Unit 2: The Solar System

The Big Idea:Planets and a variety of other bodies form a system of objects orbiting the sun.

The Center of the Solar System

Unit 2 Lesson 1 Historical Models of the Solar System

•Solar system - the sun & all of the bodies that orbit the sun.

•Heliocentric model – Sun centered, Earth and the other planets orbit the sun.•Geocentric model – Earth centered, the sun, moon and planets circling the Earth

In the beginning…Aristotle (384-322 BCE)-believed in a geocentric model, part of his logic was that we could feel no motion on Earth, so Earth couldn’t be moving. He thought we should detect a shift in position between nearby stars and far away ones.

• Parallax- apparent shift in the position of an object when viewed from different locations.

Unit 2 Lesson 1 Historical Models of the Solar System

Aristarchus (about 320 230 BCE)- proposed a heliocentric model, his attempts to measure relative distances to moon & sun have been major contribution to science

http://www.astro.cornell.edu/academics/courses/astro2201/aristarchus.htm

Unit 2 Lesson 1 Historical Models of the Solar System

Ptolemy- (100-170 CE) believed in a geocentric model.

• His model was used for 14 centuries.

• Planets moved on small circles that in turn moved on larger circles (“wheels-on-wheels”)

• Allowed people to predict the motions of planets years into the future.

Unit 2 Lesson 1 Historical Models of the Solar System

Copernicus- (1473-1543) believed in a heliocentric model with perfect

circles Kepler- (1571-1630)Realized that planetary orbits were not circular but were more like ellipses.

Unit 2 Lesson 1 Historical Models of the Solar System

Galileo Galilei (1564-1642) Improved the telescope in 1609

Observed Jupiter’s moons, Io, Europa, Callisto, and Ganymede which gave support of heliocentric model

Observed Venus’s phases

Unit 2 Lesson 1 Historical Models of the Solar System

Gravity - force of attraction between objects that is due to their masses & the distances between them. Every object in the

universe pulls on every other object.

Orbit - path that a body follows as it travels around another body in space.

Unit 2 Lesson 2 Gravity & the Solar System

http://kissedgoodbye.blogspot.com/2012/01/gravity.html

Inertia: tendency of an object to resist any change in its motion.

Kepler’s Three Laws

1.Planetary orbits are ellipses with the sun at one focus

Aphelion- where the object is farthest from the sun.Perihelion - where the object is closest to the sun.

2. Planets move faster in their orbits when they are closer to the sun.3. Distance of a planet from the sun to the time the planet takes to go once around its orbit.

Unit 2 Lesson 2 Gravity & the Solar System

Law of Gravitational ForceLaw of universal gravitation- states that all objects in the universe attract each other through gravitational force.• Centripetal force -inward

force that causes an object to move in a circular path. When planets orbit the sun, a force similar to centripetal force prevents them from

moving out of their orbits and into a straight line. The sun’s gravity is the force that keeps the planets moving in orbit around the sun.

http://www.teachersdomain.org/resource/phy03.sci.phys.mfw.roller/

Unit 2 Lesson 2 Gravity & the Solar System

http://www2.nido.cl/~science/ksupplee/Mechanics/circular%20motion/uniform%20circular%20motion.html

How the Solar System Formed TheorySolar Nebula - inward pull of gravity is balanced by the outward push of gas pressure in the cloud (perhaps the explosion of a nearby star)• Planetesimals - Collisions between these bodies

formed larger bodies from which planets formed

Here Comes the Sun• Corona-outer

atmosphere of the sun (up to 2,000,000 ˚C)

• Chromosphere-middle layer of sun’s atmosphere (6,000 ˚C)

• Photosphere- visible surface of the sun. Energy escapes into space (5,527 ˚C)

Unit 2 Lesson 3 The Sun

• Convective Zone – energy travels by convection from the radiative zone to the photosphere

• Radiative Zone - energy is transferred away from the core by radiation.

Core – very dense center of sun. Temperature of 15,000,000 ˚ C, where nuclear fusion occurs.

Unit 2 Lesson 3 The Sun

Solar Activity Sunspots-dark

areas that form on the surface of the sun.

Unit 2 Lesson 3 The Sun

Solar flare – an explosive release of energy

that can extend outward as far as the sun’s outer atmosphere Prominence- huge loops of relatively cool gas that extend outward from the photosphere

Nuclear Fusion - process by which two or more low-mass atomic nuclei fuse to form another, heavier nucleus.

Three Steps of Nuclear Fusion in the Sun

1. Deuterium - 2 H+ collide (1 P, 1 N- a heavy hydrogen)

2. Helium-3 – deuterium combines w/ another H+ (more energy/ gamma rays released)

3. Helium-4 – 2 He-3 nuclei combine to form He-4 (more energy/pair of H+ released)

turn to pgs 78-79

Unit 2 Lesson 3 The Sun

Mixing It Up Radiation: energy leaves the core in

the form of electromagnetic waves; movement of heat waves.

