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.
10. Not every star explodes. For instance, our Sun (which is a star) will never explode. Stars that are 10 to 100 times bigger than our Sun eventually explode and create a supernova explosion.he amount of energy radiated in one supernova explosion is equal to the amount of energy that is radiated by our Sun so far plus the energy that it will radiate for the rest of its life. 4. A supernova is so bright that it literally takes weeks and sometimes months for the brightness to fade away. 5.