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Arthur RossHall of Meteorites

Come PreparedThe ExhibitionThe Arthur Ross Hall of Meteorites draws on the latest research and cutting-edge technology to present a comprehensive look at meteorites. To provide focus for your visit, the “Key Concepts and Orientation” section of this guide correlates the content in the exhibition to three areas of the science curriculum: Earth and planetary science, chemistry, and physical science.

An Advanced Look at the ExhibitionWe encourage you to visit the exhibition prior to coming with your class, so that you can familiarize yourself with the information presented in the Hall, its layout, and the specimens on display. You may also want to visit the Arthur Ross Hall of Meteorites Web site, for a comprehensive overview of the exhibition: www.amnh.org/ exhibitions/ permanent/ meteorites/

Teaching in the ExhibitionUse the tour described in the “Teaching in the Exhibition” section and the activities presented in other sections of this guide to plan your visit. Prepare students for their visit by presenting one or two of the activities in the “Before Your Visit” section. You can choose to conduct a tour of the Hall or you can have students explore the Hall independently. Duplicate the map of the exhibition for students. Have them choose an activity from the “While You’re at the Museum” section. Suggest they bring clipboards, drawing paper, and a pencil with them to sketch samples and take notes. Students may also wish to bring a magnet or compass.

As an informal learning environment, the Museum offers many opportuni-ties for self-directed learning. In visiting this exhibition and related halls, students will be exposed to, and inspired by, wonderful artifacts and specimens supported by a range of media. Build flexibility into your plans to allow students to follow their interests. You can customize and adapt the tour and activities to fit the needs and abilities of your students.

Educator’s Guide

© 2003 American Museum of Natural History. All rights reserved.

Members of the Antarctica meteorite expedition examine a specimen. © Nancy Chabot

This photo of the Peekskill meteorite was captured as it headed towards Earth. © NASA, 1992

Arthur Ross Hall of Meteorites: Educator’s Guide

Orientation and Key ConceptsOrientationWhen our solar system began to take shape some 4.6 billion years ago, the Sun and planets, as we know them today, did not exist. Back then a large cloud of gas and dust known as the solar nebula swirled around the developing Sun. Within this swirling cloud, countless small objects collided and stuck together, gradu-ally forming larger and larger bodies such as asteroids and planets. Meteorites are the “leftovers”—remnants of asteroids, asteroids, and possibly even comets—and they hold clues to the earliest events in the birth of our solar system.

The Arthur Ross Hall of Meteorites explores the origins of meteor-ites, their journey through space, their fall to Earth, their recovery, and the wealth of information they hold for scientists. The exhibition is organized around a central Introductory area surrounded by three theme areas: Origins, Planets, and Impacts. The science in the Hall is presented as a web so visitors can begin their tour in any one of the four areas.

Key ConceptsThe exhibition provides an opportunity for students at all grade levels to learn about meteorites. Specific parts of the Hall address key concepts in the areas of Earth and planetary science, chemistry, and physical science.

Earth and Planetary ScienceMeteorites tell the story of the formation of the solar system and the planets.

• Our solar system formed from an initial cloud of gas and dust that scientists refer to as the solar nebula. Within this cloud, condensation occurred, creating small particles. Planets and asteroids in our early solar system formed from these particles through the processes of accretion and differentiation.

• Meteorites are made of many components, reflecting the wide range of materials and diverse physical and chemical environments present in the early solar system. They hold clues to the formation of stars, including our Sun.

• Most meteorites are older than Earth rocks, and except for rocks collected from the Moon, are the only samples we have of other worlds, such as Mars, asteroids, and possibly comets.

• Asteroids are not distributed randomly throughout the solar sys-tem, but mainly reside in the asteroid belt between the planets of Mars and Jupiter.

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The annual Leonids meteor shower occurs in mid Novem-ber © NASA, 1966

An artist’s rendering of a solar nebula. © NASA JSC, Don Dixon.


ChemistryMeteorites tell the story of the composition of the solar system and even of the galaxy beyond.

• Many “primitive” meteorites have remained essentially unchanged since the formation of the solar system and contain the oldest materials scientists can study.

