The question of the “biggest meteorite ever found” requires defining terms, as the largest object found intact differs vastly from the size of the impact structure left by a massive cosmic collision. Space rocks, fragments of asteroids or comets, constantly bombard Earth, offering tangible evidence of the solar system’s history. These extraterrestrial materials allow scientists to study pristine matter that predates the formation of our planet.
Defining the Terms: Meteoroids, Meteors, and Meteorites
The naming convention for space rocks depends entirely on their location in the solar system. A meteoroid is a small rocky or metallic body traveling through space, ranging in size from dust grains up to approximately one meter in diameter. Most meteoroids originate from the asteroid belt between Mars and Jupiter, or are debris from comets.
When a meteoroid enters Earth’s atmosphere, friction causes it to heat up and glow, creating a visible streak of light known as a meteor, often called a “shooting star”. If the object is large enough to survive this fiery passage and reaches the planet’s surface, it is then classified as a meteorite. The vast majority of incoming space material burns up completely before touching the ground.
The World’s Largest Single Meteorite
The largest single, intact meteorite ever found on Earth is the Hoba Meteorite, located in Namibia. This colossal mass has an estimated weight of around 60 tons, or approximately 130,000 pounds, making it the most massive naturally occurring piece of iron known on the planet’s surface. Its dimensions are roughly 2.7 meters by 2.7 meters, with a thickness of about 0.9 meters.
The Hoba Meteorite is classified as an ataxite, a rare type of iron meteorite with a high nickel content. Its composition is primarily an iron-nickel alloy, consisting of about 82% to 84% iron and 16% nickel. It was discovered in 1920 by a farmer plowing his field and has never been moved from its original location.
Scientists estimate the Hoba Meteorite fell to Earth less than 80,000 years ago. Its flat, tabular shape and relatively low impact speed allowed it to remain largely intact, preventing the creation of a large, discernible crater. This preserved it as the largest single specimen, unlike most large meteoroids that fragment or vaporize violently upon atmospheric entry.
Largest Impact Structures
The Hoba Meteorite is the largest found object, but the largest cosmic impacts leave behind massive geological features known as impact structures or craters. These structures represent the site of an ancient collision where the original space object was largely destroyed. The energy released by these hypervelocity events is so great that the impactor itself is often vaporized, meaning no physical meteorite remains.
The largest confirmed impact structure on Earth is the Vredefort Dome in South Africa, formed over two billion years ago. The original crater is estimated to have been between 180 and 300 kilometers (111 to 186 miles) in diameter, although erosion has significantly altered the visible structure. Another well-known structure is the Chicxulub Crater beneath the Yucatán Peninsula in Mexico, which measures about 180 kilometers (112 miles) wide and is linked to the extinction of the non-avian dinosaurs 66 million years ago.
Major Types of Meteorites
Meteorites are categorized into three main groups based on their chemical and mineral composition, providing insight into the parent bodies from which the fragments originated. The most common are stony meteorites (aerolites), which make up more than 95% of observed falls and are composed mainly of silicate minerals. Within this group are chondrites, which contain small, spherical mineral grains and represent some of the oldest materials in the solar system.
The second major category is iron meteorites (siderites), such as the Hoba Meteorite, which are composed almost entirely of an iron-nickel metal alloy. These fragments originate from the metallic cores of differentiated asteroids. The rarest group is the stony-iron meteorites (siderolites), which contain roughly equal proportions of metallic iron-nickel and silicate materials, including pallasites.