The Space Scars of Earth

Millman, Peter M.

doi:10.1038/232161a0

Cited by 11 publications

(1 citation statement)

References 5 publications

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“…The number of large impact scars recognized has been growing steadily since systematic searches began about two decades ago (Beals, Ferguson & Landau 1956), the rate of recognition having accelerated since shock metamorphism has been used as the principal criterion (French 1968). On the geologically better known continents the census of impact structures with diameter of 20 km or more and residual topographic expression is substantially complete (Millman 1971;Dence 1972). For such stable continental regions the impact record shows a size vs. frequency distribution and a rate of formation, at least since early in the Phanerozoic, comparable with those of the post mare crater population of the Moon (Robertson & Grieve 1975).…”

Section: Introductionmentioning

confidence: 99%

The contribution of major impact processes to lunar crustal evolution

Dence¹

1977

Phil. Trans. R. Soc. Lond. A

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Large terrestrial impact craters provide structural models for the interpretation, of lunar craters and basins and petrological data for comparison with complex lunar breccias. The terrestrial examples illustrate the mixing processes operative in the production of impact melts and breccias and the considerable volumes of impact melt rocks in large impact craters. Three forms of craters are found on Earth, Moon, Mars and Mercury; Simple bowl-shaped craters (smallest), central uplift, and ring structures (largest). The variations in form are interpreted as different degrees of gravitational modification which immediately follow the initial excavation. On Earth the transient cavity excavated has diameter/depth ( D/d) near 3/1 in non-porous, essentially homogeneous rocks. From Orbiter and Apollo photographic data transient cavities in the most competent lunar materials have D/d of approximately 4/1. Experiments indicate ejecta come from as deep as two-thirds rds the transient cavity depth: disturbed material from greater depths remains as the crater lining. Application to the Imbrium basin indicates a portion of the ejecta at the Apollo 15 site may have come from as deep as 100 km, and from somewhat shallower depths at the Apollo 14 site. Ultramafic green and howarditic glasses are possible candidates for these materials of deep origin. Uplift of upper mantle in the centre of the basm would contribute to the Imbrian mascon.

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Section: Introductionmentioning

confidence: 99%

The contribution of major impact processes to lunar crustal evolution

Dence¹

1977

Phil. Trans. R. Soc. Lond. A

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Molecules Detected in Interstellar Space

Menten

Wyrowski

2011

Springer Tracts in Modern Physics

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Perspective from a Younger Generation — The Astro-spectroscopy of Gisbert Winnewisser

Menten

1997

Springer Proceedings in Physics

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Gisbert Winnewisser's astronomical career was practically coextensive with the whole development of molecular radio astronomy. Here I would like to pick out a few of his many contributions, which I, personally, find particularly interesting and put them in the context of newer results.1 Beginnings -When Molecular Radio Astronomy was still Radio Astronomy 1 see also Shklovsky 1952.2 Both lines were on Townes' (1957) list! 3 Circumstellar molecules exist in the envelopes of evolved giant stars. Many species are detected there that are also found in interstellar clouds, whereas some others, have so far only been detected in a circumstellar environment. 4 See http://www.ph1.uni-koeln.de/vorhersagen/molecules/main molecules.html

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The Space Scars of Earth

Cited by 11 publications

References 5 publications

The contribution of major impact processes to lunar crustal evolution

The contribution of major impact processes to lunar crustal evolution

Molecules Detected in Interstellar Space

Perspective from a Younger Generation — The Astro-spectroscopy of Gisbert Winnewisser

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