My own current neighborhood fits this definition of a suburb that lacks the negative aspects of postwar sprawl. A 20-minute train ride from the center of Philadelphia, it boasts a retail and small office district within a short walk of most homes.
Crab supernova remnant: A supernova is an explosion of a massive supergiant star. It may shine with the brightness of 10 billion suns! The total energy output may be 10 44 joules, as much as the total output of the sun during its 10 billion year lifetime. The likely scenario is that fusion proceeds to build up a core of iron.
But only a select few stars become supernovae. Many stars cool in later life to end their days as white dwarfs and, later, black dwarfs. Star Fusion. But massive stars, many times larger than our own sun, may create a supernova when their core's fusion process runs out of fuel.hese blasts produce much of the material in the universeâincluding some elements, like iron, which make up our planet and even ourselves. Heavy elements are only produced in supernovae, so all of us carry the remnants of these distant explosions within our own bodies.