Planet Earth

Planet Earth is the third planet from the Sun. It is very familiar to all of us and sustains every life form we see around us. Humans have been living on Earth for thousands of years, but have only recently been able to discover everything we know about it today.

It was once believed that the Earth was flat and only in the 16th century did man discover that Earth is just one planet out of many others in the solar system and then in the universe. It is unique among all planets found by humans in the universe and the only one we know so far capable of sustaining life.

The surface of Earth is covered with earth and liquid water, which form the crust of our planet. Underneath this outer layer, there are many others; an upper mantle and a lower mantle with a transition region between them, as well as an outer and inner core. The Earth’s density is the largest in the solar system. The inner core is mostly composed of iron and the crust is divided into tectonic planets which float on top of the hot mantle found underneath.

Due to the planet’s unique composition and layering we have continents, oceans and a powerful magnetic field. Earth’s magnetic field provides protection from solar flares and from the Sun in general. Earth’s atmosphere is composed of nitrogen, oxygen, carbon dioxide and other gases. When it comes to temperature Earth has never seen extremes and the lowest and highest temperatures sit comfortably under acceptable ranges.

The oxygen in the atmosphere, along with the other favorable conditions like water, temperature and protection from the Sun have made it possible for life to evolve on this little rock we call home. There is no place more hospitable than Earth to live and it really is one in a million. By the way DigablePlanets.org is written from Planet Earth, great place to visit.