SOLAR SYSTEM Our sun, moon and planets and how they affect our lives

EARLY HISTORY OF ASTRONOMY Early Greek scientists decided that the earth was the center of our solar system. This idea is called a GEOCENTRIC system. The Greek scientist PTOLEMY in about 140 AD explained although the planets and sun moved in circles around the earth, they also moved in smaller circles as they circled the earth. This geocentric model was the accepted idea for over 1400 years.

EARLY HISTORY OF ASTRONOMY In 1514, the Polish astronomer NICOLAUS COPERNICUS theorized that the Greeks were incorrect and that instead of the earth being the center of our solar system, the sun was. This sun centered model is called HELIOCENTRIC and the planets revolve around the sun. 100 years after this hypothesis (about 1609), GALILEO, using his first telescope supported this heliocentric hypothesis

EARLY HISTORY OF ASTRONOMY Other astronomers such as Tycho Brahe (1598) and Johannes Kepler (1596) realized that the planets did not move in small circles within big circles, but moved in more of an oval shape called an ELLIPSE.

MODERN EXPLORATION Modern explorers use many tools to help explore our solar system and beyond. Telescopes Satellites Space Probes Space Shuttle

Telescopes Simple telescopes use mirrors to magnify things. Galileo was the first scientist to use a telescope to look in space. Newer telescopes use radio waves instead of light.

Satellite Satellites orbit around another object (ie the Moon). Man-made satellites include the space station, the shuttle and the Hubble telescope. We use satellites to hold cameras, telescopes and to transmit radio and cell phone waves.

Can you find the satellite??

Florida at night view from satellite

Space Probes Probes are unmanned space exploration vehicles. They are sent out into space to explore. They will not return to earth. Probes are the best way to get information from space.

Space Shuttle A reusable manned space vehicle. Orbits around earth. Used to study how humans react to space and to carry items to the space station.

Space Shuttle getting towed into retirement above Virginia skies in 2012

WHAT IS OUT THERE? SUN: Medium sized and middle aged star PLANETS: 8 Planets MOONS: COMETS ASTEROIDS METEROIDS

ASTEROIDS Large left over pieces of rock from planet formation still orbiting the sun. Can be made of rock or metal. Many travel in “belts” between Jupiter and Mars. /watch?v=iy19nHTVLEYhttps:// /watch?v=iy19nHTVLEY

Meteroids Small asteroids Meteoroid: When out in space. Meteor: When traveling through our atmosphere and burning. Meteorite: If they fall onto Earth

Russian Meteor

COMETS Large, frozen, dusty ball of “ice”. They orbit the sun and as they melt they get a tail behind them. om/watch?v=fGTq14qC wJkhttps:// om/watch?v=fGTq14qC wJk

THE PLANETS

Comparing the size of the planets to the moon.

Moon and Jupiter Feb

Moon, Venus, Jupiter. Feb, 2015

Planets based on composition Terrestrial or ROCKY Planets The terrestrial planets are composed primarily of ROCK and metal. They have relatively high densities, slow rotation and Rocky surfaces. They have no rings and few, if any satellites (moons). Mercury, Venus, Earth and Mars

Composition continued Jovian also known as the Gas Planets They have low densities, rapid rotation and Thick atmosphere. They have rings and lots of satellites (moons). Jupiter, Saturn, Uranus, Neptune The gas planets are composed primarily of Hydrogen and Helium..

GRAVITY Force found in all objects that attract them to each other. The amount of gravity depends on mass. Gravity is measured in weight. Where gravity is less, your weight is less. How do you brush your teeth in space?How do you brush your teeth in space?

Inertia An object in motion will remain in motion unless acted upon by an outside force. An object at rest will remain at rest unless acted upon.

ROTATION vs REVOLUTION Planets revolve around the sun. The time a planet takes to make one (1) revolution around the sun is called a YEAR. Planets travel in an ELLIPSE as they revolve around the sun.

ROTATION Rotation is when an object travels around itself on it’s axis. The earth rotates once a day. The sun rises in the east and sets in the west. Rotation gives us night and day. All planets have different length days based on how long it takes to rotate.

EARTH IS SPECIAL Earth is the 3 rd planet from the sun. The earth is a terrestrial planet. The earth is at least 4.5 billion years old. Our planet has liquid water that covers 70%.

Earth is special Earth has an atmosphere. This atmosphere is composed mostly of nitrogen and oxygen One function of the atmosphere is to protect us against the sun’s harmful rays.

Earth is Special Earth has a magnetic “shield” that also helps protect us from the sun’s harmful rays. Earth is the only planet in our solar system that we know has life. Earth has an ozone layer to shield us from harmful UV rays

MOON DANCE Earth has one natural satellite, the moon. The moons day and year are exactly the same so we only see the same side of the moon at all times. The moons gravity creates tides.

MOONS PHASES The changes in the way the moon looks from earth during the month is called phases. The phase you see depends on how much of the sunlit side of the moon is facing earth.

PHASE NAMES New Moon: Totally Black Waxing Crescent: Waxing means growing. First Quarter: We can see half of the half of the moon that is lit. Waxing Gibbous: More than half can be seen. Full Moon: You see all the lit side. Waning Gibbous: Waning means you see less! Third Quarter: Notice the half you see is reversed. Waning Crescent: It is almost gone again!

Lunar Eclipse in Bristow 2012 Full moonEclipse beginning

Solar Eclipse

THE REASON FOR THE SEASONS The reason we have the 4 seasons is that the earth is tilted. The earth is tilted on it’s axis 23.5 degrees. The tilt of the axis stays the same. Some parts of the earth get more direct light rays from the sun.

Which Season? Because of the tilt each hemisphere receives more direct sunlight during half of the year. This makes that hemisphere warmer than the other. During the other half of the year each hemisphere receives less light and is cooler. The hemispheres always experience opposite seasons from each other.

Why Tides? Due to the gravitational pull of the moon (and to a lesser extent-the sun). Whatever side of the Earth is facing the moon has a high tide. As well as the opposite side of the Earth.