The Solar System Chapter 2

Models of the Solar System In the geocentric model, Earth is at the center of the revolving planets. Aristotle stated that the earth was in the center of the solar system. Ptolemy stated that the earth was in the center of the universe. He thought that the planets moved in small circles as they moved around the sun.

Models of the Solar System In the heliocentric model, Earth and the other planets revolve around the sun. This model was developed by Nicolaus Copernicus.

Galileo Used a telescope to view the solar system. Observed the four larger moons that orbited Jupiter. Observed the phases of Venus

Brahe & Kepler Brahe carefully observed the positions of the planets. Kepler had wrote laws that explained the behavior of planets orbiting the sun.

Kepler’s Laws of Motion LAW 1: The orbit of a planet/comet about the Sun is an ellipse with the Sun's center of mass at one focus

Kepler’s Laws of Motion LAW 2: A line joining a planet/comet and the Sun sweeps out equal areas in equal intervals of time

Kepler’s Laws of Motion LAW 3: The farther a planet is from the sun, the longer the orbital period.

Forces that Keeps Planets in Orbit Around the Sun Newton concluded that two factors, inertia & gravity, combine to keep the planets in orbit. Inertia is tendency of an object to resist a change in motion. Gravity is the force that attract all objects toward each other.

The Sun The sun produces its energy from nuclear fusion (core must reach 15 million degree Celsius). Sun’s Atmosphere: The photosphere is the inner layer of the sun that makes light. The chromosphere is the middle layer and produces color. The corona is the outer layer of the sun and produces ultraviolet radiation.

Solar Features Solar winds are a stream of electrically charged particles coming from the corona. Sunspots are areas of gas on the sun that are cooler than the gases around them. Prominences are reddish loops of gas. Solar flares are large explosions of gas on photosphere.

Inner Planets Total of eight planets in our solar system. The inner planets are also called the terrestrial planets. Small in Size. Have rocky surfaces.

Mercury Mercury is 0.4 AU from the sun. Diameter is 4,878 km. Rotates every 59 days. Revolves around the sun every 88 days. Very thin atmosphere. 0 moons. Temperature between -170oC to 430oC. Very heavily cratered.

Venus Venus is 0.7 AU from the sun. Diameter is 12,104 km. Rotates every 243 days (retrograde). Revolves around the sun every 225 days. Very thick atmosphere of CO2. 0 moons. Temperature 460oC (Greenhouse Effect). Sulfuric acid rain.

Earth Earth is 1.0 AU from the sun. Diameter is 12,756 km. Rotates every 24 hours. Revolves around the sun every 365.25 days. Atmosphere of 78% nitrogen and 21 % oxygen. 1 moons. Temperature ?oC. 70% of Earth’s surface is covered by water.

Mars Mars is 1.5 AU from the sun. Diameter is 6794 km. Rotates every 24 hours. Revolves around the sun every 687 days. Thin atmosphere of CO2. 2 moons(Phobos & Deimos). Temperature -153oC to 20oC. Polar caps of dry ice. Olympus mons is the largest volcano in the solar system.

Asteriod Belt Asteroids are objects revolving around the sun that are too small and too numerous to be considered planets. The asteroid belt is located between Mars and Jupiter. Asteroids include Ceres, Pallas, Juno and Vesta. Over 300 asteroids have been identified.

What keeps planets revolving around the sun? The sun’s gravitational pull. The Planet’s mass. The planet’s magnetic field. The Sun’s inertia. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Outer Planets (Jovian Planets) Found outside the asteroid belt between the asteroids and the Kuiper Belt. These planets are large and made of gas.

Jupiter Jupiter is 5.2 AU from the sun. Diameter is 142,984 km. Rotates every 9.9 hours. Revolves around the sun every 11.9 years. Thick atmosphere of hydrogen & Helium. 63 moons (Io, Europa, Callisto & Ganymede). Temperature -110oC. Great Red spot is a large storm. Has a ring system.

Saturn Saturn is 9.6 AU from the sun. Diameter is 120,536 km. Rotates every 10.7 hours. Revolves around the sun every 29.4 years. Thick atmosphere of hydrogen & helium. 60 moons (Titan). Temperature -140oC. Has an extensive ring system.

Uranus Uranus is 19.1 AU from the sun. Diameter is 51,200 km. Rotates every 17.3 hours. Revolves around the sun every 84 years. Thick atmosphere of hydrogen & helium, with traces of methane. 27 moons. Temperature -195oC. Has a ring system. Axis is tilted 90o.

