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The Tenth Planet Shrinks Under Hubble's Gaze

starexplorer2001 writes "An object called the 10th planet by some astronomers is not as large as previously thought. New images of 2003 UB313 (aka Xena) were delivered by the Hubble Telescope and showed up as only 1.5 pixels! Now, some are calling to demote Pluto and kill Xena."

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  1. Re:atomic? by helioquake · · Score: 5, Informative

    A pixel is small, but nowhere near subatomic. It's measured only in microns.

    When photons are distributed over the CCD surfrace, it has some measureable shape (e.g., Gaussian) which can be fitted as such to characterize the shape. The quoted size of 1.5 pixel is, I think, the FWHM of the fitted Gaussian function that characterize its source.