Motions of Earth,

Moon, and Sun

Topic 3

Motions of Earth,

Moon, and Sun

Topic 3 Remember to wait for the vocabulary word to pop up at the end! Can you guess it before it comes

up?

Created by P. Bordas MS, CCC-SLP

Models That Help Explain Apparent Celestial Motions

Geocentric Model

Assumption that the Earth is stationary and that most celestial objects revolve

around it

http://laserstars.org/references/shells.gif

Heliocentric ModelAssumption that the Earth both rotates

on an imaginary axis and revolves around the sun in an orbit. The moon

revolves around the Earth.

http://boojum.as.arizona.edu/~jill/NS102_2006/Lectures/Lecture4/Copernicus_solar_system.gif

Actual Earth Motions

AxisThe imaginary line through the planet from the North Pole to the South Pole

http://www.tiltedearth.org/images/tilted-earth-axis.gif

Foucault PendulumWhen allowed to swing freely, its path will appear to change in a predictable way.

This is evidence of Earth’s rotation because the pendulum – due to inertia –

would continue to swing in the original path if the Earth did not rotate

http://farm1.static.flickr.com/20/70589378_68a6939551.jpg

Coriolis EffectTendency of all particles of matter moving at Earth’s surface to be deflected, or curve

away, from a straight-line path

http://www.seisdeagosto.com/indica/wp-content/uploads/2006/05/Coriolis_effect14.png

ConstellationA group of stars that form a pattern and are used to help people locate celestial objects

http://www.utahskies.org/deepsky/constellations/maps/virgo.jpg

Earth and Moon Motions and Time

Local TimeTime based on the rotation of Earth as

reflected in motions of the sun

Time Zones15-degree-wide longitudinal bands which

maintain the same time, created to standardize time for regions

http://www.radio6767.com/forums/uploaded/ferne/2007112313485_timezonesmap.gif

Actual Motions of Earth’s Moon

TidesThe gravitation between the Earth, the

moon, and the sun results in a cyclic rise and fall of ocean waters on Earth

http://www.atlantickayaktours.com/images/drawings/Navigation/SpringNeap-Tides-color.gif

EclipseWhen a celestial object partly or completely

comes into shadow of another celestial object

http://www.keralatips.org/wp-content/uploads/2007/02/kerala-lunar-eclipse.jpg