The Solar System contains large amounts of water, but Earth is unique among the other planets because it is the only one known to contain life. Although large bodies of water are present throughout the Solar System, the Earth is the only one that has liquid surface water. The oceans cover 71% of the planet’s surface, dwarfing its lakes, rivers, and polar ice. This abundance of water is the most important factor in determining the probability of life on Earth.


The Earth is the fifth largest planet in the solar system. It is composed of three layers, the core and mantle. The core is the deepest, averaging approximately 1,800 miles thick. The outer layer, the crust, is 19 to 31 kilometers thick. The Earth’s surface is 30 percent land, and is divided into seven continents. The crust is the most dense layer, covering only about 20 percent of the planet. Each continent is different from the others, and the ocean is a unique environment.

The outer layers of the Earth are divided into four regions. The hydrosphere consists of oceans and land. The atmosphere consists of three spherical zones: the troposphere and stratosphere. The stratosphere contains the ozone layer. The magnetosphere occupies a vast region of space, and is a key component of the Earth’s magnetism. It influences the behavior of electrically charged particles coming from the Sun.

The mantle and core of the Earth are the two hardest parts of the planet. The crust and oceans are made of softer materials than the outer layer. The hydrosphere is the smallest. The outer layers are the liquids. The atmosphere is made up of two spherical layers – the stratosphere and the troposphere. The magnetosphere is the largest region in space, and is home to the Earth’s magnetic field.

The outer layers of the Earth’s interior are its core, mantle, and crust. The hydrosphere consists of oceans. The atmosphere is made up of different spherical zones. The troposphere is where most of the Earth’s weather takes place and the stratosphere is where the ozone layer is. The magnetosphere is a huge region of space. The earth’s magnetic field dominates the behaviour of electrically charged particles from the Sun.

The mantle is 1,800 miles thick, and the outer layers of the Earth are made up of the mantle and the crust. The crust is the underlying layer, and the mantle sits on it. The mantle is responsible for earthquakes, volcanic eruptions, and mountain ranges. Its movement is similar to that of land. In some areas, sea-level topography is similar to that of the land, with the exception that it is much more extensive.

Earth’s magnetic field is generated by currents flowing in the outer core. The magnetic poles of the Earth are constantly in motion. Since the 1830s, the magnetic North Pole has been moving 24 miles each year and is expected to reach Siberia in a few decades. Other changes are occurring in the magnetic field, as the planet’s atmosphere is being obscured by the atmosphere. The current magnetic field is also changing. The strength of the magnetic field has decreased by 10 percent in the past century.