Presentation on theme: "28.2 Movement of the Moon Std 1F: Know the evidence for the dramatic effects that asteroid impacts have had in shaping the surface of planets. Objective."— Presentation transcript:
1 28.2 Movement of the MoonStd 1F: Know the evidence for the dramatic effects that asteroid impacts have had in shaping the surface of planets.Objective 1: Describe the shape of the moon’s orbit around Earth.Objective 2: Explain why eclipses occur.Objective 3: Describe the appearance of four phases of the moon.Objective 4: Explain how the movements of the moon affect tides on Earth.
2 The Moon’s Elliptical Orbit Chapter 28The Moon’s Elliptical OrbitThe moon’s orbit around Earth =ellipsethe distance between Earth and the moon variesapogee -the point at which the satellite is farthest from Earthmoon is farthest from Earthperigee - the point at which the satellite is closest to Earththe moon is closest to Earth
4 Moonrise and MoonsetThe moon appears to rise and set at Earth’s horizon because of Earth’s rotation on its axis.The moon rises and sets 50 minutes later each night becauseEarth’s rotationMoon’s revolution.
5 Lunar RotationThe moon’s revolution around Earth and its rotation on its axis take the same amount of time.Observers on Earth always see the same side of the moon.The part of the moon illuminated by sunlight changes as the moon orbits Earth.
6 EclipsesEclipse - an event in which the shadow of one celestial body falls on anotherBodies orbiting the sun cast long shadows into space.Shadows cast by Earth and the moon have two parts:Umbra- the inner, cone-shaped part of the shadowPenumbra - outer part of the shadow
7 Total Solar EclipsesSolar eclipse - the passing of the moon between Earth and the sun; during a solar eclipse, the shadow of the moon falls on Earth.During a total solar eclipseThe sun’s light is completely blocked by the moon.The umbra falls on the area of Earth that lies directly in line with the moon and the sun.
8 Partial Solar EclipseOutside the umbra, but within the penumbra, people see a partial solar eclipse.The penumbra falls on the area that immediately surrounds the umbra.
9 Effects of Solar Eclipses During a total solar eclipseSunlight that is not eclipsed by the moon shows the normally invisible outer layers of the sun’s atmosphere (diamond-ring effect)If the moon is at or near apogee during a solar eclipse, the moon’s umbra does not reach Earth.This causes an “annual eclipse” - a thin ring of sunlight is visible around the outer edge of the moon.
10 Lunar EclipsesLunar eclipse - the passing of the moon through Earth’s shadow at full moonLunar Eclipses video
11 A lunar eclipse - Earth is positioned between the moon and the sun Earth’s shadow crosses the lighted half of the moon.
12 Partial lunar eclipse - When only part of the moon passes into Earth’s umbra Penumbral eclipse - When the entire moon passes through Earth’s penumbra
14 Phases of the Moonphase - the change in the illuminated area of one celestial body as seen from another,celestial body; phases of the moon are caused by the changing positions of Earth, the sun, and the moonAs the moon revolves around Earthdifferent amounts of the near side of the moon are lighted.The shape of the visible part of the moon varies.The varying shapes are called phases.
15 Waxing Phases of the Moon Full moon- the entire near side of the moon is illuminated by the light of the sun.Waxing-gibbous phase - When the lighted part of the moon’s near side is larger than a semicircle1st-quarter phase -When a waxing moon becomes a semicircle,Waxing-crescent phase - When a sliver of the moon’s near side is illuminatedWaxing - When the size of the lighted part of the moon is increasingWaxing Phases of the Moon
16 Waning Phases of the Moon New moon - no lighted area of the moon is visible from Earth.Waning -When the lighted part of the near side of the moon appears to decrease in sizeLast-quarter phase - When the moon is waning, and it is a semicircleWaning-gibbous phase- when the moon is waning, but is still larger than a semicircleWaning-crescent phase - When only a sliver of the near side is visible
18 Tides on EarthTidal bulges (Bulges in Earth’s oceans) - form because the moon’s gravitational pull on Earth decreases with distance from the moonthe ocean on Earth’s near side is pulled toward the moon with the greatest forceBecause Earth rotates, tides occur in a regular rhythm at any given point on Earth’s surface each day.