• Many primitive meteorites contain chondrules (glassy beads) and CAIs (calcium-aluminum inclusions). Both CAIs and chondrules condensed, melted, and cooled before being bound together by a matrix made up of fine-grained dust particles. Scientists have shown that some of these particles predate the formation of our solar system. the asteroid belt.

• The compositions of meteorites and planets suggest that the chemical elements may not have been evenly distributed in the early solar nebula. The chemical makeup of planets and parent bodies relates to their distance from the Sun.

Physical ScienceMeteorites tell the story of gravitational interactions, collisions, and impacts.

• Countless impacts continue to shape the Earth and other planetary bodies in our dynamic solar system. Impacts have different effects depending on the meteorite’s size, composition, and angle of impact and whether or not the planet has an atmosphere.

• The craters on the Moon serve as a historical record of meteoritic impacts. Although terrestrial impacts create a similar historical record, most of the Earth’s craters have been erased by plate tectonics. The Moon still shows impacts that are billions of years old.

• Asteroids can change their path through the solar system. A collision between two asteroids followed by a tug from Jupiter’s gravity, may shift an asteroid into a new orbit that crosses paths with the Earth.

• In the past, asteroid impacts have caused dramatic changes on the Earth, including impact structures, climatic shifts, and at least one mass extinction.


Chondrules were among the first substances to form in the early solar nebula. © NASA JSC, Allan Treiman.

Moon craters as seen from Apollo 11. © NASA JSC, Apollo 11



Before Your VisitChoose from among these activities to prepare students for their visit.

Introduce Meteorites• Introduce meteorites to your students by discussing what they know about the subject. Pose the following

questions: What are shooting stars? What are asteroids, meteors, and meteorites? How are they alike and different? What value might meteorites have? What would you like to know about meteorites?

Differentiation• The concept of density is key to understanding how the solar system changes and why planets differentiate.

The following activity introduces students to this fundamental concept. Test the density of different objects by comparing them with the density of water. Pour corn syrup into a large clear empty container until it is 1/4 full. Slowly pour the same amount of vegetable oil into the container. Do the same with water. Watch how the three separate into layers. The water “floats” between the oil and the syrup. The water is denser than the oil, but less dense than the syrup. Drop various objects (grape, raisin, marble) into the container and watch where they settle. Infer the density of each object relative to the other objects in the container. Quantify your density scale by using a balance, graduated beakers, and the formula: density = mass/volume.

Characteristics• At the Museum, students will have the opportunity and the chal-

lenge of making close and detailed observations of meteorites. One activity to help develop these skills is to have students observe, sketch, and describe different kinds of rocks. Suggest students focus on the texture, density, color, and any components the sample might contain. For a fun approach, first try this activity with cross-sections of a variety of candy bars.

Key Words• Review the vocabulary highlighted in bold. (Glossary)

Note• Suggest students bring a magnet or compass with them to the Museum.

The Esquel meteorite is thought to have come from the core-mantle boundary of a large asteroid. © AMNH, Jackie Beckett

Teaching in the ExhibitionBelow is a suggested tour that you and your students might take through the Arthur Ross Hall of Meteorites. Questions and activities are provided for each area to help your students gain an understanding of the main concepts as they move through the exhibition. In addition, some areas of the Hall lend themselves to particular subjects of science. The Origins section explores the chemistry of meteorites. The Planets section would be of interest to students of Earth and planetary science. The Impact section presents evidence and theories that relate to the physical science of orbiting and colliding bodies. Additional activities, designed for your students to use independently or in small groups, can be found in the “While You’re at the Museum” section of this guide.


The Meteorite TheaterAs an introduction to your visit, you and your students may enjoy viewing the short film. The film presents the role of meteorites and their connection to the history of our solar system. It provides a solid foundation for understanding the concepts presented in the exhibition.

The Center AreaThe centerpiece of the exhibition is the 34-ton meteorite Ahnighito (ah-nah-GHEE-toh)—part of the Cape York (Greenland) meteorite. In this introductory area, touch-able specimens and simple text explain the differences among stony, iron, and stony-iron meteorites; the difference between falls and finds; and the surface features of meteorites. Two other pieces of the Cape York meteorite, the Woman and the Dog, are also displayed.

• Encourage your students to examine the touchable meteorites and compare them. Students might use their magnets as tools to identify the iron meteorites.

