What is a shooting star?

One of the natural phenomena that has attracted attention since the early ages when mankind looked up to the sky, is undoubtedly the star shift. A beam of light that suddenly flashes and extinguishes on a calm and cloudless night her There are some supernatural answers in every religion and culture about why and what it will produce.

Until a few centuries ago, we did not have a clear understanding of why and how stars shift. For a detailed explanation of what the star shift is, we can take a look at the following chapter in Çağlar Sunay’s book The Universe in 50 Questions (1):

What is a shooting star?

On a night when the sky is clear, where there is no light pollution, you are most likely to see a star shift in the sky. Scientists call this light show called meteor as “flowing star“ or “shooting star arasında among the people. It is not stars that cause meteors to form. In fact, the meteor is not a space event, but a light event that takes place in the atmosphere – 75 to 100 km above the ground. Every day more than a thousand tons of space dust and tiny meteors are “spilled’ on Earth. Of these, up to 10 m in diameter are called meteoroids. Meteoroids are fragments that break away from asteroids or comets. Among these, those with a diameter of a few millimeters to a few centimeters, enter the atmosphere at a speed of 10,000 km to 70,000 km per hour, “burn” and evaporate, emitting colorful and bright lights. They become part of the atmosphere. What we see as “star shift eri at night are these flashes. The color of the meteor varies according to the type of substances contained in the meteorites. If the meteoroid entering the atmosphere is larger, the burning time görünme that is, the time it appears in the sky uzun is longer and appears brighter. Those whose dimensions are measured in meters can reach the earth, although they lose most of their mass in the atmosphere. These generally fall into the oceans or into empty spaces without human habitation. (*) Among the thousands of tiny meteorites that fall to the earth every day, there is an average of 40 cm in diameter; meteorites that reach the earth are called meteorites. An average of 4 m in diameter and 20 m in meteorite impacts the Earth. The frequency of falling meteorites falling down to earth is inversely proportional. It strikes Earth every 2 million years from asteroids larger than 300 m in diameter and forms a crater of approximately 5 km in diameter, leading to regional destruction in the area it falls into (an area of ​​hundreds of thousands of square kilometers).

Every year, the Perseid meteor shower peaks on August 12-13. It is possible to see an average of 50 shooting stars per hour in areas where there is no light pollution at night. The Perseid meteor shower is caused by the rash left by the Swift-Tuttle comet. The period of this comet, discovered independently by Lewis Swift and Horace Tuttle in 1862, is 135 years.

There is an increase in the number of star shifts on certain nights of the year. When viewed from places where there is no moon and light pollution, they are truly impressive. These events are called meteor shower. On such nights you can see an average of 20-100 shooting stars per hour. This is because Earth is passing through a region of space filled with meteorites. The meteoroid-filled areas are actually trajectories where some comets once crossed and left the rash behind them.

Astronomers call comets “dirty snowballs.” Because most of a comet is ice and small pieces of rock, stones and dust. When the comet is in remote areas of its orbit to the Sun, this content remains firmly connected to each other in a frozen state. As the comet approaches the Sun, the ice melts and evaporates. The comet-forming substance is now loosely together. Over time, small stones and dust, along with gases, remain behind the main mass and form the comet’s tail that is millions of kilometers long. Some of these pieces in the tail break off the comet and remain on the orbit. So, just like planets and comets, these debris begin to spin around the Sun. Whenever Earth passes through one of these rash-covered orbits, more meteorites fall on Earth than ever before! So more shooting stars are seen. If the comet passed a few months or a few years ago, it leaves plenty of new rash behind. As the world passes through such an orbit, there is an extraordinary increase in the number of meteors. Thousands of star shifts per hour can be observed on these special nights. This is called a meteor storm.

Although not as frequent as shooting stars, comets that enter the inner parts of the Solar System every few years also create an impressive image of the sky at night, for a long time. The perimeter of the small cores is covered with a bright cloud of gas and dust of approximately 100,000 km in diameter. If the comet is large, a bright tail is formed behind it, millions of miles, or even tens of millions of kilometers (in the opposite direction to the Sun). This tail is always in the opposite direction to the Sun; because the solar wind “blows hafif these scattered light matter constantly in the opposite direction to the Sun. Such comets look much better in the sky at night. Comets are separated from asteroids by the majority of their contents being ice, stone, dust and gas, and loosely interconnected.

Comets’ tails always extend in the opposite direction to the Sun. Comets were seen as heralding ominous events in medieval Europe.

There are millions of comets in the Solar System. So far, only about 900 trajectories have been detected. About 200 of these are periodic. Most of the short-period comets – those whose period is shorter than 20 years – have a period of around seven years. These comets, estimated to come from the Kuiper Belt, have an orbit around the Sun up to Jupiter and in the same direction as the planets. They are already imprisoned in this region because of the gravitational effect of Jupiter. The majority of these comets wander in their short orbits, constantly losing matter (orbit), shrinking and disappearing. A small portion of Jupiter’s gravitational effect is sent to remote parts of the Solar System. It is estimated that comets with medium periods – periods between 20 and 200 years – and long periods – periods longer than 200 years – come from the Oort Cloud. Their orbital planes can make large angles with the ecliptic.

Comets have a great importance in the development of the Earth. Many astronomers think that most of the water on Earth is brought by comets that hit Earth. It is also thought that some of the organic substances that are thought to play a major role in the emergence of life come with comets.

Footnote:

* As human settlements take up less than 5 percent of the Earth’s surface, meteorites often fall outside these areas.

Reference: Sunay, Çağlar, Universe in 50 Questions, Science and Future Library, Istanbul, 2011, ss. 144-148.

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