Modern Astronomy

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22.1- Early Astronomy : 

22.1- Early Astronomy

Astronomy : 

Astronomy Our Solar System Orbits around Bodies Lives of Stars Meteors and Comets Constellations

Earth at the Center : 

Earth at the Center Ptolemy- 2 AD. Thought that Earth was the center of universe. Thought objects traveled in orbits around an unmoving earth.

Ptolemy : 

Ptolemy Believed the universe was perfect, unchangeable, and divine. 1st challenge to his theory was 1400 years later.

Sun at the Center : 

Sun at the Center Nicolaus Copernicus- 1473-1543 Believed that the Earth and other planets evolved around the sun.

Copernicus : 

Copernicus Believed all planets revolve around sun in same direction. Each planet took a different amount of time to rotate around the sun. Wrong about??? Also thought that orbits of planets were perfect circles

Elliptical Orbits- Johannes Kepler : 

Elliptical Orbits- Johannes Kepler Supported Copernicus but…….. Realized planets do not orbit in perfect circles but move in an elliptical orbit (egg shaped).

Slide 8: 

Planets move counter-clockwise Closest planets to the sun travel in the shortest amount of time. Vice-versa for planets further away. Which planets would take the longest to orbit the sun??

Features of the Moon : 

Features of the Moon Galileo Galilei- 1609: 1st person to look at moon through a telescope

Inertia and Gravity- Sir Isaac Newton : 

Inertia and Gravity- Sir Isaac Newton A planets motion around the sun is two things: inertia and gravity

Inertia : 

Inertia Causes the planets to move in a straight line.

Gravity : 

Gravity Pulls the planets toward the sun.

22.2- Earth- Sun- Moon Systems : 

22.2- Earth- Sun- Moon Systems

Period of Revolution : 

Period of Revolution Time it takes a planet to make one revolution around the sun On Earth we call this one year (365.25 days)

Period of Rotation : 

Period of Rotation Earth takes 24 hours to rotate on its axis. What is an axis? What are the rotation days of your planets?

Day and Night : 

Day and Night At equator the Earth rotates 1600 mph One rotation is called a day (24 hours) During rotation part of Earth faces sun while the other faces darkness The 24 hour rotation causes all parts of earth to experience both sunlight and darkness Sun- rises in the east sets in the west

Why do the seasons occur?

The Earth tilts at 23.5 ° Season are due to the tilt of the Earth Polaris (North Star)

Seasons are due to the angle of how the light from the sun hits the earth. : 

Seasons are due to the angle of how the light from the sun hits the earth.

Slide 20: 

Axis

Summer Solstice : 

Summer Solstice Solstice: sun and stop June 20 or 21 North pole is tilted 231/2 degrees toward the sun Sun reaches highest point in the sky N. Hemisphere: Longest day of sun S. Hemisphere: Shortest day of sun

Winter Solstice : 

Winter Solstice North pole is tilted 23 ½ degrees away from the sun Occurs Dec. 21st or 22nd North: Shortest day South: Longest day

Vernal Equinox : 

Vernal Equinox Neither pole is tilted toward the sun Equinox: Latin word meaning equal night First day of spring in North on March 20 or 21.

Autumnal Equinox : 

Autumnal Equinox First day of Autumn on September 22 or 23.


Slide 27: 

Can you find summer and winter for the Northern Hemisphere? B C D A

How does the sun look at different points of the year??? : 

How does the sun look at different points of the year???

Movements of the Moon : 

Movements of the Moon Perigee: Point in orbit when moon is closest to the Earth and appears larger in the sky. Apogee: Moon is at its furthest from the Earth and appears smaller in the sky. One day on the moon is the same length as a year on the moon (27.3 hrs)

8 Phases of the Moon : 

8 Phases of the Moon

Solar Eclipse : 

Solar Eclipse Occurs when the new moon comes directly between the sun and the Earth As the Earth moves in the moon’s shadow sunlight is unable to reach the Earth

2 Parts of the Shadow : 

2 Parts of the Shadow Umbra: Small inner shadow Penumbra: Large outer shadow

Umbra : 

Umbra Only people directly in the path of the umbra see a total solar eclipse in which the sun is completely blocked out

Penumbra : 

Penumbra Penumbra- only part of the sun is blocked out.

Antarctica- Total Eclipse : 

Antarctica- Total Eclipse

Lunar Eclipse : 

Lunar Eclipse Earth comes between the sun and the full moon Moon passes through the Earth’s shadow and dims the moons light to a coppery color

22-3: The Earth’s Moon : 

22-3: The Earth’s Moon

Moon : 

Moon

Lunar Module Eagle : 

Lunar Module Eagle “That’s one small step for a man, one giant leap for mankind.” Neil Armstrong- 1st human to step on the moon- June 20th, 1969

Moon’s Characteristics : 

Moon’s Characteristics Diameter: 3476 km (1/4 diameter of earth) Distance from Earth: 384,403 km Gravity: 1/6 of Earth’s Age: 4.6 B.Y.O Temperature: 100 C to -175 C.

Slide 49: 

Moon is dry, airless, and a barren world Instruments measure 3,000 moonquakes a year Crust: Outer layer 60 km thick Mantle: 800 km thick of dense rock Central Core: Melted iron Moon rocks show no traces of water No atmosphere=No weather

Slide 50: 

Highlands: Light areas containing mountain ranges that can reach up to 8 km. Maria: Dark spots that that are broad, smooth lowland plains Craters: Small to large depressions thought to be from meteorites striking the surface Rilles: Long valleys that suggest the moon once had active volcanoes.

Origins of the Moon??? : 

Origins of the Moon??? Theory One: Moon Capture Theory A ring of dust around earth slows the passing moon, allowing it to be capture by earth's gravitational pull (Now discredited)

Slide 52: 

Theory Two: Moon formed from the same swirling cloud that formed the Sun, Earth, and other planets

Slide 53: 

Theory Three: Impact Theory- A giant asteroid the size of the planet Mars struck the early Earth, tearing a chunk of material from the planet.


8 Phases of the Moon : 

8 Phases of the Moon

Slide 58: 

Moon reflects sunlight toward the Earth Phase depends on where the moon is in relation to the sun and earth

Slide 59: 

New Moon Moon comes between the sun and the Earth Side facing Earth is in darkness Can be slightly visible from reflection of light on Earth

Waxing Crescent Slim curved slice more visible to light Waxing: Lighted area appears larger

First Quarter Moon has traveled a ¼ of it’s orbit around the Earth

Waxing Gibbous More of the lighted area can be seen

Full Moon Entire lighted side is visible in the moon

Slide 64: 

Waning Gibbous Waning: When the light appears to grow smaller

Last Quarter The moons light appears to be getting even smaller Third week heading into 4th week





The End : 

The End