The origin and age of the seemingly volcanic features in the Marius Hills region are of considerable importance in understanding the evolution of the lunar surface. Terrestrial volcanic features are built up in very short times compared with the entire history of the earth. Even an extensive region such as the volcanic chain constituting the Hawaiian Islands represents a period of less than 70 million years. The absolute age and the length of time involved in building up the Marius Hills domes will be of great interest in the characterization of lunar volcanism.
The Marius Hills region is far too extensive to be covered in a single manned expedition to the moon. Fortunately a number of characteristic features of smaller scale can be visited in several areas that are no more than 70 kilometers in diameter. A mission to such an area would be able to sample and study a number of small domes 50 to 100 meters in elevation with convex slopes; steep-sided domes with rough, intricate surfaces; steeply convex or bulbous domes that are smooth and generally symmetrical; steep-sided cones with linear depressions at the summit; narrow, steep-sided ridges, and a variety of impact features.
The fourth candidate site is the region of the Apennine Mountains, which roughly form the southeastern boundary of Mare Imbrium and also the northwestern leg of a triangular highland area bounded by Mare Imbrium, the southwestern boundary of Mare Serenitatis and the northern part of Sinus Aestuum. The Apennines are among the most impressive of the lunar mountain ranges. The Apennine front rises 4,800 meters above the adjacent mare level to the west.
What can be learned about the moon by visiting this area? The Apennine front is a major physical feature of the moon, exposing an extensive vertical section several thousand meters thick for sampling and examination. Here is an opportunity to assess what may be a long period of lunar history. Are the rocks in form or physically and chemically heterogeneous? How old are they? Are they stratified? Answers to such questions could have a profound effect on our understanding of lunar history.
Two landing sites have been proposed near the Apennine front that are within five kilometers of important lunar features. One such feature is the rille, or canyonlike configuration, known as Rima Hadley. Is it a surface-flow channel or a collapsed lava tube? If it was formed by water, as has been speculated, where did the water come from and what prevented its immediate evaporation?
The Significance of Rima Hadley
Close examination of the Lunar Orbiter photographs of this rille reveals that fresh exposures of rock are visible along its walls and that blocks have fallen down the walls to the floor of the rille. Rima Hadley cuts into the Boor of a mare and thereby yields a depth and perhaps a cross section of the history of a major lunar feature. Hence it might provide answers to such questions as whether the maria are bedded deposits of lava or ash flows, sedimentary deposits that contain a sequential history of formation or simply an agglomeration of cold particulate matter accreted from space.
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5 Comments
Add CommentThe Apollo missions were truly 50 years ahead of their time. 50 years societally & technologically. We ought still to look back at what our ancestors achieved, with the resources at hand, and the will in mind, in awe.
Reply | Report Abuse | Link to thisI disagree hotblack, the Apollo missions were 7-10 behind the times. If Wernher von Braun was given the opportunity earlier, we would have gotten to the moon by 1959-62. The German scientist was way beyond his time. In one word "Brilliant". Why doesn't Nasa have any of these guys around?
Reply | Report Abuse | Link to thisPerhaps technology. But Werner Von Braun as a Nazi was societally 1000s of years behind. Better to not have achieved the moon landing and other technological goals than be a Nazi
Reply | Report Abuse | Link to thisdoron, surely you must be aware that Von Braun was a reluctant Nazi. He earned the enmity of his superiors on several occasions because of his outspoken vision of rocket-enabled space travel and exploration, rather than rocket-enabled world domination. Von Braun was not enthusiastic about the Nazis or the war. This characteristic almost cost him his life. Viewing the past through the lense of the present affords many opportunities to wax morally superior to one's ancestors. The moon landings were a culmination of Von Braun's inspired vision of human progress, and had nothing to do with the Nazi Party. Perhaps you had better get your own house in order, doron - before you ask the entire human race to discard any dreams of reaching beyond, for fear of disturbing a tree or a slumbering faun.
Reply | Report Abuse | Link to thishotblack - Do you know how much I despise those who state that "so-and-so was ahead of their time" simply because the ball got dropped later on? Apollo was firmly of its time. The moon mission could have been completed earlier than 1969 had it not been for delays. Saying that Apollo was 50 years ahead of its time is the same as saying its OK that we're currently doing nothing of consequence in space. I vehemently disagree with this state of affairs. I will add, hotblack, that using your logic, Apollo wasn't just 50 years ahead of its time. If the Chinese make it to the moon by 2020, Apollo will be officially 61 years ahead of its time. If you ignore the Chinese and just count NASA, well... you might have to wait a pretty long time to find out. They'll probably not go their again. We entered our long decline a while back.
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