Solstice and Orbit
I occur around September 22 in the Northern Hemisphere. At this time there is an equal amount of daylight and night time.
Autumnal Equinox
The phase of the Moon that occurs about a week after a full Moon when the left half of the Moon as seen from Earth's Northern Hemisphere is fully sunlit.
Last Quarter
The part of a shadow in which the light source, such as the Sun, is not completely blocked.
Penumbra
The collection of all organisms that live on Earth along with the environments in which they live.
Biosphere
The study of the materials that make up Earth and the processes that change Earth over time.
Geology
The plane containing the Earth's orbit around the Sun.
Ecliptic
A calendar based on both the phases of the Moon and the orbit of Earth around the Sun.
Lunisolar Calendar
A solar eclipse in which the Moon covers only a part of the Sun's disk, rather than completely blocking the Sun.
Partial Solar Eclipse
The part of Earth composed of water. This water is present as a liquid in the oceans, lakes, rivers, and as groundwater in pores in rocks and soil.
Hydrosphere
The study of the atmosphere.
Meteorology
The point on the orbit of a planet, asteroid, comet, or other object around the Sun where it is closest to the Sun.
Perihelion
The phase of the Moon that occurs in the days follwowing a full Moon when more than half of the near side of the Moon is still sunlit.
Waning Gibbous
A lunar eclipse that occurs when the Moon passes completely into Earth's umbra.
Total Lunar Eclipse
The rigid outer layer of Earth, composed mostly of solid rock. The lithosphere includes Earth's crust and the upper part of the underlying mantle.
Lithosphere
The study of the oceans.
Oceanography
The point on the orbit of a planet, asteroid, comet, or other object around the Sun where it is farthes from the Sun.
Aphelion
The phase of the Moon that occurs a few days after the new Moon when only a sliver of the Moon's Sunlit surface is visible from Earth.
Waxing Crescent
The darkest, inner part of a shadow.
The region around a star in which liquid water can exist on the surface of planets, and which can therefore support advanced life.
Habitable Zone
The latitude in the Northern Hemisphere (23.5 degrees N) where the Sun climbs up to directly overhead at noon on the summer solstice.
Tropic of Cancer
I occur around March 22 in the Northern Hemisphere. At this time there are equal amounts of daylight and night time.
Vernal Equinox
The shape of the sunlit portion of the Moon's face as seen from Earth.
Phase
An eclipse that occurs when the Moon passes in front of the Sun, blocking the Sun and causing the Moon's shadow to fall on a portion of Earth's surface.
Solar Eclipse
The layer of gases that surround a planet such as Earth.
Atmosphere
The latitude in the Southern Hemisphere (23.5 degrees South) where the Sun climbs up to directly overhead at noon on the summer solstice.
Tropic of Capricorn