Meteoroids, Meteors & Meteorites

Space rocks undergo an incredible transformation as they journey from the depths of space to Earth's surface. The terminology changes based on their location:

Meteoroid: A small rocky or metallic body in outer space, significantly smaller than an asteroid. Meteoroids range in size from tiny dust particles to objects up to 1 meter wide.

Meteor: When a meteoroid enters Earth's atmosphere, it vaporizes and creates a streak of light in the sky, often called a "shooting star" or "falling star."

Meteorite: If a meteoroid survives its passage through the atmosphere and lands on Earth's surface, it is called a meteorite.

Meteorites are classified into three main types based on their composition and structure. Each type provides different information about the early solar system.

Stony Meteorites: The most common type (about 94% of falls), composed mainly of silicate minerals. They are divided into chondrites (containing chondrules) and achondrites (without chondrules).

Iron Meteorites: Composed primarily of iron-nickel alloys (about 5% of falls). These are thought to come from the cores of differentiated asteroids.

Stony-Iron Meteorites: The rarest type (about 1% of falls), containing roughly equal amounts of silicate minerals and iron-nickel metal.

Meteor showers occur when Earth passes through the debris trail left by a comet or asteroid. These tiny particles burn up in our atmosphere, creating multiple "shooting stars" in a short period.

Most meteor showers are associated with specific comets. For example, the Perseids come from Comet Swift-Tuttle, and the Leonids from Comet Tempel-Tuttle.

Meteor showers are named after the constellation from which they appear to radiate. The best time to view them is typically after midnight when your location is facing the direction of Earth's orbit.

Throughout Earth's history, meteorite impacts have played a significant role in shaping our planet's surface and influencing the course of evolution.

The most famous impact is the Chicxulub crater in Mexico, which is linked to the extinction of the dinosaurs 66 million years ago. This impact created a crater approximately 180 km in diameter and released energy equivalent to billions of atomic bombs.

More recently, the 2013 Chelyabinsk meteor in Russia demonstrated that even relatively small meteoroids can cause significant damage when they explode in the atmosphere.

Meteorites provide invaluable scientific information about the early solar system. As primitive materials largely unchanged since the formation of our solar system 4.6 billion years ago, they serve as time capsules preserving information from that era.

By studying meteorites, scientists have:

• Determined the age of the solar system (4.568 billion years)
• Discovered pre-solar grains that predate our solar system
• Found amino acids and other organic compounds
• Learned about differentiation processes in early planetary bodies
• Gained insights into the composition of Mars and the Moon

Some meteorites even come from Mars and the Moon, blasted off those bodies by impacts and eventually finding their way to Earth.