1. Our Solar System includes:
The Sun
Eight Planets
Their Moons
Comets
Asteroids
How old is the solar system?
The solar system is about 4.5 billion years old.

4. Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto *(Not a planet anymore) My
Very
Elegant
Mother
Just
Served Us
Nine
Pizzas*

5. Planets come in different sizes and colors.
Are there differences among the planets in our solar system?
Planets come in different sizes and colors.
The four planets closer to the Sun are called rocky, or terrestrial, inner planets. They are small in size and similar to Earth in composition. They have no rings, and only two of them (Earth and Mars) have moons.
The four outer planets, called gas giants, are much larger than the rocky planets. They all have rings and many moons. The gas giants are made up mostly of hydrogen, helium, frozen water, ammonia, methane, and carbon monoxide.
There is a discussion over whether Pluto is a planet. Some astronomers think that Pluto might be little more than a giant comet. Its composition is similar to that of comets, and its orbit is quite different from that of the other planets.

6. Sun Is an average-sized yellow star
hot ball of gases made of hydrogen & helium
Is over 4 ½ billion years old (4.6)
Is about 110 times the diameter of Earth
1 million Earths could fit inside it
gives off heat and light
is the center of the universe
8 planets, including Earth, revolve around the Sun
((Pluto is no longer a planet).

7. Earth is the 3rd planet from the sun
supports life because of its oxygen-rich atmosphere and water
is 150 kilometers from the Sun
revolves around the sun every 365 days (year)
rotates on its tilted axis every 24 hours (day & night)
active planet that is constantly changing
Earth’s atmosphere blocks most of the sun’s rays

8. Moon is a satellite of Earth (it revolves around us)
rocky, gray satellite
¼ the diameter of Earth
does NOT produce its own light (reflects sun)
made of mountains, valleys and plains
NO WATER (unlike Earth)
NO AIR (atmosphere)
has extreme temperatures
No air + No water + extreme temp. = NO LIFE!

9. Geocentric Heliocentric Aristotle Ptolemy Copernicus* Galileo
Earth
Sun
*Sun–centered model
*We now know that the Sun is the center of the universe and we revolve around it.
*Earth –centered model
*It used to be believe that the Earth was the center of the universe.
Aristotle
Ptolemy
Copernicus*
Galileo
Greek Astronomer
Egyptian Astronomer
Polish Astronomer
Italian Astronomer

10. Nicholas changed all that!
Who was Nicholas Copernicus?
Nicholas Copernicus changed the way humans viewed their place in the Universe.
For a thousand years it was thought that the Earth was at the centre of the universe.
Nicholas changed all that!

11. Who was Nicholas Copernicus?
This was a revolutionary moment in the history of human thought.
Up to this time the earth was thought to be at the centre of the universe.
He first wrote the idea down in 1513 and finally published a book about his ideas in 1543.
But it took another 100 years for people to really accept the idea.
One famous astrologer Galileo spent a large part of his life in prison because
he believed Copernicus's ideas but the church was not yet ready to accept it.

12. Geocentric Heliocentric
Can you see the difference between the two ideas?

13. Now check out the activities on SOL PASS for Earth, Moon, Sun!