The Solar System

1. The Solar System Astronomy!!

2. What is the geocentric model? • The Earth is stationary while objects in the sky move around it.

3. Who came up with the model?How long was it accepted? • The ancient Greeks thought of this model but Ptolemy modified it. • It was accepted for almost 1400 years.

4. What is the heliocentric model? • The Earth and other planets revolve around the sun.

5. Who created it? • Greek astronomer named Aristarchus.

6. Who revised the heliocentric model and how did he revise it? • Copernicus who stated that the motion of the planets could be explained better if they were revolving around the Sun rather than the Earth.

7. Evidence? • Galileo Galilei through his observations and those of other scientists proved that the heliocentric model was in fact true.

8. What shape is the path that all of the planets follow? Explain how the shape looks. • Ellipse which is like an oval shape that have been stretched along one side.

9. What holds the planets in orbit around the sun? • There are 2 forces that hold the planet in orbit around the sun…Gravity and Inertia. • Gravity keeps them from flying off into space and inertia keeps them moving in the orbit that they are in.

10. What does our solar system consist of? • The sun, the planets, the moon that revolve around the planets, comets, and asteroids.

11. When were all of the planets discovered? • The ancient Greeks knew that Mercury, Venus, Earth, Mars, Jupiter and Saturn already existed. Uranus was discovered in 1781, Neptune in 1846 and Pluto in 1930. • This is Mercury.

12. Venus

13. Earth

14. Mars

15. Jupiter

16. Saturn

17. Uranus

18. Neptune

19. Pluto

20. How is the sun different from the rest of the planets? • The sun is a star that produces it own light through nuclear fusion…Hydrogen nuclei fusing together to make Helium nuclei. • Planets do not create light or heat.

21. What planets are closest to the sun? • Mercury, Venus, Earth and Mars (Terrestrial Planets)

22. What planets are far from the sun? • Jupiter, Saturn, Uranus and Neptune (Jovian Planets)

23. What is an astronomical unit? • This is equal to the average distance from the Earth to the Sun which is 149,598,000 Km

24. How do you explore the solar system? • Using complex telescopes, piloted aircrafts and space probes.

25. What is a space probe? Where has the US sent space probes? • A space probe is an unpiloted aircraft that carries scientific instruments to into space and transmits information back to Earth. • Mars and Saturn’s rings

26. When was the Hubble Space Telescope sent out into space and for what purpose? • 1990 • To provide images of the solar system.

27. Earth’s moon!

28. Atmosphere • The moon does not have an atmosphere. • It does not have a lot of gravity so it cannot hold gases around it. • The temperature of the moon can vary because of the lack of atmosphere.

29. What were the craters created by? • Craters are round depressions in the surface which are caused by meteoroids. • Meteoroids are chucks of rock that move through the solar system.

30. The Phases of the Moon

31. Solar Eclipse • When the shadow of the moon covers up the sun. • This happens when there is a new moon but not every new moon.

32. Lunar Eclipse • When the Earth leaves a shadow on the moon • This happens when there is a full moon.