Presentation on theme: "Objectives Distinguish between planets and dwarf planets."— Presentation transcript:
1Objectives Distinguish between planets and dwarf planets. Section 28.4Other Solar System ObjectsObjectivesDistinguish between planets and dwarf planets.Identify the oldest members of the solar system.Describe meteoroids, meteors, and meteorites.Determine the structure and behavior of comets.
2Section 28.4Other Solar System ObjectsRocks, dust, and ice compose the remaining 2 percent of the solar system.Review Vocabularysmog: air polluted with hydrocarbons and nitrogen oxides
3New Vocabulary Other Solar System Objects dwarf planet meteoroid Section 28.4Other Solar System ObjectsNew Vocabularydwarf planetmeteoroidmeteormeteoriteKuiper beltcometmeteor shower
4Section 28.4Other Solar System ObjectsDwarf PlanetsIn the early 2000s, astronomers began to detect large objects in the region of the planet Pluto, about 40 AU from the Sun, called the Kuiper belt.
5Classification in order of decreasing size 1. Planets2. Dwarf planets3. Other solar system objects.
6Section 28.4Other Solar System ObjectsDwarf PlanetsIn 2003 an object, now known as Eris, was discovered that appeared to be the same size, or larger, than Pluto.At that time, the scientific community began to take a closer look at the planetary status of Pluto and other solar system objects.
7Section 28.4Other Solar System ObjectsDwarf PlanetsCeresIn 1801, Giuseppe Piazzi discovered a large object, which was given the name Ceres, in orbit between Mars and Jupiter. Ceres is the largest asteroid. Scientists had predicted that there was a planet somewhere in that region, and it seemed that this discovery was it. However, Ceres was extremely small for a planet.
8Section 28.4Other Solar System ObjectsDwarf PlanetsCeresIn the century following the discovery of Ceres, hundreds of thousands of other objects were discovered in the area between Mars and Jupiter. Therefore, Ceres was no longer thought of as a planet, but as the largest of the asteroids in what would be called the asteroid belt.
9Section 28.4Other Solar System ObjectsDwarf PlanetsPlutoSince its discovery by Clyde Tombaugh in 1930, Pluto has been an unusual planet. It is not a terrestrial or gas planet; it is made of rock and ice.
10Section 28.4Other Solar System ObjectsDwarf PlanetsPlutoPluto has a long, elliptical orbit that overlaps the orbit of Neptune. It is also smaller than Earth’s Moon. It has three moons, two of which orbit at widely odd angles from the plane of the ecliptic.
11Dwarf Planets How many others? Section 28.4Other Solar System ObjectsDwarf PlanetsHow many others?With the discovery of objects close to and larger than Pluto’s size, the International Astronomical Union (IAU) chose to create a new classification of objects in space called dwarf planets.
12Dwarf Planets How many others? Section 28.4Other Solar System ObjectsDwarf PlanetsHow many others?The IAU has defined a dwarf planet as an object that, due to its own gravity, is spherical in shape, orbits the Sun, is not a satellite, and has not cleared the area of its orbit of smaller debris.
13Dwarf Planets How many others? Section 28.4Other Solar System ObjectsDwarf PlanetsHow many others?Currently the IAU has limited the dwarf planet classification to Pluto, Eris, and Ceres, but there are at least 12 other objects whose classifications are undecided.
14Visualizing the Kuiper Belt Section 28.4Other Solar System ObjectsVisualizing the Kuiper BeltRecent findings of objects beyond Pluto, in a vast disk called the Kuiper belt, have forced scientists to rethink what features define a planet.
15Small Solar System Bodies Section 28.4Other Solar System ObjectsSmall Solar System BodiesOnce the IAU defined planets and dwarf planets, they had to identify what was left.In the early 1800s, a name was given to the 1)rocky planetesimals between Mars and Jupiter— the asteroid belt.
16Small Solar System Bodies Section 28.4Other Solar System ObjectsSmall Solar System Bodies2)Objects beyond the orbit of Neptune have been called trans-Neptunian objects, Kuiper belt objects, comets, and members of the Oort cloud. The IAU calls all these objects, collectively, small solar system bodies.