• Invite students to compare Ahnighito with the Dog and the Woman. Point out that all three are pieces of the Cape York meteorite. Indicate that the Dog and the Woman are smooth, while Ahnighito has a rough surface. Ask students to find out why.

OriginsThis area examines the origin of our solar system and the formation of meteorites in the solar nebula. The component particles of meteorites are highlighted and organized according to their different chemical characteristics.

Featured Specimen: Three pieces of the Allende meteorite, which fell in rural Mexico in 1969. This unusual meteorite, and ones like it, contains the oldest known material formed in the solar system.

• Have students examine the thin section of Allende, identify the component particles, and read the text that explains how the chemical composition of the meteorite provides information about the formation and early evolution of the solar system.

• The next three cases highlight chondrules, CAIs, and matrix, the “stuff” primitive meteorites are made of. Have students note how each of these components formed in the solar nebula. Of particular interest is how scientists determine the age of CAIs.

• Direct students to the section on parent bodies and have them locate the pieces of the Kunashak (koo-nah-SHAK), Kyushu (kee-EW-shu), and Suizhou (SHOO-zoo) meteorites. Ask students to explore how scientists

determined that these three meteorites came from the same parent body. • The Solar System: From Hot to Cold high-

lights the uneven distribution of elements in the early solar nebula. Have students compare the chemical makeup of planets closest to the Sun with the chemical make-up of the outer planets. Ask: How does the chemical makeup of a meteorite relate to its distance from the Sun?


All three specimens of the Cape York Meteorite. © AMNH, Denis Finnin

The Orion Nebula photographed by the Hubble Telescope.© NASA, C.R. O’Dell

Origins of the Solar System © AMNH


PlanetsThis area examines the formation of the early solar system 4.6 billion years ago. Many of the meteorite specimens in this section can be used to illustrate the process of differentiation in planets.

Featured Specimen: Fragments of the Brenham meteorite. The Brenham meteorite is an example of a stony-iron pallasite meteorite and contains fragments of gemlike olivine crystals embedded in an iron-nickel alloy. Billions of years ago, this meteorite formed when a large asteroid melted, and density differences caused it to separate into an inner iron core, a mantle, and a rocky crust. The Brenham meteorite came from within the deep interior of this asteroid.

• In the three cases that follow—Crust, Mantle, and Core—students learn how planets differentiate to form a core, a mantle and a crust. Ask: What causes a planetary body to differentiate, and how does this relate to the planet Earth?

• Rare and beautiful pallasite meteorites, with combinations of gleaming metal and translucent olivine crystals, are highlighted in the Mantle case. Have students examine the pallasites. Point out that scientists have yet to find a meteorite that they can prove came from the mantle of an asteroid. Have students read the theories associated with this puzzle and decide which one makes the most sense to them.

• In the next case, students can see iron meteorites that display the Wid-manstätten pattern. Have students note how the pattern forms. Ask: How do scientists know that metal displaying this pattern is definitely from a meteorite?

• In the case that follows, students can learn about the asteroid belt between Jupiter and Mars, and view specimens from Vesta, an asteroid that “lives” in the belt. Ask: How did these meteorites get to Earth? How are scientists able to match each meteorite sample to a different part of Vesta’s surface?

• Martian meteorites are on display in the next case. Have students com-pare them to other meteorites in the Hall. Point out that, unlike Martian meteorites, most meteorites are pieces of asteroids. Have students explore how the meteorites from Mars reached the Earth and how scientists know they are from Mars.


A panoramic landscape of Mars as seen from Mars Pathfinder. © NASA AMES

The Mantle Case features pallasite meteorites. © AMNH, Denis Finnin


ImpactsThis area explores the influence of impacts on the Earth’s history; the probability of impacts of different sizes; the number and sizes of mete-orites; and our present knowledge of the asteroids, comets, and space dust that cross the Earth’s path.

Featured Specimen: A fragment of the meteorite Sikhote-Alin (ci-KO-tay ah-LEEN), which fell in Siberia in 1947. The 100-ton iron meteorite exploded at an altitude of about 15,000 feet and shattered into thousands of fragments, which uprooted trees and dug hundreds of craters in the frozen taiga.

