Bellwork 9/7 If you have a survey for me, please turn it in to the basket on the side counter. Please, take a puzzle from the bin on the front table. Ponder…what causes scientific ideas to change?

Website & Safety

How does this relate to science? Nature of Science With the pieces provided, make a square. How does this relate to science?

Origins of Modern Astronomy Astronomy & Astrology People & Tools

What is astrology? Idea that positions of celestial bodies at the time of a person’s birth can determine their future Based on 12 constellations that evenly divide up the sky Constellations Earth

Astrology was regarded as a scientific endeavor well into the 17th century Used measurements of celestial body revolutions to create calendars WHY?

Ultimately rejected as a science after being scientifically tested. Causation vs. correlation Evidence is not empirical No proposed mechanism behind HOW celestial bodies affect terrestrial events

Development of Early Astronomy …it’s a process! Ancient Greeks Used philosophical arguments to explain natural phenomena Used some observational data Most ancient Greeks held a geocentric view of the universe "Earth-centered" view Earth was a motionless sphere at the center of the universe

The Geocentric view had a LOT of issues… A large problem was that it could not explain planets’ “backwards” motion

Aristarchus (312-230 B.C.) was the first Greek to profess a Sun-centered, or heliocentric, universe Also the first to suggest planets move in a retrograde motion However, the geocentric theory would still dominate the Western world for nearly 2000 years…because a heliocentric model did not follow Aristotle’s views & was blasphemous Where would be today if this theory was accepted…?

Claudius Ptolemy A.D. 141 Geocentric model Had trouble explaining retrograde motion, but came up with Deferents and Epicycles Very complicated; difficult to measure Europe Became the most widely accepted model in Europe…because it followed Aristotle’s views

The universe according to Ptolemy, second century A.D.

Retrograde motion as explained by Ptolemy

Birth of Modern Astronomy …the process continues. 1500s and 1600s Nicolaus Copernicus (1473-1543) Concluded Earth was a planet Constructed a model of the solar system that put the Sun at the center used circular orbits for the planets Ushered out “old” astronomy Why did it take this long?

Tycho Brahe (1546-1601) Precise observer with detailed notes on celestial bodies Tried to find stellar parallax the apparent shift in a star's position due to the revolution of Earth Proposed that planets orbit in ellipses Did NOT support the Copernican Heliocentric Theory Science is NOT always a linear process…as history would have us think.

Johannes Kepler (1571-1630) Planets revolve around the Sun Went against his religious beliefs , but the math worked. Three laws of planetary motion Help from Brahe Ushered in “new” astronomy “…the last scientific astrologer was the first astrophysicist”

Galileo Galilei (1564-1642) Supported Copernican theory Used experimental data Constructed an astronomical telescope in 1609 Four large moons of Jupiter Planets appeared as disks Phases of Venus Features on the Moon Sunspots

Sir Isaac Newton (1643-1727) Law of universal gravitation Proved Kepler’s law of planetary elliptical orbits Invention of calculus

“Contemporary” Astronomers/Cosmologists Albert Einstein Theory of Relativity Edwin Hubble Proposed the universe is expanding Carl Sagan Leader in research for extraterrestrial life Stephen Hawking Theorized that the universe began at a black hole Neil DeGrasse Tyson Research on stellar evolution

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