17Small Solar System Bodies Section 28.4Other Solar System ObjectsSmall Solar System BodiesAsteroidsThere are thousands of asteroids orbiting the Sun between Mars and Jupiter. As asteroids orbit, they occasionally collide and break into fragments. When an asteroid fragment, or any other interplanetary material, enters Earth’s atmosphere, it is called a meteoroid.
18Small Solar System Bodies Section 28.4Other Solar System ObjectsSmall Solar System BodiesAsteroidsAs a meteoroid passes through the atmosphere, it is heated by friction and burns, producing a streak of light called a meteor.If the meteoroid does not burn up completely and part of it strikes the ground, the part that hits the ground is called a meteorite.
19Small Solar System Bodies Section 28.4Other Solar System ObjectsSmall Solar System BodiesKuiper beltThe Kuiper belt is a group of small solar system bodies that are mostly rock and ice. Most of these bodies probably formed in this region—30 to 50 AU from the Sun—from the material left over from the formation of the Sun and planets.
20Small Solar System Bodies Section 28.4Other Solar System ObjectsSmall Solar System BodiesKuiper beltThe Kuiper belt appears as the outermost limit of the planetary disk. The Oort cloud surrounds the Sun, echoing its solar sphere.
21Section 28.4Other Solar System ObjectsCometsComets are small, icy bodies that have highly eccentric orbits around the Sun.Located in Kuiper belt and Oort cloud.Ranging from 1 to 10 km in diameter, most comets orbit in a continuous distribution that extends from the Kuiper belt to 100,000 AU from the Sun. The outermost region is known as the Oort cloud.
22Comets Comet structure Section 28.4Other Solar System ObjectsCometsComet structureWhen a comet comes within 3 AU of the Sun, it begins to evaporate and forms a head and one or more tails. The head is surrounded by an envelope of glowing gas, and it has a small solid core.
23Comets Comet structure Section 28.4Other Solar System ObjectsCometsComet structureA comet’s tail always points away from the Sun and is driven by a stream of particles and radiation.
24Comets Periodic comets Section 28.4Other Solar System ObjectsCometsPeriodic cometsComets that repeatedly return to the inner solar system are known as periodic comets. Each time a periodic comet comes near the Sun, it loses some of its matter, leaving behind a trail of particles.
25Comets Periodic comets Section 28.4Other Solar System ObjectsCometsPeriodic cometsWhen Earth crosses the trail of a comet, particles left in the trail burn in Earth’s upper atmosphere, producing bright streaks of light called a meteor shower.Most meteors are caused by dust particles from comets.
26Section 28.4 Other Solar System Objects Study GuideKey ConceptsSection 28.4 Other Solar System ObjectsRocks, dust, and ice compose the remaining 2 percent of the solar system.Dwarf planets, asteroids, and comets formed from the debris of the solar system formation.Meteoroids are planetesimals that enter Earth’s atmosphere.
27Section 28.4 Other Solar System Objects Study GuideKey ConceptsSection 28.4 Other Solar System ObjectsMostly rock and ice, the Kuiper belt objects are currently being detected and analyzed.Periodic comets are in regular, permanent orbit around the Sun, while others might pass this way only once.The outermost regions of the solar system house the comets in the Oort cloud.
2828Our Solar System28.1 Section QuestionsWhich scientist first observed the moons of Jupiter with a telescope?a. Nicolaus Copernicusb. Tycho Brahec. Isaac Newtond. Galileo Galilei
2928Our Solar System28.1 Section QuestionsWhich observation provided evidence for the heliocentric model of the solar system?a. the nightly motion of the starsb. the rising and setting of the Sunc. the retrograde motion of planetsd. the occurrence of meteor showers
3028Our Solar System28.1 Section QuestionsKepler determined the relationship between a planet’s orbital period (P) and the length of its semimajor axis (a). Which equation correctly represents this relationship?a. P3 = a2b. P2 = a3c. P = a2d. P2 = a
3128 Our Solar System Earth is the only planet known to have life. 28.2 Section QuestionsEarth is the only planet known to have life.a. trueb. false
3228Our Solar System28.2 Section QuestionsWhich inner planet has the highest average surface temperature?a. Mercuryb. Venusc. Earthd. Mars
3328Our Solar System28.2 Section QuestionsWhich hypothesis has been suggested to explain the scarps on Mercury?a. Mercury’s crust shrank and cracked.b. Mercury once had plate tectonics.c. Mercury was eroded by flowing water.d. Mercury’s surface was covered by lava.
