Meteorites contain a record of our solar system’s evolution and how meteorite impacts could affect our future. View and learn about pieces of rock and metal, actual debris from outer space, that have survived the trip through our atmosphere and impact with the Earth’s surface. When these objects enter the atmosphere, friction, pressure, and chemical interactions with atmospheric gases cause meteorites to heat up and radiate energy. Many meteorites are vaporized on entry through the atmosphere. The museum’s collection includes different types of meteorites found around the world, including two found in Louisiana and one that’s likely from Mars!
In the nickel-iron meteorites case, students can observe meteorites that are denser than normal rocks and surprisingly heavy for their size. The largest one in our display is about the size of bowling ball and weighs 78 pounds! Ask students to observe the criss-cross, or Widmanstätten, pattern on some of the meteorites. The pattern is related to the amount of nickel in the meteorite and becomes visible after specially treating the meteorite with a chemical solution. Astronomers can use these patterns to determine if a piece iron comes from a meteorite. Nickel-iron meteorites also tend to rust because they are exposed to humidity and oxygen here on Earth, which is an alien environment for these bits of space debris. Chemical and vapor treatments help protect these meteorites from the elements and prevent or slow the rusting process.
In the stony meteorite case, students can observe various types of meteorites. Chondrites are the most common type of meteorite and are characterized by the presence chondrules, which as appear as round spots within the chondrite. Chondrules are the building blocks of chondrites and form as molten or partially molten droplets in space that come together to form larger bodies. Carbonaceous chondrites have water molecules as part of their mineral structure and are richer in carbon than other meteorites. They also include amino acids, the so-called building blocks of life, that are not found on Earth. The Murchison meteorite on display is a carbonaceous chondrite. Achondrites are stony meteorites with no chondrules. They are formed by lava flows at or near the surface of very large asteroids.
Louisiana Meteorites In the special meteorite case, students can observe slices of two meteorites found here in Louisiana – only three meteorites have ever been found in Louisiana. The Atlanta meteorite was named after the town of the same name in Winnfield Parish, and the Greenwell Springs meteorite was found near Baton Rouge. Other museums and collections in Washington, D.C., New York City, New Mexico and Vienna, Austria have pieces of the Greenwell Springs meteorite, but our museum is the only known place where it is on exhibit. A third small meteorite was found in New Orleans shortly before Hurricane Katrina, but most of it was lost in the aftermath of the storm.
Martian Meteorites Our Zagami stony meteorite is an actual piece of the planet Mars! Out of tens of thousands of collected meteorites, only about 120 are thought to be Martian meteorites because they match well with Martian rocks collected by landers. Martian rocks and meteorites are volcanic and significantly younger than most meteorites with atoms matching the Martian atmosphere between their mineral crystals. Mars is one of the few places in the solar system with volcano activity in geologically recent times.
Vesta Meteorites Several meteorites in the museum’s collection appear to be from the asteroid Vesta, which has a giant crater at its south pole. These meteorites match well with the minerals in the surface of Vesta as confirmed by the recent Dawn spacecraft, which orbited Vesta for more than a year capturing images and other measurements.
While most meteorite specimens in the museum’s collection are kept in cases to control their environment and prevent rusting and corrosion, a couple meteorites have been set aside for visitors hold. If time permits a er your students’ planetarium show, these two meteorites, one stony and one nickel-iron, will be passed around for students to examine.
Impact craters Impact craters are caused by the collision of large meteorites with Earth’s surface. More than 150 impact craters are known on Earth, but they can be difficult or even impossible to see because they are buried by sediment or have eroded. Geologists can find them through different forms of aerial imaging and drilling core samples of suspected craters. Impact craters are much larger than the objects that create them. The largest known impact crater has a diameter of 180 miles.
Tektites and Strewn Fields Tektites are an unusual form of natural glass that form when material from Earth’s surface is blasted into the upper atmosphere by the impact of asteroids or comets on Earth. The material melts, solidifies, and falls back to Earth. This process creates distinctive odd shapes, ow lines, and bubbles. Some entered the atmosphere while still nearly molten, stretching into “dog bone” shapes as they rotated. Teardrop shapes are dog bones that rotated fast enough to split in half. Small pits and gouges in tektites were caused by entry into the atmosphere at very high speeds. Regions where tektites and meteorites are found are called strewn fields. Ask students to compare the different shapes of tektites on display and the regions where they were found.
Shatter cones Shatter cones are Earth rocks found below impact craters. The cone-shaped grooves and cracks in them happen when shock waves from an impact go through the rock. Shatter cones are a key feature in determining whether a crater is volcanic in origin or due to the impact of an asteroid or meteorite because shatter cones are only found under impact craters. Ask students to look for the shatter cone shape in the rocks on display, which are especially visible in the small shatter cone from Sierra Madera, Texas.
The Great Meteor of 1957 In 1957, people across the southeastern United States witnessed an extremely bright meteor accompanied by a rumbling sonic boom that shook houses and rattled windows. Witnesses still ask about it when they visit the museum, and many think it must have hit nearby them because of how bright it appeared. However, observations from the Galveston, Texas area indicate it must have come down over the Gulf of Mexico if it survived the trip through our atmosphere. No specimen was ever recovered, but the Army Corps of Engineers estimates the object’s mass at about 600 tons! Modern calculations suggest it broke into small pieces in the atmosphere several miles high. Our meteor map shows where observations were reported, and a small “X” indicates incorrect claims of impact.