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Seasons of the year3/26/2023 ![]() ![]() If the Earth's axis were perpendicular to the ecliptic, as in the drawings here, the Sun's position in the sky would be halfway between the celestial poles, and its daily path, seen from any point on Earth, would stay exactly the same, day after day.Įach point on Earth would be carried around the rotation axis AB once a day. This section tries to explain what is seen. For those of us who live in the Northern Hemisphere where it's summer in July and winter in January, that seems backwards, doesn't it? That just goes to prove that Earth's distance from the Sun is not the cause of the seasons.Section #1 Stargazers and Skywatchers described the observed motion of the Sun across the sky, in different seasons of the year. While that is a difference of over 3 million miles, relative to the entire distance, it isn’t much.Īnd, believe it or not, aphelion (when Earth is farthest from the Sun) occurs in July, and perihelion (when we are closest) occurs in January. It is winter in December in the Northern Hemisphere, because that is when it is the South Pole's turn to be tilted toward the Sun.Įarth's perihelion (point closest to Sun) = 91,400,000 miles from SunĮarth's aphelion (point farthest from Sun) = 94,500,000 miles from Sun It is summer in June in the Northern Hemisphere because the Sun's rays hit that part of Earth more directly than at any other time of the year. Sometimes it is the North Pole tilting toward the Sun (around June) and sometimes it is the South Pole tilting toward the Sun (around December). So, throughout the year, different parts of Earth get the Sun’s direct rays. Most scientists think that that rubble, in time, became our Moon.Īs Earth orbits the Sun, its tilted axis always points in the same direction. That big hit sent a huge amount of dust and rubble into orbit. It also blasted a big hole in the surface. So instead of rotating with its axis straight up and down, it leans over a bit.īy the way, that big thing that hit Earth is called Theia. Long, long ago, when Earth was young, it is thought that something big hit Earth and knocked it off-kilter. That is why we have day and night, and why every part of Earth's surface gets some of each.Įarth has seasons because its axis doesn't stand up straight. ![]() ![]() There is a different reason for Earth's seasons.Įarth's axis is an imaginary pole going right through the center of Earth from "top" to "bottom." Earth spins around this pole, making one complete turn each day. However, in the Northern Hemisphere, we are having winter when Earth is closest to the Sun and summer when it is farthest away! Compared with how far away the Sun is, this change in Earth's distance throughout the year does not make much difference to our weather. During part of the year, Earth is closer to the Sun than at other times. It is true that Earth's orbit is not a perfect circle. And, likewise, they think Earth is farthest from the Sun in the winter.Īlthough this idea makes sense, it is incorrect. Many people believe that Earth is closer to the Sun in the summer and that is why it is hotter. And when the South Pole tilts toward the Sun, it's winter in the Northern Hemisphere. So, when the North Pole tilts toward the Sun, it's summer in the Northern Hemisphere. Throughout the year, different parts of Earth receive the Sun's most direct rays. ![]()
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