Historical Models of our Solar SystemMiss Scillieri

6th Grade

Geocentric Model• Geocentric-Earth is center

of our Solar System

• Unexplained on how planets appear to move backwards

• Ptolemy- Was an ancient Greek scientist who theorized planets and Sun move in small circles around Earth

Heliocentric Model

• Sun is center of our Solar System

• Nicholas Copernicus was a Polish astronomer, who first suggest heliocentric theory and vaguely mapped out the planets orbiting the sun in a circular orbit.

Galileo

• Supporter of Copernicus’s Heliocentric theory

• Observed moons orbiting Jupiter and theorized objects can revolve around other planets not just Earth

• Telescope was crude, he saw only 4 of 63 moons of Jupiter

• Galileo proved heliocentric theory by observing the moons of Jupiter. He was placed under house arrest. If he did not “denounce” or say his science was a lie he would face death.

Not a perfect circle…an ellipse• Tycho Brahe- studied Solar

System and made very accurate recordings of his observations- scientific method!

• Tycho’s assistant, Kepler, used information for the details of orbits, this complex math based on observations would not be published to after both men had died.

• Using Brache’s data, scientist Kepler found out that each planet moves around the sun or is “wheels on wheels” Simply put each planet orbits the Sun in an ELLIPTICAL orbit of a certain size.

• Sketch a geocentric model using the Earth and Sun:

• Sketch a heliocentric model using the Earth and Sun:

• Match the scientist to his contribution__ Used a telescope to discovery moons of

Jupiter proving HELIOCENTRIC theory

___ Supported the GEOCENTRIC theory and thought planets orbited in CIRLCES

___ Used complex math equations to prove planets move in ellipses

___ First person to theorize heliocentric theory

A. CopernicusB. GalileoC. KeplerD. Ptomely

Kepler’s Laws of Planetary Motion1st Law - Law of Ellipses

Each planet orbits the sun in a path called an ellipse or elongated circle

Ellipse is a closed curve whose path is determined by 2 points or foci within the ellipse

Focus 1 is the Sun and Focus 2 is an imaginary pointSemi-major axis = average distance from sun (AU); ½ major axis

Eccentricity

• Degree of elongation or shape of planet’s orbit

• Ratio between the foci and length of major axis

• Circular =0• Very elongated =1

2nd Law – Law of Equal Areas

• An imaginary line between the Sun and a planet sweeps out equal areas in equal times as the planet travels around the ellipse.

3rd Law – Law of Periods

• Mathematical relationship P2 = a3

• a= semi-major axis (planets average distance from Sun measured in AU’s)

• p= planet’s orbital period (time)

Newton

• Used Kepler’s Laws of planetary motion and published Principia for short. In this publication, considered to be the greatest piece of scientific literature ever written.

• Contains Newton’s laws of motion including universal gravitation.

Einstein (1879-1955)

• Changed Newton’s gravitational theory based on findings of Mercury’s orbit.

• Developed Theory of Relativity. It completely changed the way we study gravity and even changed our understanding of the universe.

Kepler’s Laws Simulations• Click http://www.physics.sjsu.edu/tomley/kepler.html

Bibliography• http://www.astro.umass.edu/~myun/teaching/a100/images/geocentric.jpg• http://www.physics.hku.hk/~nature/CD/regular_e/lectures/images/chap04/heliocentric.jpg• http://www.3villagecsd.k12.ny.us/wmhs/Departments/Math/OBrien/galileo5.jpg• http://galileo.rice.edu/sci/brahe.html• http://www.asu.cas.cz/~had/tycho.jpg• http://cseligman.com/text/history/ellipse2.jpg• http://www.windows.ucar.edu/the_universe/uts/kepler3_small.gif• http://library.thinkquest.org/27585/frameset_intro.html• http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/imgrel/merc.gif• http://zebu.uoregon.edu/~soper/Orbits/eccentricity.gif• http://www.physics.hku.hk/~nature/CD/regular_e/lectures/images/chap04/geocentric.jpg• http://outreach.atnf.csiro.au/education/senior/cosmicengine/images/cosmoimg/keplerellipse.gif