More than one million asteroids larger than 1 km exist in the main asteroid belt (MAB) between Mars and Jupiter. Their roots are in a much smaller number of larger asteroids that broke apart because of collisions, and the MAB is populated with debris fields from these collisions. Researchers have created a geological map of the MAB by tracking meteorites that fell to Earth and determining which of these debris fields they originated in.
Most modern astronomical discoveries involve enormously powerful telescopes, some of which do their job from Low-Earth Orbit or at the Sun-Earth L2 point. But this research is partly based on a decidedly lower level of technology: dash-cams and doorbell cams.
The research review, “Review of asteroid, meteor, and meteorite-type links,” was published in the journal Meteoritics and Planetary Science. Its authors are Peter Jenniskens and Hadrien Devillepoix. Jenniskens is from the SETI Institute and NASA Ames Research Center, while Devillepoix is from Australia’s Curtin University.
“With the goal to determine the origin of our meteorites in the asteroid belt, video and photographic observations of meteors have now tracked 75 meteorite falls,” the researchers write in their letter. “Six years ago, there were just hints that different meteorite types arrived on different orbits, but now, the number of orbits (N) is high enough for distinct patterns to emerge.”
The effort began 10 years ago when the authors teamed up to build a network of all-sky cameras in Nevada and California. These cameras tracked meteors as they entered Earth’s atmosphere and left their tell-tale streaks of light across the sky. Over the years, the effort grew as more professional scientists and citizen scientists joined in.
“Others built similar networks spread around the globe, which together form the Global Fireball Observatory,” Devillepoix said in a press release. “Over the years, we have tracked the path of 17 recovered meteorite falls.” Citizen scientists added to the effort with dash-cam and doorbell cam videos.
This map shows the approximate global area coverage and distribution of camera networks aimed at measuring the approach orbit of meteorite falls. Image Credit: Jenniskens & Devillepoix (2025) Meteoritics & Planetary Science.
“Altogether, this quest has yielded 75 laboratory-classified meteorites with an impact orbit tracked by video and photographic cameras,” said Jenniskens. “That proves to be enough to start seeing some patterns in the direction from which the meteorites approach Earth.”
Scientists think that meteorites that fall to Earth come from up to 95–148 distinct parent bodies. However, the meteorites with known approach orbits come from only about 15 parent bodies. In this effort, the researchers considered “large asteroids and families of asteroids that are the product of catastrophic and cratering collisions.”
An asteroid collision typically features a small object striking a larger object. The larger object is the parent body of the fragments that the Global Fireball Observatory (GFO) is trying to track. Research shows that the bulk of meteorites that reach Earth come from a small number of collisions. “The influx at Earth of a given meteorite type is dominated by debris from a relatively small number of large collisions that occurred in the last 100 Myr,” the authors explain.
The effort to map the geology of the asteroid belt involves more than video evidence. When rocks travel through space, they are subjected to cosmic rays. Asteroid fragments spend a long time in space before they reach Earth, and the rays produce new isotopes on the surface of the fragments. By measuring the abundances of different isotopes, scientists can determine how long ago an object broke away from its parent.
Researchers combine this cosmic-ray dating data with dynamical data. They determine the dynamical age of debris fields in the asteroid belt by measuring how asteroids of different sizes have spread over time. They can sort of ‘wind back the clock’ to the time of the initial collision between a parent body and an impactor.
“By measuring the cosmic ray exposure age of meteorites, we can determine that three of these twelve meteorites originated from the Karin cluster in Koronis, which has a dynamical age of 5.8 million years, and two came from the Koronis2 cluster, with a dynamical age of 10-15 million years,” said Jenniskens. “One other meteorite may well measure the age of the Koronis3 cluster: about 83 million years.”
Geologic map of the asteroid belt. Circles identify the asteroid families from which meteorites originate, and letters mark the corresponding meteorite type. The horizontal axis ranges from short orbits moving just inside the asteroid belt (left) to longer orbits just outside (right). The vertical axis shows how much the asteroid orbits are tilted relative to the plane of the planets. Blue lines are the delivery resonances. From: Jenniskens & Devillepoix (2025) Meteoritics & Planetary Science.
The researchers also identified H-chondrites, the most common type of meteorite, that follow steep orbits and come from the Nele asteroid family, one of the youngest families in the MAB. Its dynamical age is approximately 6 million years. They also found another group of H-chondrites with a cosmic ray exposure age of 35 million years. These two groups of H-chondrites are from the central main belt and the inner main belt, respectively.
“In our opinion, these H chondrites originated from the Massalia asteroid family low in the inner main belt because that family has a cluster of about that same dynamical age,” said Jenniskens. “The asteroid that created that cluster, asteroid (20) Massalia, is an H chondrite type parent body.”
They also found that L-chondrites (low-iron) and LL-chondrites (very low-iron) come mostly from the inner main belt.
“We propose that the L chondrites originated from the Hertha asteroid family, located just above the Massalia family,” said Jenniskens. “Asteroid Hertha doesn’t look anything like its debris. Hertha is covered by dark rocks that were shock-blackened, indicative of an unusually violent collision. The L chondrites experienced a very violent origin 468 million years ago when these meteorites showered Earth in such numbers that they can be found in the geologic record.”
Other researchers found a link between the LL-chondrite meteorites and the Flora asteroid family on the inner side of the asteroid belt. Now, Jenniskens and Devillepoix have confirmed it.
Human beings are pattern-seeking creatures. We seek patterns in nature to enable our survival. While evading predators, tracking migrating herds, and watching the weather for cues to plant our crops are skills most of us have abandoned, our essential pattern-seeking nature is still there. The main asteroid belt might look like a giant mess, but astronomers are finding the hidden patterns in the apparent chaos. Like understanding the behaviour patterns of dangerous predators, understanding the patterns in the MAB can also help us survive.
There’s a link between meteorites and near-Earth Asteroids (NEAs). Astronomers know of more than 37,000 NEAs and almost 2,500 of them are large enough and come close enough to Earth to pose a serious threat of a devastating impact. Can finding the patterns in meteorites in the MAB help us protect ourselves from NEAs?
“Near Earth Asteroids do not arrive on the same orbits as meteorites, because it takes longer for these to evolve to Earth,” said Jenniskens. “But they do come from some of the same asteroid families.”
Some of the links the researchers found between meteorites and asteroids aren’t as clear as others. But they’ve made progress, and there’s more to come.
The researchers say we need to increase the number of tracked meteorite falls so that they can refine the identified source regions and potentially uncover new ones. They also need more detailed analyses of meteorite cosmic ray exposures and the dynamical ages of asteroid families to strengthen our understanding of their connections. We also need to study the mechanisms responsible for the differences in orbital distributions between small meteoroids and larger NEAs.
“We are proud about how far we have come, but there is a long way to go,” said Jenniskens. “Like the first cartographers who traced the outline of Australia, our map reveals a continent of discoveries still ahead when more meteorite falls are recorded.”
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