DOCSLIB.ORG

Earth Space Science : 08 Our Solar System : 08.04 Objects in Our Solar System

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Earth Space Science : 08 Our Solar System : 08.04 Objects in Our Solar System Earth Space Science : 08 Our Solar System : 08.04 Objects in Our Solar System Objectives What can objects in our solar system tell us about its formation and future? At the end of this lesson, you will be able to: • compare characteristics of inner and outer planets • define the role of “other” solar system objects in our solar system • discuss how knowledge of our own solar system can be applied to future planetary discoveries Objects in Our Solar System My Very Excellent Mother Just Served Us Nine Pizzas Taking the first letter of each word in the above sentence gives the following: M V E M J S U N P This is the order of the planets in our solar system. You can remember the planets using this simple sentence or one like it. • Mercury • Venus • Earth • Mars • Jupiter • Saturn • Uranus • Neptune • Pluto But wait! How did scientists determine the number of planets in the solar system, anyway? What about Pluto? Do scientists still consider it a planet? When Pluto was discovered in 1930, astronomers listed it as the ninth planet in the solar system. In 2005, astronomers detected yet another large body, called Eris, beyond Pluto's orbit. A debate erupted among scientists over the characteristics a heavenly body must have to be considered a planet. To resolve the issue, in 2006, astronomers downgraded Pluto from planet to dwarf planet. (Eris is also a dwarf planet.) Why was there so much debate about how to define a planet? As with any discovery in science, new information leads to new ideas. Use the following activity to investigate the difference between a planet and a dwarf planet. Differences between Planet and Dwarf Planet Interactive Characteristics of planets and dwarf planets: • A planet o is in orbit around the sun o has sufficient mass to assume a nearly round shape o is not a satellite or moon of another object o has enough gravity to clear away smaller objects near its orbit; when a planet interacts with smaller objects, it either consumes them or slings them away with its gravity • A dwarf planet o is in orbit around the sun o has sufficient mass to assume a nearly round shape o is not a satellite or moon of another object o does not have enough gravity to clear away smaller objects near its orbit, so it exists in a zone of other, similarly sized objects The International Astronomical Union changed the definition of a planet so that all astronomers worldwide could classify new objects such as Eris, found beyond Pluto's orbit. However, astronomers today still debate the definition of a planet. In this lesson, you will be reviewing the characteristics of the inner and outer planets in the solar system. You will also investigate other objects in the solar system that orbit the sun. The debate over the definition of a planet illustrates that scientific knowledge constantly changes as scientists discover new evidence and make new observations. Often, scientists must rethink their existing hypotheses and present new ones to better explain the new information. The reclassification of Pluto as a dwarf planet is a good example of how scientists use new information to improve classification systems. In our solar system, astronomers classify planets as inner or outer. Inner and outer planets differ according to the criteria in the table below. Inner Planets Outer Planets Examples Mercury, Venus, Earth, Mars Jupiter, Saturn, Uranus, Neptune Number of Moons Few or no moons Many moons Distance from Sun Closest to the sun Farthest from sun Composition Rocky surfaces Gaseous Presence of Rings No rings Has a ring system Inner Planets Outer Planets Size Smaller size Larger size In the activities below, you will investigate each of the planets. As you investigate each planet, record detailed information in your notes. Keep the following points in mind: • Each of the planets follows an elliptical orbit around the sun. An ellipse has a shape like a flattened circle. The following diagram approximates the orbit of each planet around the sun. Note that some orbits are more elliptical than others. Public Domain • Scientists have investigated some planets more than others. The activities below do not list every mission that has been launched to explore each planet. • There are still poorly understood and undiscovered objects in the solar system. Scientists are constantly discovering new information about the planets and other solar system objects. Inner and Outer Planets Interactive A large, two-tabbed interactive divided into inner and outer planets. Each planet exists as a trading card with a front and back, as previously described The Inner Planets Card 1: Mercury Location: 47–70 million kilometers from the sun. Characteristics: Completes one orbit around the sun every 88 days. Completes one