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1543
The Theory of Heliocentrism
This theory was first proposed by Nicolaus Copernicus. He was a Polish astronomer. He first published the heliocentric system in his book: "On the Revolutions of the Heavenly Bodies." Copernicus was determined that the Earth rotates daily on its axis and that the Earth's motion affected what people saw in the heavens.
[Link text](muse.tau.ac.il) & (starchild.gsfc.nasa.gov) -
Kepler's Laws of Planetary Motion
In the early 1600's, Johannes Kepler proposed three laws of planetary motion, "The Law of Eclipses." First, The law of Orbits: all planets move in elliptical orbits, with the sun at one focus. Second, The law of Areas: a line that connects a planet to the sun sweeps out equal areas in equal times. Third, The law of Periods: the square of the period of any planted is proportional to the cube of the semi-major axis of it's orbit.
[Link text](hyperphysics.phy-astr.gsu.edu) & The Physics Classroom -
Newton's Laws of Motion
Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change it's state by the action of an external force. The second law explains how the velocity of an object changes when it is subjected to an external force. The third law states that for every action in nature there is an equal and opposite reaction. Newton showed that these laws of motion, explained Kepler's laws of planetary motion.
[Link text] (grc.nasa.gov) -
Oxygen Theory of Combustion
This theory resulted from a demanding and sustained campaign to construct an experimentally grounded theory of combustion, respiration, and calcination. Antoine Laurent Lavoisier's research in the early 1700's focused upon weight gains and losses in calcination. He hypothesized that it was probably the fixation and release of air rather than fire that caused the observed gains and losses in weight. This idea set the course of his research for the next decade.
[Link text](britannica.com) -
Newton's Universal Law of Gravitation
Newton's law of universal gravitation is about the universality of gravity. All objects attract each other with a force of gravitational attraction, gravity is universal. As the mass of either object increases, the force of gravitational attraction also increases. If the mass of one object is doubled, and so on.
[Link text] (physicsclassroom.com) -
2nd Law of Thermodynamics
The 2nd law states that the state of entropy of the entire Universe, as an isolated system, will always increase over time. The 2nd law also states that the changes in entropy in the Universe can never be negative. Energy is the ability to bring about change or to do work. In all energy exchanges, if no enters or leaves the system, the potential energy of the state will always be less than that of the initial state.
[Link text] (chem.libretexts.org) & (www2.estrellamountain.edu) -
Quantum Theory
Quantum Theory is a theoretical basis of modern physics that explains the nature and behavior of matter and energy on the atomic and subatomic level. The nature and behavior of matter and energy at that level is sometimes referred to as Quantum Physics and Quantum Mechanics. Max Planck's theory describes the spectral density of electromagnetic radiation emitted by a black body in thermal equilibrium at a given temperature.
[Link text](whatis.techtarget.com) -
Theory of General Relativity
General Relativity is a theory of space and time. Einstein's special and general theories of relativity are based on the idea that the laws of physics are the same for all observers. Albert Einstein interpreted the speed of light in a vacuum as a law of physics that should be measured the same no matter what speed you are traveling at. The constant speed of light is a law of nature that does not change.
[Link text](van.physics.illinois.edu) -
Hubble's Law of Cosmic Expansion
Edwin Hubble discovered that the Universe is expanding, with galaxies moving away from each other at a velocity given by an expression known as Hubble's Law: v=H*r. Expanding Universe, the distant galaxies we see in all directions are moving away from Earth, as evidenced by their red shifts. The red shifts of distant galaxies are proportioned to their distances from us, and the center of the Universe.
[Link text](w.astro.berkley.edu) (hyperphysics.phy-astr.gsu.edu) (www.as.utexas.edu) -
Big Bang Theory
Two astronomers discover the remnant radiation from the Big Bang while trying to characterize the sources of noise in a radio antenna they wished to use for astronomical observations. Astronomers continue to look at the Universe in a different, light, this time in the X-Ray. In 1965, observations have made it clear that there is more matter contained in galaxies than astronomers can easily account for. This leads to the idea of dark matter.
[Link text](cosmictimes.gsfc.nasa.gov)
