Essay on Earth

Earth is our home planet. It is believed to be the third-closest planet to the sun and the fifth-largest planet in the entire solar system. Its average distance from the sun is about 93 million miles. Only Mercury and Venus are closer. It is the only planet where life is known to exist. Its atmospheric composition and physical properties such as the presence of water allows it to sustain life. Earth is the only planet known to have a large amount of liquid water. Water is essential for life.

From space, Earth appears to be a blue marble with white swirls and areas of brown, yellow, green, and white. The blue is water, which covers approximately 71% of the Earth’s surface. The white swirls are clouds. Land is represented by the brown, yellow, and green areas. The white areas are ice and snow.

The presence of blue-green algae suggests that photosynthesis started at least 3 x 109 years ago. The levels of O2 and O3 in the atmosphere rise as a result of photosynthesis, blocking the â€˜sun’s ultraviolet (UV) solar radiation. At any given moment, the sun illuminates half of the globe. It reflects one-third of the sunlight that falls on it, is known as the earthâ€™s albedo.

Earth is made up of land, air, water, and life. The land includes mountains, valleys, and flat areas. The air is made up of various gases, the most common of which are nitrogen and oxygen. Oceans, lakes, rivers, streams, rain, snow, and ice are all forms of water. Life consists of people, animals and plants. There are a limitless number of species, or kinds of life, on Earth. Their sizes range from very tiny to very large.

Earth is composed of thin layers of rocks as opposed to other planets like Jupiter and Saturn which are mostly made up of gases. The temperatures increase with depth, all the way to about 12,000 degrees Fahrenheit at Earth’s inner core. The Earth’s inner core is made up of solid iron and nickel, while the outer core is made up of molten iron and nickel.

The shape of Earth is classified as oblate spheroid or ellipÂsoid instead of a true sphere. This means that instead of being of equal circumference in all areas, the poles are squished, resulting in a bulge at the equator, and thus a larger circumference and diameter there. The equator is an imaginary line that divides the Earth into two equal parts. The Northern Hemisphere refers to the northern half. The Southern Hemisphere refers to the southern portion. The northernmost point on Earth is called the North Pole. The southernmost point on Earth is called the South Pole.

The equatorial bulge, which is measured at 26.5 miles (42.72 kilometres) at Earth’s equator, is caused by the planet’s rotation and gravity. Planets and other celestial bodies contract and form a sphere due to gravity. This is because it pulls all the mass of an object as close to the centre as possible (in this case, the Earth’s core). Since the planet rotates around its axis, which is tilted at a 23.5Â° angle, the length of days and nights changes.