• Encourage students to examine the specimen of Sikhote-Alin. Have them note the fingerprint-like impressions on its surface and the twisted shape caused by the intense explosion. Ask: Why are large meteorite samples found in small craters and small meteorite fragments found in large craters?

• Students can explore craters in the Earth Impacts case. Of particular interest are the tektites and the shatter cone patterns. Have students examine how tektites and shatter cone patterns are formed. Suggest students investigate the interactive computer station: Hazards: Impacts in Our Future.

• A model of the 1,200-meter-wide Meteor Crater (Arizona), also known as Barringer Crater, is displayed in the next case along with two fragments of the Canyon Diablo meteorite that created it. Have students note how the impact formed the crater.

• Suggest students explore the Moon display along the railing. Here students can learn about the current theory of moon formation and can explore crater formation. Have students compare the Moon rocks on display. Ask them if they can identify which part of the Moon the rocks came from. Point out that the white anorthosite is from the lunar highlands, the part of the moon that looks white or bright-colored to us from the Earth; the black basalt is from the lunar mare—areas of the moon that appear dark to us from the Earth.


A model of Meteor Crater, Arizona. © AMNH

Rare specimens of moon rocks. © AMNH



While You’re at the MuseumThe following activities can be conducted by your students independently or in small groups.

Investigate• During your tour of the exhibition, look for the answers

to the questions you formulated before coming to the Museum. Use your magnet to determine which meteorites are made of iron. If you’ve brought a compass, stand far away from Ahnighito and note where the compass needle points. Walk slowly towards the meteorite. What happens? Why?

Explore• As you tour the exhibition, find specimens from the Moon,

an asteroid, a planet, and a comet. Sketch each sample and write three to four sentences describing it.outer planets. Ask: How does the chemical makeup of a meteorite relate to its distance from the Sun?

Locate• Obtain a map of the exhibition from your teacher. Locate the six specimens highlighted on the map.

Sketch and describe each specimen. Identify which meteorites are stony, iron, or stony-iron. Explain why the specimen was placed where it is and how it helps tell the story of the exhibition.

Find Evidence• Scientists hypothesize that all the planets of

the inner solar system have an iron core, a silicate mantle, and a stony crust. How do meteorites support this hypothesis? Find evidence in the exhibition and, based on your research, write a paragraph outlining your findings.

Support a Theory• What evidence presented in the exhibition supports the theory that the Moon was formed by the collision of

a small planet with the Earth? Create a storyboard that shows the Moon’s creation. Include a time line and captions describing each step.

Ahnighito Meteorite © AMNH, Denis Finnin

Widmanstatten pattern © AMNH, Jackie Beckett


Connections to Other ExhibitsOther exhibits in the Museum provide opportunities for students to reinforce, enrich, and extend their exploration of meteorites and their connections to the origin of the universe, planetary formation, and evolution.

Rose Center for Earth and SpaceCullman Hall of the UniverseThis permanent exhibition hall on the lower level of the Rose Center illuminates the stunning discoveries of modern astrophysics. Here students can examine such questions as how the universe evolved into galaxies, stars, and planets and how the atoms from which we are made were created in the hearts of stars. The hall provides hands-on interactive exhibits. The display “Impacts and Cratering” features the 15-ton Willamette meteorite.

Hayden PlanetariumOn the top level of the Hayden Sphere students can view a show in the Space Theater. Using advanced visual technology, the space shows provide realistic, sophisticated, and exciting journeys through the cosmos. The bottom level of the Hayden Sphere houses the Big Bang Theater, where students can explore the beginning of time and space by experiencing a dramatic, multi-sensory re-creation of the first moments of the universe.

Heilbrunn Cosmic PathwayUsing a range of media, text, graphic panels, and samples, this gently sloping 360-foot-long walkway explores the 13 billion years of cosmic evolution.

Scales of the UniverseThis walkway, on the second level of the Rose Center, illustrates the vast range of size in the universe, from the enormous expanse of our observable universe to the smallest subatomic particles. Through text panels, interactive computer stations, and models, the exhibit introduces students to the relative sizes of galaxies, stars, planets, and atoms.

