STARR COUNTY, Texas (ValleyCentral) — ValleyCentral spoke exclusively with the husband-and-wife scientists that recovered meteorite fragments in Starr County last week.
Marc Fries and Linda Welzenbach Fries, who referred to themselves as a “nerd couple,” are believed to be the first people to recover fragments of the meteorite that was heard and felt across many parts of the Rio Grande Valley area last week, along with Robert Ward.
Marc Fries is the cosmic dust curator for NASA, and Linda Fries is a science writer for the Department of Earth Environmental and Planetary Sciences at Rice University. Linda also worked at the Smithsonian as the Collection Manager of Meteorites at the National Museum of Natural History.
Marc added that Linda has seen more meteorites “than just about anybody on the planet.”
The race to Starr County
On Wednesday, Feb. 15, residents reported a loud blast and a fireball near the Mission-area. NASA would confirm the following day that a 1,000-pound meteor made entry near McAllen, and that meteorites did in-fact reach the ground from the event.
By 3 p.m. Thursday, Marc Fries said he and his wife were on the road to Starr County from Houston, with every minute being valuable.
“The point is to get there as quickly as possible,” Marc Fries said. “From the moment a meteorite hits the ground, they start to get altered by the Earth. They’re seeing more moisture, especially if it rains, and more oxygen than they have ever experienced before.”
When NASA released the statement, they included a graphic of a map of South Texas with “radar signatures of falling meteorites,” showing an area in Starr County. It was this kind of data that helped narrow the search efforts for the Fries.
“These weather radars are not designed to find meteorite falls, but they’re designed to find objects in the atmosphere which reflect radar,” Marc Fries said.
Finding the meteorites
Once in Starr County, the Fries began the search for meteorites, with the goal to collect 20 grams to put into a repository for scientific purposes. The couple would begin by walking roads and public lands, because anything that lands on private property is property of the owner, they said.
For this particular instance, this is exactly what happened, as the Fries had to reach out to private property owners who were willing to make an agreement so they could search the area.
“We were able to find a landowner who was willing to do that, allow us to look, and we found over the course of the weekend, five meteorites, including one that was 1.25 kilograms (2.75 pounds),” Marc Fries said.
Once the couple was boots-on-ground, they began looking for “black rocks with a rounded shape,” according to Linda Fries.
“They have a shape that is obviously modified by their atmosphere passage and by the fact they have been essentially melting by friction. Their cosmic velocity as it’s passing through the Earth’s atmosphere causes the outside of it to essentially to melt and ionize,” Linda said.
Linda said the rock itself will remain relatively cold, and only the outside fraction of the rock is melting. Additionally, she said the meteorite recovered in Starr County appears to belong to a group of meteorites called “ordinary chrondrites,” of a lower iron type.
What about the crater?
When photos of the meteorite recovery initially began to surface, many took to social media to question why there was no crater seen in the photos. Marc said the answer is due to the size of the fragments.
According to Marc, the initial 1,000-pound estimate refers to the size of the meteoroid at the top of the atmosphere, and not what hit the ground.
“When it hit the top of the atmosphere, then easily 90% of that rock is going to be just totally vaporized by the bright, incandescent fireball, and what actually reaches the ground are a bunch of fragments,” Marc said.
Marc said the fragments were like household bricks or smaller in size, and made small impact pits about an inch-thick.
And the sound?
The Fries said what residents felt and heard that Wednesday afternoon wasn’t the impact of the rock itself, but sonic boom caused during its fall.
“That track was about 35 kilometers (21.7 miles) up when the sonic boom was at its maximum,” Marc said. “It was a lot of power. The number that NASA calculated was about 8 tons of TNT … and it’s purely from kinetic energy of that meteorite getting transferred into a sonic boom.”
Marc said though it can be a scary event, it’s a natural phenomenon and is very rare.
Though the event is rare, NASA mentioned in their statement that this event should serve as a reminder to increase the understanding and protection of Earth. In September 2022, NASA conducted its first planetary defense test when it successfully redirected an asteroid.
Fries also acknowledged there is some danger.
“I sleep just fine at night knowing that this hazard is out there because the likelihood is very low,” Marc said. “But at the same time, I notice there’s an absence of dinosaurs around us.”
As for why the meteoroid wasn’t spotted beforehand, Marc said the answer boils down to the size.
“They’re just small. It becomes kind of a self-sorting thing,” Marc said. “If they’re that small that we don’t see them on the way in, then they’re that small that they probably won’t cause any damage on the ground.”
What happens now?
According to the Fries, there are still a large volume of fragments left from this meteor event.
Marc said the undiscovered meteorites will be rained on, colonized by fungi and become more and more altered by the Earth over time. The first initial batch that is discovered carries the most value for scientific purposes, but Marc gave a crude estimate that there was 100 pounds of meteorite that reached the ground from the event.
“There’s still a lot on the ground,” Marc said. “I expect that they will continue to be found probably for years… It’s gonna keep on for a while.”
If residents find what they believed to be meteorites, Linda reiterated some of the points on NASA’s website in regards to their safety.
“They are just rocks, they just happen to be from space,” Linda said. “Meteorites can’t hurt anybody. They’re not radioactive. They don’t contain anything that is hazardous to your health,” Linda said.
As for where the collected fragments will go, it remains unknown because the land owner officially owns the material, they said.
“He could go completely local, Texas Christian University, or the Smithsonian … At the moment, the short answer to the question is we don’t know yet,” Linda said.
Now a week after a moment that captured the attention of the entire Valley, Marc said the meteor event was a gift.
“I understand when the fireball occurred, it was very loud and could be downright terrifying, but it actually is a rare gift,” Marc said. “We now have meteorites in hand and can study them and learn more about them.”