Sour Grapes
Of course we're Fair and Balanced!


Mystery of planetoid Sedna

It seems there was good reason to believe that a Hubble image of this recently discovered planetoid—13.5 billion km from the Sun, more than twice Pluto's distance from the Sun—would show evidence of a companion moon. Alas, there was none. So why does it take 20-50 Earth days to complete one rotation? That's apparently the question, though I don't understand (and would really like to) why such a slow rotation would indicate the likelihood of a moon. Sedna is too small to fill one pixel in the image, setting an upper limit on its diameter of 1,600 km. If you have the bandwidth, be sure to see the 4200px x 3000px image (483.1 kB).

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