August 23, 2010 | David F. Coppedge

Moon May Be Active Today

The old story of our moon was that it was geologically dead.  Except for the occasional meteor impact, not much happens there; the interior had cooled down long ago, leaving it an inert, battered sphere.  That was before the Lunar Reconnaissance Orbiter showed scientists evidence that it has continued to shrink and form new surface features recently.  In fact, the activity may still be occurring today.
    Science Daily reported that analysis of lobate scarps and small craters is changing scientists’ ideas about the moon.  Small craters should be erased in relatively short time, but some scarps, thought to be due to lunar shrinkage, run right through them – indicating the scarps are younger than the craters.  Such lobate scarps were known from the Apollo missions but it was uncertain whether they were a peculiarity of the equatorial regions.  LRO has shown them all over the globe.  Whatever causes them must be a global phenomenon.  Furthermore, the moonquakes detected by Apollo instruments might be due to ongoing shrinkage rather than impacts as earlier thought.
    One of the scientists put his error bars far apart.  “We estimate these cliffs, called lobate scarps, formed less than a billion years ago, and they could be as young as a hundred million years,” Dr. Thomas Watters (Smithsonian) speculated.  But since “the scarps look crisp and relatively undegraded” why couldn’t they be as young as 1,000 years, or 10 years?  After all, “The moon cooled off as it aged, and scientists have long thought the moon shrank over time as it cooled, especially in its early history,” the article said.  “The new research reveals relatively recent tectonic activity connected to the long-lived cooling and associated contraction of the lunar interior.”
    The article also spoke about Mercury’s lobate scarps, which are much larger than the moon’s despite its smaller volume.  On Mercury they can be 100 miles high and snake across the surface for hundreds of miles.  Without explaining why, the article said, “the team believes the moon shrank less.”
    On a related note, Science Daily reported that the mountains on Titan, rising nearly two kilometers, may be due to shrinkage, too.  “Since the formation of Titan, which scientists believe occurred around four billion years ago, the moon’s interior has cooled significantly,” the article said, stating tradition.  “But the moon is still releasing hundreds of gigawatts of power, some of which may be available for geologic activity.”  Lessons being learned there, however, cannot be generally applied.  Jonathan Lunine opined, “These results suggest that Titan’s geologic history has been different from that of its Jovian cousins, thanks, perhaps, to an interior ocean of water and ammonia.”
    And speaking of activity, Cassini bagged another close-up view of the geysers on Enceladus, Science Daily reported.  The photos (see Imaging Team site) shows the hot jets are still going strong, years after their discovery in 2005.  The JPL press release includes photos it also took of Dione and Tethys on this, the 11th close flyby past Enceladus.

Scientists try hard to make it look like they know what they are talking about.  Describing how things look today is one thing.  That’s observation.  Telling us how they got that way is interrupted frequently by the refrain, “Scientists had long thought… but….”  Heard often enough, it’s not cause for confidence in what they are telling us now, even when they crow about nailing the age of the solar system to 5 significant figures (see New Scientist) which, by the way, they just decided is some 2 million years older than the previous value they crowed about (see Space.com).  Let’s stack their confidence in that number by the pile of mistakes in all their predictions (07/29/2010).  They don’t know, and they weren’t there, so is this science, or is it educated storytelling with unlimited withdrawals from the Ad Hoc Bank?

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Categories: Solar System

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