Secondary crater
Videos
Secondary craters are impact craters formed by the ejecta that was thrown out of a larger crater. They sometimes form radial crater chains. In addition, secondary craters are often seen as clusters or
MESSENGER image of secondary craters surrounding a primary impact site.
From the impact that formed Copernicus (upper center, yellow), ejecta blanketed the surrounding area. Blue denotes the outline of the ejecta deposit; secondary craters and crater chains are orange.
Group of secondary craters on Mars, as seen by HiRISE
Illustration of projectile fracturing prior to primary impact to show the chronological procedure of the creation of primary and secondary impacts from projectile fractures.
Tolstoj quadrangle
Videos
The Tolstoj quadrangle in the equatorial region of Mercury runs from 144 to 216° longitude and -25 to 25° latitude. It was provisionally called "Tir", but renamed after Leo Tolstoy by the Internationa
Part of eastern Tolstoj quadrangle is shown in the foreground, including Zeami, Sophocles, and Goya craters.