Rice University scientists studying rare fireball meteorite

For Houstonians who saw it, the fireball meteor that streaked across the East Texas sky last month was a brief, blazing moment of awe. For space researchers at Rice University, it was an opportunity. 

A fireball meteor landing in Houston is “incredibly rare,” said Linda Welzenbach Fries, a science writer at Rice’s department of earth, environmental and planetary sciences. “There might be 10 (fireballs) total over the entire planet in one year. To have one fall in a metropolitan area where people can go and collect it? It’s very unusual.”

Now, a team of Rice scientists is studying fragments of that meteor for insights into the earliest history of our solar system. 

Space researchers prize meteorites because many of them are time capsules from when our solar system’s planets formed about 4.6 billion years ago. Unlike rocks on Earth, which have been exposed to eons of weather and geological processes, many meteorites have spent that time hurtling through space, relatively untouched, Fries said. That means what may look like simple rocks are actually clues to the materials and conditions that gave rise to Earth.

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“(Meteorites) preserve all of those processes and all of that information in a four-and-a-half billion year-old snapshot,” Fries said.

Seeing a fireball is always lucky, but this one’s timing was especially fortuitous. The meteorite will be the first locally-sourced sample in a newly established collection at the Rice Astromaterials Research and Exploration Lab.

“This one would be the first one we classified in our collection ever, and specifically this is locally from Houston, which is why we’re so excited about it,” said Bidong Zhang, an assistant professor at Rice who leads the just-founded RARE lab. “The timing couldn’t be better.”

On the afternoon of March 21, Texans who happened to be looking skyward saw the fireball’s brilliant streak of light — brighter than Venus — and many heard its sonic boom. The one-ton, three-foot-wide rock traveled about 20 miles across northwest Houston at at least 35,000 miles per hour, before it broke apart just south of Spring, according to NASA. 

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As soon as the fireball touched down, time was of the essence for researchers hoping to recover pristine samples of the rare rocks. Meteorites can deteriorate or become altered the longer they are exposed to Earth’s weather and atmosphere, so finding samples quickly is optimal.

Zhang set out to meteor-hunt the next morning. Fries’ husband, who works at NASA, did, too. He used radar to model the meteor’s flight path, and he estimated that pieces had fallen the areas of Collins Park, Cypress Station and Ponderosa Forest, Fries said. 

Over three days, Zhang walked about 25,000 steps each day scouring the neighborhoods’ streets and parks for jet-black space rocks. He came away empty-handed. But Fries’ husband had better luck. After 25 miles of searching, he found a palm-sized sample, said Fries, his wife. 

“It’s unusual in its appearance enough to pique our interest,” Fries said, holding the sample with gloved hands in her office on Thursday. One side is encased in a deep-black crust, where the molten rock hardened as it cooled, and the other side is textured and variegated.

Rice researchers are in the process of studying two other samples of the meteor, both donated by meteor enthusiast and collector David Gonzalez. On Thursday, researchers used an electron probe microanalyzer to study one sample’s mineral chemistry, and they ooh-ed and aah-ed as the images revealed a surprise. 

The meteorite lacked chondrules, spherical features embedded in the vast majority of material that falls to Earth from space. It also appeared to be rich in the mineral enstatite, meaning it could be from a rare category of meteorites that some scientists believe are “building blocks of Earth,” said Rice research scientist Tao Sun.

“Our ordinary chondrite is, maybe, perhaps, not so ordinary,” Fries said. 

In the coming days, scientists will further analyze the samples’ mineral chemistry, oxygen isotopes and surface features and use that data to submit an official meteorite classification to the Meteoritical Society, an international organization that promotes planetary science, Fries said. The classification data will be archived for any scientists who want to study it, she said.

There are likely more meteorites in the Houston area, Fries said, and she encouraged members of the public to go look for them.

“The more material we have to study, the more we’re going to understand the asteroid that it came from,” she said, “and the more we’re going to understand, potentially, what it can tell us about Earth’s origins.”