Chapter#4 ~Solar System You are here Chapter#4 ~Solar System prepared by Huriye Gürsel

Some Definitions... Greenhouse Effect - warming of a planet’s surface as a result of atmospheric gases trapping heat. Carbon dioxide is one of these greenhouse gases. Photon - a quantum of visible light or other form of electromagnetic radiation coming from the Sun. A particle of light. Retrograde - this means that the planet is spinning backwards compared to the other planets. Revolution - one complete circle made around something. The orbit made by a planet or satellite around another body.

Rotation - the turning motion of a planet spinning on its axis. Star - a glowing, hot, gaseous mass in space such as the Sun ranging in size from that of a planet to larger than the Earth’s orbit. It generates energy by thermonuclear reactions. Terrestrial - similar in composition and density to Earth. Relating to Earth. Earth-like. Volume - amount of space an object takes up.

Some Definitions... Dwarf Planet - a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, (c) has not cleared the neighborhood around its orbit, and (d) is not a satellite. Planet - a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape and (c) has cleared the neighborhood around its orbit. Plutoids - celestial bodies in orbit around the Sun at a semi-major axis greater than that of Neptune that have sufficient mass for their self-gravity to overcome rigid body forces so that they assume a hydrostatic equilibrium (near-spherical) shape, and that have not cleared the neighborhood around their orbit.

Video 1 – Milky Way Galaxy Our Solar System as a part of Milky Way Galaxy...

My Very Easy Method Just Shows Us Names of Planets Not to scale PLUTO (Dwarf Planet) Mercury, Venus, Earth, and Mars are the inner planets. They are also known as terrestrial planets. NEPTUNE URANUS Jupiter, Saturn, Uranus, Neptune, and Pluto are the outer planets. Jupiter, Saturn, Uranus, and Neptune are also known as gas giants or Jovian planets. Pluto is a big ball of ice. SATURN MARS JUPITER EARTH VENUS MERCURY SUN Between Mars and Jupiter there is a large number of rocks orbiting the sun. Each rock is known as an ASTEROID. This ring of rocks is called the Asteroid Belt. COMETS OR METEOROIDS

Video 2 - Solar System...

Mercury (Planet) Relative position: 1st planet out from the sun. Appearance: Resembles Earth's Moon, scarred by thousands of impact craters. There are areas of smooth terrain as well as cliffs, some soaring a mile high, formed by ancient impacts. General composition: Rocky material. It is a terrestrial planet. Density: 5.43 g/cm3 Atmosphere: Almost no atmosphere. The very little atmosphere that exists is composed chiefly of oxygen, sodium, and helium. Size: .054 the volume of the Earth Planetary satellites (Moons): None Rotation: 58.65 days (very slow rotation) Revolution: 88 days to go around the Sun once. Temperatures: High: 467 °C on the sunny side of the planet. Low: -183 °C on the dark side of the planet. Mercury (Planet)

Venus (Planet) Relative position: 2nd planet out from the sun. Appearance: It is covered by thick, rapidly spinning clouds. Due to its thick cloud layer reflecting sunlight, it is the brightest planet in the sky General composition: Rocky material. It contains an iron core and a molten rocky mantle. The crust is a solid, rocky material. It is a terrestrial planet. Density: 5.24 gm/cm3 Atmosphere: Consists mainly of carbon dioxide, nitrogen, and droplets of sulfuric acid; it contains almost no water vapor. This thick atmosphere traps immense amounts of heat in a large-scale greenhouse effect. Size: .88 the volume of the Earth Planetary satellites (Moons): None Rotation: -243 days (retrograde) Revolution: 225 Earth days. Its day is longer than its year. Temperature: 450 °C. It’s hotter than Mercury due to the greenhouse effect. It is actually hot enough to melt lead. Venus (Planet)

Earth’s Place in the Universe Astronomy and planetary exploration reveal the solar system’s structure, scale, and change over time.

