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Distance from Earth to Sun

From early childhood, everyone knows that the Sun is a huge red-hot ball, a star that is far away. But on the question of what the distance from the Earth to the Sun, not every adult with a higher education can answer. This article describes how the distance from the Earth to the Sun varies throughout the year, how scientists measure this distance and how much it is significant in comparison with the remoteness of other space objects.

The sun is about a hundred and fifty million kilometers away from the Earth. The orbit of the Earth is not the right circle, but an ellipse, so the distance between the center of the solar system and the Earth at different times is not the same. Its minimum value in astronomy is called perihelion, and the maximum is called aphelion. Perihelion is one hundred forty-seven million kilometers, and the value of aphelion is one hundred and fifty-two million kilometers. Perihelion accounts for January, and aphelion - in July.

From the Earth, the Sun seems small to us. In reality, its diameter exceeds the diameter of the Earth along the equator by 109 times. The huge distance from the Earth to the Sun is the reason why we see a relatively small red-yellow circle in the sky. The moon is several times closer, but it looks less in the night sky. The distance from Earth to its only natural satellite is approximately equal to 384.3 thousand kilometers. This is 390 times less than the distance from the Earth to the Sun. The time for which sunlight reaches the surface of our planet is eight minutes and twenty seconds.

How did the scientists manage to measure the distance from the Earth to the Sun? What methods did they use? The first attempts in this direction were made in Ancient Greece, but it is possible to speak about real results only after the seventeenth century. In the late Middle Ages the parallax method was used. This method consists in the fact that, based on the data on the radius of the Earth and observations from the Earth behind the Sun, the angle is determined, under which the Earth will be visible from the Sun on the line of the horizon. The distance from one space object to another is calculated by parallactic displacement.

In the second half of the twentieth century, the scientific and technological revolution brought a new way of measuring distances in outer space. The method of radar is as follows: a pulse is sent towards the space object, a signal is received from it, and then, based on the data on the time of the double-distance pulse travel from the Earth to the object of interest, the distance is calculated at a known speed. Today dynamically developing astronomy has new ways to find out how many kilometers away from us stars and planets of little-studied galaxies. This is the Syunyaev-Zeldovich effect, based on fixing the change in the radio emission of an object in time, gravitational lensing, based on the study of the deflection of light rays in the gravitational field of an object, the method of molecular rings commonly used to estimate the distance from the solar system to any galaxy.

How do you answer the question about the distance from the Earth to the Sun? Is it big or small? Everything is relative. It is significant in comparison with the distance from the Earth to Mars or to the Moon, but it is almost insignificant in comparison with the distance to other stars and galaxies. The closest planet to the Earth is Venus, and it is 41.4 million kilometers away. Between land and Mars 78.3 million kilometers, between Earth and Mercury - 91.6 km. But Jupiter and other giant planets are farther from the Earth than the Sun.

Such measurements as parsec and light year are often used to measure cosmic spaces. At a distance of one parsec, the annual parallax of a space object is one second (hence the name "parsek" - parallax per second). The light year is the distance that light passes through the year. These values are used for measurements to study distant celestial bodies. So, for example, from the Earth to the star Alpha Centauri the light goes four years, to Sirius - eight and a half years, and to the orange giant Betelgeuse - 650 years!

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