4th Grade Science Vocabulary Chapter 2 Vocabulary in 4th Grade Science Ch. 2 Universe Galaxy Planet Revolve Phase Axis Comet Moon Constellation Sun Star Solar System Rotate Orbit What do we call a natural body that revolves around a planet? Moon What do we call the star at the center of the solar system? Sun What do we call a pattern of stars that form an imaginary picture of design in the sky? Constellation What do we call a huge ball of very hot gases in space? Star What do we call a star and all the planets and other objects that revolve around it? Solar System What do we call a large body that revolves around a star? Planet What do we call a ball of ice, rock, and frozen gases that orbits the sun? Comet What do we call an imaginary line that runs through the center of Earth from the North Pole to the South Pole? Axis What do we call the path of one object in space around another object? Orbit What do we call spinning around an axis? Rotate What do we call traveling in a closed path? Revolve What do we call one of the shapes the moon seems to have as it orbits Earth? Phase What do we call a grouping of gas, dust, and main stars, plus any objects that orbit those stars? Galaxy What do we call everything that exists in space? Universe