The expanding remains of a supernova explosion in the Milky Way are shown in this composite image, on the left, of the supernova remnant G1.9+0.3. NASA's Chandra X-ray Observatory image obtained in early 2007 is shown in orange and the radio image from NRAO's Very Large Array (VLA) from 1985 is in blue. The difference in size between the two images gives clear evidence for expansion, allowing the time since the original supernova explosion (about 140 years) to be estimated.
The most recent supernova in our Galaxy has been discovered by determining the age of the supernova remnant known as G1.9+0.3. To determine the age, astronomers tracked how quickly it is expanding, by comparing a radio image from 1985 to a Chandra image taken in 2007. The expansion rate was confirmed with another radio observation with the VLA in 2008. The difference in size between these images gives clear evidence for expansion, allowing the age of the remnant and the time since the original supernova explosion (about 140 years) to be estimated.
呵呵,好久没发自翻图了。。。
URL:http://chandra.harvard.edu/photo/2008/g19/more.html