Chapter 4: The Origin of Modern Astronomy (Summary & Reflection)
Chapter 4 of “Astronomy: The Solar System and Beyond” starts with a description of the geocentric view that that the Early Greeks held of the universe. It was Aristotle’s conclusion that the Earth is spherical in shape. In A.D. 140, the Ptolemaic system, a more refined form of the Greeks’ geocentric view, was presented by Claudius Ptolemy. According to Ptolemy, the planets orbited the Earth in epicycles or small circles. It was Nicolaus Copernicus who proposed that the sun is at the center of the universe and the plants orbit around it. Tycho Brahe made the most precise astronomical observations than his predecessors, which were used by Johannes Kepler to develop the three laws of planetary motion. During his life, some very important discoveries were made by Galileo that supported Copernicus’s view that the sun is at the center of the solar system. The force of gravity for proven by Sir Isaac Newton, and the law of universal gravitation was developed and tested by him. Kepler had always been baffled why planets moved along orbits and this problem was solved by Newton’s laws of motion and law of gravity, and this is how the concept of Orbital Motion was born. An in-depth and interesting summary of the astronomical efforts that were made through the ages has been provided in this chapter. It was always perplexing for me how astronomical concepts that we read about today came to be and reading this chapter leaves me in awe about the advancements that astronomers were able to make through the ages without modern astronomical equipments that are used today. The chapter itself contains all the necessary information that one might need to know in order to find out where modern astronomy originated from. There is a lot that can be learned about the origin of modern astronomy from the Greeks to the shaping of the astronomy that we study as a subject.
Chapter 5: Light and Telescopes (Summary & Reflection)
As the title of Chapter 5 of “Astronomy: The Solar System and Beyond” suggests, this chapter presents an in-depth overview of some very important concepts related to light and telescopes, and also introduced readers to several different types of telescopes. This chapter defines light as a particle and a wave, along with terms such as electromagnetic radiation, photon, and wavelength, and the significance of light in the investigation of objects such as stars, galaxies, etc. is also stated. The Electromagnetic Spectrum has also been explained in the chapter. Some of the key concepts explained in the chapter include the wide range of radiations that are a part of electromagnetic waves, from gamma rays to radio waves. The physical properties of different types of radiations are the same, but their frequency or wavelength happens to be different. This chapter clarifies that different types of telescopes, such as the ones described, are designed for various types of radiations. The chapter explains how telescopes function by detecting radiation from outer space. Optical telescopes and Radio telescopes are two particularly notable types of telescopes that have been described in the chapter. The chapter concludes with an introduction of High Energy Astronomy and its emphasis on X-ray astronomy. Even though chapter before this is more historical in nature, this chapter seems to be lengthier and in-depth. It is understandable why, since this chapter explains everything there is to know about light and provides a complete description of various telescopes that are used today. In particular, the information provided in this chapter about special instruments used in astronomy can be considered as a bonus. Chapter 4 made me realize how important telescopes have been and the role they have played in the advanced of astronomy. The fact that this chapter is about light and telescopes will carry on whatever readers learn in the previous chapter.
Works Cited
Seeds, M. A., and D. E. Backman. "Chapter 4: The Origin of Modern Astronomy." Astronomy, the solar system and beyond. 6. Belmont, CA: Brooks/Cole Pub Co, 2009. Print.
Seeds, M. A., and D. E. Backman. "Chapter 5: Light and Telescopes." Astronomy, the solar system and beyond. 6. Belmont, CA: Brooks/Cole Pub Co, 2009. Print.
