What does a spectropist do?

Everything attracted towards the center of earth but gravity is zero at the center of earth.why? What happens when mermaids are in water and they look at the full moon? What is an absolute magnitude? What other planets did differentiation occur? How much did Dennis Tito pay to get to space? What is the smallest planet in our solar system and what is the farthest planet from the sun? Invisible path on which planets travel in the space? What is a natural light show caused by particles in the air that at charged by solar particles? Put the planets in order from least to most moons? Why do satellites not fall to earth? What does the red and green light indicate when seen together at night? Billions of years from now the sun will progress through different stages as it ages In chronological order these stages are? Who discovered the constellation Lyra? What words describe the clouds? What is a star dennison trade mark pocket watch worth serial no 230101? What is a space helmet made of? What is the correct sequence of layers of the atmosphere from innermost to outermost? How do you tell if the 1783 nova constellatio mark 1000 coin is a fake? What should a hot-air balloonist do to get higher? How many constellations are circumpolar?