rotation on its axis every 58.65 Earth days. Diameter is 4,880 kilometers. Satellites: None. Surface: Covered with rocky cliffs and valleys with many craters from impacts by other objects during the formation of the solar system. May contain water ice at the North and South Poles. Atmosphere: Because there is virtually no atmosphere on the planet to trap heat, temperatures range from 430 degrees Celsius in the day to −180 degrees Celsius at night, which is the largest day and night temperature differential in the solar system. Interior: Contains a liquid metallic core. Exploration: In 1974 and 1975, the Mariner 10 mission photographed Mercury for the first time. In 2008 and 2009, the Messenger mission studied the planet in even greater detail. Fun Facts: Mercury rotates only three times for every two orbits it completes around the sun. That means Mercury’s year is only slightly longer than its day. Card 2: Venus Location: 108.5–108.9 million kilometers from sun. It has a nearly circular orbit. Characteristics: Completes one orbit every 225 days. Completes one rotation on its axis every 243 days. Diameter is 12,100 kilometers. Satellites: None. Surface: The surface is covered with volcanoes. Temperatures are hot enough to melt lead. Atmosphere: The atmosphere comprises thick clouds of carbon dioxide and sulfuric acid, resulting in a powerful greenhouse effect. The atmosphere moves with winds at speeds of 360 kilometers per hour. Temperatures are a constant 470 degrees Celsius. Interior: Contains an iron core but does not have a magnetic field because of its slow rotation. Exploration: In 1962, the Mariner 2 became the first spacecraft to send back information about Venus, which is the first time humans had explored another planet in the solar system. Beginning in 1990, the Magellan spacecraft photographed 98 percent of the planet’s surface. Fun Facts: Venus is the brightest planet in the night sky. If you could observe sunrise on Venus, the sun would rise in the west and set in the east because Venus rotates in the opposite direction as Earth. Card 3: Earth Location: 146–152 million kilometers from the sun. Characteristics: Completes one orbit around the sun every 365.26 days. Completes one rotation on its axis every 23.93 hours. Diameter is 12,756 kilometers. Satellites: One moon, named the Moon (with a capital M). Surface: Water covers 70 percent of Earth’s surface. The land surfaces are covered by a rocky terrain of mountains, valleys, deserts, and glacial regions. Atmosphere: Atmosphere consists mostly of nitrogen (78 percent) and oxygen (21 percent). Temperatures range from 58 degrees Celsius to −88 degrees Celsius. Interior: Contains a molten metallic core made of nickel and iron. Exploration: Scientists are constantly seeking to understand our home planet with missions to the upper atmosphere and the deepest depths of the ocean. Fun Facts: Earth is tilted on its axis approximately 23.5 degrees from the vertical, which causes changing seasons. Card 4: Mars Location: 205–249 million kilometers from the sun. Characteristics: Completes one orbit around the sun every 687 days. Completes one rotation on its axis every 24.6 hours. Diameter is 6,785 kilometers. Satellites: Two moons, Phobos and Deimos, discovered in 1877. Surface: The rocky surface contains many mountains, canyons, volcanoes, ice, and craters. The surface appears red as a result of iron oxide (better known as rust) in the Martian soil. Atmosphere: The atmosphere is composed of carbon dioxide, nitrogen, and argon. Temperatures range from 20 degrees Celsius to −125 degrees Celsius [Source: NASA] Interior: A layer of water ice is thought to exist just under the surface of Mars. The core is likely to be made of iron. Exploration: The Mars rovers, named Spirit and Opportunity, found evidence that liquid water may have existed on the planet billions of years ago or perhaps more recently. The Phoenix rover landed in 2008 to further investigate the existence of water. It confirmed that liquid water exists in the polar regions. Fun Facts: Olympus Mons, located on Mars, is the largest volcano in the solar system, rising 23 kilometers above the planet’s surface. The darkened line across the equatorial region is the Valles Marineris. The canyon system is more than four times deeper than the Grand Canyon. The Outer Planets Card 5: Jupiter Location: 741–817 million kilometers from the sun. Characteristics: Completes one orbit around the sun every 12 years. Completes one rotation on its axis every 9.9 hours. Diameter is 142,800 kilometers. Satellites: Jupiter has at least 63 known moons. The four largest moons—Io, Europa, Callisto, and Ganymede—are called the Galilean moons after their discovery by Galileo in 1610. There are at least three ring systems around the planet, although these were discovered only recently by the Voyager I spacecraft in 1979. Surface: Beneath the atmosphere, the gases are under so much pressure that they form a liquid.
