Term | Definition |
Astronomy | The science that studies the universe. |
Geocentric | Models/beleifs pertaining to the Earth as being the center of the universe, and that other planets orbit it. |
Heliocentric | The models showing that the sun is the center of the universe, and that other planet orbit it. |
Retrograde motion | The westward shift deriving from the Earth and another planet's own motion around the sun. |
Ellipse | An oval shaped path taken by a planet during orbit. |
Astronomical Unit (AU) | The average distance between Earth and the sun. |
Rotation | The turning and spinning of a body on it's axis |
Revolution | The motion of a body around some point in space. |
Precession | The slight movement of Earth's axis. |
Perihelion | The time in which the Earth is closest to the sun; usually around the 3rd of January. |
Aphelion | The time in which the Earth is farthest from the sun; around the 4th of July. |
Perigree | The point where the Earth is closest to the moon. |
Apogee | The point where the Earth is farthest from the moon. |
Phases of the moon | The result of the sunlight reflected on the moon combined with the moon's own movements. |
Solar eclipse | When the moon moves in a line directly between the Earth and the sun. |
Lunar eclipse | When the moon moves withen the Earth's own shadow. |
Crater | Round depressions in the surface of the moon. |
Terrestrial planet | Relativly small and rocky planets. |
Jovian planet | Gas giants. |
Nebula | A cloud of dust and gas in space. |
Planetesimal | Small, irregualrly shaped bodies formed by the colliding/combining of matter in space. |
Asteroid | Small rocky bodies that drift through space. |
Comet | Peices of rocky and metallic materials held together by frozen gases. |
Coma | The glowing head of a comet as the it gets closer to the sun and begind to vaporize. |
Meteoroid | A small solid particle that drifts through space. |
Meteor | Metoeoids that enter Earth's atmosphere, then burn up. |
Meteorite | A meteoroid that reaches Earth's surface. |
Electromagnetic spectrum | The arraingement of rays according to their wavelengths and frequinces. |
Photon | Light that creates a stream of paticles. |
Sceptroscopy | The study of the properties of light that depend on wavelength. |
Doppler Effect | The percieved change in wavelength of a wave that is emitted from a source moving towards or away from an object. |
Refracting Telescope | A telescope that uses a lens to bend or refrect light. |
Reflecting Telescope | A telescope that uses a concave mirror that focuses the light infront of a mirror, rather than behind it, like a lens. |
Radio Telescope | A telescope that detects and percieves radio waves using an antenna. |
Hubble Telescope | The first space telescope, built by NASA. |
Space Shuttle | A spacecraft propelled by rockets used to venture outside of the Earth's atmosphere. |