The earth is our home, the only place in the universe where we know for sure that life exists. The earth was formed a little over 4.5 billion years ago from a swirling cloud of gas and dust that produced our entire solar system, including our star. , the sun. According to the best theories of scientists, this gas and dust collapsed into a disk, merging different parts of the disk on each planet in our solar system.
Where is the earth?
Our planet is located in a tiny corner of the Milky Way, 25,000 light years from the galactic center and 25,000 light years from the edge, according to Universe Today. Our solar system resides in a smaller arm called the OrionCygnus arm, which branches off from the Sagittarius arm, one of the two in the galaxy major spiral arms.
The circumference of the earth is 40,075 kilometers, making it the largest rocky planet in the solar system. Our planet orbits 93 million miles (150,000 km) from the Sun, which gives it the correct temperature for liquid water on the surface, the only known body to do so.
What is the earth made of?
Several huge landforms known as continents exist at various points on the earth’s surface. The largest continent, sometimes referred to as AfroEurasia (though more commonly divided into Africa, Europe, and Asia) has a total area of 32,800,000 square miles (84,950,000 square kilometers). km), according to the Encyclopedia of World Geography. The Americas together cover 16,428,000 square miles (42 million square kilometers), while the frozen continent of Antarctica is 5,405,000 square miles (14 million square kilometers) and the area of Australia is 2,970,000.
The processes beneath the earth’s crust cause these continents to move in geological time periods. Geologists have discovered underground continents buried well below the surface, and while no one knows exactly how or when they formed, they can be just like Earth’s crust is a thin layer that extends, on average, about 30 km below our feet which, according to the U.S Geological Survey, contains mostly silicate and lithic bedrock; the mantle is the next layer and extends approximately 2,900 km below the land’s surface.
A common misconception is that all of the rock in the mantle melts into magma; In fact, most of it is in a highly viscous form that is so thick that it takes millions of years for their movement to be felt. In the center of the earth there is a nickel-iron core that is liquid on the outside, up to 2,260 km away, but is crushed into a solid form by incredible pressure at the lowest depths.
According to NASA, the atmosphere of our planet consists of 78% nitrogen, with an additional 20% oxygen, 0.9% argon and 0.04% carbon dioxide as well as traces of other gases. Most human activities take place in the lowest atmospheric layer, the troposphere. Stretching 5 to 9 miles (8 to 14.5 km) above our heads; Above it lies the stratosphere, in which clouds and weather balloons fly up to 50 km high, followed by the mesosphere, which extends upwards. 85 kilometers high (here meteorites burn) and the thermosphere, which extends into space, is at least 600 kilometers high.
Human activities have a major impact on the climate and weather in the earth’s atmosphere. By adding excess carbon dioxide that traps the sun’s infrared radiation, human industry is heating our planet from global warming, causing widespread disruption. This includes an increase in average temperatures of 1.3 degrees Celsius. September 2019 had some of the highest temperatures on earth.
The Earth’s Surface
The Earth is tilted 23.4 degrees around its axis, which means that sunlight falls unevenly on the planet’s surface over the course of the year, causing seasonal fluctuations over most of the planet. However, as different regions experience different variations in sunlight, the earth’s surface is often divided into three main climatic zones: the polar regions in the Arctic and Antarctic, which start above or below 66 degrees Celsius, north or south latitude; the middle temperate zones, between 23 and 66 degrees north or south latitude; and the tropical regions between the Tropic of Cancer at 23 degrees north and the Tropic of Capricorn at 23 degrees south, according to the National Oceanic and Atmospheric Administration.
The highest point above sea level is the summit of Mount Everest. at 29,029 feet (8,848 meters). A crescent-shaped fissure at the bottom of the western Pacific Ocean known as the Mariana Trench is the deepest location on our planet and extends up to 36,037 feet (10,984 m).
At 6,853 m, the Nile is the longest river in the world. km) in northeast Africa. Lake Baikal in Russia is the largest and deepest freshwater lake with 5,521 cubic miles of water (23,013 cubic kilometers). A volume roughly equivalent to that of the five Great Lakes of North America combined.
Life on Earth
Perhaps the most surprising thing about Earth and the property that has made it unique in the entire known cosmos is the presence of living organisms. One of the oldest pieces of evidence of microbial life suggests that it was present on our planet as early as 3.95 billion years ago. How exactly these microscopic creatures came to be remains a mystery, although experts have pioneered many theories. of our planet and occupies niches that extend from the upper atmosphere to the depths of the rocky surface.
Strange and complex biospheres exist around hydrothermal vents on the ocean floor and in almost every rock and crevice that has ever been explored. The question of worlds in our solar system or beyond remains an open question, although the diversity of life on earth has given scientists hope that life in extreme environments could exist throughout the universe.
Original article on Science Atom.