HILLSBOROUGH, NEW JERSEY — A fragment of the Hillsborough meteorite crashed through the roof of a house in Hillsborough, New Jersey, on July 16, 2024, delivering to scientists one of the most pristine and chemically rich extraterrestrial samples ever recovered. The meteorite, named Hillsborough, entered Earth’s atmosphere at 32,000 miles per hour, created a sonic boom felt across New York City and New Jersey, and scattered fragments across the region after breaking apart approximately 22 miles aboveground.

The fireball was witnessed by observers in five states—New York, New Jersey, Connecticut, Rhode Island, and Pennsylvania—with 60 reports collected by the SETI Institute. Radar from Newark Liberty International Airport tracked a debris cloud falling from near Staten Island into New Jersey, and the meteor’s trajectory carried it just south of the Statue of Liberty before fragments reached the ground. One piece, weighing more than 2 pounds (about 1.35 kilograms), pierced the roof of a home and landed in the master bedroom, causing no injuries.

The homeowner reported hearing a loud crash, discovering a hole in the ceiling, and noticing a strong sulfur-like odor along with black fragments and dust covering the bed and carpet. Acting quickly, the homeowner collected the material using disposable gloves and aluminum foil, storing it in glass jars, and later patched the roof before evening rain arrived.

A study detailing the meteorite’s composition was published in the journal Science Advances on Wednesday, July 17, 2024. Led by meteor astronomer Peter Jenniskens of the SETI Institute and NASA’s Ames Research Center, the research team classified the object as a CM carbonaceous chondrite, specifically a CM½ type—an intermediate between CM1 and CM2 subtypes—and noted it is only the second witnessed fall of this classification. "Thanks to the homeowner’s quick reaction, these are the most pristine CM1/2 meteorites we know of," Jenniskens said. He added, "A forensic study of the fragments revealed that they contained preserved bits from near the surface of a small primitive asteroid where it experienced concentrated salty fluids — a process not previously known from this type of proto-planet world." In subsequent correspondence, Jenniskens wrote, "It is the first CM type meteorite that contained bits of rock that preserved the subsurface of the original asteroid," and emphasized, "We really have a unique window here on the physical properties of the parent asteroid."

Mineralogist Jangmi Han of NASA’s Johnson Space Center, a co-author of the study, identified microscopic fractures within the meteorite filled with sodium-rich material left behind by ancient brines. The analysis revealed high concentrations of sodium, suggesting the presence of salty fluids or brines that once circulated within the parent asteroid. Scientists also detected fragile sodium-carbonate salts—a discovery never before made in a CM carbonaceous chondrite.

While similar salts have been found in samples returned from asteroids Bennu and Ryugu by NASA’s OSIRIS-REx and JAXA’s Hayabusa2 missions, the Hillsborough meteorite marks the first time such compounds have been identified in a naturally fallen CM chondrite. Meteorite researcher Mike Zolensky, also of NASA Johnson Space Center and a study co-author, noted, "The chips of the most salt-rich bits of this meteorite are quite comparable to the samples returned by the Hayabusa2 and OSIRIS-REx missions," adding, "They're not identical. They're different in some very interesting ways, but they've seen very similar processes."

The meteorite also contains a diverse array of carbon-bearing compounds, amino acids, and prebiotic molecules. Danny Glavin, a senior scientist in the Astrobiology Analytical Laboratory at NASA’s Goddard Space Flight Center and co-author of the study, described the findings as exceptional. "One of the big surprises for me when we analyzed a small chip of the Hillsborough meteorite was the complexity of amino acids and other organic compounds," he said. Glavin added, "We detected a complex suite of amino acids, the fundamental building blocks of proteins, in water extracts of the Hillsborough meteorite." He emphasized their extraterrestrial origin: "Most of the amino acids detected in Hillsborough are rare or nonexistent in life on Earth, so they are truly extraterrestrial in origin." In an email, Glavin further noted, "There are hundreds of amino acids in this meteorite and the majority of them do not occur naturally on Earth," and observed, "The suite of amino acids in Hillsborough was even more diverse than those found in pristine samples returned from the carbon-rich asteroids Bennu and Ryugu."

While the meteorite’s precise origin remains under study, conflicting hypotheses exist. One source suggests it originated from a protoplanet that formed just outside Jupiter’s orbit, while another indicates it may have come from a larger body in the inner asteroid belt between Mars and Jupiter—a region more typical for CM chondrites. Jenniskens outlined a possible history in a written explanation: "Some time ago, a significant asteroid family was formed in a large collision and some 6 Myr ago a smaller collision destroyed one of these asteroids, from which a piece ended up in near-Earth orbit.

That piece experienced heat/cold cycles from spinning in the sunlight and fragmented about 200,000 years ago. Then it still took that long to hit the small target of Earth."

Some of the recovered fragments will be curated at the American Museum of Natural History in New York City. Denton Ebel, a curator at the museum, said, "We are thrilled that nature delivered such a precious asteroid sample on our doorstep."

The Hillsborough meteorite’s exceptional preservation—due to rapid collection and minimal terrestrial contamination—provides an unprecedented opportunity to study the chemical and physical conditions of early solar system bodies. Its combination of ancient brine evidence, fragile salts, and an unusually diverse set of extraterrestrial amino acids offers new insights into the processes that may have contributed prebiotic ingredients to early Earth. The fact that it is the first CM chondrite to show preserved subsurface asteroid material and sodium-carbonate salts links it directly to findings from recent sample-return missions, creating a rare bridge between laboratory analysis of naturally delivered meteorites and spacecraft-collected asteroid samples.