Humbaba is a crater on Jupiter's moon Ganymede. It is approximately in diameter and it exhibits a dark ray system, a rare type of feature on Ganymede. This makes Humbaba the largest dark crater on Ganymede.
Humbaba is named after a mighty creature from Mesopotamian mythology known as Humbaba, who was the guardian of the cedar forest where the gods lived. According to the ancient story of the Epic of Gilgamesh, after King Gilgamesh became friends with the wild man Enkidu following a wrestling match that ended in a stalemate, he suggested that they embark on adventures together to immortalize their names in history. Gilgamesh proposed that they defeat and slay Humbaba to accomplish this.
The International Astronomical Union (IAU) has ruled that craters on Ganymede's surface should be named after deities, heroes and places from Ancient Middle Eastern mythology, which includes Mesopotamian mythology. The IAU approved Kittu's name in the year 2000.
Humbaba crater is located in the southern latitudes of Ganymede, about two-thirds of the way from the equator to the moon's south pole. To its west lies the sprawling grooved terrain known as Babylon Sulci, while to its east is the dark, ancient region called Nicholson Regio.
Humbaba is part of the Nabu crater quadrangle of Ganymede (designated Jg11). It is located near the southwestern corner of the quadrangle.
Humbaba is located on the side of Ganymede that is always facing JupiterâÂÂa result of the moon's synchronous rotationâÂÂnear its subjovian point (i.e. the point on a moon directly facing Jupiter where the planet will always be overhead). This means that an observer standing inside Humbaba crater will always see Jupiter almost overhead at all times.
Humbaba is approximately wide. The crater has a dark interior and exhibits a unique double halo configuration, characterized by dark ejecta material surrounded by bright ejecta. This makes Humbaba the widest dark crater on Ganymede.
The source of the dark material is still debated. According to a study by Namitha Baby, the dark material was excavated by the impactor from about to below Ganymede's surface.
On the other hand, Dr. Paul Schenk's studies emphasize the possibility that the dark material within and around dark craters originated from the impactors themselves, which spread the material on the moon's surface during impact.
Galileo was the first spacecraft to image Humbaba crater. During its orbit around Jupiter from December 1995 to September 2003, the probe flew by Ganymede several times. During a close encounter with the moon in June 1997, Galileo captured high-resolution images of Humbaba and its surrounding terrain. As of 2026, Galileo's images remain the highest-quality views of Humbaba available.
The European Space Agency's (ESA) Jupiter Icy Moons Explorer (Juice), launched in April 2023, is scheduled to reach Jupiter in July 2031. In July 2034, Juice is expected to enter a low orbit around Ganymede at an altitude of approximately . The high-resolution images of Humbaba crater that will be returned by the spacecraft are expected to help planetary scientists better understand the nature of Ganymede's unique dark craters.