August 26, 2014
The New Horizons space probe left Earth in 2006 and reached Neptune Monday, on its way to Pluto, which it is expected to reach in July 2015. (Photo courtesy NASA)
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Tucson scientist joins panel touting 2015 visit to 'dwarf planet'
Tucson scientist David Grinspoon joined a panel Monday talking about NASA's New Horizons mission to Pluto