A bright green fire ball illuminates the sky above the management area of the wildlife of Babcock near Punta Gorda, Florida. Credit: Diana Robinson (Flickr, CC By-NC-ND 2.0)
Much of what scientists know about the first sun system come from meteorites: ancient rocks that travel through space and survive to inflame themselves in the terrestrial atmosphere. Among the meteorites, a type – called Condriti Carbonacei – stands out as the most primitive and provides a unique look at the childhood of the Solar System.
Carbonaceous chondrites are rich in water, carbon and organic compounds. They are “hydrated”, which means that they contain water tied into the rock minerals. The components of the water are blocked in crystalline structures. Many researchers believe that these ancient rocks have played a crucial role in providing water to early earth.
Before hitting the earth, the rocks that travel through space are generally indicated as asteroids, meteoroids or comets, depending on their size and composition. If a piece of one of these objects reaches the earth, it becomes a “meteorite”.
From the observation of asteroids with telescopes, scientists know that most asteroids have carbon -rich carbon compositions. The models provide that most meteorites – over half – should also be carbonate. But less than 4% of all the meteorites found on Earth are carbons. So why is there such a lack of correspondence?
In a study published in the magazine Nature Astronomy on April 14, 2025, my colleagues planetary scientists and I have tried to answer a secular question: where are all the carbonaceous chondrites?
Sampling Network Missions
The desire of scientists to study these ancient rocks has guided the recent spatial removal missions. The Missions of Hayabusa2 of the NASA of Osiris -rex and Jaxa have transformed what the researchers know about primitive and carbon asteroids.
The meteorites found sitting on the ground are exposed to rain, snow and plants, which can change them significantly and make the analysis more difficult. Hence, the Osiris -rex mission ventured into Asteroid Bennu to recover an unchanged champion. The recovery of this sample has allowed scientists to examine in detail the composition of the asteroid.
Likewise, Hayabusa2’s journey towards the Asteroid Ryugu has provided pristine champions of another asteroid rich in water.
Together, these missions have allowed planetary scientists like me to study pristine carbonate material and fragile as asteroids. These asteroids are a direct window on the bricks of our sun system and the origins of life.
The conductor of Condrite Carbonace
For a long time, scientists hypothesized that the terrestrial atmosphere filtered carbon debris.
When an object affects the terrestrial atmosphere, it must survive significant pressure and high temperatures. Carbonaceous chondrites tend to be weaker and more crumbly than other meteorites, so these objects cannot bear the possibility.
Meteorites usually begin their journey when two asteroids collide. These collisions create a pile of rock fragments of hundredth sizes in a meter. These cosmic crumbs approach the Solar System and, in the end, can fall on earth. When they are smaller than one meter, scientists call them meteoroids.
Meteoroids are too small for researchers to see with a telescope, unless they are about to hit the earth and astronomers are lucky.
But there is another way that scientists can study this population and, in turn, understand why meteorites have such different compositions.
Meteora observation networks and fireball
Our research team used the terrestrial atmosphere as our detector.
Most of the meteoroids that reach the earth are small particles of sand size, but occasionally, bodies up to a couple of meters of diameter shots. The researchers estimate that about 5,000 tons of micrometorites land on earth every year. And, every year, between 4,000 and 10,000 large-sized golf-dimensions or larger dimensions on earth. They are more than 20 every day.
Today, digital cameras have made the observations 24 hours a day of both practical and convenient night sky. High sensitivity sensors at low cost and automated detection software allow researchers to monitor large sections of the night sky for bright flashes, which signal a meteoroid that affects the atmosphere.
Research teams can sift these real -time observations using automated analysis techniques or a very dedicated doctorate. Student: to find priceless information.
Our team manages two global systems: Fripon, a network driven by the French with stations in 15 countries; And the global Observatory of Fireball, a collaboration started by the team behind the desert fireball network in Australia. Together with other open -accessing data sets, my colleagues and I used the trajectories of almost 8000 impacts observed by 19 observation networks spread in 39 countries.
By comparing all the meteoroid impacts recorded in the terrestrial atmosphere with those that successfully reach the surface as meteorites, we can identify which asteroids produce strong enough fragments to survive the trip. Or, on the contrary, we can also identify which asteroids produce weak material that do not often present themselves on earth as meteorites.
The sun is cooking the rocks too much
Surprisingly, we discovered that many pieces of asteroids do not even arrive on earth. Something begins to remove weak things while the fragment is still in space. The carbonate material, which is not very resistant, is probably decomposed through heat stress when its orbit brings it closer to the sun.
While carbonaceous chondrites orbit the orbit close, and then far from the sun, the temperature changes form cracks in their material. This process fragments and effectively removes weak and hydrated boulders by the population of objects near the earth. Everything that has remained after this thermal crack must survive the atmosphere.
Only 30% -50% of the remaining objects survive the atmospheric passage and become meteorite. The pieces of debris whose orbits bring them closer to the sun tend to be significantly more durable, making them many more likely to survive the difficult passage through the terrestrial atmosphere. We call it a prejudice of survival.
For decades, scientists have presumed that only the Earth’s atmosphere explains the scarcity of carbonaceous meteors, but our work indicates that much of the removal occurs in advance in space.
In the future, new scientific progress can help confirm these results and better identify meteoroid compositions. Scientists must improve the use of telescopes to detect objects before hitting the earth. The most detailed modeling of how these objects break in the atmosphere can also help researchers study them.
Finally, future studies can find better methods to identify what these fire balls are done in the use of meteor colors.
Patrick M. Shober is a post -Endorship member in the Planetary Sciences of NASA.
Patrick M. Shober has received funding from the 2020 horizon of the European Union’s research and innovation program as part of the Skłodowska-Curie Skłodowska Skircase contract n. 945298. Patrick M. Shober currently receives funding from the NASA post-dictate program.
This entry was originally published on The conversation. He is republished with a Creative Commons license.