Earth (Planet) Relative position: 3rd planet out from the sun. Appearance: The Earth looks blue and green from space with clouds moving through the atmosphere. The surface of the Earth is 70% water and 30% land. General composition: Rocky material. It is a terrestrial planet. It has a nickel-iron core with a molten mantle and solid rocky crust. Density: 5.52 gm/cm3 Atmosphere: Mostly oxygen (21%) and nitrogen (78%). Some argon, carbon dioxide, and water vapor. Size: 40,000km (24,8000miles) around at the equator. Planetary satellites (Moons): 1 - The Moon Rotation: 23 hours, 56miutes (1 day) Revolution: 365.25 days Temperature: Mean surface 15 °C to 20 °C Special feature: Earth sustains life as we know it. Water exists in all three states (solid, liquid , and gas) on the Earth. There is a delicate balance between its oceans, air, land, and life.

The moon orbits the Earth... Sun Earth Kepler’s Laws (on the board!) moon ...as the Earth orbits the Sun.

As the Earth orbits around the Sun, it also spins on its own axis; which is tipped, like a globe’s.

At any time, half of the Earth faces the sun and therefore receives light. This part is in day. This part is in night. The other half faces away from the Sun, and so receives very little light.

What causes the Earth’s seasons? As the Earth orbits the Sun, when its axis tips towards the Sun, the weather gets warmer. When it tips away, the weather gets colder, causing the Earth’s seasons.

In the northern hemisphere: spring here In the northern hemisphere: winter here autumn here summer here summer here autumn here winter here In the southern hemisphere: spring here

The Earth rotates on its axis at c 900 miles an hour The Earth rotates on its axis at c 900 miles an hour! As it rotates, the Earth is also orbiting the Sun at a speed of c 67,500 miles an hour! But, don’t worry! Thanks to the Earth’s gravity and atmosphere, we won’t fall off.

So, when the Sun ‘rises’ in one side of the world, on the other side, it’s about to ‘set’.

It’s some sort of a cycle! Now, with your partner, discuss these ideas about the moon: It’s some sort of a cycle! I think the moon is a light source? I think it keeps changing shape?

Why does the moon appear to change shape? Earth moon moon moon moon new moon full moon It takes the moon 28 days to orbit the Earth. For 27 days out of this cycle, the Sun cannot shine on the whole of the surface, facing the Earth. The light from the Sun can only shine on the whole surface for one night in each cycle: a full moon. On one night, no light from the Sun can reach the moon at all: a new moon.

Do you know... how long it takes the Earth to spin round once? which direction the Earth turns? how long it takes the Earth to orbit the Sun once? which direction the Earth orbits the sun? It takes 24 hours. It turns anti-clockwise. It takes 365¼ days. It turns anti-clockwise.

Mars (Planet) Relative position: 4th planet out from the sun. Appearance: Mars appears red due to the iron oxide in its soil. It has polar ice caps that grow and recede with the seasons, and it has dust storms, which cause giant dunes, wind streaks, and wind-carved features. General composition: Rocky material. It is a terrestrial planet. Density: 3.94 gm/cm3 Atmosphere: Mostly carbon dioxide, nitrogen, and argon. Size: .149 times the volume of the Earth. Planetary satellites (Moons): 2 Moons Rotation: 24 hours, 33 minutes. Revolution: 686.67 days. Temperature: -87 °C to -5 °C Special Features: Mars has the largest volcanic mountain in the solar system, Olympus Mons (27 km high and 600 km across); volcanoes in the northern Tharsis region that are so huge they deform the planet's roundness; and a gigantic equatorial rift valley, the Valles Marineris. This canyon system would stretch from New York to Los Angeles; the Grand Canyon could fit into one of the side canyons of this great chasm.

It is also heavily cratered with a small lumpy appearance. Moons of Mars Phobos Gouged by a giant impact crater and beaten by thousands of meteorite impacts, Phobos is on a collision course with Mars. It may collide with Mars in 50 million years or break up into a ring. Deimos It is also heavily cratered with a small lumpy appearance.

