Featured Image - February 3, 2009
Sklodowska crater (127 km diameter; named after Marie
Sklodowska-Curie, the famous chemist) is located on the eastern limb
of the Moon (18.2 ° N, 95.5 ° E), southeast of Mare Smythii.
Smaller (i.e., less than about 20 km diameter) craters on the Moon,
Gallus, are bowl-shaped. However, craters that are larger than 20
km transition into what are called complex craters like the Imbrium-aged
Sklodowska (Figure 1) and have terraced walls with a central peak. We
have no samples from this crater, but geologic mapping using
remotely-sensed data indicates that it formed at roughly the same time
(geologically speaking) as nearby Tsiolkovsky
Figure 1.Sklodowska crater, a complex lunar crater located on the Moon's eastern limb. (Apollo Image AS15-M-1968 [NASA/JSC/Arizona State University])
In Figure 1 you can clearly see Sklodowska's well-defined
central peak and terraced walls. The central peak formed when the
materials in the center of the impact zone beneath the crater, which
had been heavily compressed by the shock of the initial impact,
rebounded. The terracing on Sklodowska's crater walls is thought to
have occurred as one of the last steps of the crater-forming process.
The crater wall materials, which were weakened and fractured by the
impact, succumbed to the pull of the Moon's gravity and slumped
following the original impact event. From the initial impact to the
final slumping, this complicated process took only minutes to
The Moon's intensely cratered surface bears witness to the power and
frequency of impacts throughout the history of the Solar System. The
impact process is affected by many factors, including the size and
speed of the bolide, and the composition of the target materials.
Impact craters provide lunar scientists the opportunity to determine relative ages
of materials, compositional variations at depth, and the thickness of
the lunar regolith. One of the key objectives of the forthcoming Lunar Reconnaissance Orbiter
Camera will be to study lunar impact craters at incredibly high
resolutions (50cm/pixel) which will help us to better understand the
physics of the crater-forming process.
For more information:
Impact Craters at the Lunar and Planetary Institute
Stoffler et al., 2006. Cratering History and Lunar Chronology, Rev. Min. Geo., Vol. 60, pp.519-596.