TheNewAstronomy ppt The New Astronomy Nicholas Copernicus 1473 1543 Accounted for problems with calendar by introducing re introducing the heliocentric model of the universe The New Astronomy Fixed Star Background Sidereal Day Time it takes for the stars to return to directly overhead at a given time Because the starts are so far away this time corresponds to one rotation of the earth on it s axis The New Astronomy Fixed Star Background Solar Day Time it takes for the sun to return to directly overhead Because the sun is not so far away as compared to the stars the earth must rotate a bit farther to get the sun directly overhead Sidereal Day Time it takes for the stars to return to directly overhead at a given time Because the starts are so far away this time corresponds to one rotation of the earth on it s axis The New Astronomy Tycho Brahe 1546 1601 Constructed an observatory and made detailed measurements of the stars and planets Introduced a modified heliocentric universe with the earth s sphere centered on the sun and all other celestial spheres centered on the earth The New Astronomy Johannes Kepler 1571 1630 Believed in geocentric universe Problem with celestial spheres what holds them up Kepler attempted to construct the universe including the spacing between the spheres which was known by using the 5 platonic solids as scaffolding Kepler s Laws 1 The orbits of the planets are ellipses with the sun at one focus of the ellipse 2 The line joining the planet to the sun sweeps out equal areas in equal times as the plates travels around the ellipse 3 The ratio of the squares of the revolutionary periods P of two planets is equal to the ratio of the cubes of their semimajor axes a P21 P22 a31 a32 Kepler s Laws 1 The orbits of the planets are ellipses with the sun at one focus of the ellipse Kepler s Laws 1 The orbits of the planets are ellipses with the sun at one focus of the ellipse X X Focus Kepler s Laws 1 The orbits of the planets are ellipses with the sun at one focus of the ellipse X X Major Axis Kepler s Laws 1 The orbits of the planets are ellipses with the sun at one focus of the ellipse X X Semimajor Axis Kepler s Laws 1 The orbits of the planets are ellipses with the sun at one focus of the ellipse X X Minor Axis Kepler s Laws 1 The orbits of the planets are ellipses with the sun at one focus of the ellipse X X Semiminor Axis Kepler s Laws 1 The orbits of the planets are ellipses with the sun at one focus of the ellipse dma df X X Eccentricity e is the ratio of the distance between the foci to the length of the major axis e df dma Kepler s Laws 1 The orbits of the planets are ellipses with the sun at one focus of the ellipse Note on geometry a is the length of the semimajor axis a 1 e X X a 1 e Eccentricity e is the ratio of the distance between the foci to the length of the major axis e df dma Kepler s Laws 1 The orbits of the planets are ellipses with the sun at one focus of the ellipse Terminology The point of closest approach to the sun is called the Perihelion The point of furthest distance from the sun is called the Aphelion Perihelion Aphelion a 1 e a 1 e Kepler s Laws 1 The orbits of the planets are ellipses with the sun at one focus of the ellipse 2 The line joining the planet to the sun sweeps out equal areas in equal times as the plates travels around the ellipse 3 The ratio of the squares of the revolutionary periods P of two planets is equal to the ratio of the cubes of their semimajor axes a P21 P22 a31 a32 Kepler s Laws 2 The line joining the planet to the sun sweeps out equal areas in equal times as the plates travels around the ellipse Kepler s Laws 2 The line joining the planet to the sun sweeps out equal areas in equal times as the plates travels around the ellipse Equal time intervals Kepler s Laws 2 The line joining the planet to the sun sweeps out equal areas in equal times as the plates travels around the ellipse Implications Planets move faster and slower in their orbits Kepler s Laws 1 The orbits of the planets are ellipses with the sun at one focus of the ellipse 2 The line joining the planet to the sun sweeps out equal areas in equal times as the plates travels around the ellipse 3 The ratio of the squares of the revolutionary periods P of two planets is equal to the ratio of the cubes of their semimajor axes a P21 P22 a31 a32 Kepler s Laws 3 The ratio of the squares of the revolutionary periods P of two planets is equal to the ratio of the cubes of their semimajor axes a P21 P22 a31 a32 Note If P is measured in fraction of earth years and a is measured in a u then P2 a3 See Table 2 1 Period is the amount of time it takes for the planet to complete one orbit The New Astronomy Definition Astronomical Unit A U One A U is defined to be equal to the length of the semimajor axis of the orbit of the earth The New Astronomy Galileo Galilei 1564 1642 Basics of modern Mechanics the study of motion The New Astronomy Some Physics Background Fundamental Quantities and Units Quantity MKS Unit Mass Kilogram Distance Meter Time Second Temperature Kelvin Amount of Substance Moles Electric Current Amperes Luminous Intensity Candela The New Astronomy Some Physics Background Adopted the position of Renee Descartes that objects tended to maintain their motion a property later called inertia by Newton Mass kilograms is the amount of material in an object The New Astronomy Galileo Galilei 1564 1642 Basics of modern Mechanics the study of motion x position meters d distance meters d x v speed velocity meters second v x t Velocity includes direction speed does not a acceleration meters second2 a v t An object accelerates if the magnitude and or direction of the velocity changes In mathematics means change in The New Astronomy Some Physics Background Other Quantities Quantity Expression MKS Unit Force ma Newtons Kinetic Energy m v2 Joules Charge Coulombs Electric Field N C Magnetic Field Tesla The New Astronomy Galileo Galilei 1564 1642 All objects in free fall near the surface of the earth accelerate at 9 8 m sec2 Symbol g 9 8 m sec2 The New Astronomy Galileo Galilei 1564 1642 Made a telescope observed the moons on Jupiter First observation of something that did not orbit the earth ruled out geocentric universe in favor of heliocentric universe University of Dayton Flyer Observatory 09 18 09 The New Astronomy Isaac Newton 1643 1727 1 Everybody continues in …
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