Introduction to distance of earth from sun:
Earth, as we all know, is the third planet from Sun. Earth revolves around Sun in an elliptical orbit. Due to the orbit of Earth being elliptical and not perfectly circular, the distance between Sun and Earth varies with the position of Earth.
Mean Distance between Earth and Sun
As it is very difficult to be able to continuously measure the distance between Earth and Sun, distances at the farthest and closest points are determined and the mean distance is calculated from them and used as a reference. These two points are:
Aphelion: Earth is farthest from Sun at Aphelion. This occurs during summer in the Northern Hemisphere - around the first week of July. The distance of Earth from Sun at Aphelion is about 152 million km (94.4 million miles).
Perihelion: Earth is closest from Sun at Perihelion. This occurs during winter in the Northern Hemisphere - around the first week of January. The distance of Earth from Sun at Perihelion is about 147 million km (91.3 million miles).
The mean distance between Earth and Sun (calculated from the mean of the distance at Aphelion and distance at Perihelion) is 149.5 million km.
Mathematically it can be expressed as:
Mean distance between Earth and Sun = (Distance at the farthest point or Aphelion + Distance at the closest point or Perihelion) / 2
= (152 + 147)/2 million km
= 149.5 million km
The exact value of the distance from Earth and Sun has been established as 149, 597, 870.7 kilometers (92,955,887.6 miles) and is also called 1 astronomical unit (or AU).
Implications on Distance of Earth from Sun
While we may think that Earth-Sun distance is critical in maintaining average temperatures on Earth and hence using a mean value would be misleading. But this is not true. The variation in distance due to the elliptical orbit is 5 million km. (This can be calculated by subtracting the distance at Perihelion from the distance at Aphelion. i.e. 152 – 147 million km.) This is a very small percentage of the actual distance between Earth and Sun (149.5 million km) and hence does not cause a significant change in the average temperatures on Earth.
Earth, as we all know, is the third planet from Sun. Earth revolves around Sun in an elliptical orbit. Due to the orbit of Earth being elliptical and not perfectly circular, the distance between Sun and Earth varies with the position of Earth.
Mean Distance between Earth and Sun
As it is very difficult to be able to continuously measure the distance between Earth and Sun, distances at the farthest and closest points are determined and the mean distance is calculated from them and used as a reference. These two points are:
Aphelion: Earth is farthest from Sun at Aphelion. This occurs during summer in the Northern Hemisphere - around the first week of July. The distance of Earth from Sun at Aphelion is about 152 million km (94.4 million miles).
Perihelion: Earth is closest from Sun at Perihelion. This occurs during winter in the Northern Hemisphere - around the first week of January. The distance of Earth from Sun at Perihelion is about 147 million km (91.3 million miles).
The mean distance between Earth and Sun (calculated from the mean of the distance at Aphelion and distance at Perihelion) is 149.5 million km.
Mathematically it can be expressed as:
Mean distance between Earth and Sun = (Distance at the farthest point or Aphelion + Distance at the closest point or Perihelion) / 2
= (152 + 147)/2 million km
= 149.5 million km
The exact value of the distance from Earth and Sun has been established as 149, 597, 870.7 kilometers (92,955,887.6 miles) and is also called 1 astronomical unit (or AU).
Implications on Distance of Earth from Sun
While we may think that Earth-Sun distance is critical in maintaining average temperatures on Earth and hence using a mean value would be misleading. But this is not true. The variation in distance due to the elliptical orbit is 5 million km. (This can be calculated by subtracting the distance at Perihelion from the distance at Aphelion. i.e. 152 – 147 million km.) This is a very small percentage of the actual distance between Earth and Sun (149.5 million km) and hence does not cause a significant change in the average temperatures on Earth.
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