ISSN:
1573-0794
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Geologie und Paläontologie
,
Physik
Notizen:
Abstract When Galileo first turned his improved spyglass to view the Moonfrom Padua, he was astounded at what he saw: “And it is like the face of theEarth itself ... which is marked here and there with chains of mountains anddepths of valleys” (Galilei, 1610). His remarks about his new discoveries captured the joy which ultimately drives every planetary explorer: “I render infinite thanks to God for being so kind as to make me alone the first observer of marvels kept hidden in obscurity for all previous centuries” (Galilei, 1610). Four centuries later his intellectual heirs have expanded human understanding ofour place in the universe with an elegant symmetry. The Apollo and Luna programsdemonstrated that the origin and history of the Earth and the Moon are intimately linked. Two decades later the Galileo spacecraft swung by the Moon to obtain a gravity-assist from Earth in order to complete its exploration journey to Jupiter and the Galilean satellites. The Galileo spacecraft was the first to return to the Moon with modern sensors, and its brief passage provided dramatic evidence that the farside of the Moon held secrets unimagined from study of the nearside. Subsequent missions, Clementine and Lunar Prospector, provided the first global assessment of lunar topography and composition, and placed the farside in context. There are few of the extensive plains of basaltic lava on the farside of the Moon. This fact is clearly a product of the earliest history of the Moon (the first 500 My), the details of which are being investigated from clues that remain on the Moon today. The dominant feature on the lunar farside is the enormous South Pole–Aitken Basin, which extends from the south pole to the crater Aitken, just 15° south of the equator. This basin includes the deepest area on the Moon and appears as a slightly darker circular region encompassing the lower half of the lunar farside. The compositionof the interior is uniquely enriched with iron-bearing minerals derived from deeper layers within the Moon (lower crust or possibly mantle). Planetary explorers normally use indirect geophysical methods to probe below the surface of a body, and South Pole–Aitken presents a rare window into the interior. The challenge is to decipher the many processes involved in an impact event of this magnitude and the subsequent history of smaller events. This challenge can certainly be achieved with current technology, but it will likely take theingenuity of scientists and engineers and further exploration to accomplish.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1023/A:1017009108769
Permalink
