Unknow facts about Earth

Approximately 78 percent of Earth's atmosphere is nitrogen, 21 percent is oxygen, 0.9 percent is argon, and the remaining 0.1 percent consists of other gases. 

The average temperature on the Earth’s surface is around 15 degrees Celsius. 

The global population is estimated to be around 8 billion, which is calculated by adding up the populations of all countries and areas in the world. 

The second layer of Earth's atmosphere is the stratosphere, of which the ozone layer is one layer. 

Earth is the only planet (or the moon) known to have consistent, stable bodies of liquid water on its surface. 

The Sun is located in the center of the Solar System and the planets rotate around it. The Earth rotates on its axis from east to west. 

The Earth rotates once in  hours with respect to the Sun, but once every    hours,    minutes, and seconds with respect to the stars. 

As far as we know, Earth is the only planet that supports life. 

Most other bodies in the Solar System, like Earth, formed 4.5 billion years ago from gas in the early Solar System. 

Earth is the third planet from the sun. It is the only world known to support an atmosphere with free oxygen, oceans of liquid water on the surface, and life. 

The largest earthquake to shake the United States was a magnitude-9.2 temblor that struck Prince William Sound, Alaska, on Good Friday, March 28, 1964. 

Currents of electricity flowing in the molten core create Earth's magnetic field.