Geological Chronicle
Gibbs is an impact crater situated near the eastern limb of the Moon, less than its own diameter northeast of the larger crater Hecataeus. Because of its position close to the edge of the visible lunar disk, the 78.76-kilometer-wide crater appears foreshortened to observers on Earth, with visibility shifting according to lunar libration. The crater chain Catena Humboldt extends past its southern margins along a northeastern trajectory.
The perimeter of Gibbs departs from a standard circular geometry, featuring an outward bulge to the north that produces an onion-like outline. Its southeastern wall shows a straightened contour, accompanied by low breaks in the rim at the northern and southern extremes, though the structure remains only modestly eroded. Across the interior floor, the southwestern half remains relatively level, while irregular ridges traverse the northeastern floor alongside a small craterlet northwest of the midpoint.
A youthful Copernican impact crater named Mirzakhani sits on the northeastern rim of Gibbs, marked by an iron-rich meteoritic impact melt and dense rockfalls. This small impact generated a bright ray system that forms a high-albedo skirt along the rim, casting faint ray traces across the floor of Gibbs. In 1964, the International Astronomical Union formally named the crater in honor of American mathematical physicist Josiah Willard Gibbs.