Load more

Recommended publications
  • Modern Astronomical Optics - Observing Exoplanets 2
    Modern Astronomical Optics - Observing Exoplanets 2. Brief Introduction to Exoplanets Olivier Guyon - [email protected] – Jim Burge, Phil Hinz WEBSITE: www.naoj.org/staff/guyon → Astronomical Optics Course » → Observing Exoplanets (2012) Definitions – types of exoplanets Planet (& exoplanet) definitions are recent, as, prior to discoveries of exoplanets around other stars and dwarf planets in our solar system, there was no need to discuss lower and upper limits of planet masses. Asteroid < dwarf planet < planet < brown dwarf < star Upper limit defined by its mass: < 13 Jupiter mass 1 Jupiter mass = 317 Earth mass = 1/1000 Sun mass Mass limit corresponds to deuterium limit: a planet is not sufficiently massive to start nuclear fusion reactions, of which deuterium burning is the easiest (lowest temperature) Lower limit recently defined (now excludes Pluto) for our solar system: has cleared the neighbourhood around its orbit Distinction between giant planets (massive, large, mostly gas) and rocky planets also applies to exoplanets Habitable planet: planet on which life as we know it (bacteria, planets or animals) could be sustained = rocky + surface temperature suitable for liquid water Formation Planet and stars form (nearly) together, within first few x10 Myr of system formation Gravitational collapse of gas + dust cloud Star is formed at center of disk Planets form in the protoplanetary disk Planet embrios form first Adaptive Optics image of Beta Pic Large embrios (> few Earth mass) can Shows planet + debris disk accrete large quantity of
    [Show full text]
  • JUICE Red Book
    ESA/SRE(2014)1 September 2014 JUICE JUpiter ICy moons Explorer Exploring the emergence of habitable worlds around gas giants Definition Study Report European Space Agency 1 This page left intentionally blank 2 Mission Description Jupiter Icy Moons Explorer Key science goals The emergence of habitable worlds around gas giants Characterise Ganymede, Europa and Callisto as planetary objects and potential habitats Explore the Jupiter system as an archetype for gas giants Payload Ten instruments Laser Altimeter Radio Science Experiment Ice Penetrating Radar Visible-Infrared Hyperspectral Imaging Spectrometer Ultraviolet Imaging Spectrograph Imaging System Magnetometer Particle Package Submillimetre Wave Instrument Radio and Plasma Wave Instrument Overall mission profile 06/2022 - Launch by Ariane-5 ECA + EVEE Cruise 01/2030 - Jupiter orbit insertion Jupiter tour Transfer to Callisto (11 months) Europa phase: 2 Europa and 3 Callisto flybys (1 month) Jupiter High Latitude Phase: 9 Callisto flybys (9 months) Transfer to Ganymede (11 months) 09/2032 – Ganymede orbit insertion Ganymede tour Elliptical and high altitude circular phases (5 months) Low altitude (500 km) circular orbit (4 months) 06/2033 – End of nominal mission Spacecraft 3-axis stabilised Power: solar panels: ~900 W HGA: ~3 m, body fixed X and Ka bands Downlink ≥ 1.4 Gbit/day High Δv capability (2700 m/s) Radiation tolerance: 50 krad at equipment level Dry mass: ~1800 kg Ground TM stations ESTRAC network Key mission drivers Radiation tolerance and technology Power budget and solar arrays challenges Mass budget Responsibilities ESA: manufacturing, launch, operations of the spacecraft and data archiving PI Teams: science payload provision, operations, and data analysis 3 Foreword The JUICE (JUpiter ICy moon Explorer) mission, selected by ESA in May 2012 to be the first large mission within the Cosmic Vision Program 2015–2025, will provide the most comprehensive exploration to date of the Jovian system in all its complexity, with particular emphasis on Ganymede as a planetary body and potential habitat.
