The luminous star around which Earth and other planets revolve; composed mainly of hydrogen and helium

A celestial body that revolves around a planet

The slant of Earth's axis which is 23.5 degrees from vertical compared to Earth's orbital plane around the sun; as a result the North Pole always points to the North Star

The circular movement about an axis or a point.

The outer atmosphere of the sun. A thin, extremely hot plasma over 1,000,000 deg. Celsius compared to around 6,000 deg. Celsius for the visible surface

An attractive force that acts between all matter, has mass, and is proportional to that mass

The full moon passes into Earth's shadow causing the moon to appear reddish in color when the sun, Earth, and moon directly line up; lasts for 1 - 3 1/2 hours

An obscuring from the light of a celestial body by the passage of an object bet/ the celestial body and the observer or bet/ the celestial body and its source of illumination

A phenomenon or process that involves multiple steps and repeats itself

The branch of science that studies the physical universe beyond Earth's atmosphere

A self-luminous celestial body consisting of a mass of gas held together by its own gravity in which the energy is generated by nuclear reactions in its interior

Two regions of a planet at the extremities of its rotational axis

Imaginary line through Earth that extends from the N. Pole to the S. Pole and is the center for Earth's rotation