Скачать презентацию The Solar System Copernicus 1473 equant and Скачать презентацию The Solar System Copernicus 1473 equant and

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  • Количество слайдов: 11

The Solar System Copernicus (1473) • equant and doubling of Moon - disturbing • The Solar System Copernicus (1473) • equant and doubling of Moon - disturbing • revived Aristarchus' heliocentric model De Revolutionibus Orbium Coelestium (1543) • Sun at centre, all planets orbit Sun, Moon orbits Earth • stars are on CS, at rest • Earth rotates • Mercury, Venus, Earth, Mars, Jupiter, Saturn • same geometric tools as Ptolemy (no equant)

retrograde motion: result of relative motion of Earth and planets • no savings in retrograde motion: result of relative motion of Earth and planets • no savings in complexity • same predictions as Ptolemy • predicts periodic shift of stars - not observed • preface implied it was not to be taken seriously • banned 1616

Tycho Brahe (1546) • Alfonsine and Prutenic tables disagreed • new star (nova) 1572, Tycho Brahe (1546) • Alfonsine and Prutenic tables disagreed • new star (nova) 1572, lack of motion meant it was on CS • more accurate predictions require better observations • prolific instrument maker • repetition of measurements • calibration • Uraniborg (1576)

 • accuracy of 1 arcminute (1 ) 1 degree = 60 arcminutes 1 • accuracy of 1 arcminute (1 ) 1 degree = 60 arcminutes 1 arcminute = 60 arcseconds 1 = 60 = 3600 • 1577 – comet path crosses other planets' orbits - solid crystal spheres do not exist • lack of parallax implies large distances to stars in heliocentric model • preferred geocentric model • hybrid model – Earth at centre, Moon and Sun orbit Earth, other planets orbit Sun • 1599, Prague – hires Kepler to analyse data

Celestial Coordinates • Declination (dec. ) – latitude • angle above the celestial equator Celestial Coordinates • Declination (dec. ) – latitude • angle above the celestial equator (degrees) • Right Ascension (RA)– longitude • measured eastward from location of Sun at vernal equinox • measured in hours, minutes, seconds (1 hr = 15 degrees, 1 minute RA = 15 arcminutes)

Johannes Kepler (1571) • • favoured Sun-centred solar system analysed Brahe's data for Mars Johannes Kepler (1571) • • favoured Sun-centred solar system analysed Brahe's data for Mars best deferent/epicycle orbit disagreed with data rejected deferents/epicycles Kepler’s Laws of Planetary Motion 1 st Law (1609): Planets revolve around the Sun in elliptical orbits with the Sun at one focus Orbit specified by semi-major axis (size) and eccentricity (shape)

2 nd Law (1609): As a planet orbits the Sun, a line joining the 2 nd Law (1609): As a planet orbits the Sun, a line joining the Sun and the planet sweeps out equal areas in equal times Planets move faster in their orbits when closer to Sun (speed) The larger the orbit, the longer the period (time for one orbit) Mercury 3 mo. Venus 7. 4 mo Earth 1 year Mars 3 rd Law (1619): The square of a planet's orbital period is proportional to the cube of its semi-major axis 1. 9 year Jupiter 12 years Saturn 29 years

 • absolute sizes of orbits unknown • tries to explain telative orbit sizes • absolute sizes of orbits unknown • tries to explain telative orbit sizes using geometric solids • suggests that physical force is responsible for orbits • produces Rudolphine Tables

Galileo Galilei (1564) • supports Copernicus' model • 1609 – constructs telescope (3 -20 Galileo Galilei (1564) • supports Copernicus' model • 1609 – constructs telescope (3 -20 ) • 1610 – reports observations in Siderius Nuncius Ø many stars not visible to naked eye Ø Milky Way composed of many stars Ø some nebulae also made of stars Ø Moon has craters, mountains Ø planets appear as discs Ø Jupiter has satellites

Later Observations Ø Sun has sunspots Ø Saturn had structures attached Ø Venus showed Later Observations Ø Sun has sunspots Ø Saturn had structures attached Ø Venus showed all phases • Jupiter's moons and Venus' phases evidence against geocentric Geocentric Heliocentric

A Dialogue on the Two Great World Systems (1632) • A Dialogue on the Two Great World Systems (1632) • "debate" between geocentric and heliocentric ideas • obviously favoured heliocentric • Roman Inquisition forces Galileo to recant, placed under house arrest • Dialogue banned until 1835 Mid - 1600's • universe is heliocentric, infinite, stars scattered randomly • Earth is one of the planets • Earth rotates on axis • orbits described by Kepler's Laws