    [Show full text]
  • The Solar System Cause Impact Craters
    ASTRONOMY 161 Introduction to Solar System Astronomy Class 12 Solar System Survey Monday, February 5 Key Concepts (1) The terrestrial planets are made primarily of rock and metal. (2) The Jovian planets are made primarily of hydrogen and helium. (3) Moons (a.k.a. satellites) orbit the planets; some moons are large. (4) Asteroids, meteoroids, comets, and Kuiper Belt objects orbit the Sun. (5) Collision between objects in the Solar System cause impact craters. Family portrait of the Solar System: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, (Eris, Ceres, Pluto): My Very Excellent Mother Just Served Us Nine (Extra Cheese Pizzas). The Solar System: List of Ingredients Ingredient Percent of total mass Sun 99.8% Jupiter 0.1% other planets 0.05% everything else 0.05% The Sun dominates the Solar System Jupiter dominates the planets Object Mass Object Mass 1) Sun 330,000 2) Jupiter 320 10) Ganymede 0.025 3) Saturn 95 11) Titan 0.023 4) Neptune 17 12) Callisto 0.018 5) Uranus 15 13) Io 0.015 6) Earth 1.0 14) Moon 0.012 7) Venus 0.82 15) Europa 0.008 8) Mars 0.11 16) Triton 0.004 9) Mercury 0.055 17) Pluto 0.002 A few words about the Sun. The Sun is a large sphere of gas (mostly H, He – hydrogen and helium). The Sun shines because it is hot (T = 5,800 K). The Sun remains hot because it is powered by fusion of hydrogen to helium (H-bomb). (1) The terrestrial planets are made primarily of rock and metal.
    [Show full text]
  • Planetary Rings
    CLBE001-ESS2E November 10, 2006 21:56 100-C 25-C 50-C 75-C C+M 50-C+M C+Y 50-C+Y M+Y 50-M+Y 100-M 25-M 50-M 75-M 100-Y 25-Y 50-Y 75-Y 100-K 25-K 25-19-19 50-K 50-40-40 75-K 75-64-64 Planetary Rings Carolyn C. Porco Space Science Institute Boulder, Colorado Douglas P. Hamilton University of Maryland College Park, Maryland CHAPTER 27 1. Introduction 5. Ring Origins 2. Sources of Information 6. Prospects for the Future 3. Overview of Ring Structure Bibliography 4. Ring Processes 1. Introduction houses, from coalescing under their own gravity into larger bodies. Rings are arranged around planets in strikingly dif- Planetary rings are those strikingly flat and circular ap- ferent ways despite the similar underlying physical pro- pendages embracing all the giant planets in the outer Solar cesses that govern them. Gravitational tugs from satellites System: Jupiter, Saturn, Uranus, and Neptune. Like their account for some of the structure of densely-packed mas- cousins, the spiral galaxies, they are formed of many bod- sive rings [see Solar System Dynamics: Regular and ies, independently orbiting in a central gravitational field. Chaotic Motion], while nongravitational effects, includ- Rings also share many characteristics with, and offer in- ing solar radiation pressure and electromagnetic forces, valuable insights into, flattened systems of gas and collid- dominate the dynamics of the fainter and more diffuse dusty ing debris that ultimately form solar systems. Ring systems rings. Spacecraft flybys of all of the giant planets and, more are accessible laboratories capable of providing clues about recently, orbiters at Jupiter and Saturn, have revolutionized processes important in these circumstellar disks, structures our understanding of planetary rings.
