Solar System Formation of the Solar System MODELS

Solar System Formation of the Solar System

MODELS OF THE SOLAR SYSTEM • There are two main models that have existed in history 1. ____________________________ • Also called the Ptolemy Model 2. ____________________________ • Also called the Copernican Model

GEOCENTRIC MODEL • Model with Earth in the _______________ • Everything in space revolved around the ________ – Proposed by many including the famous Greek philosopher, Aristotle, around 350 BC – In 140 AD, ____________ expanded Geocentric Model o Could ___________________ motion of the sun and planets o Used mathematics and little observation o Very complicated o Used for over 1000 years

Think! • What did Aristotle propose about the Solar System? • Define ‘geocentric’:

HELIOCENTRIC MODEL • Model with _______ in the center of the Solar System • In 1543, Nicolaus Copernicus moved the sun to the center. • Was ______________by scientific community

DEVELOPMENT OF THE HELIOCENTRIC MODEL • In 1605, Johannes Kepler improved the model by proposing that the orbits around the sun are ___________, or ovals, rather than circles. • In 1609, Galileo Galilei made a ____________ – Key __________________ that allowed important _________________ to be made in support of the Heliocentric Model • In 1687, Sir Isaac Newton ties it all together - Explained that __________________ keeps the planets in orbit around the sun, and satellites in orbit around planets.

Think! • What did each of these scientists do or say to build on our knowledge of the Solar System: • Copernicus? • Kepler? • Newton?

STEPS THAT LEAD TO THE CHANGE FROM GEOCENTRIC TO HELIOCENTRIC • Ptolemy & Aristotle didn’t have the ___________________to make good ___________________ • Ptolemy could _____________, but the model was very complicated and he didn’t make many observations • Copernicus, Kepler, Galileo, & Newton each _________________________ to the development of the Heliocentric Model

FORMATION OF THE SOLAR SYSTEM • According to dating of rocks, scientists believe the solar system is approximately _______________ • ___________________: model for the formation of the solar system in which the sun and planets condense from a cloud (or nebula) of gas and dust. NEBULAR MODEL PROCESS 1. Nebula began to collapse due to gravity 2. Nebula then formed a ________________ • Supporting evidence for the disk: o Planets lie in the ___________________ o Planets have almost circular orbits (they are ellipses though) o Planets orbit in the same direction as the material in the center.

NEBULAR MODEL PROCESS, CONTINUED 3. Center becomes hottest part with most material = __________ 3. ______________ formed around the Sun by the accretion of matter in the disk. • PLANETESIMAL = ________ that become ______ 4 a) Planetesimals become larger as gravity attracts more material to them 4 b) They then _______________________ to become even larger = the Planets

Nebular Model

Think! • What are 2 pieces of evidence that support the Nebular Model?

SOLAR SYSTEM BODIES SMALLER THAN MOONS • ASTEROID: fragments of rock that orbit the sun – ______________ of the “smaller” bodies – Asteroid Belt = Between __________________ • COMET: small body of _________________________ loosely packed together that follows an elliptical orbit (“dirty snowballs”) - Some comets have two tails: • __________________: made of gases; blown by solar wind so it always is pointed away from the sun • __________________: made of dust; less affected by solar wind so often curved by the comet’s orbital motion

Halley’s Comet • Orbits the sun every ___________ • Next time it passes the Earth is in 2061 • Notice two tails

SOLAR SYSTEM BODIES SMALLER THAN MOONS • METEOROID = small pieces of rock that _________________________. • METEOR = meteoroid that _________________________( most burn up before reaching the ground). • “Shooting Stars” = meteors • METEORITE = meteor that ______________

Think! • How are “smaller bodies” (asteroids, comets, and meteoroids) the same? • How are they different?