The Gottesman Hall of Plant EarthIn the exhibit “How has Earth evolved?” students can explore the early events in the Earth’s 4.6-billion-year history. The exhibit illustrates the evolution of Earth from when the planet took shape around a molten iron core to the earliest signs of life. Also presented is evidence of the evolution of the Earth’s atmosphere, as seen in a 2.4-billion-year-old specimen of a banded iron formation from Ontario, Canada. A display featuring meteorites can also be found in this hall.

The Dinosaur HallsA cross-section of rock containing the 65-million-year-old asteroid impact ejecta layer is displayed between the Hall of Ornithischian Dinosaurs and the Hall of Primitive Mammals. Here students can further explore the widely held theory that an asteroid impact 65 million years ago led to the extinction of the dinosaurs and other animals.

The Harry Frank Guggenheim Hall of MineralsThe minerals in this hall are systematically arranged according to their chemical properties. Students can examine minerals composed of a single element, such as gold and copper, and groups that combine several elements, such as silicates. A meteorite is displayed to the left as you enter the hall.


The Willamette Meteorite © AMNH, Denis Finnin


Map of the Hall



Back in the ClassroomExtend students’ understanding by conducting one or more of the following activities.

Follow-Up Discussion• Hold a debriefing session in which students share their impressions of the exhibition, their results from their

investigations, and the answers they found to the questions they had. Suggest that students use Internet resources to investigate any additional questions. (Refer to the resources section for suggested Web sites.)

Impacts and Cratering• Students can create impact craters by varying the velocity or

mass of a dropped object, and observing and measuring its ef-fects. Place a large shallow baking pan or box on the floor. Fill with 2 inches of flour. Sprinkle a thin layer of cocoa powder over the surface. Drop a marble straight into the pan near the cen-ter. Remove the marble and have students examine the crater that was formed and the material that was ejected. Then drop a golf ball and a Superball in different parts of pan from the same height as the marble. Have students compare the craters that result. Fill over the holes and cover with more cocoa if needed. Have students explore cratering by varying the angle and veloc-ity of the balls. Point out that impact craters are formed by the kinetic energy that is released when a moving mass (ball) hits a stationary body (pan). The formula for determining kinetic energy (K) is half the mass (M) of an object times the velocity (v) squared: K=Mv2. The formula for the velocity of the dropped objects is: v = √2gh, where g is gravity and h is the height from which the object was dropped. For the Earth, gravity is constant at 980cm/sec2. Have students calculate the mass of the balls and the kinetic energy that is released when each is dropped.

Heading Off Impacts• Pose this hypothetical scenario to students: An asteroid (2 km in

diameter) is headed to the Earth and will most likely strike the planet in 10 years. You and your team have been asked to prepare a plan to deflect the asteroid. Since the hit would cause immense catas-trophe, you have unlimited funds. Have students work in teams to prepare their plans and present them to the class. The class can discusse the merits of each plan and can vote to select the best plan. Students can visit the Nasa Web site Asteroid and Impact Hazards (http://impact.arc.nasa.gov/index.html) to learn what steps are being taken to deter asteroid impacts.


This photo of the asteroid Eros was taken by the NEAR space-craft. © NASA NEAR

An artist’s rendering of what might occur when a massive asteroid hits the Earth. © NASA, Don Davis


Correlation of Performance Standards to the Hall of Meteorites (New York City, New York State)

Middle School

New York City Standards

Physical Science ConceptsS1a demonstrate understanding of properties and changes of properties in matter S1b demonstrate understanding of motion and forcesS1c demonstrate understanding of transfer of energy

Earth and Space Science ConceptsS3a demonstrate understanding of the Earth system S3b demonstrate understanding of Earth’s historyS3c demonstrate understanding of Earth in the solar system, such as the predictable motion of planets, moons, and other solar systems

Scientific Thinking, Tools and Technology, Communication, and Investigation

Scientific ThinkingS5a. Frame questions to distinguish cause and effect; and identifies or controls variables in experimental and non-experimental research settings S5b. Use concepts from Science Standards 1-4 to explain a variety of observations and phenomena S5c. Use evidence from reliable sources to develop descriptions, explanations, and models S5d. Propose, recognize, analyze, consider, and critique alternative explanations; and distinguish between fact and opinion S5e. Identify problems; proposes and implements solutions; and evaluate the accuracy, design, and outcomes of investigations S5f. Works individually and in teams to collect and share information and ideas Scientific Tools and TechnologiesS6a. Use technology and tools to observe and measure objects, organisms and phenomena S6b. Record and store data using a variety of formats S6c. Collect and analyze data using concepts and techniques in Mathematics Standard 4 S6d. Acquire information from multiple sources S6e. Recognize sources of bias in data

