Physical Science

• Tycho Brahe

  Danish Astronomer and a nobleman known for his accurate and comprehensive astronomical and planetary observation.
• Tycho brahe was assisted by mathematician named Johannes Kepler.
• Built an observatory financed by the king of Denmark - King Frederick II. It is known as a naked eye observatory with over-sized instruments (mural gradient) since the telescope had not yet been invented
• Johannes Kepler (1571-1630) A German mathematician and astronomer who used the planet data of Tycho Brahe and developed Three Laws of Planetary Motion
• Johannes kepler work on Martian data allowed him to formulate the correct laws of planetary motion, thus eventually achieving a place in the development of astronomy far surpassing that of Brahe.
• Based on Brahe's data, he was able to realize that the orbits of the planets were ellipses, thus 3 Laws of Planetary Motion was formulated
• 2nd Law: The law of equal areas ➤ The radius vector describes an equal area in equal times. ➤ The motion is uniform but in order for an object along an elliptical orbit to sweep out the area at a uniform rate, the object moves faster when the vector radius is short and slower when the vector radius is long ➤ Planets move faster when closer to the sun and slower when farther from the sun. ➤ The speed at which any planet moves through space is constantly changing
• First Law: Law of Ellipses ➤ Planets move in an elliptical orbit with the Sun at one focus. ➤ The orbits of the planets are elliptical. ➤ Circular and elliptical orbits having the same period and focus. ➤ Motion is not uniformly circular. ➤ The shape of the orbit is elliptical and the Sun at one focus
• What is the name of 1st law of planetary motion?

  Law of ellipses
• 3rd Law: Harmonic Law ➤ The ratio of the squares of the revolutionary periods (P) for the two planets is equal to the ratio of the cubes of their mean distances (R) from the sun. P12/P22=R13/R23 ➤ This law was published in 1619 in his book entitled Harmonices Mundi.
• The third law states that the square of the orbital periods of two planets is directly proportional to their average distances from the sun.
• Galileo's observation was explained by Brahe through a model of the solar system that Venus has phases without making it necessary for Earth to be moving
• What is the name of 2nd law of planetary motion?

  The law of equal areas
• What 3rd law is called in planetary motion?

  Harmonic Law
• Melc 2