Geophysics - Earth, Sun, Solar System and Universe

The Big Bang Theory

Astronomers believe that the universe began as a result of a very large and powerful explosion. This huge and powerful explosion is called the Big Bang. The Big Bang theory explains how the universe began. The Big Bang theory states that a very small, hot, dense ball of matter exploded and expanded outward, creating space. The universe is believed to have expanded from that explosion and is still expanding today. According to this theory, all the energy of all the matter in the universe was once concentrated in a very small, very small place. It was very hot and very dense. (extremely hot and dense) About 15 to 20 million years ago, the Big Bang occurred, and the energy of the condensed matter was spread out in all directions. The fastest-moving matter traveled furthest first. The energy also traveled farther away from where the Big Bang began.

If the Big Bang Theory were true, the energy released from the Big Bang explosion would have spread throughout the universe. This energy is called background radiation. In fact, scientists have found that the background radiation is almost the same throughout the universe. Therefore, the discovery of this constant background radiation is a support for the Big Bang Theory and a proof of the Big Bang Theory.

After the Big Bang, all matter and energy spread out in all directions and distances, and gravity began to act on all objects. Gravity is the force of attraction that objects exert on each other. In all objects, objects tend to exert an attraction on each other. Because of this force of attraction, objects come together and form large clusters and solids. Sometimes, very large planets and solids are formed from these clusters and solids. These planets and solids form galaxies in the universe. Even though such clusters of stars are formed, the objects in these clusters of stars are still affected by the original Big Bang, so they continue to move away within the region of the cluster of stars. From there, astronomers discovered that all star clusters are still moving away from the center of the universe (the origin of the Big Bang). This means that the objects that were scattered by the Big Bang are still moving away from the point where the Big Bang started, even though they are now clumped together by gravity.

An Open Universe

Most astronomers have identified two possible ways the universe could have started after the Big Bang. If the galaxies had continued to expand outward, the universe would have continued to expand. This idea is called the open external universe. (But it does not mean that it would have expanded forever.) During the expansion of the universe, stars would have burned up all their energy and would have died. So at some point in the future of the expansion, there would be nothing left, and the expansion would have led to total emptiness. But even if the universe were expanding, it would not have been possible for billions of years before it would have ended.

A Close Universe

Many astronomers also don't like the idea that the open universe will always expand. Because there are so many objects in the universe (suns, stars, planets, etc.), the gravitational attraction between them is so great that it can't be contained.

The gravitational forces are so strong that they are thought to eventually slow down the movement of stars away from each other. The expansion of the universe is also thought to eventually come to a standstill. At that point, gravity is thought to pull the stars back toward the center of the universe (where the explosion started) and cause them to move backwards. When that happens, we will begin to see a blue shift in the spectrum of light from all the stars. Note: There are seven wavelengths of light in the rainbow. Starting with violet, indigo, and blue, ending with red. In that order. If the light-emitting objects are pointing forwards from the Earth (away from us), we will see a red shift, and if they are pointing backwards towards the Earth (away from us), we will see a blue shift. This phenomenon is called the Doppler Effect. If the galaxies were to move back toward the center of the universe, the energy of the matter would come closer and closer to each other and would be re-concentrated at the center. Over the course of billions of years, all the matter and energy would be condensed into a very small, very dense object. Then there would be another Big Bang. The universe would repeat this process over and over again. This regular process of exploding and re-condensing, which is what we call the Close Universe. It is thought that the Big Bang occurred every 80 to 100 million years during this close universe.

Oscillating Theory

According to the Close Universe, a theory based on the Big Bang Theory, there are an extremely large number of objects (suns, stars, planets, etc.) that have attracted each other, and the gravitational forces between them have increased, resulting in an extremely large gravitational force, which has slowed down the expansion rate of the universe, and eventually all objects (due to the large gravitational force) will return to a point (like the original state). However, some astronomers believe that the universe will not return to a point, but will contract and expand again, and vice versa, according to the Oscillating Theory (the principle of interaction). Because the stars and planets in the universe attract each other due to the law of gravity and will come together when they get close to each other, although it is assumed that these stars and planets will not return to a point, They stated that the universe could not be condensed to a single point due to the heat of the sun, and that the universe did not return to a single point, but rather expanded, contracted, and then oscillated back and forth.

Solar System ( family)

The group of stars (all the stars and planets) together is called a galaxy. Astronomers estimate that there are ten thousand (10 ¹¹ ) million stars in the universe. A galaxy is thought to contain between ten thousand (10 ¹¹ ) and twenty thousand (2 x10 ¹¹ ) stars. The Milky Way galaxy, which includes our Earth, also contains about ten thousand million stars. Among these ten thousand million stars, the Sun, which is indispensable to our world, is one. Stars in the universe are divided into three types: first, second, and third, according to their size and explosive power. The star we humans own (the Sun) is a third-class star. The Solar System is a very small part of the Milky Way Galaxy. The Milky Way Galaxy is a very small part of the Universe. Our Milky Way Galaxy is shaped like an arm. Its main cluster is a large cluster of stars that are arranged in a spherical shape, with two arms radiating out from the center. Our Solar System, which includes our Earth and nine planets, is a small part of the Milky Way Galaxy, located at the end of one of the arms of the Milky Way. (Figure 1.1)