Everything You Need to Know About Planet Earth

Planet Earth is the one that houses all forms of life that we know in the universe. Its age is about 1/3 that of the universe. and, let's face it, she is also very beautiful. The interior has a heavy metal core, and a lighter earth crust wrapped in a thin layer of air to breathe, with vast oceans, fertile plains, beautiful mountains, rivers with fresh water, lakes and water tables, around a star that warms us, and provides us with energy.

But how did our home appear? And what is it made of?

4.6 billion years ago, Earth was created from the remains of dead stars, which have gathered in a gigantic cloud of dirty gas. The gas cloud has become denser at its center, and formed an accretion disc. Small particles have started to clump together into larger and larger objects, until we get the objects we call "planets" today. This process took between 10 and 20 million years, and is still not well understood. At that time, the solar system was young and chaotic. A giant object, about the size of Mars returned to collison with our house. The impact was violent, and if the object had been more massive, he could have destroyed the Earth. Matter from Earth has been projected into orbit, and formed the Moon, which is the largest satellite relative to its planet in the solar system.

 Back then, Earth was a hellish furnace, constantly hit by asteroids, with seas of lava, and a toxic atmosphere. But things were going to change at all because the Earth has cooled. Water from inside the Earth came out on the surface and fell in rain, to re-vaporize immediately and become clouds. Millions of asteroids have brought more and more water to our planet. Earth's water occupies roughly this volume compared to the total volume of our planet. Today, water occupies 71% of the Earth's surface while land areas occupy 29%. 97.5% of the water is salt water, and only 2.5% is fresh water. Fresh water is 69% in the form of ice and snow, 30% is underground, and only 1% remains in liquid form on the surface. But even this small part is essentially frozen.

Tectonics support:

Only a small part of the water remains to form lakes and rivers, and an even smaller part is found in living things. So, little by little, the Earth has cooled, and its surface formed a thin crust. But inside, the hot rocks continued to swirl moving the crust from below and fracturing it here and there. This process is called "plate tectonics", and it still continues today. We'll dedicate a full post to it later. For the moment, let's just say that the earth's crust consisted of giant plates that move. When they meet, they fold, crumble and form the mountains OR suddenly plunge deep into the Earth, creating deep pits and faults.

This is how the highest peak on Earth was formed: Mount Everest, and the deepest pit: the Marianas pit. From our point of view, the mountains and crevasses of the Earth are truly impressive but when we look at the Earth in section, you can see how small they really are. The part we stand on is the crust, which is about 50 kilometers thick, although it can vary between 5 and 70 kilometers. About that, the deepest hole man has ever dug has a depth of 12,262 kilometers (twelve point two hundred sixty-two). After the crust comes the coat. It is a rocky shell of silicates which has a thickness of around 2,900 kilometers. The mantle consists of upper mantle and lower mantle. The upper coat can also be cut into different zones. Its upper part, which is viscous and supports the crust, is called "lithosphere"

Then comes the "asthenosphere" which consists of less fluid, generally solid ores. The lower mantle descends deeply to the core of the Earth. The Earth's core is a liquid layer of iron and nickel about 2,266 kilometers thick. Temperatures range from 4,000 ° C at 5.700 ° C. And in the center is the inner core. It’s mainly solid, a bullet made of an iron-nickel alloy with a radius of around 1,200 kilometers: 70% of the size of the Moon, and a temperature close to the surface of the Sun. It is growing slowly at a speed of about 1 millimeter per year. Now, to put things in perspective, that thin layer of mixed crystallized matter that was previously part of the mantle, is where we live. Let's talk about the Earth's magnetic field. It is an invisible phenomenon which diverts high energy particles from the Sun and other sources, allowing us to live in a stable environment, radiation having only a small impact on Earth.

 But why is Magnetic field here?

 In reality, we don't know much about it. We know it has to do with the Earth's core. In this metal sphere, large electric currents flow in complicated patterns. This causes a magnetic field which manages to stabilize following the laws of electrodynamics. The whole system is called "dynamo". But do not think that this phenomenon is perfectly understood.

what to think of this air that surrounds us?

 By its volume, air essentially consists of nitrogen, oxygen, argon, carbon, variable amount of water vapor and small amounts of other gases. Humans are very dependent on the lowest layer of this atmosphere: the troposphere, where meteorological phenomena are formed. It is 12 kilometers thick on average. Above is the stratosphere, where we find the ozone layer that protects us of the most aggressive rays of the Sun. Above is the mesosphere: the coldest part of the Earth with an average temperature of around -85 ° C. About 80 kilometers above us is the thermosphere. The transition with space is blurred, with no clear border, but humans have decided that space begins here.

Photo by Louis Reed on Unsplash

At about 100 km altitude, the Earth stops and space begins, although the atmosphere there still extends a little. In this region we find the ionosphere, northern Lights and the ISS (international space station). And the highest layer is the exosphere which extends up to 10,000 km altitude. It mixes fluidly with the outside space where there is no atmosphere. The atoms and particles in this area are so far apart that they can travel hundreds of kilometers before colliding with each other. OKAY. Human beings, in their current form, only existed for 200,000 years, or 0.004% of Earth's history. Really not long. And here we are living on a thin wet layer of a small wet rock. Rock that we call: Earth. It is the product of the most fundamental mechanisms of the universe, the result of a constant process of creation and destruction which occurs in the universe, all the time, helped by luck, the laws of the universe and random events, we are very lucky.

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