Science Chapter 1 and 2: Astronomy Flashcards
Sphere
A round, three dimensional object whose surface is the same distance from its center at all points; Earth is a sphere that bulges someone at the equator and is slightly flattened at the poles.
Axis
Imaginary vertical line that cuts through the center of Earth and around which Earth spins.
Rotation
Spinning of Earth on its imaginary axis which takes about 24 hours to complete and causes day and night to occur.
Revolution
Earth’s year long elliptical orbit around the sun.
Ellipse
Elongated closed curve that describes Earth’s year-long orbit around the sun.
Solstice
Twice yearly point at which the Sun reaches its greatest distance north or south of the Equator.
Equinox
twice yearly time each spring and fall when the sun is directly over the equator and the number of daylight and nighttime hours are equal worldwide.
Moon phase
Change in appearance of the Moon as viewed from the earth due to the relative positions of the moon, earth, and sun.
New moon
Moon phase that occurs when the moon is between Earth and the sun, at which point the moon cannot be seen because its lighted half is facing the Sun and its dark side faces Earth.
Waxing
Describes phases following a new moon, as more of the moon’s lighted side becomes visible.
Waning
Describes phases that occur after a full moon, as divisible lighted Side of the Moon grow smaller.
Lunar eclipse
occurs when Earth’s shadow falls on the moon.
Maria
dark-colored, relatively flat regions of the moon formed when ancient lava reached the surface and filled craters on the moon surface.
Electromagnetic spectrum
arrangement of electromagnetic radiation according to their wavelengths.
Refracting telescope
An optical magnifying instrument in which light from an object passes through a double convex lens and is bent to form an image at the focal point.
Reflecting telescope
An optical magnifying instrument that uses a concave mirror in the base of the telescope to focus light from an object and form an image at the focal point.
Observatory
A building used to house an optical telescope; often has a dome-shaped roof that can be open for viewing.
Radio telescope
An instrument that collects and records radio waves traveling through space and can be used day or night under most weather conditions; provides information to map the universe and look for life on other planets.
Optical telescopes
A telescope that uses light, which is a form of electromagnetic radiation, to produce magnified images of objects.