Earth’s Motion and the Universe

1. Earth’s Motion and the Universe

2. Earth’s Hierarchy • The Universe is madeofgalaxies • Galaxies are madeof many stars • Some stars have planetary systems (similar to our solar system) • Earth is a satellite planet of one particular star, the Sun Earth’s size in the universe video.

3. Expanding Universe Edwin Hubble- most galaxies have a red shift in the light they emit • This indicates that all galaxies are moving away from Earth • The red shift of a galaxy depends on its distance from Earth red shift video

4. The Universe is Expanding • The farther away the galaxy is from Earth, the faster it is moving away • All points in the galaxy are moving away from all other points

5. Early Ideas of Earth’s Motion • Astronomers assumed that the sun, planets, and stars orbited a stationary Earth, known as the geocentric model, meaning earth-centered

6. NicolausCapernicussuggested that the Sun was the center of the solar system- sun-centered or heliocentric model • Galileo Galileimade many discoveries to support the heliocentric model • Isaac Newton discovered the law of universal gravitation- which explains how the Sun governs the motion of the planets

7. Barycenter- the balance point between 2 orbiting bodies • If 1 of 2 bodies orbiting each other is more massive than the other, the center of mass is closer to the more massive body

8. An ellipse is an oval shape that is centered over 2 points called foci, instead of a single point • The Sun is one of the foci

9. The shape of a planet’s elliptical orbit is defined by its eccentricity- a ratio of the distance between the foci to the length of the major axis. • Ranges from 0-1

10. JohanneKeplerdemonstrated that Copernicus’ ideas were correct • Planetary orbits, such as that of the Earth, follows Kepler's 3 Laws: Kepler's Laws Kepler’s 1st Law: each planet orbits the Sun in an ellipse shape rather than a circle

11. Kepler’s 2nd law: Imaginary line between the Sun and a planet sweeps out equal amounts of area in equal amounts of time • Kepler’s 3rd law: Mathematical relationship between size of ellipse and orbital period • Orbital Period-length of time is takes for a planet to travel a complete elliptical orbit around the Sun. make one revolution of the Sun. Kepler’s 3 Laws Explained.

12. Earth’s Axis Nutation Wobbling around the axis Occurs over an 18 year period and is due to the Moon Could change amount of seasonal affects Precession • A change in direction of the axis, but without any change in tilt • This changes the stars seen around the Pole but doesn’t affect the seasons

13. The mass lost in the fusion of hydrogen into helium is converted into energy, which powers the Sun • At the Sun’s rate of hydrogen fusing, it is about halfway through its lifetime, with another 5 billion years left

14. Energy from the Sun • The Electromagnetic Spectrum • The arrangement of electromagnetic radiation according to wavelengths • The light we see coming from the sun is the visible light. The Electromagnetic Spectrum

15. What happens to the energy from the Sun? Most energy absorbed, but some is scattered by the atmosphere.

16. Impact of Solar Energy on Earth

17. Universe Song