What created this unusual space ribbon? Most assuredly, one of the most violent explosions ever witnessed by ancient humans. Back in the year 1006 AD, light reached Earth from a stellar explosion in the constellation of the Wolf ( Lupus ), creating a “guest star” in the sky that appeared brighter than Venus and lasted for over two years. The supernova, now cataloged at SN 1006 , occurred about 7,000 light years away and has left a large remnant that continues to expand and fade today. Pictured above is a small part of that expanding supernova remnant dominated by a thin and outwardly moving shock front that heats and ionizes surrounding ambient gas. SN 1006 now has a diameter of nearly 60 light years . Within the past year, an even more powerful explosion occurred far across the universe that was visible to modern humans, without any optical aid, for a few seconds.
Note: Free Astronomy Course Taught Online by an APOD Editor digg_url = 'http://apod.nasa.gov/apod/ap080915.html'; digg_skin ='compact';