meteoritesespecially

Meteorites are fragments of celestial bodies that survive their passage through Earth's atmosphere and land on the surface. Most originate from asteroids in the inner solar system, but some are fragments from the Moon or Mars that were ejected into space before reaching Earth.

They are broadly classified into three main types: iron meteorites, stony meteorites, and stony-iron meteorites. Iron meteorites consist mainly of metallic iron-nickel. Stony meteorites are further divided into chondrites and achondrites; chondrites are the most common and contain small spherical grains called chondrules, representing primitive solar system material, while achondrites show igneous textures and lack chondrules. Stony-iron meteorites contain significant portions of both metal and silicate minerals.

Most meteorites originate from asteroids, though some samples come from the Moon or Mars. Chondrites formed in the early solar system about 4.56 billion years ago and are valuable for studying solar nebula processes. Radiometric dating of meteorites provides a timeline for planetary formation and solar system evolution.

Meteorites are collected as falls, when observers witness them, or finds, when fragments are discovered long after the event. Identification relies on features such as a fusion crust, regmaglypts, and distinctive mineral compositions. Analyses use petrography, microscopy, isotopic measurements, and other instrumental methods to determine origin, age, and history.

Notable meteorites include Allende, a carbonaceous chondrite that yielded information about early solar system processes; Murchison, famous for ancient organic compounds; Hoba, the largest known intact meteorite; and Chelyabinsk, a prolific fall in 2013.