to its shape. This chaotic terrain, characterized by hummocks, prominent ridges, and dark reddish-brown components, is the youngest feature in its region.
The Platypus's northern "torso" and southern "bill," linked by a fractured "neck," disrupt the surrounding terrain with a lumpy matrix of ice blocks, while ridge formations collapse into the feature's edges.
NASA notes that these formations suggest that Europa's ice shell may give way where pockets of subsurface briny water exist. Approximately 31 miles (50 kilometers) north of the Platypus, double ridges accompanied by dark stains suggest the presence of cryovolcanic deposits.
These images indicate possible ongoing surface activity and the existence of subsurface liquid water on Europa. The detailed images from the SRU offer a valuable reference for future missions, including NASA's Europa Clipper and the European Space Agency's (ESA) Juice.
