Sun-Earth Interactions

The Sun influences a variety of physical and chemical processes in Earth’s atmosphere. NASA continually monitors solar radiation and its effect on the planet.

Earth’s atmosphere stretches from the surface of the planet up to as far as 10,000 kilometers (6,214 miles) above. After that, the atmosphere blends into space. Not all scientists agree where the actual upper boundary of the atmosphere is, but they can agree that the bulk of the atmosphere is located close to Earth’s surface—up to a distance of around eight to 15 kilometers (five to nine miles).

The atmosphere is divided into five different layers, based on temperature. The layer closest to Earth’s surface is the troposphere, reaching from about seven and 15 kilometers (five to 10 miles) from the surface. The troposphere is thickest at the equator, and much thinner at the North and South Poles. The majority of the mass of the entire atmosphere is contained in the troposphere—between approximately 75 and 80 percent. Most of the water vapor in the atmosphere, along with dust and ash particles, are found in the troposphere—explaining why most of Earth’s clouds are located in this layer. Temperatures in the troposphere decrease with altitude.

EARTH-SUN RELATIONSHIPSIt is the earth’s relationship to the sun, and the amount of light it receives, that is responsible for the seasons and biodiversity. The amount of sun a region receives depends on the tilt of the earth’s axis and not its distance from the sun. The northern hemisphere experiences summer during the months of June, July, and August because it is tilted toward the sun and receives the most direct sunlight. Inversely, summer for the southern hemisphere takes place during the months of December, January, and February because that is when it receives the most direct sunlight. Did you know that the earth is approximately 3.2 million miles closer to the sun in January than in June?