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Science Frontiers ONLINE No. 131: SEP-OCT 2000 |
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The Earth Made Mars Different
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Day's abstract follows:
Mars has surface features that are not seen on inner planets or moons. These are hemispheric asymmetries, idiosyncratic surface fracturing, localized vulcanism, altitude differences, chains of pits, and the nature of dry river-like channels. Other features include extensive loss of an early atmosphere and liquid water. There is interest in the lower-altitude northern region, with its surface formed after the period of heavy bombardment, as a possible ocean basin. The evidence for this is very sparse: no river deltas, no river networks, little debris at the ends of the catastrophic flow channels. The surface is consistent with the stripping anticipated by a Roche-limit encounter. The low-density Martian moons appear to be unconsolidated material of higher density; they appear to be from low-gravity aggregation of that part of the Martian debris that went into orbit as a short-lived ring. A Roche-limit encounter is invoked as a reasonable hypothesis to explain these features. Earth, Mars' nearest planetary neighbor, may have provided that encounter. The Roche limit is 2.9 Earth radii.
The Roche limit is that distance within which Mars would begin to be torn apart by the gravitational pull of nearby Earth.
(Day, Richard A.; "A Roche-Limit Encounter Explains Martian Features," Society for Scientific Exploration paper, 2000.)
Comment. Anomalists with long memories will see immediately that Day's theory is displaced Velikovskyism. Velikovsky had Venus straying close to Earth in recent times to account for historical and geological evidence of terrestrial catastrophism.
Another related theory claims that the earth's moon was created when Mars dealt earth a glancing blow -- a reversal of Day's scenario. Obviously, both cannot be correct.
Other Sites of Interest
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