When the supernova remnant RCW 103 was first observed 25 years ago, it seemed to be a textbook example of a massive star's death: a gaseous cloud of ejected material surrounding a neutron star only about 12 miles across. But new observations from ESA's XXM-Newton satellite show that the neutron star, which is located in the central blue dot in the image above, behaves like no other object ever before observed. The star emits x-rays in a cycle that repeats every 6.7 hours, which is tens of thousands of times longer than expected for a young neutron star. Scientists don't yet know what is causing the star to pulsate so slowly, but they hope further observations will shed light on the unique object. The findings appear in the July 6 issue of Science Express.