Musa Patera
Musa Patera is a surface depression on Ganymede, the largest moon of Jupiter. The –wide depression consists of curvilinear and arcuate cliffs and, based on studies of its structure, is considered a potential cryovolcano caldera.
Naming
Musa Patera is named after a wadi in the modern country of Jordan, near the famous archaeological site of Petra. Wadis are desert river valleys that are usually dry and flow with water only during periods of heavy rainfall.The International Astronomical Union's (IAU) chose the name in line with the convention that states that paterae on Ganymede should be named after wadi river valleys in the Middle East, a region that includes Jordan. The name was approved by the IAU in 2015.
Location
Musa Patera is located in the southern hemisphere of Ganymede, near the boundary between two bright grooved-terrain regions on the moon, Sippar Sulcus and Mummu Sulcus. The patera lies to the northwest of the bright and prominent ray crater Osiris. To the east of Musa Patera are two other paterae, Rum Patera and Natrun Patera, while to its northeast lies the crater Bes. To the south of the patera is the crater Khonsu.Musa Patera is located within the Apsu quadrangle of Ganymede.
The maps of Ganymede published by the United States Geological Survey classify Musa Patera as part of Mummu Sulcus, whereas articles by NASA and the Jet Propulsion Laboratory consider the patera to be part of Sippar Sulcus.
Due to Ganymede’s synchronous rotation as it orbits Jupiter, one side of the moon always faces its parent planet while the opposite side never does. Musa Patera is located on the hemisphere that never faces Jupiter; therefore, an observer at Musa Patera would never see Jupiter in the sky.
Potential Cryovolcanism
Musa Patera is a potential, ground-level cryovolcano on Ganymede.The Galileo spacecraft's images reveal that one of these structures contains a lobate, flow-like feature representing the strongest candidate yet identified for an icy volcanic lava flow on Ganymede. The structure consists of a prominent depression with scalloped walls and internal terraces, measuring approximately 55 kilometers in length and 17–20 km in width. Within the floor of this depression lies a lobate deposit 7–10 km wide, characterized by outward-curving ridges that appear to trend downslope toward a cross-cutting lane of grooved terrain. The morphology of the feature is consistent with volcanic eruptions that may have excavated a channel, emplaced a flow, and eroded into the surface.
Elevation modeling further indicates that the westernmost caldera-floor material is comparable in height to adjacent grooved terrain but decreases eastward, where it approaches the elevation of nearby, lower-lying smooth terrain. This smooth terrain, which generally lacks grooves or stripes, extends across the upper portion of the image and crosscuts a similar but grooved band in the lower right.
However, as of 2025, evidence for cryovolcanism on Ganymede remains ambiguous, and higher-spatial-resolution imaging from future missions is needed.
Exploration
As of 2025, Musa Patera has been clearly photographed by only two space probes: Voyager 2 the Galileo space probe.Although Voyager 2 was able to photograph Musa Patera during its flyby of Ganymede in July 1979, the depression was too small and the probe was not close enough to capture any important details in the images.
Galileo was able to provide excellent-resolution images of Musa Patera during its orbit around Jupiter between December 1995 and September 2003. In May 1997, the probe flew as low as above the patera, and was able to resolve details as small as. As of date, Galileo's images of Musa Patera are the best available images of the depression.