Meteors shine when they enter Earth's atmosphere due to intense friction between the meteorite and air molecules. This friction generates heat that vaporizes the meteorite, creating a luminous trail called a meteor.
Meteors are generally small rocky or metallic fragments, often originating from comets or asteroids. These particles drift through space, quiet until they cross the path of Earth's orbit. Most are tiny, the size of a grain of sand or a pebble, while some can occasionally reach the size of a balloon or larger. When they enter our atmosphere at breakneck speeds (tens of thousands of km/h), they become visible: these are the famous shooting stars. Certain times of the year give rise to spectacular "showers," such as the Perseids in August.
When a meteor rushes towards Earth, it enters our atmosphere at full speed—sometimes at tens of kilometers per second! At this hellish pace, it collides with air molecules, generating impressive friction. All this turmoil produces extreme heat, easily reaching several thousand degrees. The result: the meteor heats up so much that its surface begins to burn, melt, and even completely vaporize. It is precisely this rise in temperature caused by atmospheric friction that gives the meteor its bright and fiery appearance.
When a meteorite comes crashing into the atmosphere at high speed, it heats up so much that the air molecules all around are violently jostled and shaken. This big commotion causes what is known as ionization: molecules lose one or more electrons and become electrically charged. Other molecules gain energy without losing an electron; they are said to be in an excited state. Very quickly, these excited molecules seek to return to normal, and to do that, they release the excess energy in the form of light. It is thanks to all this electric turmoil that the meteor shines with such intensity!
The bright passage of a meteor results mainly from the excitation and then the rapid de-excitation of the molecules in the atmosphere. When the meteor rushes at high speed, it transfers energy to the atoms present in the air. These atoms gain an excess of energy and become unstable, then immediately release it in the form of light: this is light emission. The observed color mainly depends on the type of atom involved: for example, oxygen atoms often emit green, sodium manifests as a yellowish or orangish hue, and iron gives a light yellow shade. Depending on their chemical composition and the entry speed into the atmosphere, meteors can therefore display a whole range of different colors, making the light show all the more astonishing.
It is estimated that about 48.5 tons of meteorites reach the Earth's surface each year, but most fall into the oceans and go unnoticed.
Every day, about 100 tons of dust and small space particles enter the Earth's atmosphere and burn up before even reaching the surface of our planet, thus going unnoticed by most observers on Earth.
The shooting stars associated with meteor showers are generally caused by the Earth's passage through debris left by comets, while the meteorites found on the ground most often come from asteroids.
During a meteor shower, the shooting stars appear to originate from the same point in the sky called the 'radiant.' This illusory point results from a perspective effect related to the Earth's movement through space as it passes through a cloud of particles.
Most shooting stars are made up of very small particles that completely disintegrate in the atmosphere. It is extremely rare for a sufficiently large fragment to reach the Earth's surface in the form of a meteorite. Generally, even these meteorites do not pose a significant risk to the personal safety of individuals.
The different colors observed due to the heating of the meteor primarily depend on the speed at which it enters the atmosphere and its chemical composition. For example, a dominant green often suggests the presence of copper or nickel, while red hues may indicate a higher content of silicon or oxygen.
A meteor generally enters the atmosphere at speeds ranging from 11 km/s to 72 km/s. This high speed causes intense friction with the atmospheric air, responsible for its bright heating.
Most meteors become visible when they reach an altitude of about 80 to 120 km above the Earth. It is within this relatively dense atmospheric layer that their bright heating occurs.
These recurring meteor showers occur when the Earth passes through the dusty trail left by certain comets in their orbit around the Sun. Since this encounter happens every year at the same time, these meteor showers appear on regular dates.
A meteor is the luminous phenomenon observed when a small body (meteoroid) enters the Earth's atmosphere, while a meteorite is a fragment of that body that reaches the surface of the Earth. Most meteors completely disintegrate before reaching the ground.
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