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Download The Evolution of the Solar System
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The Evolution of the Solar System By: Saroeun Son • It is believed that the solar system and all the other solar system all originated from the big bang. The big bang happened about 20 billion years ago. It was an explosion where all hot matter was sent throughout the universe. These violent explosions, as implied by the Big Bang theory, continue to explode to this day expanding our universe. • As the matter cools down, they formed many galaxies and stars. About 4.5 billion years ago our star, the Sun, was born. This was the beginning of our solar system. Our galaxy, the Milky Way, is one of the many galaxies that were formed. Inside the Milky Way, we have many stars, solar systems, and other types of space matter being created. How the Big Bang Theory was Implied The big bang theory assumes that the universe began from a singular state of infinite density. This means that the universe started off as a single state and continues to expand to this day. But how was it started? Eintein had believed that the universe is still expanding as the world went on, and from this he created an equation to explain its expansion. Einstein did not finish his equation, but a scientist named Alexander Friedmann completed his equations in 1922. How the Big Bang Theory was Implied • Then in 1927, George Lemaitre used the equations to devise a theory that had the concept of the universe expanding. George Gamow and R.A. Alpher named the theory “Big Bang.” This is how the term “Big Bang” came to be. Birth Of The Solar System • Scientists assumed that around 4.6 billion years ago, in the darkness of space, a large cloud of gas and dust once spun round like a huge flat disk, millions and millions of kilometers across. This huge cloud was known as a nebula, and most of the gas in the nebula was hydrogen. Birth Of The Solar System • Many years later, the spinning nebula collapsed under gravity and compressed to form a rotating gas globule. The gravity of the spinning nebula pulled together a massive, tightly packed lump, shaped like a ball. The process of the collapse took about 10 thousand to 1 million years. Birth Of The Solar System • As the collapse continued, the temperature and pressure within the globule increases. In time it became a spinning disc, with most matter concentrated in the center. The central core continued to collapse under gravity, becoming smaller and hotter. When the core reached the temperature of about 27, 000, 000, 000 F, a nuclear fusion began and our Sun was born. Birth Of The Solar System • As soon as the Sun was ignited with its fires, it released solar winds that pushed the surrounding dust and gases all around areas. Grains of dust collided and formed bigger and bigger lumps. Some of these lumps crashed together and formed planets, drawn together under gravity. The four solid rock planets, Mercury, Venus, Earth, and Mars were created. In the outer regions of the disk, the solar wind was weaker. The remaining dust and gas condensed into the larger gaseous planets: Jupiter, Saturn, Uranus and Neptune. Birth Of The Solar System • Between the orbits of Mars and Jupiter there is a relatively large gap in the solar system, where you might expect to find a planet. But instead there is a swarm of much smaller bodies, called asteroids, or minor planets. This area is called the Asteroid Belt. Around 2500 of these bodies have been discovered, and are usually just chunks of rock measuring a few kilometers across. Most of them have an orbit around the Sun between Mars and Jupiter, but some have orbits farther out or closer in, sometimes quite near to the Earth. The Brightness of the Sun • As the new star grew larger and became more tightly packed, the gas at its center became very hot, making the Sun shine more brightly. But like any other star, the Sun cannot keep shining forever. • As far as scientist can tell, it has been shining for about 4.6 billion years and it is about halfway through its life span. This means that the Sun should keep shining for about another 4.6 billion years, if it keeps shining as it does today. The Brightness of the Sun • The Sun shines by fusing hydrogen into helium. Since there is limited amount of hydrogen in the Sun’s core region to serve as fuel for shining, the Sun must stop shining as we see it today when it uses up its core hydrogen fuel supply. • The Sun is able to keep shining throughout a very long life span of billion years, because it takes very little mass of hydrogen nuclei to produce an enormous amount of energy. Life on Earth • Scientists have believed that life on our planet, Earth, began about three and a half billion years ago. That was only one billion years after the Earth was formed. The first plants and animals lived in the oceans. Then, over 400 million years ago, living things appeared on dry land. Dinosaurs appeared 200 million years, and human beings didn’t develop until 198 million years after that. The End