Scientific Communication S7a. Represent data and results in multiple ways S7b. Argue from evidence S7c. Critique published materials S7d. Explain a scientific concept or procedure to other students S7e. Communicate in a form suited to the purpose and the audience



Scientific Investigation S8a. Controlled experiment S8b. Fieldwork S8c. Design S8d. Explain a scientific concept or procedure to other students S8e. Secondary research

New York State Learning Standards for Math, Science, & Technology

Standard 1 Analysis, Inquiry, and Design/Scientific Inquiry1. Develop explanations of natural phenomena2. Test proposed explanations using conventional techniques and procedures3. Analyze observations

Standard 2 Information Systems1. Use information technology to retrieve, process, and communicate

Standard 4 Science: Physical Setting1. Use principles of relative motion and perspective to describe Earth and celestial phenomena2. Observe and describe properties of materials and distinguish between chemical and physical changes 3. Observe and describe energy changes as related to chemical reactions.4. Describe how energy and matter interact through forces that result in changes in motion

High School

New York City Standards

Physical Science ConceptsS1a demonstrate understanding of structure of atoms S1b demonstrate understanding of structure and properties of matter S1c demonstrate understanding of chemical reactions S1d demonstrate understanding of motions and forces S1e demonstrate understanding of conservation of energy and increase in disorder S1f demonstrate understanding of interactions of energy and matter

Earth and Space Science Concepts S3a demonstrate an understanding of energy in the Earth system S3b demonstrate understanding of geochemical cycles S3c demonstrate understanding of origin and evolution of the Earth system S3d demonstrate understanding of origin and evolution of the universe

Scientific Thinking S5a. Frame questions to distinguish cause and effect; and identifies or controls variables in experimental and non-experimental research settings. S5b. Use concepts from Science Standards 1-4 to explain a variety of observations and phenomena.



S5c. Use evidence from reliable sources to develop descriptions, explanations, and models; and makes appro-priate adjustments and improvements based on additional data or logical arguments. S5d. Propose, recognize, analyze, consider, and critique alternative explanations; and distinguish between fact and opinion. S5e. Identify problems; propose and implement solutions; and evaluate the accuracy, design, and outcomes of investigations. S5f. Work individually and in teams to collect and share information and ideas.

Scientific Tools and Technologies S6a. Use technology and tools to observe and measure objects, organisms and phenomena S6b. Record and store data using a variety of formats S6c. Collect and analyze data using concepts and techniques in Mathematics Standard 4 S6d. Acquire information from multiple sources S6e. Recognize sources of bias in data, such as observer and sampling biases.

Scientific Communication S7a. Represent data and results in multiple waysS7b. Argue from evidence, such as data produced through his or her own experimentation or by others.S7c. Critique published materials, such as popular magazines and academic journals.S7d. Explain a scientific concept or procedure to other studentsS7e. Communicate in a form suited to the purpose and the audience

Scientific Investigation S8a. Controlled experiment S8b. Fieldwork S8c. Design S8d. Explain a scientific concept or procedure to other students S8e. Secondary research

New York State Learning Standards for Math, Science, & Technology

Standard 1 Analysis, Inquiry, and Design/Scientific Inquiry1. Develop explanations of natural phenomena2. Test proposed explanations using conventional techniques and procedures3. Analyze observations

Standard 2 Information Systems1. Use information technology to retrieve, process, and communicate

Standard 4 Science: Physical Setting1. Use principles of relative motion and perspective to describe Earth and celestial phenomena2. Observe and describe transmissions of various forms of energy3. Describe how energy and matter interact through forces that result in changes in motion



