The following picture has been posted in the Astronomy section (by Dave C426913). https://www.physicsforums.com/file:///C:/Users/John/AppData/Local/Temp/msohtml1/01/clip_image001.jpg [Broken] Source: http://www.space.com/4643-incredible-comet-bigger-sun.html Why does the comet fluctuate in size but the sun does not? Why does it appear to get smaller but not bigger? P.S. I was not able to post the image, but you can see it via the link. If you copy the picture to another document you will see the same effect i.e. the image fluctuation is not embedded.