Neptune Neptune is 30 AU from the sun. Diameter is 49,500 km. Rotates every 16.1 hours. Revolves around the sun every 165 years. Thick atmosphere of hydrogen & helium. 13 moons (Triton). Temperature -200oC. Has an ring system. Had a Great Dark Spot that has since disappeared.

Kuiper Belt The region of the Solar System beyond the planets extending from the orbit of Neptune (at 30 AU) to approximately 55 AU from the Sun.

Oort Cloud & Comets The Oort cloud is where the comets are found. Comets are dirty snowballs that orbit the sun. A comet has a head and tail, the head is made of the nucleus and coma. The tail of the comet always points away from the sun because of the solar winds. Halley’s comet appears every 76 years.

Meteoroids, Meteors & Meteorites Meteoroids are pieces of rocks flying through space. Meteors are meteoroids that have entered the earth’s atmosphere, burning up because of friction. Meteorites are meteors that reach the surface of earth.

Life Beyond Earth “Goldilock’s condtions” Liquid water. Suitable temperature. Atmosphere. The Drake Equation: R=The number of suitable stars. Fp=The fraction of these stars that have planets. Ne=The number of Earth-like planets. Fl=The fraction of Earth-like planets where life develops. 

Drake Equation(continued) Fi=The fraction of life sites where intelligent life develops. Fc=The fraction of intelligent life sites where communication develops. L="The "lifetime" (in years) of a communicative civilization. N=The number of communicative civilizations within the Milky Way today.

An icy object that has an elongated orbit around the sun is referred to as a(n)…. Asteroid Comet Meteor Meteorite 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Light from the sun is reflected of the surface of each Why does a meteoroid or asteroid create a streak of light when entering the Earth’s atmosphere? Light from the sun is reflected of the surface of each Energy is released form the objects Lightning is produced form these objects Light is a result of friction from the gasses in the atmosphere 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Review Questions Which planet is the largest? (Jupiter) Which planet is the smallest? (Mercury) Which planet has the most Moons? Which planet has the most extensive ring system? (Saturn)

Review Questions Which planet has the Greenhouse Effect? (Venus) Which planet has the largest volcano in the solar system? (Mars) Which planet rotates on its side? (Uranus) Which person developed the heliocentric model of the solar system? (Copernicus)

Review Questions Who stated that planets orbited the sun in elliptical orbits? (Kepler) Which two factors keep planets in orbit around the sun? (gravity & inertia) What is the largest moon in our solar system? (Ganymede) Which moon has volcanic activity? (Io)

Review Questions What part of the sun produces light? (photosphere) What are the cooler dark areas on the sun’s surface called? (sunspots) What do we call the large chunks of ice orbiting the sun in the Oort Cloud? (comets) What is found between Mars & Jupiter? (asteroids)

Review Questions What are shooting stars? (meteors) What do you call a meteor before it enters earth’s atmosphere? (meteoroids) What do you call a meteor after it enters earth’s atmosphere? (meteorites) What is the outer-most atmosphere of the sun? (corona)

Review Questions What layer of the sun produces color? (chromosphere) What is the center of the sun called? (core) How many planets have been identified in our solar system? (8) What do we call explosions on the surface of the sun? (solar flares)

Review Questions What do we call extensions of burning gases on the sun? (prominences) Which planet is red because of the iron oxides on the surface? (Mars) What is the most abundant gas found in our solar system? (hydrogen) Who developed the first telescope? (Galileo)

Review Questions Who calculated the positions of planetary orbits? (Brahe) Who developed the geocentric model of the solar system? (Ptolemy or Aristotle) Which planet is the most heavily cratered and has a very thin atmosphere? (Mercury) Which of the outer planets is not a gas giant? (Pluto)

Review Questions List the order of the planets from the closest to the sun to the farthest from the sun? (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto) Which planet has the moon Titan? (Saturn) Which planet has the moons Phobos & Deimos? (Mars) Which planet has living organisms? (Earth)

Review Questions Which planet has the Great Red Spot? (Jupiter) Which planet had the Great Dark Spot? (Neptune) Which planet has the density less than that of water? (Saturn) Which planet has a longer day than year? (Venus)

Review Questions Which planet has about the same length of day as earth? (Mars) Which planet has about the same diameter as earth? (Venus) Which planet are we most likely to send a manned space mission to? Which moon of Jupiter is most like earth? (Europa) Which two planets have no moons? (Mercury & Venus)