On Friday, the aphelion day took place, which means that Earth was farther from the Sun than any other day of the year. The reason why this happens is the fact that the orbit of our planet is an ellipse with the sun in its center. Because of this, Earth reaches its farthest point on the orbit every July and its innermost point, called perihelion, every January.
Farther from the sun does not mean colder
It might be hard to believe, especially considering the extremely high temperatures in the Northern Hemisphere, but the amount of sunlight that Earth receives in July is 7 percent lower than it takes place in January. However, thanks to our planet’s moderate tilt, Earth gets a lot of direct sunlight even at its farthest from the sun, which makes the hot summer north of the equator possible. But what would happen if Earth had much greater swing? We can see that very well using Mars as an example.
Mars and its seasons
Over the year on the Red Planet, the amount of sunlight it receives can vary up to 31 percent, which has a strong effect on the planet’s seasons. Due to Mars’ dramatic orbit, the swing between seasons in the Northern Hemisphere is moderate, while the Southern Hemisphere’s seasons are extreme. The planet’s ice caps can be used to show the difference, as in the south the ice reaches more than twice as far as it does in the north. Another side effect of the Red Planet’s swing is the formation of dust storms.
Pluto has even flatter orbit compared to Mars, which makes the amount of sunlight that reaches the dwarf planet vary by up to 64 percent. The planet’s closest approach also shifts across the seasons, currently occurring in spring and fall.
Compared to Mars and Pluto, Earth’s orbit and seasons are stable, and are expected to remain this way.