3428Our Solar System28.3 Section QuestionsWhich gas gives Uranus and Neptune their blue color?a. hydrogenb. heliumc. methaned. nitrogen
3528 Our Solar System How many of the four gas giant planets have rings? 28.3 Section QuestionsHow many of the four gas giant planets have rings?a. oneb. twoc. threed. four
3628Our Solar System28.3 Section QuestionsWhich elements have the highest abundance in gas giant planets?a. iron and nickelb. hydrogen and heliumc. silicon and oxygend. calcium and magnesium
3728Our Solar System28.4 Section QuestionsWhich solar system object is most abundant in the Oort cloud?a. rocky planetsb. asteroidsc. cometsd. dwarf planets
3828 Our Solar System What causes most meteor showers? 28.4 Section QuestionsWhat causes most meteor showers?a. dust from the paths of cometsb. asteroids breaking up in the atmospherec. pieces from the Moon or Marsd. particles left from the interstellar cloud
3928 Our Solar System Which characteristic must a dwarf planet have? 28.4 Section QuestionsWhich characteristic must a dwarf planet have?a. It must be smaller than Pluto.b. It must be beyond Neptune.c. It must be rocky.d. It must be spherical.
40Chapter Assessment Questions 28Our Solar SystemChapter Assessment QuestionsWhich inner planet has retrograde rotation?a. Mercuryb. Venusc. Earthd. Mars
41Chapter Assessment Questions 28Our Solar SystemChapter Assessment QuestionsSuppose that two objects in space move apart until the distance between them is double. How does the gravitational force between these objects change?a. It decreases by a factor of two.b. It decreases by a factor of four.c. It decreases by a factor of eight.d. It decreases by a factor of ten.
42Chapter Assessment Questions 28Our Solar SystemChapter Assessment QuestionsWhich statement describes the gas giant planets?a. They have a high density.b. They have a thin atmosphere.c. They have a cratered surface.d. They have many moons.
43Chapter Assessment Questions 28Our Solar SystemChapter Assessment QuestionsWhich planet has an axis of rotation that is nearly in its orbital plane?a. Jupiterb. Saturnc. Uranusd. Neptune
44Chapter Assessment Questions 28Our Solar SystemChapter Assessment QuestionsHow do comet tails form?
45Chapter Assessment Questions 28Our Solar SystemChapter Assessment QuestionsPossible answer: As a comet approaches the Sun, ices in the comet vaporize, or turn to gas. Dust is also released as the comet dissipates. Particles and radiation streaming away from the Sun then push the gas and dust away from the Sun. The gas often forms a blue tail that points directly away from the Sun. The dust sometimes forms a separate white tail because it is not pushed as much by the solar particles and radiation.
46Standardized Test Practice 28Our Solar SystemStandardized Test PracticeWho described the behavior of gravity?a. Tycho Braheb. Clyde Tombaughc. Nicolaus Copernicusd. Isaac Newton
47Standardized Test Practice 28Our Solar SystemStandardized Test PracticeWhich characteristic distinguishes Earth from the other inner planets?a. the presence of an atmosphereb. the presence of an iron corec. the presence of volcanoesd. the presence of surface oceans
48Standardized Test Practice 28Our Solar SystemStandardized Test PracticeExamine the illustration. What relationship exists between the areas of the segments of the planet’s orbit?
49Standardized Test Practice 28Our Solar SystemStandardized Test PracticeAnswer: Kepler’s second law states that a planet sweeps out equal amounts of area in equal amounts of time. Therefore, each segment of the planet’s orbital ellipse has the same area.
50Standardized Test Practice 28Our Solar SystemStandardized Test PracticeWhere are most of the asteroids in the solar system?a. between the orbits of Mercury and Venusb. between the orbits of Earth and Marsc. between the orbits of Mars and Jupiterd. between the orbits of Uranus and Neptune
51Standardized Test Practice 28Our Solar SystemStandardized Test PracticeHow is Pluto classified by astronomers?a. as an outer planetb. as a dwarf planetc. as a large cometd. as a small solar system body