Glossaryaccretion: The accumulation of material, under the influence of gravity, to form a galaxy, star, planet, or moon.achondrite: A stony meteorite without chondrules.anorthosite: An igneous rock made up almost entirely of plagioclase feldspar.asteroid: A small rocky or metallic body that orbits a star.asteroid belt: The region of the solar system where most of the asteroids orbit. It lies between the orbits of Mars and Jupiter.astronomy: The scientific study of the universe.astrophysics: The branch of astronomy that deals with the physics of astronomical objects and phenomena.atmosphere: The gaseous envelope surrounding a star, planet, or satellite and bound to it by gravity.

basalt: A fine-grained, dark-colored igneous rock composed primarily of plagioclase feldspar and pyroxene; other minerals, such as olivine and opaques, are usually present.bleb: A small, usually rounded inclusion of one material in another.

calcium-aluminum inclusions (abbreviated CAIs): Small rocks composed of calcium and aluminum, the first to condense in our solar system. chondrite: A stony meteorite containing chondrules imbedded in a fine-grained matrix of pyroxene, olivine, and nickel-iron.chondrule: A small, rounded body found embedded in certain meteorites that formed when clumps of dust grains drifting in the solar nebula melted and solidified rapidly, forming small crystals. comet: A small solar system body made of ice and dust that moves in an elliptical orbit around the Sun. A typical comet has a solid nucleus a few kilometers in diameter. When it nears the inner solar system, the ices evaporate and form an extended and diffuse atmosphere that is blown away from the Sun by the solar wind and radiation pressure to form a prominent tail of gas and dust.condensation: The formation of a liquid or solid from the gaseous state.core: The central region of a planet or moon, frequently made of different materials from the surrounding regions (mantle and crust); the Earth is thought to have a core of metallic iron and nickel.crater: A bowl-shaped depression on a planet or moon created from above by the impact of an extraterrestrial body or from below by a volcanic eruption.crust: The outermost solid layer of the Earth or of similar bodies.

density: The amount of matter in a prescribed volume of material.differentiation: The chemical zonation caused by differences in the densities of minerals; dense materials sink, less dense materials float.

ejecta: Material thrown out from and deposited around an impact crater.element: A substance composed of atoms having the same number of protons in each nucleus.extraterrestrial: Located or originating outside the Earth and its atmosphere.

fall: The designation given to a meteorite that was observed as it came through the Earth’s atmosphere and that was retrieved soon afterward.find: The designation given to a meteorite that was found, but not observed to fall.fusion crust: The dark glassy coating on the surface of a meteorite, caused by heating as the meteorite entered the atmosphere.



fall: The designation given to a meteorite that was observed as it came through the Earth’s atmosphere and that was retrieved soon afterward.find: The designation given to a meteorite that was found, but not observed to fall.fusion crust: The dark glassy coating on the surface of a meteorite, caused by heating as the meteorite entered the atmosphere.

gas-giant planet: A giant planet with a massive and deep atmosphere that surrounds a relatively small rocky core.gravity: The force of attraction acting between any two masses (according to Isaac Newton); the curvature of space by matter (according to Albert Einstein).

hydrogen: The lightest, simplest, and most abundant element in the universe.

impact: The forceful striking of one body, such as a meteorite, against another body, such as a moon or planet.impact crater: The hole or depression formed by a meteorite colliding with a surface.inclusion: A fragment of one rock enclosed in another rock.iron meteorite: A meteorite consisting of metallic iron and nickel.isotope: Elements having an identical number of protons in their nuclei but differing in their number of neutrons.

kilometer (abbreviated km): A unit of length equal to 1,000 meters, or .62 miles.kinetic energy: The energy inherent in a body due to its motion; with greater speed and mass, the kinetic energy increases.Kuiper Belt: A doughnut-shaped region of comets in orbit beyond Neptune, assumed to be the oldest surviving remnant of the original solar nebula and the source of short-period comets.Kuiper Belt objects (abbreviated KBOs): The comets that populate the Kuiper Belt.

law of gravitation: The law stating that any two bodies attract each other with a force that increases in proportion to their masses and decreases in proportion to the square of the distance between them (discov-ered by Isaac Newton).light-year: The distance that light travels in one year (63,000 astronomical units, or 9.46 trillion kilometers), a convenient unit of measurement for interstellar distances.long-period comet: A comet with an orbital period exceeding 200 years. Such long-period comets have very elongated elliptical orbits, and can have an orbital period of more than a million years. They originate from the Oort cloud in the outermost reaches of our solar system.

