Our Solar System Lessons 1-3

1. Our Solar System Lessons 1-3

2. Lesson 1

3. Lesson 1

4. Original thoughts on the solar system (and astronomy): • Claudius Ptolemy: Earth is the center. • He thought that because when you look at the sky at night, you can see all the stars moving around Earth. Therefore, Earth must be at the center. • Nicolaus Copernicus: The sun is the center of the solar system. • He thought that because of the observations that he had made.

5. Solar System: A group of astronomical (space) objects composed of planets or planet-like stuff revolving around a star. In our solar system, eight planets revolve around the sun; and one dwarf planet (Pluto).

6. Space Distances: Astronomical (space) unit is often used. One AU equals 150 million kilometers

7. Starting distance in AU km 150,000,000 AU km 1 AU Ending distance in km

8. *The AU units cancel each other out and you’re left with km. So, your answer is in km. km 150,000,000 AU km 1 AU

9. Example: Starting distance in AU km 150,000,000 135 20,250,000,000 AU km 1AU Ending distance in km

10. Example: Starting distance in AU km 150,000,000 135 20,250,000,000 AU km 1AU Ending distance in km

11. You can do the reverse as well… Starting distance in km AU 1 km AU 150,000,000 km Ending distance in AU

12. You can do the reverse as well… Starting distance in km AU 1 3.2 480,000,000 km AU 150,000,000 km Ending distance in AU

13. Formation of the Solar System Nebular hypothesis: A cloud of gas and dust in space, known as a nebula, began to rotate. It condensed into a flattened disk. As the dust and gas condensed, gravity pulled the gas and dust ever closer together. At the center of the nebula, the particles of gas and dust were pulled so tightly together that they combined, or fused, together, initiating nuclear fusion . Once nuclear fusion began, the sun was born.

14. Solar System Models: These were created to explain observations of how planets and other objects in the night sky moved. Thegeocentric model put Earth at the center of the solar system. The heliocentric model puts the sun at the center of the solar system.

15. Models: Claudius Ptolemy: Ptolemy wrote a book that contained the key astronomical ideas of the time. From about 150 AD, his model dominated scientific thought. He thought the solar system was geocentric—the planets and sun travel around Earth in “epicycles,” or large perfectly circular orbits. His model is also known as the Ptolemaic view of the solar system. Prior to Ptolemy, other ancient philosophers, such as Aristotle, also suggested the universe was geocentric, but Ptolemy was the first to explain this model in detail. Nicolaus Copernicus: Copernicus is considered the father of modern astronomy. Born in 1543, he used scientific measurements of the planets and stars. He published a book with the then-controversial idea that Earth was not at the center of the universe. He provided data and evidence to show that the solar system was heliocentric. This idea was not very popular in his day because it challenged the Ptolemaic view which had become the Roman Catholic Church’s official explanation. To the church, Copernicus’s idea that Earth was not at the center of the universe was antireligious heresy.

16. Models: Tycho Brahe: Brahe built one of the first scientific observatories designed solely to study the sky. He was a diligent note taker and made many calculated observations of the movement of objects in the universe. He is known as the “man with the golden nose” because he lost the tip of his nose during a duel and had a brass and gold nose replacement. Johannes Kepler: Brahe hired Kepler as an assistant in the late 16th century. After Brahe’s death, Kepler used the meticulous notes and data gathered by Brahe to make discoveries about the motion of the planets. Kepler’s work proved Copernicus’s view that the solar system was heliocentric. Kepler also introduced the word “satellite” and became the first person to suggest the sun rotates.

17. Models: Galileo Galilei: Galileo was the first person to scientifically observe rotation of celestial objects. He constructed one of the earliest telescopes and was the first to use a telescope to study the night sky. He identified several of Jupiter’s moons by studying the planet. This led him to suggest that it was like a solar system in miniature with Jupiter at the center. The church rejected Galileo’s views and threatened him with death. Sir Isaac Newton: Newton was a mathematician and philosopher credited with many discoveries. He was the first to describe gravity and how the planets moved as a result of gravitational forces. He invented the reflecting telescope, which today is the main type of telescope used by astronomers. He also discovered that white light is made up of all colors, enabling astronomers to better understand the composition of stars.

18. Practice! Discover page 2, “Model Development” tab; “check your understanding”

19. VOCABULARY ALERT! An object orbiting another object is called a satellite. The length of time it takes a planet to complete its orbit defines that planet’s year and is called the revolution rate. The length of time it takes a planet to complete one rotation defines that planet’s day and is called the rotation rate.

20. Kepler’s laws Kepler’s laws allow you to calculate the shape and duration of a planet’s orbit. **Please use the interactive activity on Discover page 2, “Kepler’s Laws” tab to help in your understanding of these three laws.

21. Kepler’s 1st law tells us: “A planet travels around the sun in an elliptical orbit with the sun at one focus.”  The planet's path is an ellipse (oval/ egg-shaped) with the Sun at a focus (off-center).

