What is the peristerum?

How does hades job work? What is the stand for a rocket called? Different kinds of galaxes? How did gravity falls get its name? 2. What country was the first to launch an artificial satellite? How do space shuttles aid space exploration? What is the name of the first satellite of the Philippines? What is the best planet search technique currently suited for finding Earth-like planets? Inventor of stethescope? Why does the moon reflected so much light? When did valentina died? What time did Spring arrive? Is Zeus a titan? What Ice crystals or flacks that fall from the sky are called? How many stars in total make up the constellation Cygnus? What the dr from Dr. Who's real name? What fuel is environment friendly as a rocket fuel? What are the probable sources of smoke particles found in the atmosphere? What does chromosphere do? What are some interesting facts about gravity?