Building planets

Part of Hall of Meteorites.

Building Planets section at the Hall of Meteorites. C. Chesek/©AMNH

 

Pieces of asteroids and planets that fall to Earth as meteorites reveal the processes at work deep inside planets-including our own.

The farmland near Brenham, Kansas, is flat and almost entirely free of rocks-yet farmers in the 1880s occasionally bent their plows on mysterious metallic objects. Homesteader Eliza Kimberly noticed that the odd black rocks resembled a meteorite she had seen as a schoolgirl in Iowa. Despite teasing from her husband and neighbors, she collected a large pile of the "iron rocks," and after five years of letter-writing she convinced a scientist to look at them. They were indeed meteorites.

The remarkable Brenham meteorite fragments contain gemlike olivine crystals embedded in an iron-nickel alloy. Billions of years ago, this rock and iron mixture formed when a large asteroid melted and separated into an iron core and a rocky crust. Meteorites that come from the deep interiors of such asteroids provide tantalizing clues about the interior of Earth and other planets.

C.1.2 searching for meteorites.jpg
In the 1920s, Harvey Nininger visited the Kimberly farm in Brenham, Kansas, where more than a ton of meteorites had been discovered. Examining a large oval depression-previously thought to be just a buffalo wallow-he concluded it was actually a crater formed by the impact of a large meteorite. His 1933 excavation, performed with the help of his family (above), proved him correct. The crater formed by the Brenham meteorite was one of the first impact craters discovered in the United States and one of Nininger's greatest successes.
Nininger Collection/American Meteorite Laboratory Photo Archives

In This Section

Exhibit Brenham (AMNH 3813) Some 20,000 years ago, a meteorite scattered over three tons of fragments in the vicinity of Brenham, Kansas. Exhibit Crust As the solar system formed more than four billion years ago, primitive particles collided and clumped into larger and larger bodies. Exhibit Mantle The rock-forming minerals found in the mantles of planets and asteroids is often mixed with iron from their cores - why? Exhibit Core Without Earth's molten outer core, life as we know it would not exist. Exhibit Iron crystals Iron-nickel alloys in meteorites form distinctive crystal shapes. Exhibit Vesta Asteroid HED meteorites - composed of howardites, eucrites and diogenites - originated from the asteroid Vesta. How did they get here? Exhibit Meteorites From Mars Pieces of Mars that fall to Earth as meteorites gave us our first samples of the surface of another planet. Exhibit Peekskill Meteorite On October 9, 1992, a brilliant fireball flashed over Peekskill, New York, startling fans at a high school football game. Exhibit Building the Solar System Meteorites represent the early steps on the journey from particles to planet - when vapor and dust condensed into minerals.   Missions: Bringing the Solar System Home In this hall, see how recent missions to extraterrestrial objects give us insight to the origin of our planet.