It is not easy to find out how the earth was built, because it happened 4.2 billion years ago, and no one was there to look. So scientists have had to observe how the earth is seen now and all the other planets, moons and debris of the solar system.
They have concluded that the earth was built in the same way that a large snowball would be built to make a snowman. The mass that would become our home rolled through the planetary debris (rocks floating in space) for more than 100 million years, adding more and more material, until it became a full -size planet.
How do scientists know like me that this is what happened? In the first place, the studies of the size, composition and location of asteroids and comets, many of which are as old as the Earth, indicate that 4,200 million years ago the solar system had the current appearance of Saturn, with space of space rocks orbiting around the sun. There is still a ring of this type around the sun: it is called asteroids belt and it is between Mars and Jupiter The rocks in orbit.
All other bodies that we know today as planets began as similar rings of space waste. A swirl, or balancing area, was developed in each of these rings and caused the rubble to be grouped into a snowball effect. But these pieces of rubble were asteroids that crashed violently against growing planets.
We can see those impacts on planets and moons whose surfaces have not eroded or renovated. If you look at the moon or the planet Mercury, you can see that they are covered with asteroid impact craters.
When asteroids or comets hit these planets under construction, they crashed into their surfaces at speeds of up to 65,000 to 80,000 kilometers per hour. The impacts caused huge explosions that emitted huge amounts of dust and broken or melted rock.
In fact, scientists believe that the moon was once part of the earth, until a great asteroid crashed into the earth so force that the moon separated and shot the space. There, he began to orbit the earth as he does now.
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Everything you have to know about how ‘the earth was built
Most of the great asteroids and comets collided with the earth when I was young, about 4,000 million and a half years ago. The number of this type of collisions has constantly decreased since then. However, at least 100 tons of space rock the dust size rain on the earth every day, increasing the size of our planet little by little.
The earth also clashes with space rocks, called meteors, which appear as fleeting stars in the night sky. Some of these meteors come from an impact that hit Mars at some point, breaking the rock of the planet’s surface and shooting it to the outer space. These rocks have been falling to Earth since then.
What is the difference between an asteroid and a kite? Asteroids are large space rocks, while comets are large dirty ice balls. Meteors are smaller, usually the size of pebbles or even dust.
About 65 million years ago, a huge asteroid hit the land in the Gulf of Mexico. The huge explosion of Chicxulub caused large tsunamis throughout the ocean and raised so much dust in the air that caused the extinction of dinosaurs.
Another great impact of asteroid about 35 million years ago, created a huge crater in the area that is now Chesapeake Bay, near Washington, DC more recently, in 1908, an asteroid probably exploded over Tunguska, Russia, sweeping 2,150 square kilometers of trees. Fortunately, no one lived in the area, so they had no known victims.
Once a mass of space waste gathered on Earth, many processes continued to shape the planet’s surface. The wind, the water, the heat and the cold make the rocks wear and break and make the ground erosion. The mountains are created when pieces of the earth’s crust collide and crack. The rivers and glaciers wear out the planet’s surface to make it smoother.
Earth is a dynamic planet that is being constantly built, and these processes will continue for billions of years in the future.
*Alexander E. Gates is a professor of Earth and Environmental Sciences at Rutgers – Newark University
This article was originally published in The Conversation/Reuters.
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