We explain what meteorites are, their origin and composition. Also, what are its characteristics, its classification and the most famous meteorites.

What are meteorites?
Meteorites are fragments of space rock arriving on the surface of a planet or natural satellite from outer space. Although the most studied are those that approach Earth, the fall of meteorites has also been verified on Mars and the Moon.
It is estimated that thousands of meteorites approach Earth annually, but only a few survive the erosion generated by the gases that make up the atmosphere. Most of them are very small and disintegrate before reaching the surface.
The meteorites They are classified into three main types: metallic, composed mainly of iron and nickel; rocky, composed mainly of silicates and minerals; and mixed, which contain both metallic and rocky components.
When a meteorite reaches the surface, its impact can have several consequences. The most frequent is the formation of craters, and its extent will depend on the size of the meteorite and the energy released upon impact. Sometimes, in the case of larger meteorites composed of metallic materials, the impact can cause an explosion.
Characteristics of meteorites
Meteorites have the following characteristics:
- They are fragments of space rock that reach the atmosphere of a planet.
- They can be composed of rocky or metallic materials.
- There is evidence of meteorite impacts on Earth, Mars and the Moon.
- Their impacts can generate craters and explosions.
- They provide information about the formation of other celestial bodies.
How are meteorites formed?
Meteorites originate from comets or asteroids.. Comets are celestial bodies composed mainly of ice, dust and rocks, and asteroids are rocky or metallic objects that orbit the Sun.
Comets and asteroids sometimes suffer fragmentation processes due to collisions between them, the action of solar radiation or gravitational forces. These collisions can generate smaller fragments called meteoroids.
Meteoroids can cross Earth's orbit and sometimes collide with our planet. When a meteoroid enters the Earth's atmosphere, it is called a meteor. Friction with the atmosphere generates heat and causes the meteor to heat up and light up, forming a luminous trail in the sky known as a shooting star. If the meteoroid is large enough to resist erosion from entering the atmosphere and reach the Earth's surface, it is called a meteorite..
What are meteorites made of?

Meteorites can have various compositions, but, generally speaking, they are classified into three categories:
- metallic meteorites. They are mainly composed of iron and nickel. Metallic meteorites are less common compared to rocky ones.
- rocky meteorites. They are composed mainly of minerals similar to terrestrial rocks. They are the most common type of meteorite that reaches Earth, since 86% of the total have this composition.
- Mixed meteorites. They are composed of both metallic and rocky elements. They are the least common type of meteorite.
meteor showers

Meteor showers, also known as star showers, are celestial events in which a significant increase in the number of meteors (or shooting stars) is observed in the sky.. These meteor showers occur when the Earth passes through the orbit of a comet or passes through a cloud of particles.
During these events, fragments of dust and rocks from the comet enter the Earth's atmosphere, burn up due to friction, and create the characteristic light trails in the sky.
Meteor showers are regular, predictable phenomena that can occur at specific times of the year, when the Earth crosses these cometary orbits. Each meteor shower has a radiant, which is the point in the sky from which the meteors appear to come. These radiants are associated with the constellation to which the comet belongs or the region of space where the particles originated.
Some of the most famous and frequent meteor showers are:
- Quadrantids. They occur during the first days of January, and are most intense around the 3rd and 4th of this month. They have their radiant near the constellation of Boyero.
- Lyrids. They are observed between April 16 and 25. They have their radiant near the constellation of Lyra. This meteor shower is caused by particles left behind by comet C/1861 G1 Thatcher.
- Perseids. They are one of the most popular meteor showers and occur between mid-July and late August, peaking around August 12 and 13. The radiant is in the constellation of Perseus.
- Draconids. Also known as Giacobínids, they occur during the first days of October, with their radiant in the constellation of the Dragon. This rainfall can be variable and some years experience an unusual increase in activity.
- Orionids. They are produced by debris from Halley's Comet. They are visible for one week between October 16 and 27. Its radiant is in the constellation of Orion.
The study of meteorites

Meteorites are an important source of extraplanetary materials that represent an enormous opportunity for scientific study.
Meteorite identification is based on visual characteristics and laboratory analysis, including mineralogical and chemical tests. Academic institutions, natural history museums and astronomical observatories participate in the study of meteorites. For example, the Smithsonian Institution in the United States, the Natural History Museum in London, and the National Science Museum in Japan have collections of meteorites and conduct research in this field.
Meteorites provide information about the formation and evolution of the solar system and about the composition of asteroids and comets. Additionally, the study of meteorites can shed light on organic chemistry and geological processes in other celestial bodies.
famous meteorites
Some famous meteorites in history are:
- Alan Hills 84001. It was a meteorite that came from Mars, in which some scientists believed they detected a fossil of bacteria, which would prove the past existence of life on the red planet. It impacted Antarctica.
- Canyon Diablo. It was a metallic meteorite that impacted the Earth 50,000 years ago and produced the Barringer crater in Arizona, United States. The fragments of this meteorite were used by Native American people as weapons.
- Allende. It was a meteorite that impacted Mexico in 1969. It proved to have carbon content and to be older than the Earth.
- Cape York. It was one of the largest metallic meteorites in history. It impacted Greenland 10,000 years ago and the Inuit people used it as a source of iron.
References
- Iberdrola. (2024). Meteorites on Earth: how many fall per year and why don't we see them? https://www.iberdrola.com/
- La Plata Museum. (sf) Meteorites. Faculty of Natural Sciences and Museum, National University of La Plata. https://www.museo.fcnym.unlp.edu.ar/
- Rodríguez, H. (2023). These are the most famous meteorites that have fallen on Earth. National Geographic Spain. https://www.nationalgeographic.com.es/