| Term | Definition |
|---|---|
| meteor | a streak of light in the sky produced by the burning of a meteoroid in Earth's atmosphere. |
| asteroid belt |
any of thousands of dense rocky objects in orbit around the sun between Mars and Jupiter. |
| comet | A ball of ice, dust, and frozen gases that orbits the sun. |
| revolution | the movement of an object around another object. |
| rotation | the spinning motion of a planet on its axis. |
| outer planets | gas giant planets found outside of the asteroid belt. |
| inner planets | terrestrial (earth-like) planets that are dense solids located between the sun and the asteroid belt. |
| gravity |
the attractive force between two objects.
(The more massive an object, the greater its gravitational force. Example: Earth’s gravity is greater than the gravity of the moon.) |
| axial tilt | the invisible axis that are tilted allowing for seasons to occur. |
| probe | a robotic spacecraft that leaves Earth’s orbit and explores space. |
| satellite | any object that revolves around another object in space. Can be artificial or natural like the moon |
|
Heliocentric Theory |
Nicolaus Copernicus’ idea that the Earth, planets, and stars all revolved around the Sun. |
| Geocentric Theory | Aristotle & Ptolemy believed that the Earth was the center of the Universe and all objects revolved around it. |
| tides | the rise and fall of sea levels caused by the combined effects of gravitational forces exerted by the Moon. |
| greenhouse effect | is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without an atmosphere. |
| illuminated |
to light up
The moon is illuminated by the sun. |
| celestial objects | Known collectively by astronomers as celestial bodies, astronomical objects, and astronomical bodies, they are the stuff that fills the empty space of the universe. |
| lunar eclipse | occurs when the Earth is between the sun and moon. Sunlight is blocked by the Earth. |
| solar eclipse | occurs during the NEW MOON PHASE when the moon passes between the Sun and Earth, and the moon fully or partially blocks the Sun. |
| autumn | the season between summer and winter known as fall in North America. |
|
equinox
Autumnal Equinox = first day of autumn; occurs around the 22nd of September Vernal Equinox = first day of spring; occurs around the 20th of March |
the time and date when the sun passes directly over the equator; the length of day and night are equal (12 hours each) |
| solstice | the time and date when the sun is at its greatest distance from the equator; length of day and night show greatest difference |
| orbit |
revolve around
circle around go around travel around |
| diameter | The equator is the diameter of the Earth |
| survivable temperatures | the highest and lowest temperatures that humans can stand without dying |
| astronomer |
the study of celestial objects (stars, galaxies, planets, moons, asteroids, comets and nebulae) and all phenomena that originate outside the atmosphere of Earth |