Convection:currents are created when there are differences in temperature & density within a fluid.

Conduction: transfer of energy (heat) by direct contact between 2 materials with different temperatures.

http://www.physics.arizona.edu/~thews/reu/the_science_behind_it_all.html

http://outreach.atnf.csiro.au/education/senior/astrophysics/stellarevolution_mainsequence.html

Unit 2 Lesson 3 The Sun

Mercury

Distance from sun: 0.39 AU Moons: Zero Temp: -184˚C to 427˚C Name: Merurius by Romans b/c it appears to

move swiftly Rotation-last almost 59 Earth days Revolution-88 days Smallest planet with craters

http://www.bobthealien.co.uk/venus.htm

Unit 2 Lesson 4 The Terrestrial Planets

Venus

• Distance: 0.72 AU• Moons: Zero• Temp:(465 ˚C) CO2 traps the sun’s energy• Name: Roman goddess of love. Considered

brightest & most beautiful• Rotation- 243 Earth days• Revolution- 225 days• 1000s of volcanoes & craters• Sulfuric acid rain• Retrograde rotation (clockwise)

Earth Distance from sun: 1 AU Moons: 1 Temp: -89˚C to 58 ˚C Name: means “on the ground” Only planet that supports life Liquid water, energy source Atmosphere contains O2 Only planet divided into tectonic plates

Mars

• Distance from sun: 1.52 AU• Moons: 2• Temp: -140˚C to 20 ˚C• Name: Roman god of war b/c its

red, bloodlike color• Rotation- 24 h 37 min• Revolution- 1.88 Earth years • Olympus Mons- largest volcano/mtn in solar

system• Valles Marineris – longest canyon in solar

system• Thin CO2 atmosphere

Unit 2 Lesson 4 The Terrestrial Planets

http://en.wikipedia.org/wiki/Mars_Exploration_Rover

Jupiter

Distance from sun: 5.20 AU Moons: 63

Io-most volcanic Europa Callisto Ganymede

Temp: -150˚C Name: (Zeus by Greeks) Jupiter by Romans

was the most impt deity. Rotates fastest – 9 h 55 min Revolution– 11.86 Earth years Great Red Spot (large storm)

Saturn

• Distance from sun: 9.58 AU

• Moons: 60• Enceladus • Titan

• Temp: -180˚C • Name: Roman name for

Greek Kronos (father of Jupiter)

• Farthest planet from Earth that ca be seen by the naked eye

Unit 2 Lesson 5 The Gas Giant Planets

http://www.gearthblog.com/blog/archives/2006/04/google_jupiter.html

• Rotation- 10 h 39 min• Revolution- 29.5

years• Planetary ring system• Made of H+ & He

Uranus

• Distance from sun: 9.58 AU• Moons: 27

• Miranda • Temp: -210˚C • Name: Greek deity of the sky, the father

of Kronos & grandfather or Jupiter Rotation- 17 h 24 min Revolution-84 years Made of H+ & He Atmosphere of methane Tilted on its side as it orbits the sun

Neptune • Distance from sun: 9.58 AU

• Moons: 13• Triton-orbits opposite

• Temp: -220˚C • Name: Roman god of the sea• Rotation-16 h 7 min• Revolution- 164.8 years• H+/He and methane • Great dark spot

Unit 2 Lesson 5 The Gas Giant Planets

http://www.bobthealien.co.uk/neptune.htm

Small Bodies in the Solar System dwarf planets- celestial body that orbits the sun, is round because of its own gravity. Ceres (between Mars & Jupiter) Pluto Haumea Makemake Eris

Kuiper Belt- orbits just beyond Neptune

Kuiper belt object (KBO) -any of the minor bodies in the Kuiper belt. They are made of methane ice, ammonia ice, and water ice.

Comets

Comet -small body of ice, rock, &

dust that follows a highly elliptical orbit around the sun.

Oort cloud - spherical region that surrounds the solar system

http://janus.astro.umd.edu/front/pages/links/Comets2.html

On the Rocks Asteroid – small, irregularly shaped, rocky object that orbits the sun. Most located in the asteroid belt between

the orbits of Mars and Jupiter Some are rich in carbon, others rocky with

cores or iron and nickel

Burned Out Meteoroid -rocky body, ranging in size from that of a sand grain to that of a boulder, which travels through space.

Meteor -bright streak of light that results when a meteoroid burns up in Earth’s atmosphere.

Meteorite - a meteoroid that reaches Earth’s surface without burning up.