The Sun, the Moon, & the Earth, Study notes of Astronomy

Download The Sun, the Moon, & the Earth and more Study notes Astronomy in PDF only on Docsity! The Sun, the Moon, & the Earth • The motions of the Earth, Moon, and Sun cause many different types of phenomenon including: • Solar Eclipses • Lunar Eclipses • Tides • Seasons • Moon Phases The Sun’s Six Layers The sun has six layers. Each is unique in temperature and purpose. Earth’s Tilt ★ The Earth’s axis remains pointed in the same direction at all times as the Earth revolves around the Sun. ★ The combination of the revolution around the Sun and the fixed angle of the Earth’s axis result in seasonal changes ○ temperature changes ○ angle of sunlight ○ number of daylight hours. ★ It’s the TILT, not the distance between the Earth and the Sun that causes seasonal changes Earth’s Tilt Earth’s Tilt ★ The equator divides the Earth into Northern and Southern hemispheres. ○ The seasons are flipped for each hemisphere. (i.e. Summer in the USA is Winter for Australia) ○ When the tilt of Earth is toward the Sun in a particular hemisphere, there is a longer length of day and the season is summer. ○ When both hemispheres are receiving the same amount of sunlight, the length of day and night is equal. This occurs in fall/autumn and spring. ○ When the tilt of Earth is away from the Sun in a particular hemisphere, there is a shorter length of day and the season is winter. Earth’s Tilt ★ There are 4 days a year that mark the changes in the seasons ○ Vernal Equinox (Spring), March 21st, The day and night are the same length ○ Summer Solstice (Summer), June 21st, Longest day of the year ○ Autumnal Equinox (Fall/Autumn), September 21st, The day and night are the same length ○ Winter Solstice (Winter), December 21st, The shortest day of the year. Seasons In your partner pairs (desk pairs), figure out what position the Earth and Sun would be in at the different times of the year. Cut out the the diagrams of the Earth and place them on the chart. Fill in the boxes on the back of the chart with info about each season. Eclipses Eclipses occur when an object in space moves in between two other objects and causes a shadow. When three celestial bodies line up to create an eclipse it is called SYZYGY. Solar Eclipses ★ Solar Eclipses occur when the Moon crosses the path between the Sun and the Earth. ○ Solar Eclipses can only happen during a NEW MOON ○ They can be total or partial depending on the position of each of the objects. ○ Total solar eclipses only happen in the same area every 375 years Solar Eclipses ★ Being able to see an eclipse in the same spot is very rare, but about 4 happen every calendar year and can be seen at different places all over the world. ○ Total lunar eclipses are more common than total solar eclipses ○ To be able to see a total solar eclipse you need to be in the perfect spot. ★ Why do eclipses happen so infrequently? ○ Syzygy happens very rarely because of how everything orbits. ■ The orbit of the moon is slightly angled around the Earth and doesn’t always cross the Earth or the Sun’s path ○ The apparent size of the objects in the sky Eclipses No solar eclipse occurs when the Moon is not directly between the Sun and Earth.  1 Ce oe D eNO) =i arAN Lunar Eclipses ★ Lunar Eclipses appear red due to the Earth’s atmosphere ○ The light gets filtered through and creates a red hue just like sunrises and sunsets have red and pink tints WHAT’S THE DIFFERENCE? Lunar Eclipse • Occurs when the shadow from the Earth falls on the Moon • Light is blocked from the Sun (The Moon does not create its own light!) • Turns dark red and is sometimes called a “Blood Moon” • Pretty common and can be hours long Solar Eclipse • Occurs when the Moon moves in front of the Sun and casts a shadow on Earth • The Earth doesn’t create its own light either (depends on the sun for light and heat) • The Sun is blocked so it almost looks like it does at night • Stars are visible • “counterfeit night” • A halo of light can peek around the Moon from the Sun • Very short and rare Moon Phases ● Some eclipse effects can be confused with the changing phases of the moon, but the moon phases are not caused by shadows. ● Moon phases are caused by the light from the sun falling on the Moon’s surface. ● At all times one half of the moon is reflecting light from the sun but our perspective on Earth allows us to only see part of the illuminated surface. Lunar Movements ★ The Moon rotates on its axis and revolves around the Earth as the Earth revolves around the Sun. ★ It takes about 27 Earth days for the Moon to rotate on its axis and about 29 ½ Earth days (month) for it to revolve around the Earth. ○ Because the Moon’s period of rotation on its axis and period of revolution around the Earth are nearly the same, the same side of the Moon always faces Earth. Moon Phases ★ Changes in the Moon’s position as it revolves around the Earth results in more or less of the sunlight reflected from the Moon being visible when observing the Moon from the Earth. This causes the Moon to appear to change shape ★ Light “moves” from right to left across the face of the moon What causes tides? ❏ Tides are the rise and fall of the surface levels of Earth’s ocean water caused by the gravitational effects of the Sun and Moon on Earth. ❏ The effects of tides are can be seen the most along ocean coasts. ❏ Moon orbits Earth ❏ High Tide - the waters of Earth closest to the Moon bulge outward toward the Moon. Another high tide occurs on the opposite side of Earth. ❏ Low tides occur in the areas between the two high tides. ❏ As the Earth rotates on its axis, any given location will rotate into and out of the tidal bulge. This results in the changes between high and low tides over the course of 24 hours. Tides Tides