Earth: The Elegance of Universe | Abdullah Al Moinee

Abdullah Al Moinee

[ www.daily-sun.com/arcprint/details/142869/Earth:-The-Elegance-of-Universe/2016-06-10 ]

Every aspect of nature reveals a deep mystery and touches our sense of wonder and so does Earth. We are a way for the cosmos to know itself and approaching the greatest of mysteries. Mystery creates wonder and wonder is the basis of man's desire to know which opens the threshold of curiosities. And our home ‘Earth’ also arouses curiosity among us. We, living on Earth, have just awakened to the great oceans of space and time from which we have emerged. Our home, Earth, is the third planet from the sun and the only world known to support an atmosphere with free oxygen, oceans of liquid water on the surface and ‘life’.

Earth is the only planet not named after a god. The other seven planets in our solar system are all named after Roman gods or goddesses. The name derives from Old English and Germanic. In Roman Mythology, the goddess of the Earth was Tellus and Earth was a personified goddess in Germanic paganism. Well, Earth was once believed to be the centre of the universe. Eventually, the view that the Sun was at the centre of the universe was postulated by Copernicus, though this is also not the case.

Earth is made up of hydrogen gas, stardust, and gravity. The gas and dust floating in space were drawn together by gravity and they formed into a spinning disc. As this disc collided with and absorbed rock bodies, the Earth formed. Astronomers believe the formation of Earth was relatively quick. Earth is one of the four terrestrial planets like Mercury, Venus and Mars. They are called a terrestrial planet because it is made almost entirely of rock and metal. Researchers calculate the age of the Earth by dating both the oldest rocks on the planet and meteorites that have been discovered on Earth. Earth is about 4.54 billion years old. Because Earth formed inside the snow line—meaning it was close enough to the sun that water, carbon, and nitrogen were all in a gaseous state—the elements so essential to supporting life had to be supplied in some other way. They were carried to the Earth by dirty snowballs—asteroids that retained water in hydrated minerals.

The atmospheric pressure on Earth's surface averages 101.325 kPa, with a scale height of about 8.5 km. It has a composition of 78% nitrogen and 21% oxygen, with trace amounts of water vapor, carbon dioxide and other gaseous molecules. The height of the troposphere varies with latitude, ranging between 8 km at the poles to 17 km at the equator, with some variation resulting from weather and seasonal factors. Earth has a powerful magnetic field. This phenomenon is caused by the nickel-iron core of the planet, coupled with its rapid rotation. This field protects the Earth from the effects of solar wind. The main part of Earth's magnetic field is generated in the core, the site of a dynamo process that converts kinetic energy of fluid convective motion into electrical and magnetic field energy. At the equator of the magnetic field, the magnetic-field strength at the surface is 3.05 × 10−5 T, with global magnetic dipole moment of 7.91 × 1015 T m3. It is mentionable that Earth’s rotation is gradually slowing. This deceleration is happening almost imperceptibly, at approximately 17 milliseconds per hundred years, although the rate at which it occurs is not perfectly uniform. This has the effect of lengthening our days, but it happens so slowly that it could be as much as 140 million years before the length of a day will have increased to 25 hours. The Earth takes 365¼ days to complete its orbit round the Sun. The Earth’s year is therefore 365 days long but the ¼ days are added up and every fourth year has one extra day, on the 29th of February. This fourth year is called a Leap Year (366 days) and is always a year which can be divided exactly by 4.

The only natural satellite that Earth has is Moon. It is the fifth largest natural satellite. The birth of Earth’s moon is singularly important because it stabilizes Earth’s tilt. Without the moon, Earth would still have wild changes in climate and be uninhabitable. The stabilizing tug of the moon tempers Earth, resulting in the minor tip that causes summer and winter seasons. The sun’s diameter is about 109 times greater than Earth’s, whereas Earth is just about four times larger in diameter than the moon. The diameter of Earth is 7,917.5 mi. A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra (shadow). This can occur only when the sun, Earth and moon are aligned (in "syzygy") exactly, or very closely so, with the Earth in the middle. On the other hand, a solar eclipse is a type of eclipse that occurs when the Moon passes between the Sun and Earth, and the Moon fully or partially blocks ("occults") the Sun. Both eclipses occur only at new moon. Moreover the theory of Pangaea states that all of Earth’s current continents were originally a single supercontinent that existed some 200 million years ago during the Paleozoic and Mesozoic eras. The northern part of the supercontinent, North America and Eurasia, was called Laurasia—and Gondwana, the southern part, was made up of Australia, South America, Africa, Antartica, and India.

Well, the beginning of Industrial Revolution marked the beginning of human intervention affecting Earth’s environment by producing enough carbon dioxide to affect the atmosphere’s global balance and chemical composition that triggers the environmental pollution, global warming, climate change and natural calamities. Now it’s our duty to save our beautiful Earth from further damages. Otherwise we may face the threat of extinction.

Moinee, A. Al. “Earth: The Elegance of Universe” The Daily Sun. 6(226). 10 Jun. 2016. Morning Tea. 6(23).