orientation & key concepts

Orientation

The annual Leonids meteor shower occurs in mid November.
©NASA, 1966
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When 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, gradually forming larger and larger bodies such as asteroids and planets. Meteorites are the "leftovers"—remnants of planets, 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 meteorites, 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 Concepts

The 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 Science

Meteorites tell the story of the formation of the solar system and the planets.

An artist's rendering of a solar nebula.
©NASA JSC, Don Dixon
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  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 system, but mainly reside in the asteroid belt between the planets of Mars and Jupiter.

Chemistry

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

Chondrules were among the first substances to form in the early solar nebula.
©NASA JSC, Allan Treiman
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  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 chemical composition of some meteorites provides clues as to where their original source, or parent bodies, may have resided in the early solar system. Today, most parent bodies of meteorites exist in 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 Science

Meteorites 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.