Four Fascinating Meteorites That Provide Clues to Understanding Our Solar System

The Meteorites exhibition, now open at the Museum. Photo: J. Knight. 

Meteorites have been falling to Earth for literally hundreds of millions of years—and continue to land here today. Most meteorites come from the asteroid belt, a ring of rocky debris orbiting the Sun between Jupiter and Mars. This belt formed 4.6 billion years ago. So, by studying meteorites, we can continue learning about the very origins of our solar system. Here are four kinds of meteorites you can see for yourself at the Museum:

1. The only fossil meteorites in the Americas

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A flat stone slab that's reddish in color, with a green object in the center, surrounded by a tan-colored ring
Fossil L chondrite meteorite that fell to Earth 465.9 million years ago. Found in 1996. Courtesy of Mario Tassinari. 

Fossil meteorites are so rare that only 101 have been discovered to date (and four of them are here at The Field Museum!). But what is a fossil meteorite? The fossilization process for meteorites happens in the same way that organisms—plants and animals—become fossilized. The meteorite’s original materials are gradually (very, very gradually) replaced by minerals in the ground surrounding it.

All of the fossil meteorites that have been discovered so far come from the same spot: deep in a limestone quarry in Sweden that used to be an ancient sea. Based on the age of the rock around them, we know that the now-fossilized meteorites fell to Earth about 466 million years ago. They’re debris from a major collision event that happened in the asteroid belt when they broke off of what’s called the parent body. These meteorites were some of the first pieces to arrive on Earth after the collision. 

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A man wearing work clothes and rain boots standing on a muddy, rocky shelf
The quarry in Sweden where the fossil meteorites were found. Credit: Birger Schmitz. 
See how the fossil meteorite test works on The Brain Scoop.  

2. Rare green meteorites

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An irregularly shaped stone with a rough outer surface and a shiny spot that is green and orange
One of two ungrouped achondrite green meteorites on display in the Meteorites exhibition. Courtesy of the Boudreaux family. 

These are ungrouped meteorites that came from asteroids we didn’t even know existed until a few years ago. “Ungrouped” means that these meteorites don’t fit the classification of any previously documented meteorites—in other words, that they’re from small planets that scientists haven’t sampled before. That’s what makes an ungrouped meteorite an exciting find: it’s a window into a part of our solar system that remains to be explored. The hope is that one day, we’ll have enough samples of this new type that we’ll be able to identify a new group of meteorites. In addition, the two meteorites that we have appear green, which is very unusual. Most meteorites have a thin black outer fusion crust, and inside, they are either light or dark gray, or black. 

3. The Chelyabinsk meteor

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A large irregularly shaped stone that's mostly smooth and gray, with ripples
Fragment of the Chelyabinsk meteor, courtesy of the Boudreaux family. 

You probably remember hearing the news reports about this one: a brilliant, blinding explosion that took place over the Russian district of Chelyabinsk in 2013. In fact, the fireball burned brighter than the sun. It was caused by the explosion of an enormous meteor as it entered Earth’s atmosphere at an extremely high speed.

The meteor was estimated to weigh about 11,000 metric tons (or about 24,250,000 pounds, nearly as heavy as the Eiffel Tower) before it exploded. The shockwave caused injuries to more than 1,500 people—a very rare occurrence of a meteorite fall directly impacting people’s lives. The Chelyabinsk meteor was probably a once-in-100-years event, but it made us realize how vulnerable we humans really are to meteorite impacts. 

4. A Mars meteorite

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A large black and orange stone with many depressed areas

Just as meteorites fall to Earth, they also land on other planets. Thanks to 3D photographs taken by NASA’s Mars Exploration Rover Opportunity, we’re able to get a close-up, detailed look at an iron meteorite spotted on Mars. A life-size replica of this Mars meteorite was created using imagery and data gathered by the Opportunity. Found in 2009, the real meteorite is still on Mars.

See these meteorites and more on display in the exhibition Meteorites.

 

Several of the specimens on display were loaned or donated by private collector Terry Boudreaux. For over a decade, Terry Boudreaux has continuously provided The Field with loans and donations of precious and fresh meteorites for research and exhibit. The fossil meteorite specimens were loaned by private collector Mario Tassinari from Sweden.