Meteorites. These cosmic wanderers have fascinated people for ages. Looking up at the night sky, each of us has at least once seen what looks like a star falling from its place, leaving a bright trail as it rushes downward. Imagine the awe of people centuries and millennia ago when a meteorite fell before their eyes. The thunderous roar, the hissing and cracking, a fiery ball streaking across the sky and crashing with an incredible boom! The memory of such an event became legends and myths, and people kept fragments of the celestial stone as sacred relics. It is no surprise that even scientists were long reluctant to recognize meteorites as real, considering tales of them to be mere fiction. It wasn’t until 1794, with the study of the Pallas Iron—a large meteorite found in Siberia—that the extraterrestrial origin of these objects was confirmed.

Over two hundred years have passed since then, and today meteorites are under the close scrutiny of scientists from various fields. Meteorites have become part of global popular culture, appearing in films and science fiction novels. It’s high time we finally learn what these visitors from space are.

Apart from planets and stars, space is filled with various objects. There are asteroids—bodies resembling planets but far smaller. Asteroids have their own orbits around the Sun, and some even have moons. There’s cosmic dust—tiny particles of matter dispersed throughout space. And then there are intermediate objects of moderate size. Their sizes range from 0.1 mm to 10-30 m. These are called meteoroids. They can be scattered in space, move along random trajectories, or have relatively stable orbits. Sometimes, entire clusters of meteoroids are encountered—so-called swarms.

When such a meteoroid enters the gravitational field of a planet, its trajectory changes, and it gradually heads toward the planet’s surface. Occasionally, planets also collide with asteroids.

The spectacular phenomenon of a cosmic body burning up in the atmosphere is called a meteor (or bolide). Only when the cosmic body, regardless of size, reaches the planet’s surface can it be called a meteorite.

Of course, every meteorite is unique, and no two meteorites are the same. But based on their composition, they are divided into three main groups:

• Stony Meteorites: This is the largest group. 92.8% of all meteorites that reach Earth are stony, and of these, 92.3% are called chondrites. Remarkably, their composition is identical to that of the Sun, except for the light gases hydrogen and helium. How is this possible? The Solar System formed from a giant interstellar gas-dust cloud. Under the influence of gravity, matter was drawn to the center, forming a protostar. As the mass of material falling onto it increased, the temperature of the protostar rose, and eventually, thermonuclear reactions ignited in its core. Thus, the Sun was born. The remaining matter from the gas-dust cloud formed all other cosmic objects in the Solar System. Chondrites are precisely the smallest particles formed from the material of the gas-dust cloud. One could say that both they and the Sun are made of the same material. The primary minerals in their composition are various silicates.
• Metallic Meteorites: Another large group, making up 5.7% of all meteorite falls on Earth. They mainly consist of an iron-nickel alloy, are very strong, and are almost impervious to corrosion.
• Iron-Stony Meteorites: The rarest (and most beautiful) meteorites, constituting just 1.5%. They have a complex structure in which the metallic part is interwoven with silicate formations.

About 5-6 tons of meteoritic material falls on Earth daily. This amounts to around 2,000 tons per year. It may seem like a significant figure, but most meteorites burn up in the atmosphere before reaching the ground. Of the remainder, a significant portion falls into the ocean or sparsely populated areas, simply because they occupy most of our planet. Only in rare cases does a meteorite fall in a populated area, witnessed by people.

Cosmic bodies move at tremendous speeds. When entering the atmosphere, a meteorite’s speed can reach 11 to 72 km/s. Friction with the air causes it to ignite and start glowing. Generally, most meteorites burn up without reaching the surface. A large meteorite gradually slows down and cools. What happens next depends on many factors—mass, initial speed, angle of entry into the atmosphere. If the meteorite manages to slow down, its trajectory may change to almost vertical, and it will simply fall to the ground. Sometimes the internal structure of the meteorite is uneven and unstable. In such cases, it explodes in the air, and its fragments fall to the ground. This phenomenon is called a meteorite shower. But if the meteorite’s speed is still high (about 2-4 km/s) and it is massive enough, a powerful explosion occurs when it collides with the Earth’s surface.

At the site of a large meteorite impact, a meteorite crater—astrobleme—is formed. On Earth, such craters are not always visible because weathering and other geological processes erode them. But on other planets, traces of colossal meteorite bombardments can be seen.

There are meteorite craters in Russia as well. The largest of them is in Eastern Siberia. This is the Popigai crater, with a diameter of 100 km, making it the fourth largest in the world. Popigai was formed 35.7 million years ago due to a collision with a large asteroid. There are reports that diamond deposits are hidden in its depths, but detailed information about this was classified during the Soviet era. The oldest Russian crater (and one of the oldest in the world) is the small Suavjärvi crater in Karelia. Its diameter is only 3 km, and now a lake occupies it. But its age—2.4 billion years—is impressive.

The chances of a meteorite hitting a person are extremely slim. Only two confirmed cases of a meteorite striking a person have been recorded, and both times the individuals sustained only minor bruises. There are also about a dozen reports of people dying from a meteorite strike over the past two centuries, but they lack official confirmation.

Nevertheless, denying the danger of meteorites would be unwise. The example of the Chelyabinsk meteorite shows that even the indirect effects of a large cosmic object’s explosion can be destructive.

In popular culture, a stereotype has developed that meteorites may be radioactive or carry spores of monstrous alien diseases. These modern myths are perpetuated by science fiction and cinema but lack any basis. No radioactive meteorites have ever been discovered. Not a single one.

For a piece of stone or a meteorite to be radioactive, it must contain radioactive substances, such as uranium. But over time, their radioactivity decreases. The rate of this decrease is characterized by a value known as the half-life. And this value is much shorter than the average age of any meteorite that falls to Earth.

But isn’t there radiation in space, like from the sun? Yes, but it’s important to understand that being exposed to radiation doesn’t mean becoming radioactive. If you spent the weekend inside a nuclear reactor, you probably wouldn’t feel well afterward. But you still wouldn’t emit radiation yourself.

Some meteorites contain complex organic compounds and are therefore of immense interest to scientists. But no microorganisms or traces of alien life have yet been found on them.

In ancient times, meteorites could serve as objects of religious worship. Meteorite iron was known long before people learned to smelt iron from ore. Objects made from meteorite iron were highly valued; one example is a dagger found in Tutankhamun’s tomb.

Today, meteorites are primarily of scientific interest. They can tell us much about the early days of our Solar System and distant worlds.

However, iron and iron-stony meteorites are used in jewelry. Their unique beauty is derived from the crystalline structure of their lattice. Intertwined crystal needles, complex geometric shapes, and fractal compositions. Scientifically, this phenomenon is called Widmanstätten patterns. They form during the very slow cooling of an iron-nickel alloy heated to extreme temperatures. In space, there is no air, no heat carrier, so a meteorite cools over an infinitely long period—just a few degrees per million years. In iron-stony meteorites, the amorphous metallic matrix contains silicate inclusions, including olivine. The yellow-green transparent varieties of this mineral are genuine gemstones. Such structure and features cannot be artificially created. The very appearance guarantees the authenticity and uniqueness of jewelry made from a “fallen star”—a meteorite.