... 1006 AD: Supernova in the Sky . ... The expanding debris cloud from the stellar explosion is still visible to modern astronomers, but what did the supernova look like in 1006? Skylab Over Earth . ... Many scientific tests were performed on Skylab, including astronomical observations in ultraviolet and X-ray light. NGC 7635: Bubble in a Cosmic Sea . ... Shiny NGC 253, sometimes called the Silver Dollar Galaxy, is one of the brightest spiral galaxies visible - and also one of the dustiest. ...