Details of Gosses Bluff impact crater in the orange semi-desert of Australia and Arandes on Mars. Gosses Bluff crater is 22 km in diameter and about 142 m.y. old; the eroded remnant of the 5-km inner peak ring is visible (arrow). On the right is the 28-km-diameter Martian crater Arandes. A central peak can be seen at the center of the crater.