Chapter 22 Earth and Space science flashcards

What is the heliocentric model?

A model that places the Sun at the center of the solar system.

What is a planet?

A round celestial body that orbits the Sun, has enough gravity to become nearly spherical, and has cleared smaller objects from its orbital path.

What is light pollution?

The glow from city lights at night that makes distant stars harder to see and reduces the effectiveness of telescopes.

What is blueshift?

A shift toward shorter wavelengths in an object's spectrum, showing that the object is moving toward Earth; it is caused by the Doppler effect.

What is a solar eclipse?

An event that occurs when the Moon passes between Earth and the Sun, casting a shadow on Earth and blocking some or all of the Sun's light.

what is a barycenter?

The center of mass of two or more bodies orbiting one another, and the point around which they orbit.

What is revolution?

Motion around a central point, such as an object orbiting another object.

What is the Doppler effect?

The observed change in the frequency of light or sound when its source moves toward or away from the observer.

What is the penumbra?

The wider, lighter part of the Moon's shadow, where only part of the Sun is blocked during a solar eclipse.

What does waxing mean?

Growing larger or becoming more fully illuminated; a waxing Moon is moving toward the full-moon phase.

What is a new moon?

The lunar phase when the Moon appears dark from Earth because its sunlit side faces away from Earth.

what is intertia?

The tendency of an object to resist changes in its motion.

what is an absorption spectrum?

A spectrum with dark lines where specific wavelengths of light have been absorbed by a substance, such as a star.

what is nutation?

A periodic change in the tilt, or inclination, of a rotating object's axis.

what is precession?

The slow movement of the axis of a spinning body around another axis.

What does waning mean?

Growing smaller or becoming less illuminated; a waning Moon is moving away from the full-moon phase.

What is the geocentric model?

A model that places Earth at the center of the universe.

what is the corona?

The Sun's outer atmosphere, normally invisible but visible as a halo around the Moon during a total solar eclipse.

what is parallax?

The apparent change in an object's position caused by a change in the observer's position.

What is an emission spectrum?

A spectrum produced when a source directly emits radiation or reemits absorbed radiation.

What is a constellation?

A group of stars that appears to form a pattern in the sky, viewed from Earth, and given a name for identifying locations in the night sky.

What is rotation?

The turning or spinning of an object on its axis.

What is a lunar eclipse?

An event that occurs when Earth passes between the Sun and the Moon, causing Earth's shadow to darken the Moon.

what is an astronomical untit (AU)?

The average distance between Earth and the Sun, commonly used to measure distances within the solar system.

What is retrogade motion?

The apparent temporary backward, or westward, movement of a planet across the sky before it resumes moving eastward.

What is a full moon?

The lunar phase when the Moon appears round and fully illuminated because its sunlit side is facing Earth.

what is redshift?

A shift toward longer wavelengths in an object's spectrum, showing that the object is moving away from Earth; it is caused by the Doppler effect.

what is the umbra?

The darkest, narrow part of the Moon's shadow, where the Sun is completely blocked during a solar eclipse.

what is a cresent moon?

A lunar phase in which the Moon appears as a thin crescent.

what is a gibbous moon?

A lunar phase, either waxing or waning, in which most of the Moon is illuminated and only a small section is dark.