On November 8, 2006, the planet Mercury drifted directly between the Earth and the sun and appeared in silhouette to those with telescopes and proper solar filters.  This image shows the progression of the tiny planet at 10-minute intervals during that afternoon.  On the left of the image appears a sunspot that had only recently rounded the eastern side of the sun.  The sun's limb appears darker than its face because, in this direction, we're looking along the cooler edge of the sun's photosphere.