Building planets main content.

Building planets

Part of Hall of Meteorites.


Exhibition Text

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.

For Educators

Topic: Astronomy

Subtopic: Planets

Keywords: Astrophysics, Olivine, Iron-nickel alloys, Astrogeology, Asteroids, Planets--Geology, Meteorites, Iron

Audience: General