Download (or the Earth) is the third planet from the Sun, and

Earth (or the Earth) is the third planet from the Sun, and the densest and fifth
-largest of the eight planets in the Solar System. It is also the largest of the
Solar System's four terrestrial planets. It is sometimes referred to as the wor
ld, the Blue Planet,[21] or by its Latin name, Terra.[note 6]
Earth formed approximately 4.54 billion years ago by accretion from the solar ne
bula, and life appeared on its surface within one billion years.[22] The planet
is home to millions of species, including humans.[23] Earth's biosphere has sign
ificantly altered the atmosphere and other abiotic conditions on the planet, ena
bling the proliferation of aerobic organisms as well as the formation of the ozo
ne layer which, together with Earth's magnetic field, blocks harmful solar radia
tion, permitting life on land.[24] The physical properties of the Earth, as well
as its geological history and orbit, have allowed life to persist. The planet i
s expected to continue supporting life for another 500 million to 2.3 billion ye
ars.[25][26][27]
Earth's crust is divided into several rigid segments, or tectonic plates, that m
igrate across the surface over periods of many millions of years. About 71% of t
he surface is covered by salt water oceans, with the remainder consisting of con
tinents and islands which together have many lakes and other sources of water th
at contribute to the hydrosphere. Earth's poles are mostly covered with solid ic
e (Antarctic ice sheet) or sea ice (Arctic ice cap). The planet's interior remai
ns active, with a thick layer of relatively solid mantle, a liquid outer core th
at generates a magnetic field, and a solid iron inner core.
Earth interacts with other objects in space, especially the Sun and the Moon. At
present, Earth orbits the Sun once every 366.26 times it rotates about its own
axis, which is equal to 365.26 solar days, or one sidereal year.[note 7] The Ear
th's axis of rotation is tilted 23.4° away from the perpendicular of its orbital p
lane, producing seasonal variations on the planet's surface with a period of one
tropical year (365.24 solar days).[28] Earth's only known natural satellite, th
e Moon, which began orbiting it about 4.53 billion years ago, provides ocean tid
es, stabilizes the axial tilt, and gradually slows the planet's rotation. Betwee
n approximately 3.8 billion and 4.1 billion years ago, numerous asteroid impacts
during the Late Heavy Bombardment caused significant changes to the greater sur
face environment.
Both the mineral resources of the planet and the products of the biosphere contr
ibute resources that are used to support a global human population.[29] These in
habitants are grouped into about 200 independent sovereign states (193 United Na
tions recognized sovereign states), which interact through diplomacy, travel, tr
ade, and military action. Human cultures have developed many views of the planet
, including personification as a deity, a belief in a flat Earth or in the Earth
as the center of the universe, and a modern perspective of the world as an inte
grated environment that requires stewardship.