The Scientific Revolution: Astronomy, Method, and Physics

Posted on Apr 6, 2025 in Physics

Factors Favoring the Scientific Revolution

  • Adoption of Arabic numerals over Roman numerals.
  • Invention of the printing press (around the 1450s).
  • Secularization of scientific methodology and the rise of the new bourgeoisie.
  • Great sea voyages, which spurred advancements in shipbuilding and navigation tools (e.g., sails, compasses).
  • Humanist interest in crafts and agriculture.
  • Improved calculations for directing cannon fire.
  • Fusion of science and technique (e.g., telescope, microscope).

New Astronomy

Nicolaus Copernicus (1473-1543)

Proposed Heliocentrism, challenging Ptolemaic cosmology and established scientific views.

Johannes Kepler (1571-1630)

Advanced the mathematization of modern science.

Kepler’s Laws of Planetary Motion

  1. 1st Law: Planets orbit the Sun in elliptical paths, with the Sun at one focus.
  2. 2nd Law: The radius vector connecting a planet to the Sun sweeps out equal areas in equal amounts of time.
  3. 3rd Law: The square of a planet’s orbital period is proportional to the cube of the semi-major axis of its orbit (average distance from the Sun).

Galileo Galilei (1564-1642)

Galileo’s Contributions

  • Advanced the method of resolution and composition.
  • Used mathematics as the language of physics.
  • Promoted the concept of the rationality of the universe.
  • Introduced scientific concepts and explanations that aided his successors (e.g., concepts related to mass, weight, inertia).

Hypothetical-Deductive Method

  1. Observe the phenomenon repeatedly to distinguish essential from accidental features.
  2. Formulate an explanatory hypothesis.
  3. Test the hypothesis through experimentation (contrasting).
  4. If the hypothesis is verified, formulate it as a law.
  5. Express the law mathematically.

Francis Bacon (1561-1626)

Emphasized the utility of science.

  • Authored Novum Organum, proposing a new methodology for modern science, opposing Aristotle’s Organon.
  • Argued the purpose of science is not merely discovering truth (Aristotle), but dominating nature to improve human life (‘Knowledge is power’).
  • Criticized Aristotle’s method for prioritizing deduction over induction and for performing induction carelessly.
  • Bacon’s method aimed to establish rigorous rules for induction.
  • Critical Part (Destructive): Aimed to eliminate prejudices (which he called ‘Idols’) hindering the mind.
  • Constructive Part: Introduced tables of induction (presence, absence, degrees).

Isaac Newton and the Principia Mathematica

Published Mathematical Principles of Natural Philosophy (often called the Principia Mathematica).

Newton’s Method and Principles

  • Emphasized a method based on experimentation and observation, deriving principles from phenomena.
  • Stated that science consists of laws expressed mathematically.
  • Laws are induced from phenomena and tested against them; experimentation is fundamental to knowledge.

Newton’s Laws of Motion

  1. 1st Law (Inertia): An object remains at rest or in uniform motion in a straight line unless acted upon by an external force.
  2. 2nd Law: The change in motion (acceleration) is proportional to the applied force and occurs in the direction of the force (F=ma).
  3. 3rd Law: For every action, there is an equal and opposite reaction.

Law of Universal Gravitation

Formulated the Law of Universal Gravitation: ‘Two bodies attract each other with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.’ This universal law explains diverse phenomena (e.g., falling objects, tides). Terrestrial gravity is a specific instance of universal gravitation.