Meteorite

Space rocks fall from far away.

They move through the air very fast. The air makes them get very hot. This can make a bright fireball.

Some rocks look like stones. Some look like metal. Some are a mix of both. They can even make a small pit in the ground.

These rocks are very old. They are like tiny pieces of space.

A meteorite is a rock from outer space. It falls to the surface of a planet or moon.

When the rock enters our air, it heats up. This happens because of friction and pressure. The rock can become a bright fireball. Some people call these shooting stars. Astronomers call the brightest ones bolides.

Most meteorites come from broken pieces of asteroids. There are three main types of meteorites. Stony meteorites are mostly made of rock. Iron meteorites are made of metal. Stony-iron meteorites have both rock and metal.

Some meteorites are very old. Chondrites are stony rocks that are 4.55 billion years old. They are like building blocks for planets. Some meteorites come from the Moon or Mars.

When a rock hits the ground, it might make a small pit. Large ones can make big craters.

Scientists found that some meteorites have things like sugar and water. These might be ingredients for life.

A meteorite is a rock from outer space that lands on a planet or moon.

It starts its journey as a meteoroid traveling through space. When it hits our atmosphere, things change very quickly. Friction and pressure cause the object to heat up and release energy. This creates a bright fireball that people often call a shooting star. The brightest fireballs are known by astronomers as bolides. Once the object settles on the ground, it is finally called a meteorite.

How a meteorite changes depends on how it enters our air. As it travels, the heat melts the surface in a process called ablation. This can sculpt the rock into strange shapes. Some meteorites develop shallow indentations that look like thumbprints. These small marks are called regmaglypts. If the rock stays in one position, it might grow a nose cone shape. Eventually, the molten surface cools into a thin, dark layer called a fusion crust.

Scientists group these space rocks into three main categories. Most meteorites are stony meteorites called chondrites. These are about 4.55 billion years old and contain tiny round bits called chondrules. They are often seen as the building blocks of planets. About 6% are iron meteorites made of iron and nickel. These often come from the cores of ancient, broken planetesimals. The last group is stony-iron meteorites, which are a mix of both metal and rock.

Space rocks hit our world more often than you might think. About 35 to 40 objects with a diameter of one meter enter our atmosphere every year. This happens roughly once every ten days. Most small meteorites only make a tiny pit when they land. However, very large objects can create huge impact craters. Famous examples include the Barringer Meteor Crater and the Odessa Meteor Crater. Large iron meteorites are the ones most likely to create these big craters.

Studying meteorites helps us understand the history of our solar system. Some meteorites are special because they come from the Moon or Mars. They are the only materials from other planets that humans have ever recovered. Scientists have even found interesting things inside them. In 2018, researchers found liquid water and organic substances in very old meteorites. In 2019, they even detected sugar molecules. These discoveries show that meteorites might carry the ingredients needed for life.

A meteorite is a rock that originated in outer space. It has fallen onto the surface of a planet or a moon. This journey begins when a meteoroid enters a planetary atmosphere. As the object moves, friction and pressure cause it to heat up. This process causes the object to radiate energy. This creates a bright fireball, which many people call a shooting star. Astronomers call the brightest examples of these fireballs bolides.

When the object finally settles on a surface, it is called a meteorite. There are two ways scientists categorize these arrivals. If the object is observed during its flight and then recovered, it is a meteorite fall. All other recovered meteorites are known as meteorite finds. Most meteorites are quite small. They usually arrive at the surface at their terminal velocity. This means they only create a small pit upon impact. However, larger objects can create massive hypervelocity impact craters.

As a meteoroid enters the atmosphere, it undergoes a process called ablation. This is when the heat melts the surface of the rock. Ablation can sculpt the meteorite into unique shapes. Some meteorites develop shallow, thumbprint-like indentations called regmaglypts. If the object maintains a fixed orientation, it may develop a conical nose cone shape. As the object slows down, the molten surface layer solidifies. This forms a thin, dark layer known as a fusion crust.

Scientists traditionally divide meteorites into three broad categories based on their makeup. Stony meteorites are composed mainly of silicate minerals. About 86% of meteorites are chondrites, a type of stony meteorite. These contain small, round particles called chondrules. These particles were likely melted while floating in space. Chondrites are roughly 4.55 billion years old. They are often called the building blocks of the planets. Another stony group is the achondrites, which make up about 8% of meteorites.

Iron meteorites make up about 5% of observed falls. These are largely composed of ferronickel alloys like kamacite and taenite. Most iron meteorites likely come from the cores of ancient, molten planetesimals. When these planetesimals collided, their metal cores broke apart. Iron meteorites are very durable and often survive atmospheric transit intact. This is why they are frequently responsible for large impact craters. Examples include the Barringer Meteor Crater and the Odessa Meteor Crater.

Stony-iron meteorites represent the remaining 1% of meteorites. These contain large amounts of both metallic and rocky material. One type is called a pallasite, which may come from the boundary of a planetesimal's core. Another type is the mesosiderite. While rare, these objects provide a look at the complex layers of early space bodies.

Space rocks hit Earth with surprising frequency. Roughly 35 to 40 objects with a diameter of one meter enter the atmosphere every year. This averages out to about one event every ten days. Most of these objects disintegrate before they reach the ground. However, very large stony objects can reach the surface. These objects can weigh tens of millions of tons. Such impacts are very rare but can be extremely energetic.

Meteorites are vital for understanding the chemistry of our solar system. Some meteorites come from the Moon or Mars. These are the only materials from other planets that humans have recovered. Scientists have found complex organic compounds in meteorites. These include substances found in DNA, such as uracil and cytosine. In 2018, researchers found liquid water and prebiotic substances in 4.5 billion-year-old meteorites. In 2019, scientists even detected sugar molecules. These findings suggest meteorites may carry the ingredients for life.