Earth-Moon-Sun System Flashcards
(19 cards)
Rotation
The spinning of a body, such as a planet, on its axis. For Earth, one full rotation takes 24 hours and defines a day.
Orbit
The path an object takes as it revolves around another in space.
Revolution
The motion of a body that travels around another body in space. Earth completes one revolution around the sun in about 365 1/4 days (one year).
Day
For Earth, this is 24 hours.
Season
A pattern of temerature and other weather trends that are affected by Earth’s tilt and its revolution around the sun.
Equinox
A day when sunlight shines equally on the Northern and Southern Hemispheres: day and night are approximately equal in length.
Solstice
A day when the area of sunlight is at a maximum in one hemisphere and at a minimum in the other. It marks the start of summer or winter.
Axis
An imaginary straight line that runs from the North Pole to the south Pole on which Earth rotates. Eartyh’s axis is tilted at 23.5 degrees.
Year
The time it takes Earth to complete one full revolution around the sun, which is about 365 1/4 days.
Eclipse
An event during which one object in space casts a shadow onto another. Lunar and solar eclipses occur when the moon or Earth passes through each other’s shadows.
Midnight Sun
A phenomenon where, during summer in the polar regions, the sun remains visible at midnight, resulting in 24 hours of daylight.
Satellite
A body that orbits a larger body in space. TYhe moon is Earth’s natural satellite.
Penumbra
The lighter part of a shadow that surrounds the umbra, where only part of the light is blocked.
Umbra
The darkest part of a shadow, where all light is blocked during an eclipse.
Lunar Phases
The changes in the appearance of the moon from Earth as the moon revolves around Earth. The phases include new moon, crescent, first quarter, gibbous, and full moon.
Tide
The daily changes in the level of ocean water caused mainly by the gravitational pull of the moon and, to a lesser extent, the sun.
Tidal Range
The difference between the levels of ocean water at high tide and low tide.
Spring Tide
A tide with the largest tidal range, occuring when the sun, the moon, and Earth are in a straight line (during the new moon and full moon phases).
Neap Tide
A tide with the smallest tidal range, occuring when the sun, Earth, and the moon form a 90 degrees angle (during thr first and third quarter moon phases).
