A meteor is the visible path of a meteoroid that enters the Earth's (or another body's) atmosphere, commonly called a shooting star. The visibility is due to the heat produced by the atmospheric entry. A very bright meteor, brighter than the apparent magnitude of Venus, may be called a fireball or bolide.

Meteorites are a solid portion of a meteoroid that survives its fall to Earth, or some other body. Meteorites are classified as stony meteorites, iron meteorites, and stony iron meteorites, and further categorized according to their mineralogical content. They range in size from microscopic to many meters across. Of the several tens of tons of cosmic material entering Earth’s atmosphere each day, only about one ton reaches the ground - an object’s survival chances depending on its initial mass, speed of entry, and composition. Incoming meteoroids with masses between 10^-6 g and 1 kg tend to burn up completely as meteors. Smaller objects are dramatically slowed down without being incinerated and fall as a continuous, gentle, invisible rain of micrometeorites. Larger objects, up to 1,000 tons, are decelerated to a lesser extent, fall through the lower atmosphere at high speed, causing them to glow brightly as a fireball. A meteor striking the Earth or other object may produce an impact crater.

Most meteors disintegrate in the atmosphere, making impact events (Earth impacts) on the surface of Earth uncommon. About 500 baseball-sized rocks reach the surface each year. Large meteorites may strike the ground with considerable force, leaving behind a meteor crater. The kind of crater will depend on the size, composition, degree of fragmentation, and incoming angle of the meteor. The force of collision may cause widespread destruction. Occasional damage to property, livestock, and even people has been recorded in historic times. In the case of comet fragments, which are largely composed of ice, a considerable concussion may occur, even though no fragment of the original meteoroid survives.

Stony Meteorites

A meteorite composed of silicate minerals, but that may have up to 25% metal (iron and nickel) by weight. Stony meteorites are extremely heterogeneous as a group, ranging from samples of primordial matter that have remained more or less unchanged for the last 4.5 billion years to highly evolved rocks from differentiated worlds, such as the Moon or Mars. They account for 95% of all known falls. The majority (86% of all falls) are chondrites, the rest achondrites.

Iron Meterorites

A meteorite composed mainly of iron (Fe) and nickel (Ni) in the form of two nickel-iron alloys, kamacite and taenite. Due to their metallic makeup and extraordinary weight, iron meteorites are easy even for a layperson to tell from ordinary rocks. Also, because they rarely break up in the air and suffer much less from the effects of ablation during their passage through the atmosphere, they are usually much larger than stony or stony-iron meteorites. All known iron meteorites together have a mass of more than 500 tons - about 89% of the entire mass of all known meteorites. Yet they are comparatively rare, accounting for just 5.7% of witnessed falls.

There are two ways of classifying iron meteorites. The older, structural method is based on characteristic crystalline features that show up when the meteorites are sectioned, etched, and polished. This results in three subdivisions: hexahedrites (with 4 to 6% Ni), octahedrites (the most common type, with 6 to 12% Ni), and ataxites (with more than 12% Ni). The newer chemical method is far more precise but depends on sophisticated instruments, including electron microprobes and X-ray spectroscopes, to look at the quantities of trace elements such as germanium, gallium, or iridium present. The concentrations of the trace elements are plotted against the overall nickel content on logarithmic scales to resolve well-defined chemical clusters, each representing a distinct chemical group. Fourteen groups, labeled by Roman numbers and letters, such as "IAB", have been recognized so far. It is believed that the iron meteorites of each chemical group share the same origin and formed on a common parent body. Iron meteorites come mostly from the cores of small differentiated asteroids that were disrupted by devastating impacts shortly after their formation.

Stony-Iron Meteorites

A meteorite composed of roughly equal amounts by weight of silicate minerals and nickel-iron. Modern meteoritics considers the stony-irons to consist of just two groups, the mesosiderites and the pallasites; however, there is a gradual shading into metal-rich stony meteorites such as the lodranites (once considered to be stony-irons) and silicate-rich iron meteorites. Stony-iron meteorites are less abundant than their stony and iron cousins, comprising a total known mass of some 10 tons—about 1.8% of the entire mass of all known meteorites.

Micrometeorite

The smallest type of object that reaches the surface of the Earth (or some other planet or moon) from space. Two varieties occur: cosmic spherules and interplanetary dust particles. The former are round and about 1 millmeter or less in diameter. Interplanetary dust particles are irregular in shape and less than 0.05 millimeter in size. Micrometeorites are mineralogically different from larger meteorites and probably originate in comets. Their small size allows them to radiate heat away so that they are not melted during their passage through the atmosphere. Most are recovered from the clay beneath the oceans far from land and ice from Antarctica and Greenland. Others have been collected in the stratosphere.

Tektites

Molten terrestrial material 'splashed' from an impact crater can cool and solidify into an object known as a tektite. Tektites are up to a few centimeter sized objects of glass, which are formed by the impact of large meteorites on Earth's surface. The impact melts material from Earth's surface and catapults it up to several hundred kilometers away from the impact site. The molten material cools and solidifies to glass. Although a meteorite impact causes the formation, the precursor material of tektites is of terrestrial origin. The color of tektites is black or olive-green and their shapes varies from rounded to irregular. Because of the formation process, locations where tektite can be found are often associated with impact craters.