mantle: The part of the Earth (or other rocky body) lying between the outer crust and the central core, consist-ing mostly of iron and silicate minerals.matrix: The smaller-sized grains in a rock when the rock consists of large grains or fragments surrounded by smaller grains.meteor: A bright streak of light produced by a small fragment of rock or metal that burns up as it enters the atmosphere.meteorite: A fragment of rock or metal that has landed on the Earth from interplanetary space. Most meteor-ites come from asteroids, but a few are from other planets or satellites.meteoriticist: A person who studies meteorites.



meteoriticist: A person who studies meteorites.

nebula: An immense cloud-like mass of interstellar gas and dust, generally in the spiral arms of a galaxy.

Oort cloud: A spherical cloud of trillions of comets extending about halfway to the nearest stars and weakly bound by the Sun’s gravity. Long-period comets originate from the Oort cloud.orbit: The path of one celestial body moving around another under the force of gravity.orbital period: The time interval for a body to complete one orbit around another.oxygen: An element consisting of atoms with eight protons. Two oxygen atoms combine to make molecular oxygen (O2), and three combine to make ozone (O3). The Earth’s atmosphere is 21 percent molecular oxygen.

physics: The study of matter and energy, and the forces and fields by which they interact in space and time.planet: An astronomical body with enough mass for its gravity to make it spherical but not enough to generate nuclear energy. Planets have non-intersecting orbits around stars or drift freely in space.planetesimal: One of the family of asteroid-sized bodies that first condensed out of the disk of the solar nebula and later collided to form the planets.plutino: A subclass of Kuiper Belt objects which, like Pluto, orbit the Sun twice during every three orbits of Neptune.

regmaglypt: Any of various small indentations or pits on the surface of meteorites.resonance: One of the natural states of oscillation in a physical system, such as the periodic swing of a pendulum or vibration of a spring.

satellite: A body that orbits around a larger body.short-period comet: A comet with an orbital period of less than 200 years, the most famous example being Halley’s comet, which appears every 76 years. Short-period comets come from the Kuiper Belt and typically orbit the Sun in the same direction as the planets.solar nebula: The cloud of gas and dust that formed the young Sun and the surrounding planets.solar system: The Sun and all the objects bound to it by gravity (planets, satellites, asteroids, comets).spectroscope: An optical instrument designed to spread out light into the spectrum of its component colors.star: A self-luminous body held together by gravity and with a central temperature sufficient to liberate energy by nuclear fusion.stony-iron: A class of meteorites composed mostly of a mixture of silicates and iron metal.strewn field: A generally elliptical pattern of distribution of recovered meteorites, formed when a meteor is fragmented as it passes through the atmosphere.sublime: To evaporate directly from the solid to the vapor phase. For example, the ice caps on Mars sublime and re-condense with the seasons.

tektites: The small fragments of melted and aerodynamically shaped rock that were ejected from a large impact crater.

vaporize: To change something from a liquid or a solid to a gaseous state, as in rock that is completely changed to gas during large impacts.velocity: The speed and direction of an object’s motion.volatile: Able to vaporize at relatively low temperatures. Ices of water, methane, carbon dioxide, and ammonia are volatile.



CreditsResources for Learning is made possible by a generous grant from The Louis Calder Foundation.

This material is based upon work supported by the National Aeronautics and Space Administration under Grant No. NAG5-12855 issued through the Office of Space Science.

This guide was developed by the Education Department and the National Center for Science Literacy, Education, and Technology.

The restoration of the Arthur Ross Hall of Meteorites is made possible through the generosity of the Arthur Ross Foundation.

Written and produced by: Christine Economos

Content research: Armistead Booker, Rachel Berger Connolly, Dana Leibowitz, Minna Palaquibay, Zohar Ris

Review: Denton Ebel, Robert A. Fogel, Myles Gordon, Rosamond Kinzler

Copyedited by: Michele Albright

Thanks to: Craig Chesek, Jane Murray, Sarah Wilson

Illustrations: Map: Kascha Semon, Student Resource Pages: Kascha Semon, Eric Hamilton


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