Modern Astronomy

• Tyco Brahe - Danish astronomer and nobleman, Invented different astronomical instruments, with the help of his assistants, and made as extensive study of the solar system.

  
• Johannes kepler - He was born to a poor German family and studied as a scholar at the University of Tubingen in 1589. When King Frederick II died, and the successor did not fully support. Brahe’s work Emperor Rudolf II recommended Johannes Kepler to work for him as an assistant.

  
• Nicolas Copernicus - Nicolaus Copernicus was a Polish astronomer who put forth the theory that the Sun is at rest near the center of the Universe, and that the Earth, spinning on its axis once daily, revolves annually around the Sun. This is called the heliocentric, or Sun-centered, system.

  
• Galileo Galilei - sparked the birth of modern astronomy with his observations of the Moon, phases of Venus, moons around Jupiter, sunspots, and the news that seemingly countless individual stars make up the Milky Way Galaxy.

  
• Isaac Newton - Established the Law of Universal Gravitation. Concurred that the Earth rotates around the Sun. Provided rationale that explained Kepler's three laws. Newton's three laws of motion and law of gravitation provided a solid foundation for understanding planetary motion.

  
• The law of ellipses - He postulated that instead of a circular path, planets follow an oval or an ellipse orbit.
• The law of equal areas - When an imaginary line is drawn from the center of

  the Sun to the center of a planet, the line will sweep

  out an equal area of space in equal time intervals.
• Law of Harmonies - It states that that the ratio of the squares of the periods of two planets is equal to the ratio of the cubes of the

  average distances of these two planets from the Sun