    [Show full text]
  • Oil, Earth Mass and Gravitational Force
    A peer reviewed version is published at: https://doi.org/10.1016/j.scitotenv.2016.01.127 Oil, Earth mass and gravitational force Khaled Moustafa Editor of the Arabic Science Archive (ArabiXiv) E-mail: [email protected] Highlights Large amounts of fossil fuels are extracted annually worldwide. Would the extracted amounts represent any significant percentage of the Earth mass? What would be the consequence on Earth structure and its gravitational force? Modeling the potential loss of Earth mass might be required. Efforts for alternative renewable energy sources should be enhanced. Abstract Fossil fuels are intensively extracted from around the world faster than they are renewed. Regardless of direct and indirect effects of such extractions on climate change and biosphere, another issue relating to Earth’s internal structure and Earth mass should receive at least some interest. According to the Energy Information Administration (EIA), about 34 billion barrels of oil (~4.7 billion metric tons) and 9 billion tons of coal have been extracted in 2014 worldwide. Converting the amounts of oil and coal extracted over the last 3 decades and their respective reserves, intended to be extracted in the future, into mass values suggests that about 355 billion tons, or ~ 5.86*10−9 (~ 0.0000000058) % of the Earth mass, would be ‘lost’. Although this is a tiny percentage, modeling the potential loss of Earth mass may help figuring out a critical threshold of mass loss that should not be exceeded. Here, I briefly discuss whether such loss would have any potential consequences on the Earth’s internal structure and on its gravitational force based on the Newton's law of gravitation that links the attraction force between planets to their respective masses and the distances that separate them.
    [Show full text]
  • Physics 100: Homework 5 Solutions 1) Somewhere Between the Earth
    Physics 100: Homework 5 Solutions 1) Somewhere between the Earth and the moon, the gravitational force on a space shuttle would cancel. Is this location closer to the moon or to the Earth? Explain your answer. The gravitational force on the shuttle due to the moon is proportional to the shuttle’s mass, the moon’s mass, and inversely proportional to the square of the shuttle-moon distance. That due to the Earth is proportional to the shuttle’s mass, the Earth’s mass, and inversely proportional to the square of the shuttle-Earth distance. Since Earth mass >> moon mass, the shuttle must be much closer to the moon in order for the two attractions to cancel. 2) Which is greater, the gravitational pull of the moon on the Earth or that of the sun on the Earth? Which has a greater effect on our ocean tides, the sun or the moon? Explain your answers. The gravitational pull of the Sun on the Earth is greater than the gravitational pull of the Moon, about 180 times as large due its much greater mass, as explained in class. The tides, however, are caused by the differences in gravitational forces by the Moon on opposite sides of the Earth. The difference in gravitational forces by the Moon on opposite sides of the Earth is greater than the corresponding 2 difference in forces by the stronger pulling but much more distant Sun. The difference, 1/(d+Dearth) – 2 1/d , where Dearth is the diameter of Earth, is greater for the moon (smaller d) than it is for the sun (larger d), which is the math-way of saying what we said in class about the inverse-law flattening out… 3 a) A particular atom contains 47 electrons, 61 neutrons, and 47 protons.
