Definitions Flashcards
Define summer solstice.
Time of year when the Northern Hemisphere has its longest day and the Southern Hemisphere has its shortest day. It is the beginning of summer in the Northern Hemisphere.
Define winter solstice.
Time of the year when the Northeren Hemisphere has its shortest day and the Southern Hemisphere has its longest day. It is the beginning of winter in the Northern Hemisphere.
Define vernal equinox.
Time of year when day and night are of equal of length; beginning of spring in the Northern Hemisphere.
Define autumnal equinox.
Time of year in the fall when day and night are of equal of length; beginning of autumn in the Northern Hemisphere.
Define magnetosphere.
Area around the Earth that extends beyond the atmosphere, in which the Earth’s magnetic force operates.
Define Van Allen radiation belt.
Two doughnut-shaped regions of charged particles formed when the Earth’s magnetosphere traps some of the particles in the solar wind.
Define aurora.
Bands or curtains of colored lights produced when particles trapped by the Van Allen radiation belts collide with particles in the upper atmosphere.
Define highlands.
Mountain ranges on the moon
Define maria.
Smooth lowland plains on the moon.
Define rille.
Valley on the moon
Define perigee.
Point of a satellite’s orbit closest to the earth.
Define apogee.
Point of a satellite’s orbit farthest from the Earth.
Define solar eclipse.
Blocking of the sun that occurs when the new moon comes directly between the sun and the Earh.
Define umbra.
Inner part of a shadow
Define penumbra.
Outer part of a shadow
