Earth is the third planet in our solar system, fortunate place in the solar system we inhabit. Ours is the only planet in the solar system, enclosed regularly by water, as well as being the only one with an atmosphere is mostly nitrogen and oxygen. His temperature various life suitable for the way we see it, range from -50 ° C to 50 ° C, with an average 22 º C. Water has created a system of movement and erosion unique in the solar system. The planet we populate is a rarity that still cannot find a similar model or in our solar system or other systems that are discovered, so far, which appear unapproachable.
Ours is the only one with a large satellite: the Moon, Mars has two moons, but both are small. We are approximately 150 million kilometers from the Sun sometimes happen glaciations, the last happened 10,000 years ago. It is not known with certainty the reason thereof, could be caused by slight variations in the Sun, however, the most accepted theory is that of Yugoslav scientist Milutin Milankovic (1879-1958), a result of which has been called certain cycles "Milankovic cycles," which attributes the ice ages a series of small movements, consider for example, the period of rotation of the Earth, which is not constant, there are variations as well as an "extension" which is caused by resistance of the tides of the ocean against the seabed, an effect that is essentially due to the moon, and the translation around the Sun tilt of the Earth is 23.5 degrees, but this undergoes a change in a long period, ranging between 21 º to 24.5 º which tells us that the more you tilt the axis of the Earth, the seasons of our planet vary having colder winters and warmer summers. You must also take into account that our orbit around the Sun, not a circle, which sometimes makes us more about the Sun and other further, this form of the orbit of the Earth, sometimes even longer or clipped over a period of time ranging from 100,000 to 400,000 years, in this case, Earth would be so far from the Sun, sunlight would not receive the same way, so the temperature can drop dramatically. Interglacial periods have an average life of 10,000 years.