Sun, Moon, and Earth

Earth Rotation- Earth spinning on its axis Axis- imaginary line that passes through Earth’s center from north to south poles Rotation causes day and night (clockwise- east to west) Takes Earth 24 hours (1 day) to rotate once on its axis

Earth Revolution- movement of one object around another object One complete revolution around the sun= 1 year Earth’s path as it revolves around the sun; orbit which is elliptical (oval) Orbit- the path an object takes around another during a revolution

Earth Calendar Earth’s orbit around the sun takes about 365 ¼ days (365.25 days) or 1 year Leap year every 4 years we make up the extra day. February has 29 days in leap year. (4 x ¼ =1) The time between one full moon and the next is about 29 ¼ days

Seasons Latitude- Distance north or south from the equator; measured in degrees Equator gets more solar energy (radiation)- straight sun rays Higher latitudes are colder- angled sun rays

Seasons Earth’s tilt is 23.5˚ North or South making the axis tilt toward the sun part of the year and away from the sun the other part; always points toward the north star Seasons are determined by how light hits Earth

Seasons

Seasons When north is tilted toward the sun, Northern Hemisphere has summer, Southern has winter When Northern Hemisphere is tilted away from sun, has winter, Southern has summer Solstice- the two days of the year when the sun is directly overhead

Seasons Summer- Northern Hemisphere is tilted toward the sun; more hours of daylight June- Summer solstice, longest day of the year, June 21, first day of summer

Seasons Winter- Northern hemisphere tilted away from sun, less hours of day light December- Winter solstice; shortest day of the year, December 21, first day of winter

Seasons

Seasons Equinox- equal day and night, sun directly above the equator; March 21- Vernal equinox, spring September 23- Autumnal equinox, fall

Moon The moon is a satellite of Earth: it revolves around the Earth Moon has almost no atmosphere Surface- detailed study of moon rocks gathered by astronauts Craters- cover much of the moon’s surface Highlands- mountains Maria- once flooded with molten material; appear as dark, flat areas

Moon The position of the moon, Earth, and the sun cause the phases of the moon, eclipses, and tides. The moon’s movement Moon’s revolution is about 27.3 days Moon’s rotation is about 27.3 days The moon’s “year” and “day” take the same amount of time. The “far side” of the moon always faces away from Earth; you never see it.

Moon Gravitational pull- the moon and Earth both pull on each other Moon’s density is about the same density as Earth’s outer layers Formation- Collision Theory- states that about 4.5 billion years ago a large object collided with Earth; material from this collision was thrown into orbit around Earth, eventually forming the moon.

Moon Phases Phases: the different shapes of the moon that we see from Earth What causes the phases? The moon reflects light from the sun; half of the moon is always lit, and half is dark. The amount of sunlit side of the moon that faces Earth As the moon revolves around Earth, the light side of the moon rotates around, changing the amount we see from Earth.

Moon Phases Full- the entire lit side of the moon is seen Gibbous- over half of the lit side is seen Quarter- you can only see half of the lit side of the moon (1st and 3rd/Last) Crescent- less than half of the lit side is seen; thumbnail shaped New- the entire dark side is seen

Moon Phases It takes about 29.5 days from one new moon to the next : 1 complete cycle Waxing- the amount of lit side of the moon seen is increasing Waning- the amount of lit side of the moon seen is decreasing http://sunshine.chpc.utah.edu/labs/moon/lunar_phase3.swf http://youtu.be/2aFGNGEcDOk http://youtu.be/3PycZtfns_U

Moon Phases

Tides Tide- the daily rise and fall of Earth’s coastlines Tidal bulge- the moon’s gravitational pull on the water at the point closest to the moon, and on the opposite side creates a bulge of water; high tide Low tide- the points between the high tide points have low tide. There are 4 tides a day; 2 high and 2 low

Tides Spring tide- at the new and full moons, the sun and moon are lined up. Their combined gravitational pull creates the biggest difference between high and low tides. Neap tide- at the 1st and 3rd quarters of the moon, the sun and moon pull at right angles to each other. This makes the least difference between the high and low tides.

Tides

Tides

Eclipses When the moon’s shadow hits Earth or the Earth’s shadow hits the moon Solar Eclipse- the moon passes between Earth and the sun casting a shadow on the Earth; a new moon in which the moon blocks the view of the sun. Lunar Eclipse- when the Earth passes between the sun and the moon

Eclipses Lunar Eclipse Umbra - darkest part of a shadow Penumbra- part of the shadow surrounding the darkest part

Eclipses

Sun Energy from the sun lights and heats Earth’s surface The only star in our solar system Is a yellow Dwarf star The corona forms the sun’s outer atmosphere The photosphere is the visible part of the sun that we see from Earth. The core is where the sun’s energy is produced.

Sun