Post by Chicago Astronomer - Astro Joe on Aug 23, 2006 1:34:39 GMT -6
Geologists and astronomers wrangle over words
On 16 August the International Astronomical Union (IAU) floated a proposal for a definition of the word 'planet', in part to end the confusion about whether Pluto is a planet or not. But their solution, which assigns Pluto and its neighbours to a subset of planets called 'Plutons', is so far just creating more confusion and angst.
Scientists have pointed out that the word 'pluton' is already taken by geology, making at least one geologist hopping mad. Furthermore, astronomers have argued that the definition just doesn't fit with their intuitive sense of what a planet is — leading, already, to a second proposed definition. The confusion will probably continue until this Thursday, at least, when IAU members will put the proposals to a vote.
Plutons, under the first IAU draft definition, would be round astronomical objects that take more than two centuries to orbit the Sun. That, broadly speaking, includes most objects in the Kuiper belt, a ring of large debris beyond the orbit of Neptune.
But a pluton in geology is a large bubble of molten rock that solidifies underground, points out Allen Glazner, a geologist at the University of North Carolina at Chapel Hill who has devoted a decade of study to the stuff. On 18 August, Glazner wrote a letter to the IAU accusing them of "hijacking our perfectly good [definition] and causing endless confusion."
Plutons are common in geology, Glazner says. "It's what the Earth's crust is constructed from, especially the continental crust," he says. "It's really, really fundamental." They're not too hard to find either. For example, Yosemite National Park's Half Dome, in California, is a pluton that became exposed after it formed beneath the Earth.
Spell checked
Owen Gingerich, an astronomer at Harvard University in Cambridge, Massachusetts, and chair of the IAU committee that created the definition, says that they were aware of its usage amongst geologists, but unaware of its importance to the field. "Since the term is not in the MS Word or the WordPerfect spell checkers, we thought it was not that common," Gingerich wrote in an e-mail to news@nature.com. The geologic definition of the word does appear in common dictionaries, including the Oxford English.
Gingerich says that he believes the two definitions can coexist, "We think words can (and frequently do) have alternative meanings - for example, is there mercury on Mercury?" he says. He adds that he is willing to consider alternative terms to describe Pluto-like objects.
But Glazner disagrees. "If it was two really different fields it might not matter, but planetology and geology are really close," he says. "It would be amazingly confusing."
Full story here: www.nature.com/news/2006/060821/full/060821-4.html
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I think the geologist is petty and territorial about his field. Oh...did I use field, like in " a field of igneous rock"? ...
