Earth's Orbit is not a Perfect Circle

Earth, our home planet, is a beautiful blue and white ball when seen from space. Earth is the third planet from the Sun and the only one in the solar system known to harbor life. Earth is the only planet known to support life and to have liquid water at the surface. Earth is about 93 million miles (150 million kilometers) from the sun. Earth is a small planet in the vastness of space. Earth travels in its orbit at 66,700 miles (107,000 kilometers) an hour, or 18. Earth takes 24 hours to spin completely around on its axis so that the sun is in the same place in the sky.

Earth's axis is not straight up and down, but is tilted by about 23 1/2 degrees compared to the orbital plane.WeatherWeather is the combination of events in the atmosphere and climate is the overall accumulated weather in a certain location. Images can be generated based on a full-color image of the Earth by day and night, a topographical map of the Earth, up-to-date weather satellite imagery, or a composite image of cloud cover superimposed on a map of the Earth, a color composite which shows clouds, land and sea temperatures, and ice, or the global distribution of water vapor. There are numerous ways to reduce home cooling costs, such as ceiling fans, natural ventilation, minimizing heat gain, weather sealing, insulating, window shading and glazing, roof lightening and landscaping.CrustThe crust and the upper portion of the mantle are called the lithosphere. The solid Earth consists of a thin outer layer, the crust, with a thick rocky layer, the mantle, beneath it. The thin crust is made up of natural chemicals called minerals composed of different combinations of elements.

Two elements, silicon and oxygen, make up almost three-fourths of the crust. Oxygen is the most abundant chemical element in rocks in Earth's crust, making up about 47 percent of the weight of all rock. Continental crust averages about 25 miles (40 kilometers) thick, but it is thicker in some areas and thinner in others. Rocks can melt more easily near the crust if they contain water, which lowers their melting point. Metamorphic rocks develop deep in Earth's crust when heat or pressure transform other types of rock. Where conditions are right, small pockets of magma form beneath and within the crust.Earth's orbit lies on an imaginary flat surface around the sun called the orbital plane. Earth's orbit is not a perfect circle. Earth, other planets, large moons, and stars -- in fact, most objects in space bigger than about 200 miles (320 kilometers) in diameter -- are round because of their gravity. Earth is slightly closer to the sun in early January (winter in the Northern Hemisphere) and farther away in July. Earth's spin causes it to bulge slightly at its middle, the equator. Earth is surrounded by a thin layer of air, the atmosphere. Earth is composed of several layers, or spheres, somewhat like the layers of an onion. Earth's crust grows hotter by about 70 degrees F per mile (25 degrees C per kilometer) of depth.