    [Show full text]
  • Planetary Ring Dynamics - Matthew Hedman
    CELESTIAL MECHANICS - Planetary Ring Dynamics - Matthew Hedman PLANETARY RING DYNAMICS Matthew Hedman University of Idaho, Moscow ID, U.S.A. Keywords: celestial mechanics, disks, dust, orbits, perturbations, planets, resonances, rings, solar system dynamics Contents 1. Introduction to Planetary Ring Systems 2. Orbital Perturbations on Individual Ring Particles 3. Inter-particle Interactions 4. External Perturbations on Dense Rings 5. Conclusions Acknowledgements Glossary Bibliography Biographical Sketch Summary Planetary rings provide a natural laboratory for investigating dynamical phenomena. Thanks to their proximity to Earth, the rings surrounding the giant planets can be studied at high resolution and in great detail. Indeed, Earth-based observations and spacecraft missions have documented a diverse array of structures in planetary rings produced by both inter-particle interactions and various external perturbations. These features provide numerous opportunities to examine the detailed dynamics of particle- rich disks, and can potentially provide insights into other astrophysical disk systems like galaxies and proto-planetary disks. This chapter provides a heuristic introduction to the dynamics of the known planetary rings. We begin by reviewing the basic architecture of the four known ring systems surrounding the giant planets. Then we turn our attention to the types of dynamical phenomena observed in the various rings. First, we consider how different forces can modify the orbital properties of individual ring particles. Next, we investigate the patterns and textures generated within a ring by the interactions among the ring particles. Finally, we discuss how these two types of processes can interact to produce structures in dense planetary rings. 1. Introduction to Planetary Ring Systems Ring systems surround all four of the giant planets in the outer solar system.
    [Show full text]
  • Scientific Goals for Exploration of the Outer Solar System
    Scientific Goals for Exploration of the Outer Solar System Explore Outer Planet Systems and Ocean Worlds OPAG Report v. 28 August 2019 This is a living document and new revisions will be posted with the appropriate date stamp. Outline August 2019 Letter of Response to Dr. Glaze Request for Pre Decadal Big Questions............i, ii EXECUTIVE SUMMARY ......................................................................................................... 3 1.0 INTRODUCTION ................................................................................................................ 4 1.1 The Outer Solar System in Vision and Voyages ................................................................ 5 1.2 New Emphasis since the Decadal Survey: Exploring Ocean Worlds .................................. 8 2.0 GIANT PLANETS ............................................................................................................... 9 2.1 Jupiter and Saturn ........................................................................................................... 11 2.2 Uranus and Neptune ……………………………………………………………………… 15 3.0 GIANT PLANET MAGNETOSPHERES ........................................................................... 18 4.0 GIANT PLANET RING SYSTEMS ................................................................................... 22 5.0 GIANT PLANETS’ MOONS ............................................................................................. 25 5.1 Pristine/Primitive (Less Evolved?) Satellites’ Objectives ...............................................
    [Show full text]
  • Origin and Evolution of Saturn's Ring System
    Origin and Evolution of Saturn’s Ring System Chapter 17 of the book “Saturn After Cassini-Huygens” Saturn from Cassini-Huygens, Dougherty, M.K.; Esposito, L.W.; Krimigis, S.M. (Ed.) (2009) 537-575 Sébastien CHARNOZ * Université Paris Diderot/CEA/CNRS Paris, France Luke DONES Southwest Research Institute Colorado, USA Larry W. ESPOSITO University of Colorado Colorado, USA Paul R. ESTRADA SETI Institute California, USA Matthew M. HEDMAN Cornell University New York, USA (*): to whom correspondence should be addressed : [email protected] 1 ABSTRACT: The origin and long-term evolution of Saturn’s rings is still an unsolved problem in modern planetary science. In this chapter we review the current state of our knowledge on this long- standing question for the main rings (A, Cassini Division, B, C), the F Ring, and the diffuse rings (E and G). During the Voyager era, models of evolutionary processes affecting the rings on long time scales (erosion, viscous spreading, accretion, ballistic transport, etc.) had suggested that Saturn’s rings are not older than 10 8 years. In addition, Saturn’s large system of diffuse rings has been thought to be the result of material loss from one or more of Saturn’s satellites. In the Cassini era, high spatial and spectral resolution data have allowed progress to be made on some of these questions. Discoveries such as the “propellers” in the A ring, the shape of ring-embedded moonlets, the clumps in the F Ring, and Enceladus’ plume provide new constraints on evolutionary processes in Saturn’s rings. At the same time, advances in numerical simulations over the last 20 years have opened the way to realistic models of the rings’ fine scale structure, and progress in our understanding of the formation of the Solar System provides a better-defined historical context in which to understand ring formation.