Jupiter (Planet) Relative position: 5th planet out from the sun. Appearance: It is sometimes called a “mini-solar system” because of its numerous moons and several rings. Jupiter appears striped because light and dark belts are created by strong east-west winds. General composition: It is a gas giant, meaning it is mostly made of gases. Jupiter's core is probably not solid but a dense, hot liquid with a consistency like thick soup. Density: 1.76 gm/cm3 Atmosphere: Mostly hydrogen, helium and methane. Size: 1316 times the volume of the Earth. It is the planet with the highest gravity in the solar system. Planetary satellites (Moons): 63 Moons; some of them have been named and some have alphanumeric designations. Rotation: 9 hours, 54 minutes Revolution: 11.86 Earth years Temperature: -108 °C Special Feature: The Great Red Spot has existed for at least 100 years, and perhaps longer. It is a hurricane-like storm on Jupiter. (Galileo reported seeing a similar feature nearly 400 years ago). Three Earths could fit across the Great Red Spot.

Moons of Jupiter 1. Io 2. Europa 3. Ganymede 4. Callisto 5. Amalthea 6. Himalia 7. Elara 8. Pasiphae 9. Sinope 10. Lysithea 11. Carme 12. Ananke 13. Leda 14. Thebe 15. Adrastea 16. Metis 17. Callirrhoe 18. Themisto 19. Megaclite 20. Taygete 21. Chaldene 22. Harpalyke 23. Kalyke 24. Iocaste 25. Erinome 26. Isonoe 27. Praxidike 28. Autonoe 29. Thyone 30. Hermippe 31. Aitne 32. Eurydome 33. Euanthe 34. Euporie 35. Orthosie 36. Sponde 37. Kale 38. Pasithee 39. Hegemone 40. Mneme 41. Aoede 42. Thelxinoe 43. Arche 44. Kallichore 45. Helike 46. Carpo 47. Eukelade 48. Cyllene 49. Kore 50. S/2003 J2 51. S/2003 J3 52. S/2003 J4 53. S/2000 J11 54. S/2000 J5 55. S/2003 J9 56. S/2003 J10 57. S/2003 J12 58. S/2003 J15 59. S/2003 J16 60. S/2003 J17 61. S/2003 J18 62. S/2003 J19 63. S/2003 J23 BACK | The Solar System | Sun | Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune | Pluto (Dwarf Planet) | Asteroids | Comets | Meteors, Meteoroids, and Meteorites | End Show |

Moons of Saturn 1. Mimas 2. Enceladus 3. Tethys 4. Dione 5. Rhea 6. Titan 7. Hyperion 8. Iapetus 9. Erriapus 10. Phoebe 11. Janus 12. Epimetheus 13. Helene 14. Telesto 15. Calypso 16. Kiviuq 17. Atlas 18. Prometheus 19. Pandora 20. Pan 21. Ymir 22. Paaliaq 23. Tarvos 24. Ijiraq 25. Suttungr 26. Mundilfari 27. Albiorix 28. Skathi 29. Siarnaq 30. Thrymr 31. Narvi 32. Methone 33. Pallene 34. Polydeuces 35. Daphnis 36. Aegir 37. Bebhionn 38. Bergelmir 39. Bestla 40. Farbauti 41. Fenrir 42. Fornjot 43. Hati 44. Hyrokkin 45. Kari 46. Loge 47. Skoll 48. Surtur 49. S/2004 S7 50. S/2004 S12 51. S/2004 S13 52. S/2004 S17 53. S/2006 S1 54. S/2006 S3 55. Greip 56. Jarnsaxa 57. Tarqeq 58. S/2007 S2 59. S/2007 S3 60. Anthe BACK | The Solar System | Sun | Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune | Pluto (Dwarf Planet) | Asteroids | Comets | Meteors, Meteoroids, and Meteorites | End Show |

