XVI. At the end of the 20th century a supernova was observed on Earth, an explosion of an old star. It was the first supernova visited in the Milky Way. Now, four hundred years later, astronomers from the Max Plank institute have been able to observe some remains of this supernova.
What they have seen is not the explosion they saw in 1572, but their 'echo'. As astronomers have explained, when the star explodes, light expanded in all directions. Those who saw him at that time saw the light that went to Earth.
The one who went in other directions followed his path and part of it bounced the interstellar dust particles. In fact, the light you have seen now is a light bounced in a dust located hundreds of light years from the star.