The Earth is the third planet from the sun. It is home town for us. It is only astronomical object, we know in the universe; where life exists.
Our home planet formed over 4.5 billion years ago. It is 150 million km (1 AU) away from the sun.
It is the only world in our solar system with liquid water on the surface. Earth is the rocky planet with solid and dynamic surface of mountains, canyons, Plains and more.
Erath’s atmosphere is 78% nitrogen, 21 % oxygen, and 1% other. Erath’s atmosphere is not only support to perfect balance to breath and live, but it protects us from incoming Meteoroids, most of which break up in our atmosphere before they can strike the surface.
Day and Year
The Earth orbit counter wise direction around the sun at an average distance of 150 million km in 365.256 solar days with rotational period of 24 hours 6 minutes.
The Earth and Earth’s moon orbit a common barycentre every 27.32 days relative to background star. When combined with the Earth–Moon system’s common orbit around the Sun, the period of the synodic month, from new moon to new moon, is 29.53 days.
Earth’s orbital and axial planes are not perfectly aligned. Earth’s axis is tilted some 23.44 degrees from the perpendicular to the Earth–Sun plane, and the Earth–Moon plane is tilted up to ±5.1 degrees against the Earth–Sun plane. Without this tilt, there would be an eclipse every two weeks, alternating between lunar eclipses and solar eclipses.
Structure and Surface
The earth’s internal structure is divided in many of layers like other terrestrial planets. The top most or outer layer of the earth is crust. The earth’s Crust goes about 30km deep on average on continent and 5km from the bottom of the ocean to top the mantle. The outer layer is a chemically distinct silicate solid crust, which is underlain by a hot and highly viscous solid mantle, the thickest layer. Mantle is about 2900 km thick. The crust and the cold, rigid, top of the upper mantle are collectively known as the lithosphere, and it is of the lithosphere that the tectonic plates are composed.
Beneath the mantle, an extremely low viscosity liquid Outer core lies above a solid inner core. This layer is about 1,400 miles (2,300 kilometres) thick, made of iron and nickel fluids. The bottom most layer – inner core is solid sphere about 1221 km in radius (about 1/5th radius of the earth). It is made of mostly iron and nickel metal and having temperature is high as 5,400 Celsius.
Out of total surface area of the earth, 70 % area is below sea level and covered by the Ocean water, has an average depth of 4 km and contains 97% of the earth’s water. Most of the earth’s mountains and volcanoes are hidden under the ocean. The Remaining 30 % area has terrain that varies greatly from place to place and consists of mountains, deserts, plains, plateaus, and other landforms. The elevation of the land surface varies from the low point of −418 m at the Dead Sea, to a maximum altitude of 8,848 m at the top of Mount Everest.
Size and Distance
The mean diameter of earth is 12742 km. It is not perfectly sphere, so its radius is vary from point to point. At equator its radius is 6378.1 km and at pole it is 6356.8 km.
The Earth is located at an average distance of 150 million km (1 Astronomical unit) from the sun.
The mass of earth is 5.97×1024 kg and its volume is 1.083×1012km3.
The Earth’s atmosphere composed of 78 % nitrogen, 21 % oxygen, and 1 5 other gases such as carbon dioxide, Argon, and neon. Three-quarters of the atmosphere’s mass is contained within the first 11 km (6.8 mi) of the surface. This lowest layer is called the troposphere, which drives the weather and climate through redistribution of thermal energy. Our atmosphere shields us form harmful radiation coming from outer space. It also protects us from meteoroids, most up which burn up in the atmosphere before strike the surface.
The mean surface temperature of earth is 14oC (287.16K), which is perfect for life.
Orbital and escape velocity
The Earth’s average orbital speed is 29.78 km/s, which is fast enough to travel a distance equal to Earth’s diameter, about 12,742 km, in seven minutes, and distance to the Moon, 384,000 km in about 3.5 hours. The Earth’s escape velocity is 11.2 km/s.
The earth’s magnetic field is generated by rotating melted iron-nickel core. The field extends outwards from the core, through the mantle, and above the earth’s surface. The extent of the Earth’s magnetic field in space defines the Magnetosphere.
Magnetosphere protects us from solar Wind. The charge particle of solar wind, when interact with the earth’s magnetic field; they collide with air molecules above our planet’s magnetic poles. These air molecules get excited and ionize and begin to glow causing the Aurora.
Earth has one natural satellite called Moon. Moon is the brightest and nearest most familiar object in the night sky. It is at a distance of 384,400 km from the sun, with diameter of one quarter of the Earth’s.
Scientist believes that Formation of the Moon is the result of collision billions of years ago. When a large Asteroid collides with Earth, a portion earth interior displaces. The resulting chunks clamp together and form our moon.
The gravitational attraction between the Earth and the Moon causes tides on Earth. Our moon is tidal locking with earth: its rotation period is the same as the time it takes to orbit Earth. As a result, it always presents the same face to the planet.
Earth has no any Ring.
Earth is the only place we know, where life exist. Water and Hospitable temperature make the planet to evolve life. More than one third of the earth’s surface is covered by water, which provide good environment to evolve complex organic molecule.
The distance of the Earth from the Sun, as well as its orbital eccentricity, rate of rotation, axial tilt, geological history, sustaining atmosphere, and magnetic field all contribute to the current climatic conditions at the surface.
Humans are living here since millions of Year and exploring the earth and outside the earth the till now. The first human to orbit the earth was Yuri Gagarin on 12 April 1961. As of April 2018, there are 1,886 operational, human-made satellites orbiting the earth to observe weather, making fast communication and lots.
In ancient Roman religion and myth Tellus mater (Mother earth) is a goddess of earth. The word tellus is also a common Latin noun for land, territory, earth, and ground.
In Hindu Mythology the earth is called prithvi, derived from the Sanskrit word.
Quick Discover :
Distance from the sun:
1 Astronomical unit
Average orbital speed:
Equatorial rotational velocity:
365.25 Earth days
24 hours 6 min.
Potential for Life:
Only Known Planet have life
Image credit :
Image7: image credit : universediscover/aniketkumar