Roper et al. have recently compared two Chandra X-ray images to measure the expansion of a supernova remnant (SNR) in the Large Magellanic Cloud. The images above show (at left) the X-ray image of SNR 0509–67.5 in the 0.5–8.0 keV energy range from data taken in the year 2000, (centre) the X-ray image from 2007, and (right) the difference image between the 2007 epoch and the 2000 epoch X-ray data. The difference results in a nearly complete shell, indicating observable uniform expansion. The colour bar is in units of photons/s/keV/cm^2. SNR 0509–67.5 (J0509-6731) is a young (approximately 400 yr old) Type Ia supernova remnant, and Roper et al. estimate an expansion speed of 7500 +/- 1700 km/s, which is consistent with an optical expansion study on this object. In addition, they examine the medium in which the SNR is expanding by examining the CO and neutral H I gas using radio data obtained from Mopra, the Australia Telescope Compact Array, and Parkes radio telescopes. More details are available from the paper , published in Monthly Notices of the Royal Astronomical Society .