    [Show full text]
  • Gravity on Earth
    National Grade Level Science 9-12 Foundation GRAVITY ON EARTH Did you know that your weight is different This slice of the Earth’s surface shows a mountain, an ocean, and the depending on where you are on the surface atmosphere. Section A is two thirds rock and one third air while Section of the Earth? While the Earth has an average B is one quarter rock, one quarter water, and one half air. The sections gravitational force, different locations on are the same size but Section A has more mass in the space so it has a Earth have gravitational forces that are larger stronger gravitational pull. or smaller than average. This is because each location has more or less mass than the average. Density of: A B Gravity is a physical force of attraction between Air objects. Objects with a small mass have a weak gravitational force while those with a large mass have a strong force. Water You are held down to the Earth’s surface because it has a strong gravitational force. You Rock actually exert a gravitational force on the Earth, but because your mass is many times smaller than the Earth’s mass, your pull is much less than the Earth’s. These differences in gravity are tiny so scientists have to use very sensitive satellites to measure differences around the world. These satellites can Gravity is measured as how fast objects even detect dense features deep within the earth that increase the accelerate towards each other. The average gravitational pull at the surface.
    [Show full text]
  • Moons and Rings
    The Rings of Saturn 5.1 Saturn, the most beautiful planet in our solar system, is famous for its dazzling rings. Shown in the figure above, these rings extend far into space and engulf many of Saturn’s moons. The brightest rings, visible from Earth in a small telescope, include the D, C and B rings, Cassini’s Division, and the A ring. Just outside the A ring is the narrow F ring, shepherded by tiny moons, Pandora and Prometheus. Beyond that are two much fainter rings named G and E. Saturn's diffuse E ring is the largest planetary ring in our solar system, extending from Mimas' orbit to Titan's orbit, about 1 million kilometers (621,370 miles). The particles in Saturn's rings are composed primarily of water ice and range in size from microns to tens of meters. The rings show a tremendous amount of structure on all scales. Some of this structure is related to gravitational interactions with Saturn's many moons, but much of it remains unexplained. One moonlet, Pan, actually orbits inside the A ring in a 330-kilometer-wide (200-mile) gap called the Encke Gap. The main rings (A, B and C) are less than 100 meters (300 feet) thick in most places. The main rings are much younger than the age of the solar system, perhaps only a few hundred million years old. They may have formed from the breakup of one of Saturn's moons or from a comet or meteor that was torn apart by Saturn's gravity.
    [Show full text]
  • Voyage Into Planet Earth Booklet
    VOYAGE INTO PLANET EARTH DO YOU EVER WONDER what’s beneath your feet? how deep does the Earth go, and what would you find? Scientists know more about Understanding the planet is certain distant galaxies than challenging because it changes they do about what lies miles all the time. beneath your feet. Throughout Earth’s history, these Scientists have explored many changes have resulted in the areas of the Earth’s crust, but formation of distinctive layers. that just scratches the surface in understanding the planet. The Earth has four layers, which are stacked like the layers on It may seem like the Earth an onion. As you peel back the is made up of one big, solid layers, you find the crust, mantle, rock. It’s really made up of outer core, and inner core. You a number of parts, some are can only see the top layer, the constantly moving! crust, which sustains life—plants, animals, and people! on a voyage into planet LET’S Earth—from the crust into the GO inner core—and explore each layer. what’s beneath your feet? how deep does the Earth go, and what would you find? As you move through the Earth’s layers from the crust to the core, the planet gets hotter. The red, yellow, and orange indicate changes in temperature. The first stop on our journey is the crust. It is the relatively thin, THE rocky outer skin that you stand on top of every day. Scientists have spent EARTH’S a lot of time studying the outer crust of the planet.
    [Show full text]