Image: Astronomy Picture of the Day: 700 Kilometers Below Comet Hartley 2
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Multiverses: 700 Kilometers Below Comet Hartley 2
Credit: NASA, JPL-Caltech, UMD, EPOXI Mission
Astronomy Picture of the Day - 2010 November 8
Explanation: What kind of comet is this? Last week, NASA's robotic EPOXI spacecraft whizzed past Comet 103P/Hartley, also known as Comet Hartley 2, and recorded images and data that are both strange and fascinating. EPOXI was near its closest approach -- about 700 kilometers away -- when it snapped the above picture. As expected, the comet has indeed shown itself to be a tumbling iceberg orbiting the Sun between Earth and Jupiter. However, unexpected features on the images have raised many questions. For example, where are all the craters? Why is there a large smooth area around the middle? How much of Comet Hartley 2 is a loose pile of dust and ice shards? Future analyses and comparisons to other comet nuclei may answer some of these questions and, hopefully, lead to a better general understanding of comets, meteors, and the early Solar System.