Unit 2: The Solar System
Mrs. Morgan8th Grade
The Big IdeaPlanets 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
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 Force
Law 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 Theory
Solar 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
By Radiation – energy leaves the core in the form of electromagnetic waves
By Convection – energy (heat) is transferred by the circulation or movement of matter
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
Extreme to the Core
Unit 2 Lesson 4 The Terrestrial Planets
Terrestrial planets - the four small, dense, rocky planets that orbit closest to the sun
• astronomical unit (AU) - average distance between the sun & Earth, or approximately 150 million km.
http://physics.uoregon.edu/~jimbrau/astr121/Notes/Chapter6.html
Mercury
Period of Rotation-last almost 59 Earth days
Period of revolution-88 days
Temps range from -184˚C to 427˚C
Smallest planet with craters
Venus• Retrograde rotation
(clockwise)
• Rotation- 243 Earth days
• Revolution- 225 days• Temp- 465 ˚C; CO2
traps the sun’s energy• Thousands of
volcanoes & craters• Sulfuric acid rain
http://www.bobthealien.co.uk/venus.htm
Unit 2 Lesson 4 The Terrestrial Planets
Earth
Only planet that supports life
Liquid water, energy soursce
Atmosphere contains O2
Only planet divided into tectonic plates
Mars• 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
A Giant Among Giants!
•Gas giants have deep, massive gas atmospheres, made up mostly of hydrogen & helium. No surface to stand on. Large and cold.
http://www.daviddarling.info/encyclopedia/G/gasgiant.html
Unit 2 Lesson 5 The Gas Giant Planets
Jupiter
Rotates fastest – 9 h 55 min
Revolution– 11.86 Earth years
Great Red Spot 63 moons
Io Europa Callisto Ganymede
Saturn• Rotation- 10 h 39 min• Revolution- 29.5 years• Planetary ring system• Made of H+ & He• 60 moons
• Enceladus • Titan
Unit 2 Lesson 5 The Gas Giant Planets
http://www.gearthblog.com/blog/archives/2006/04/google_jupiter.html
Uranus
Rotation- 17 h 24 min Revolution-84 years Made of H+ & He Atmosphere of
methane Tilted on its side as it
orbits the sun 27 moons
Miranda
Neptune• Rotation-16 h 7 min• Revolution- 164.8
years• H+/He and methane • Great dark spot• 13 moons
• Triton-orbits opposite
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 tht 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.