Presentation Transcript
The Solar System :The Solar System Ch 29
29.1 Models :29.1 Models Aristotle 350 B.C. Geocentric, didn’t explain retrograde motion
Ptolemy epicycles 150 A.D.
Copernicus 1500 heliocentric, planets move in same direction, at different speeds
Galileo confirmed motion
Slide 3:Brahe made detailed observations of planets and stars
Kepler, as Brahe’s assistant explained planetary motion mathematically
Slide 8:Law of Ellipses, planets follow ellipses determined by two points, called the foci (focus) the sun is at one focus.
Slide 9:Perihelion, closest to the sun
Aphelion, farthest from the sun
Slide 10:Distance from the sun is the average of the perihelion and the aphelion (147 million km and 152 million km average to 149.5 million km, 1 AU, Astronomical Unit)
Slide 11:Law of Equal Area
An Arc formed by the location of a planet at the beginning and end of a set time period and the sun will always have the same area
Slide 12:The planets move faster when close to the sun, but the legs are shorter, and the planets move more slowly away from the sun, but the legs are longer
Slide 13:Law of periods, period is the amount of time it takes for the planet to orbit the sun
K x R3 = P2
K= constant
Slide 14:K=1 when distance is in AU
Calculate p for Jupiter with 5.2 AU for r
Solve for an asteroid with a radius of 4 AU
Slide 15:K x R3 = P2
Newton explained the motion was due to gravity and inertia, the tendency of objects to continue in a straight line until acted upon
Slide 16:Newton was only mostly correct, it took Einstein’s Laws of Relativity to correctly predict the orbit of Mercury
The rotation of Venus is retrograde, ie clockwise, Uranus rotates sideways
Asteroids, Comets and Meteoroids :Asteroids, Comets and Meteoroids Asteroids are the minor planets, largest being Ceres, 1000 km across
Asteroids made up of carbon appear dark, those make of iron and nickel appear shiny and the asteroids with silicates look like Earth rocks