Uranus (Planet) Relative position: 7th planet out from the sun. Appearance: It has a blue-green color from the methane gas above the deeper clouds. Methane absorbs red light and reflects blue light. It does have a small system of rings. General composition: It is a Gas giant, meaning it is mostly made of the gases hydrogen and helium, with a small amount of methane and traces of water and ammonia. It has no solid surface, but it does contain a liquid core made mostly of “icy” materials (water, methane, and ammonia) Density: 1.30 gm/cm3 Atmosphere: Mostly hydrogen, helium, and methane. Size: 52 times the volume of the Earth. Planetary satellites (Moons): 27 Moons Rotation: 17 hours, 11 minutes Revolution: 84.02 Earth years Temperature: -197 °C Links to Uranus sites: Exploring the Planets - Uranus Missions to Uranus StarDate: Uranus Special feature: Uranus’ axis is tilted so that it seems to rotate on its side. This tilt gives it seasons that last over twenty years. | The Solar System | Sun | Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune | Pluto (Dwarf Planet) | Asteroids | Comets | Meteors, Meteoroids, and Meteorites | End Show |

Moons of Uranus 1. Cordelia 2. Ophelia 3. Bianca 4. Cressida 5. Desdemona 6. Juliet 7. Portia 8. Rosalind 9. Mab 10. Belinda 11. Perdita 12. Puck 13. Cupid 14. Miranda 15. Francisco 16. Ariel 17. Umbriel 18. Titania 19. Oberon 20. Caliban 21. Stephano 22. Trinculo 23. Sycorax 24. Margaret 25. Prospero 26. Setebos 27. Ferdinand

Neptune (Planet) Relative position: 8th planet out from the sun. Appearance: Neptune has a blue color because of the methane in its atmosphere. The methane reflects blue light while it absorbs red light. It has a small system of rings and periodically Great Dark Spots (hurricane-like storms) appear. General composition: It is a Gas giant, meaning it is mostly made of the gases hydrogen, helium, and methane. It has no solid surface, but its liquid core is composed of water and other “melted ices.” Density: 1.76 gm/cm3 Atmosphere: Mostly hydrogen, helium,and methane. Size: 44 times the volume of the Earth. Planetary satellites (Moons): 13 Moons Rotation: 16 hours, 4 minutes Revolution: 164.79 Earth years Temperature: -200 °C Special features: Neptune is actually the farthest planet from the Sun for a 20-year period out of every 248 Earth years due to Pluto’s unusual elliptical orbit.

Moons of Neptune 1. Triton 2. Nereid 3. Naiad 4. Thalassa 5. Despina 6. Galatea 7. Larissa 8. Proteus 9. Halimede 10. Psamathe 11. Sao 12. Laomedeia 13. Neso BACK | The Solar System | Sun | Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune | Pluto (Dwarf Planet) | Asteroids | Comets | Meteors, Meteoroids, and Meteorites | End Show |

Pluto (Dwarf Planet) Charon Relative position: 9th planet out from the sun. Appearance: A large frozen ball of ice. General composition: Rocky core surrounded by water ice. Density: 2.0 gm/cm3 Atmosphere: Frozen most of the time. When it is closest to the Sun the bright layer of frozen methane, nitrogen, and carbon monoxide thaws out and gives it a thin atmosphere. Size: .005 the volume of the Earth. It is the planet with the lowest gravity in the solar system. Planetary satellites (Moons): 3 1. Charon 2. Hydra 3. Nix Rotation: -6.39 days (retrograde) Revolution: 247.9 Earth years Temperature: -233 °C Links to Pluto sites: Missions to Pluto Pluto Portal StarDate: Pluto | The Solar System | Sun | Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune | Pluto (Dwarf Planet) | Asteroids | Comets | Meteors, Meteoroids, and Meteorites | End Show |

