How is a meteorite different from a regular rock?

Meteors are a familiar concept to many, but meteorites may still be quite foreign.

Essentially, both meteorites and meteors are fragments from space that fall to Earth. They are debris from asteroids, comets, or other objects in the solar system. But why are they referred to by different names? In fact, these are two completely distinct concepts.

Meteorites (meteoroids) are natural objects from outer space that impact the Earth’s surface. When a meteorite enters Earth’s atmosphere, the compressed pressure causes it to heat up and emit light, which may include the burning of its outer layer.

Meteorites are natural objects from outer space that impact the Earth’s surface.

Meteorites can be small asteroids or extinct comets, with masses ranging from 10⁻¹⁰ to 10⁴ kg and diameters from a few micrometers to several meters. Small meteorite particles are referred to as micrometeorites. Larger meteorites are remnants and fragments from comets or asteroids. The remaining debris from aging comets that have ceased to shine continue to move in their original elliptical orbits. Only when Earth’s orbit intersects these invisible meteor trails does their presence become evident. As they penetrate Earth’s atmosphere, they ignite at altitudes of 150 to 120 km, causing the phenomenon known as shooting stars; particularly bright meteors are referred to as fireballs (bolides).

A meteorite measuring only 30 to 40 cm in size can create a burning air zone around it extending several hundred meters. The surface temperature of a meteorite can reach 1,600°C, and at altitudes above 100 km, its surface melts, transforming into gas, vaporizing rapidly, and emitting light. A meteorite must have sufficient mass, high density, and relatively slow motion (speed less than 20 km/s) to avoid completely burning up in the atmosphere. Meteorites are the remnants of meteors that have entered the atmosphere, lost some mass through burning, and fallen to the Earth’s surface.

Meteorite craters are divided into two groups based on their formation sequence.

According to Wikipedia, there is also a concept known as meteorite craters. Meteorite craters are depressions on the surface of the Earth, planets, or moons with solid surfaces, created by the impact of meteorites. Meteorite craters are categorized into two groups based on their formation sequence.

Primary meteorite craters are formed from the initial impact of a meteorite. Secondary meteorite craters occur due to debris from the initial impact falling back onto the planet’s surface.

Meteorites are not only found on Earth but are also found on the surfaces of Mars and the Moon.

Previously, meteorite craters were considered distinctive features of the Moon, while the few meteorite craters on Earth were viewed as rare phenomena.

From Earth, approximately 300,000 meteorite craters can be observed on the Moon’s surface through binoculars. In reality, results from photographs taken by artificial satellites orbiting the Moon or from landers on its surface estimate the number of meteorite craters larger than 1 meter in diameter to be around 3 x 10¹² (including the far side of the Moon). The density of meteorite craters on Mercury is similar to that on the Moon.

In summary, when it is still in outer space, it is called a meteor. Once it passes through the atmosphere and lands on the Earth’s surface, it is referred to as a meteorite.

Meteorites provide scientists with valuable information about the formation and development of the solar system. Studying meteorites can help scientists better understand the origins and compositions of materials in space, and it may even shed light on the origins of life on Earth.