Meteor, Meteoroid, Meteorite

A meteoroid is a relatively small (from the size of a grain of sand to a boulder) fragment of fragments in the solar system. If any part of a meteor lasts all the way down to the earth’s surface, it is called a meteorite. When a meteoroid (or other object) hits the Earth, a (impact) crater usually forms at the point of impact. Molten terrestrial material “ejected” during crater formation can cool and solidify into an object known as tektite.

A meteorite is a body that forms when a meteoroid hits Earth or another cosmic body with a solid surface. The vast majority of meteorites are stone chondrites, but there are also iron meteorites.

In order for a meteorite to hit the ground, the meteoroite must be at least 1 meter in diameter and weigh at least 1 ton. In addition, it must move at a low speed, i.e. 10 to 20 km / s. From the whole meteoroid, only a few kilograms fall to the earth’s surface, because the vast majority of matter melts and evaporates by flying through the atmosphere.

A micrometeoroid is a meteoroid with microscopic dimensions, with a diameter d <~ μm. It is part of interplanetary dust in the solar system. When it encounters the Earth, a micrometeoroid, unlike a meteoroid, does not burn and does not glow like a meteor, but breakes itself by friction against the upper layers of the atmosphere and slowly falls to the Earth.

A meteor is a name for a visible phenomenon in the atmosphere that results from the meteoroid flying through the Earth’s atmosphere (or the atmosphere of another body). After the meteoroid enters the Earth’s atmosphere, a light phenomenon occurs due to air pressures and subsequent ionization of air particles. In the night sky, it manifests itself as a rapid flight of a luminous object, so it is also known as a shooting star. Sometimes it happens that the body just flies through the upper layers of the Earth’s atmosphere and returns to outer space. In this case, it is a tangential meteoroid.

The bright luminosity of the meteor is due to the temperature produced by entering the atmosphere. An average bright meteor has a brightness of about 0 to 3 magnitudes. This corresponds to the size of a pinhead (for the fastest meteoroids of comet origin) to the size of a small ball (the slowest meteoroids composed of iron). Very bright meteors, brighter than Venus, are also referred to as bolids. With different chemical compositions, the meteor has different colors:

Orange- yellow (sodium), Yellow (iron), Blue- green (magnesium), Violet (calcium), Red (atmospheric nitrogen and oxygen).

Meteors often group into meteor showers. The speed at which a meteor flies through the atmosphere is somewhere between 10 and 70 kilometers per second.

 The kinetic energy of a 1 gram particle (a ball with a diameter of 1-2 millimeters) is the same as the energy of a Trabant (natural satellite) crushing an object (such as a wall) into which it crashed at a speed of about 100 kilometers per hour.

Therefore, most meteoroids evaporate in the atmosphere, the temperature of the body itself reaches thousands to tens of thousands of degrees Celsius. Most meteors come from cometary parts, which are very fragile due to their (largely icy) content. Their average density is less than the density of water. The comet’s material is so fragile that it could be crushed in the hands.

An estimated 25 million meteoroids, micrometeoroids and other space debris enter Earth’s atmosphere each day, which results in an estimated 15,000 tonnes of that material entering the atmosphere each year.

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