AstronomyAstronomyQuestions 1 - 3Questions 1 - 3

Question 1Question 1

Geocentric ModelGeocentric Model – Earth is the – Earth is the center of the universe with all space center of the universe with all space bodies revolving around the Earth.bodies revolving around the Earth.

Question 1Question 1

Heliocentric ModelHeliocentric Model – Sun is the center – Sun is the center of the universe with all space bodies of the universe with all space bodies revolving around the Sun.revolving around the Sun.

• Modern Heliocentric ModelModern Heliocentric Model – Sun is the – Sun is the center of the Solar Systemcenter of the Solar System

Question 2Question 2

The Sun revolves around the The Sun revolves around the Earth every 24 hours.Earth every 24 hours.

Question 2Question 2

The Sun revolves around the The Sun revolves around the Earth every 24 hours.Earth every 24 hours.

The Moon revolves around the The Moon revolves around the Earth approximately every 25 Earth approximately every 25 hours.hours.

All stars revolve around the All stars revolve around the Earth every 24 hours.Earth every 24 hours.

Question 2Question 2 The Sun revolves around the Earth every 24 The Sun revolves around the Earth every 24

hours.hours. The Moon revolves around the Earth The Moon revolves around the Earth

approximately every 25 hours.approximately every 25 hours. All stars revolve around the Earth every 24 All stars revolve around the Earth every 24

hours.hours. All planets revolve around the Earth.All planets revolve around the Earth. You can’t feel the Earth rotate or revolve.You can’t feel the Earth rotate or revolve.

• If Earth rotated, you would feel 1000 mph wind.If Earth rotated, you would feel 1000 mph wind. Earth is the largest/most massive object in Earth is the largest/most massive object in

space; therefore everything revolves space; therefore everything revolves around it.around it.

Question 3Question 3

Prove the Earth is moving - North Prove the Earth is moving - North StarStar

Question 3Question 3

• North Star – If the North Star stays still North Star – If the North Star stays still while other stars revolve in the sky, it while other stars revolve in the sky, it might mean the Earth is spinning and might mean the Earth is spinning and that the Earth’s northern axis is pointing that the Earth’s northern axis is pointing to the North Starto the North Star

Prove the Sun is in the center - Prove the Sun is in the center - Retrograde MotionRetrograde Motion

Question 3Question 3

Demonstrate Retrograde MotionDemonstrate Retrograde Motion Retrograde Motion – a periodic Retrograde Motion – a periodic

backward movement or westward backward movement or westward loop made by a planet as seen by loop made by a planet as seen by Earth when moving in the skyEarth when moving in the sky• http://alpha.lasalle.edu/~smithsc/Astronomy/images/mars.movhttp://alpha.lasalle.edu/~smithsc/Astronomy/images/mars.mov

Question 3Question 3

Retrograde ActivityRetrograde Activity

Question 3Question 3

Explanation of Retrograde Motion – Explanation of Retrograde Motion – when Earth lines up with a planet when Earth lines up with a planet and passes that planet because of its and passes that planet because of its inner orbit, the planet will appear to inner orbit, the planet will appear to move backwards (westward) in the move backwards (westward) in the Earth’s sky. Earth’s sky. • http://www.mhhe.com/physsci/astronomy/applets/Retro/frame.htmlhttp://www.mhhe.com/physsci/astronomy/applets/Retro/frame.html