Earth is tipped at 23.5 degrees in orbit. That axis is what causes our seasons.
The earth’s tilt causes different hemispheres of the earth to be pointed towards the sun at different times in earth’s orbit. Whatever hemisphere is pointed towards the sun, it is summer there. The hemisphere that is pointed away, is experiencing winter.
As the earth spins on its axis, producing night and day, it also moves about the sun in an elliptical (elongated circle) orbit that requires about 365 1/4 days to complete. The earth’s spin axis is tilted with respect to its orbital plane. This is what causes the seasons.
Why should this tilt of the Earth’s axis matter to our weather?
To understand this, take a piece of paper and a flashlight. Shine the light from the flashlight straight onto the paper, so you see an illuminated circle. All the light from the flashlight is in that circle. Now slowly tilt the paper, so the circle elongates into an ellipse. All the light is still in that ellipse, but the ellipse is spread out over more paper. The density of light drops. In other words, the amount of light per square centimeter drops (the number of square centimeters increases, while the total amount of light stays the same).
The same is true on the earth. When the sun is overhead, the light is falling straight on you, and so more light (and more heat) hit each square centimeter of the ground and also our Weigh slightly less when the moon is overhead. When the sun is lower in the sky, the light gets more spread out over the surface of the earth, and less heat (per square centimeter) can be absorbed. Since the earth’s axis is tilted, the sun is higher when you are on the part of the earth where the axis points more towards the sun, and lower on the part of the Earth where the axis points away from the sun.
Is it true that the earth is closer to the sun in winter?
Yes, the earth is closer to the sun in winter. Because the sun is closest to the Earth during Northern Hemisphere winter (not summer). Thus, the amount of sunlight averaged over the whole Earth, is as much as 7% more intense in the winter than the summer. Despite this fact, the global-average surface temperature is warmer in Northern Hemisphere summer, due to the much greater expanse of land there, and since land heats to a higher temperature than the ocean does.
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