22. Kepler’s second law states that the motion of the planets around the sun covers the same area in the same amount of time. The planet speed changes along the orbit, (it moves slower in the more distant parts of the orbit). Lines are drawn to the planet position at equal 1/10 period intervals. These lines are closer together in the outer part of the orbit since the planet position does not change as rapidly there. http://www.physics.sjsu.edu/tomley/Kepler12.html

23. Kepler’s third law defines the time it takes a planet to complete one orbit around the sun. The time it takes a planet to make one orbit is called the period (P). According to the law, the square of the period (or P) equals the cube of the distance to the planet in AU (or A).

24. For example, Mars completes one orbital period about every 1.85 Earth years. Mars’ average distance from the sun is about 1.5 AU (or 225 million kilometers). From these facts, P = 1.85 and A = 1.5. So Kepler’s third law is correct: 1.85 squared and 1.5 cubed both equal approximately 3.5.

25. Given the equation P2 = A3, what is the orbital period, in years, for the planet Saturn? (Saturn is located 9.5 AU from the sun.) P2? A = 9.53

26. Given the equation P2 = A3, what is the orbital period, in years, for the planet Saturn? (Saturn is located 9.5 AU from the sun.) P2? A = 9.53 = 857.375

27. Given the equation P2 = A3, what is the orbital period, in years, for the planet Saturn? (Saturn is located 9.5 AU from the sun.) P2? A = 9.53 = 857.375 857.375 =

28. Given the equation P2 = A3, what is the orbital period, in years, for the planet Saturn? (Saturn is located 9.5 AU from the sun.) P2? A = 9.53 = 857.375 857.375 = ~29 P = ~29 years

29. Given the equation P2 = A3, what is the orbital period, in days, for the planet Mars? (Mars is located 1.52 AU from the sun?) P? A = 1.523

30. Given the equation P2 = A3, what is the orbital period, in days, for the planet Mars? (Mars is located 1.52 AU from the sun?) P? A = 1.523 = 3.511

31. Given the equation P2 = A3, what is the orbital period, in days, for the planet Mars? (Mars is located 1.52 AU from the sun?) P? A = 1.523 = 3.511 3.511 =

32. Given the equation P2 = A3, what is the orbital period, in days, for the planet Mars? (Mars is located 1.52 AU from the sun?) P? A = 1.523 = 3.511 3.511 = 1.83 years (*we need the answer in days so…) 1.83 years 365 days in a year

33. Given the equation P2 = A3, what is the orbital period, in days, for the planet Mars? (Mars is located 1.52 AU from the sun?) P? A = 1.523 = 3.511 3.511 = 1.83 years (*we need the answer in days so…) 1.83 years 365 days in a year = 684 days P = ~684 days

35. Lesson 2

36. Lesson 2

37. For there to be gravity… does there need to be air?

38. Gravity- A force of attraction between two objects that depends on two things: mass and distance. 1.) The larger the mass the greater the gravitation attraction. 2.) The closer the two objects the stronger the attraction. Air resistanceis caused by the friction between a falling object and the particles in air. The amount of air resistance a falling object experiences is based on the shape of the object and the speed at which it falls.

39. Galileo His observations of the movement of objects on Earth led him to conclude that all objects accelerate as they fall.

40. Accelerationis the rate of change in velocity. When we are talking about the acceleration of a falling object it would be: “… an increase in speed over time”. Acceleration of a falling object is due to gravity. All objects fall at a constant rate, the only reason we see them falling different is due to other forces acting on the objects. Positive acceleration can result from an increase in speed. Negative acceleration, also called deceleration, results from a decrease in speed.

41. Newton Newton observed that planets moved in an orbital path around the sun.

42. Newton’s laws of Motion • 1st law: An object in motion will remain in motion, at a constant velocity, unless an outside force acts on it. And an object at rest will remain at rest unless an outside force acts on it. • Example: This ball will sit here forever, and ever, and ever unless something acts on it; like someone kicks it.

43. Outside force – a push!

44. 2nd law: Force = mass x acceleration Would the same "force” (push or pull) be used to move each guy below? If no, why?

45. The less mass (the boy) the less force needed for acceleration.

46. The greater the mass (the sumo wrestler)the more force needed for acceleration.

47. 3rd law: For every force (action) there is an equal and opposite force (reaction). Raft moves Diver moves Equal in speed (acceleration) and opposite in direction.

48. Einstein Einstein says that time and space are intricately related. Called the space-time continuum, time and space can be thought of as a sort of fabric. Objects within time and space will bend this “fabric,” creating a gravitational force.

49. Be sure to do the following activity on the “Discover” page, under the “Einstein in space” tab; at the bottom.

50. Earth has a magnetic field, called the magnetosphere. Earth’s magnetic field creates a sort of “shell” that protects Earth from much of the sun’s radiation. Earth's magnetic field interacts with the radiation from the sun. Earth’s atmosphere is filled with air molecules.Ions from the sun collide with the air molecules in Earth’s atmosphere.The molecules become excited and give off light as they calm down. Auroras (a.k.a. = Northern/Southern Lights)