人类观测星系的历程
People have always looked into the sky and tried to explain what they saw. Some early civilizations created fantastic stories to explain the patterns above us. Our modern scientific understanding shows the truth is more extraordinary than any of these tales. Some small dots of light in the sky are actually enormous objects called galaxies, made up of billions of stars, some so far away that it took billions of years for the light to reach us. These galaxies are shaped, not by the exploits of gods, but by a whole range of incredible objects, like black holes in space from which nothing can ever escape.