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MODERN ASTRONOMY

MODULE 3: SECOND SEMESTER

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AGENDA OF THE LESSON

Module 3 and 4

Module 1 and 2

Performance Task #1 and Written work #2

Goals of the discussion

DISCUSSION

REVIEW

Instruction for PT #1

OBJECTIVES

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OBJECTIVES

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OBJECTIVES OF THE LESSON

At the end of the lesson, the students are able to;

1. discuss the notable contributions of some of the notable astronomers of modern astronomy;

2. describe the relationship of Brahe and Kepler to the discovery of planetary motion; and

3. realize the importance of the laws of planetary motion.

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TRY TO RECALL by ANSWERING THE QUESTIONS (10mins)

WHAT

What are their contribution/findings in the field of astronomy

WHO

Who are the philosophers you can remember from the discussion and the module?

WHY

Why do you think it is important?

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02

REVIEW ACTIVITY

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TOPIC DISCUSSION

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INTRODUCTION

Throughout human history, scientists have struggled to understand what they see in the night sky. After 14 centuries since Ptolemy, five noted scientists made important discoveries that gave rise to the birth of modern astronomy. These were Nicolaus Copernicus, Tycho Brahe, Johannes Kepler, Galileo Galilei and

Isaac Newton.

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—GALILEO GALILEI

“You cannot teach a man anything; you can only help him find it within himself .”

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TERMS TO UNDERSTAND

astronomical unit (AU)

eccentricity

the unit of length defined as the average distance between Earth and the Sun; this distance is about 1.5 × 108 kilometers or 1.5 x 1011 metres

The distance between the foci of an ellipse is proportional to the length of its major axis.

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EXAMPLE

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TERMS TO UNDERSTAND

Ellipse

Foci

a closed curve for which the sum of the distances from any point on the ellipse to two points inside (called the foci) is always the same

(plural: foci) one of two fixed points inside an ellipse from which the sum of the distances to any point on the ellipse is constant

Astronomical unit (AU)

Eccentricity

the unit of length defined as the average distance between Earth and the Sun; this distance is about 1.5 × 108 kilometers or 1.5 x 1011 metres

in an ellipse, the ratio of the distance between the foci to the major axis

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EXAMPLE

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TERMS TO UNDERSTAND

Semimajor axis

Orbital speed/period

half of the major axis of a conic section, such as an ellipse

Orbital period- the time it takes an object to travel once around the Sun

Orbital speed- speed= time X mass

Major Axis

Orbit

the maximum diameter of an ellipse

the path of an object that is in revolution about another object or point

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EXAMPLE

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TYCHO BRAHE

  • a Danish astronomer and nobleman who made accurate observations of the movement of celestial bodies in an observatory built for him by King Frederick II of Denmark in 1576.

  • He was able to invent different astronomical instruments, with the help of his assistants, and made an extensive study of the solar system.
  • He was able to determine the position of 777 fixed stars accurately.

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TYCHO BRAHE- the mentor of Kepler

King Frederick II of Denmark

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TYCHO BRAHE- moved to Prague and supported by Emperor

Rudolf II

Emperor Rudolf II

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JOHANNES KEPLER

  • Kepler was born to a poor German family and studied as a scholar at the University of Tübingen in 1589.
  • He worked as an assistant of Tycho Brahe when Emperor Rudolf II assigned Brahe as an imperial mathematician

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Tycho Brahe and Johannes Kepler

FACT 1

They had unsteady relationship. Brahe mistrusted Kepler, fear of being shadowed by his assistant.

FACT 2

Brahe assigned to Kepler the interpretation of his observations of Mars, whose movement did not match Brahe’s calculations.

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Kepler's Discoveries from Brahe's Data and other

Near in the Sun- move fastest

Far from the Sun- move slowest

Useful in determining the position of planets for the past 1000 years and the future 1000 years

After his mentor died, he became the imperial mathematician

Law of Ellipses, Law of Equal Areas, Law of Harmonies

Force from the Sun

Planetary Motion

Brahe died

Rudolphine Tables

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The law describes how fast a planet moves in its orbit. A planet moves fastest when it is nearest the Sun and slowest when it is farthest from the Sun, and still, the same area is swept out by the line in equal amounts of time.

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a planet’s orbital period is proportional to the size of its orbit (its semi-major axis).

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  • The law of harmonies applies to natural satellites
  • Example: moons orbiting other planets
  • The time it takes for a moon to orbit a planet squared is proportional to the cube of its average distance from the planet
  • Jupiter's moon, Europa, is an example
  • Europa's orbit around Jupiter squared is proportional to the cube of its average distance from Jupiter

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  • The law of harmonies can be applied not only to planetary motion but also to the motion of galaxies.
  • The gravitational interactions between two galaxies can be described using this law, where the time it takes for the galaxies to orbit around each other squared is proportional to the cube of their average distance from each other.
  • This helps astronomers understand and predict the behavior of galaxies in the universe.

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ISAAC NEWTON

  • English Mathematician, physicist
  • Gave an accurate explanation and supporting details on the proposed law of Johannes Kepler
  • Laws of Motion (Inertia, Acceleration, Interaction)

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Our understanding of the elliptical motion of planets about the Sun spanned several years and included contributions from many scientists. Answer the following questions.

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QUESTIONS TO ANSWER!

Johannes Kepler

Which scientist is credited with the long and difficult task of analyzing the

data?

Tycho Brahe

Which scientist is credited with the collection of the data necessary to support

the planet's elliptical motion?

Isaac Newton

Which scientist is credited with the accurate explanation of the data?

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The Aristotelian and Galilean

Conceptions of Vertical,

Horizontal and Projectile Motions

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FACTS about MOTION

  • The first evidence of the study of the motion of heavenly bodies can be traced back to the people of Sumeria and Egypt.
  • While the Greeks were the first ones to study systematically and in detail the heavenly bodies.
  • Geocentric View- Ptolemy
  • Heliocentric View - Copernicus

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The Aristotelian and Galilean

Conceptions of Vertical,

Horizontal and Projectile Motions

Images reveal large amounts of data, so Our current understanding on the physics of motion did not happen overnight. Instead, it gradually developed as philosophers took up previously held philosophies and improved on it or gave critique identifying possible weakness or inconsistencies with observations.

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I. Aristotle’s Concept of Vertical Motion, Horizontal Motion, and Projectile Motion

1. Vertical Motion- Vertical motion is referred to as natural motion. In a natural motion, the object will move and will return to its natural state based on the object's material or composition - earth, water, air, and fire.

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2. Horizontal Motion

An object moving in a violent motion requires push or pull to maintain horizontal motion. Motion continues only so long as there is an applied force to an object. When the force is removed, motion stops.

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3. Projectile Motion

Projectile motion of an object is parallel to the ground until it is the object's time to fall back into the ground. An impetus will be kept by the object until such time that the initial force is forgotten, and the object returns to its natural state to stop moving and fall to the ground.

He viewed projectile motion as natural and violent motion. He said that

heavy objects fall faster than light ones.

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Any Questions?

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Written Work 2

Experiment and Guide Question

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Performance Task 1

Video Presentation of Experiments

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Link

https://docs.google.com/document/d/1ISEjSiEfLlzergtjjmWixErNajqpUwwZCS_O4GM-x-Y/edit?usp=sharing

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THANK YOU

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ALTERNATIVE RESOURCES