Asteroids Asteroids are either rocky or metallic objects that orbit the Sun. They are too small to considered planets but are sometimes called planetoids. They can be anywhere from the size of a pebble up to a 1000km (620 miles) in diameter; the asteroid Ceres is an example of an asteroid that is this large. They have been found inside Earth’s orbit and all the way out past Saturn’s orbit. Most asteroids, however, are located in the asteroid belt which exists between the orbit’s of Mars and Jupiter. Links to Asteroids sites: Missions to Asteroids The Nine Planets: Asteroids StarDate: Asteroids | The Solar System | Sun | Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune | Pluto (Dwarf Planet) | Asteroids | Comets | Meteors, Meteoroids, and Meteorites | End Show |

Asteroid Belt

Comets Comets - small, fragile, irregular- shaped body composed of a mixture of non-volatile grains and frozen gases. Components of Comets can be seen by clicking on the link. Their orbits are elliptical (oval) or parabolic (U-shaped). The orbit brings them in very close to the Sun and swings them far out into space, sometimes out past Pluto. Example of a comet’s orbit. As comets approach the Sun, radiation from the Sun evaporates the ice and gases, creating the lone tail. The closer to the Sun, the longer the tail of the comet. The tail of the comet always faces away from the Sun because of the solar wind coming from the Sun.

Components of Comets BACK | The Solar System | Sun | Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune | Pluto (Dwarf Planet) | Asteroids | Comets | Meteors, Meteoroids, and Meteorites | End Show |

Example of a Comet’s Orbit Comet 2P/Encke BACK | The Solar System | Sun | Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune | Pluto (Dwarf Planet) | Asteroids | Comets | Meteors, Meteoroids, and Meteorites | End Show |

Meteors, Meteoroids, and Meteorites Meteoroids - asteroids that are on a collision course with Earth. Meteor - streak of light created when a meteoroid strikes our atmosphere at high velocity and friction causes the chunk of space matter to burn up. Meteorite - what is left that strikes the Earth’s surface if the meteoroid does not burn up completely. 92.8% of all meteorites are composed of silicate (stone), and 5.7% are composed of iron and nickel; the rest are a mixture of the three materials. Stony meteorites are the hardest to identify since they look very much like terrestrial rocks. Meteorite sample that is from the crust of the asteroid Vesta

Did you know? One day on Venus lasts 117 Earth days. Jupiter whips around in just 9 hours and 57 minutes. One day on Mars is about the same as one day on Earth.

Sun The Sun is a star at the center of our solar system. It is estimated to be 4.5 billion years old. It supports all life on Earth through photo- synthesis and is the ultimate source of all food and fossil fuel. It is 333,400 times more massive than the Earth (this means that 333,400 Earths can make up the Sun). 99.86% of all the mass of the solar system is found in the Sun. The core of the Sun is 16 million °C. The surface of the Sun is 7000° C It takes several hundred thousand years for photons to escape from the dense core and reach the surface. The Sun generates energy the equivalent of 100 billion tons of TNT exploding every second.

Nuclear Fusion in the Sun The Sun is basically a huge ball of hydrogen gas held together by the gravity created by its own mass. Under the intense pressure created at the centre of the Sun by gravity, hydrogen nuclei are fused together to produce helium nuclei. Very simply stated, four hydrogen nuclei are fused into one helium nucleus, however one helium atom has less mass than four hydrogen atoms. The fusion process releases enough energy to account for the lost mass. The energy released by nuclear fusion in the Sun's core heats the Sun. The hot Sun radiates light into space, warming the Earth and the other planets. About 1300 watts per square meter reaches the Earth's orbit, of which about 1000 watts per square meter reaches the Earth's surface (on a clear day).

The Moon The Moon is the Earth’s only natural satellite. The Moon contains no water and has no atmosphere Its has about 1/6 the mass of the Earth, therefore it has 1/6 the gravitational pull of the Earth. It is 384 401 km from the Earth. It takes 27.32 days to orbit the Earth once. The gravitational pull of the Moon is responsible for the Earth’s tides. The surface of the Moon is covered with craters and flatlands. The craters are due to repeated meteorite bombardments while the dark, flatlands are the result of ancient lava flows.

Dwarf Planets

Video on Dwarf Planets...

Video Solar System – “Did You Know?”