What seemed to be rock-solid assumptions about the nature of small asteroids may end in collections of rubble or even a cloud of dust, but in such findings lies the lure of the unexpected.<\/p>\n
Northern Arizona University researchers David Trilling<\/strong> and Michael Mommert<\/strong>, while playing a well-defined role in the NASA Asteroid Initiative<\/a>, are beginning to wonder if they have found a separate path of investigation.<\/p>\n The two researchers presented their findings about asteroid 2011 MD on Thursday during a NASA event updating progress on the path to capturing a small asteroid and relocating it for a closer look by astronauts in the 2020s.<\/p>\n The job of Trilling and Mommert was to use the infrared capabilities of the Spitzer Space Telescope to determine the size of 2011 MD, which needs to be within a narrow range for the mission to succeed. Trilling, an associate professor, explained that using infrared light is the most accurate way to determine an asteroid\u2019s size because visible light through a traditional telescope fails to distinguish a small, highly reflective asteroid from a large one with little reflectivity.<\/p>\n At around 6 meters in diameter, 2011 MD is just right. But that\u2019s not the whole story.<\/p>\n \u201cPeople have assumed that small asteroids are debris from collisions of larger asteroids, so those really small guys would be just single slabs of rock flying in space,\u201d said Mommert, a post-doctoral researcher. \u201cBut we found that this one is 65 percent empty.\u201d<\/p>\n The findings, which suggest a flying cluster of rocks or a cloud of dust with a solid rock at its nucleus, are similar to observations the NAU researchers published earlier this year of yet another asteroid, 2009 BD.<\/p>\n Trilling said long-held assumptions are yielding to something \u201cweirder and more exotic. The first time you see it, you think, \u2018Well, that\u2019s just an anomaly.\u2019 But two out of two, and you start to think that maybe the small ones really don\u2019t look like everyone thought.\u201d<\/p>\n