Homo sapiens live on the third planet from the Sun.
Earth -LRB- from Eorðe -LSB- Γαια , Gaia -RSB- Terra -RRB- , otherwise known as the World or the Globe , is the third planet from the Sun and the only object in the Universe known to harbor life .. Sun. Sun. planet. planet. Universe. Universe. life. life. It is the densest planet in the Solar System and the largest of the four terrestrial planets .. planet. planet. Solar System. Solar System. According to radiometric dating and other sources of evidence , Earth formed about 4.54 billion years ago .. radiometric dating. radiometric dating. formed. Age of the Earth. billion years ago. bya. Earth 's gravity interacts with other objects in space , especially the Sun and the Moon , Earth 's only natural satellite .. Sun. Sun. Moon. Moon. natural satellite. natural satellite. During one orbit around the Sun , Earth rotates about its axis over 365 times ; thus , an Earth year is about 365.26 days long .. Sun. Sun. orbit around the Sun. Earth's orbit. rotates about its axis. Earth's rotation. year. year. Earth 's axis of rotation is tilted , producing seasonal variations on the planet 's surface .. planet. planet. axis of rotation. #Axial tilt and seasons. seasonal variations. season. The gravitational interaction between the Earth and Moon causes ocean tides , stabilizes the Earth 's orientation on its axis , and gradually slows its rotation .. Moon. Moon. gravitational interaction. gravity. ocean tides. Tide. ocean. ocean. Earth 's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years .. tectonic plates. Plate tectonics. About 71 % of Earth 's surface is covered with water , mostly by its oceans .. covered with water. Water distribution on Earth. The remaining 29 % is land consisting of continents and islands that together have many lakes , rivers and other sources of water that contribute to the hydrosphere .. land. Land#History of land on Earth. hydrosphere. hydrosphere. The majority of Earth 's polar regions are covered in ice , including the Antarctic ice sheet and the sea ice of the Arctic ice pack .. polar regions. Polar regions of Earth. Antarctic ice sheet. Antarctic ice sheet. Earth 's interior remains active with a solid iron inner core , a liquid outer core that generates the Earth 's magnetic field , and a convecting mantle that drives plate tectonics .. mantle. Mantle ( geology ). Within the first billion years of Earth 's history , life appeared in the oceans and began to affect the Earth 's atmosphere and surface , leading to the proliferation of aerobic and anaerobic organisms .. life. life. aerobic. Aerobic organism. Some geological evidence indicates that life may have arisen as much as 4.1 billion years ago .. life. life. billion years ago. bya. Since then , the combination of Earth 's distance from the Sun , physical properties , and geological history have allowed life to evolve and thrive .. Sun. Sun. life. life. geological history. Geological history of Earth. In the history of the Earth , biodiversity has gone through long periods of expansion , occasionally punctuated by mass extinction events .. biodiversity. biodiversity. mass extinction events. extinction event. Over 99 % of all species that ever lived on Earth are extinct .. species. species. extinct. extinct. Estimates of the number of species on Earth today vary widely ; most species have not been described .. species. species. Over 7.4 billion humans live on Earth and depend on its biosphere and minerals for their survival .. Over 7.4 billion humans. World population. biosphere. biosphere. Humans have developed diverse societies and cultures ; politically , the world has about 200 sovereign states .. societies. Society. about 200 sovereign states. List of sovereign states