ASTRONOMY

The universe is everything that exists, including planets, stars, galaxies, the contents of intergalactic space, and all matter and energy.

The universe started as a single point. That point was extremely dense. It became unstable and exploded outward. Today the universe continues to expand. The origin of the Big Bang theory can be credited to Edwin Hubble.

Put these in order of size: galaxysolar systemuniverse universegalaxy solar system

OUR SOLAR SYSTEM

Formation of the Solar System Began to look like a solar system about 4.6 billion y.a. Nebular Theory:The sun and the planets formed from a rotating disk of dust and gases.

Formation of the Solar System *Remember!: any two objects in space attract each other-  GRAVITATIONAL ATTRACTION The growth of planets began as solid bits of matter that collided and clumped together through a process called accretion. *****think about dust*****

“My Very Eager Mother Just Served Us Noodles” Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune To remember the order of the planets, just remember this sentence…

Solar System Models geocentric model : model of the solar system –Earth is the center of the solar system –believed until 1600’s

heliocentric model : model of the solar system –the sun is the center and the planets revolve around it

orbit –path a planet follows (around the sun)

The Earth-Sun-Moon System

The Earth–Moon–Sun System Everything is in motion The sun revolves around the galaxy. Sun is not stationary in our solar system. It actually moves as the planets tug on it, causing it to orbit the solar system's barycenter.

Precession caused by the gravitational pull of the Sun and the Moon on the Earth –slow, wobbling of the spinning Earth’s axis, with a period of about 26,000 years Therefore, the North Celestial Pole will not always point towards the same star field.

Draw this diagram on your notes

Nutation – latin: “to nod” small irregularity, or wobbling, in the precession of the equinoxes. –change in the angle—½ degree one way or the other. occurs over an 18 year period and is due to the Moon exclusively. This would very slightly increase or decrease the amount of seasonal effects.

EARTH’S MOVEMENTS

Kepler’s Laws of Planetary Motion 1 st law : planets orbit the sun in a path called an ellipse

2 nd law: planets move fastest when they are closest to the sun in their orbits

3 rd law: the farther away a planet orbits, the longer the planet takes to revolve around the sun *Think about a track*

revolution : movement of the Earth around the sun –takes days (1 year) –THIS IS THE EARTH TRAVELING ALONG IT’S ORBIT! *Why do we have a leap year?

Rotation spinning around an axis What are some examples of things that rotate? Tops, Ballerinas, Figure skaters, cyclones, Tornadoes, a merry-go-round, Earth

One rotation = 360° Time for one rotation = 24 hours 360° ÷ 24 = 15°/hr

Night and Day What causes night and day? The rotation of the Earth The side of the Earth that is facing the sun has daylight, the side of the Earth away from the sun has night. Because of the Earth’s rotation the sun appears to rise in the east and set in the west. What is another name for the North Star? Polaris

Seasons What two things cause the difference in the seasons? 1.The angle of the sun’s rays 2.The length of the days …how much or how long There are two kinds of rays from the Sun: 1.Direct- occurs when Earth is tilted toward the Sun 2.Indirect-occurs when Earth is tilted away from the Sun In the Summer, we get the direct rays from the sun and the days are longer. (But we are farther away from the Sun) In the Winter, we get indirect rays from the Sun and the days are shorter. (But we are closer to the Sun)

The Earth is tilted 23 ½ °on its axis. Either the Northern Hemisphere or Southern Hemisphere tilts towards the sun

Rising and Setting of the Sun Rising and Setting of the Moon The Seasons Changing Constellations Movement of Stars through the sky

MOON

*add to your vocabulary section in your notebook* *next 3 slides*

waxing : when the size of the visible portion of the moon is increasing When would this occur? waning : when the size of the visible portion of the moon is decreasing When would this occur?

new moon : no lighted area of the moon is visible from the Earth. full moon : entire side of the moon facing Earth is lit

crescent: less than half of the side facing the Earth is lit gibbous: more than half of the side facing the Earth is lit

The Sun Fill-in your notes, highlight and make side notes as necessary.

The Sun is considered a _______, because it is a big ball of gas, at the center of the ___________.

Sun Facts Continued.. It is made up of mostly _________ and ________ gases. It takes 8 minutes and 19 seconds for light to travel from the Sun to the Earth.

Where does the sun get it’s power? Energy is produced by Fusion (joining of nuclei)

Nuclear Fusion in the Sun Two hydrogen nuclei with low masses combine to form helium Occurs in the sun where the temperature is high *FUSE=come together

The Sun’s Energy Electromagnetic Energy- energy radiated by the Sun in the form of waves. What other words could be used to describe the sun’s energy or light coming to Earth?

The Sun’s Energy Waves- energy traveling from one point to another. Long wavelength = Low energy. Short wavelength = High energy.

Wavelength and Visible Light

What happens to the energy once it reaches the Earth’s atmosphere? -some light is reflected -some light is absorbed -HEAT!

Heat Heat can be transferred by three methods: 1.radiation 2.convection 3.conduction *draw a little diagram *

Radiation ______ transferred to the Earth through electromagnetic waves –Sometimes referred to as … _________ The Earth _______ this energy as heat, warming the planet

Convection Occurs in ______ and ______ only. transfer of heat by physical movement has a cyclical motion: hot medium goes up, cold medium goes down Examples: - boiling water - heating/cooling of home

Mantel Convection Same method as convection – through motion. Only occurs in Mantle (portion of Earth’s interior)

Conduction heat transfer as a result of direct contact. Conduction occurs through TOUCH Example: -Stovetop

Does the Sun’s energy affect Earth? _____________- Plants use the Sun’s energy to make food. Why is this process important to plants?

How else do we use the Sun’s energy? ____________We use the Sun’s energy to power our homes through Solar Panels. Are homes the only use for solar panels?

How does the sun help make life on Earth possible?