Only by recognizing your mistakes and repairing them can you make science evolve. A scientist must always remain modest and criticize his own theories. Without imagination, Newton would never have figured out the theory of gravity when he saw an apple falling from a tree and wondered why the moon didn't fall as well. The Universe is believed to have been created between 10 and 20 billion years ago. . One of the most persistently asked questions of all time is: How was the universe created? In the pass, a group of people believed that the universe had no beginning or end and was simply infinite. But since the advent of the Big Bang theory, this belief was no longer accurate. The universe was forced to take on the properties of a finite phenomenon, having a history and a beginning. About 15 billion years ago, a huge explosion occurred and triggered the expansion of the universe. This explosion is known as the big bang. What existed before this event is completely unknown and can only be speculated. The Big Bang essentially involved an explosion of space within itself, unlike the normal explosion of a bomb whose fragments were thrown outwards. The Big Bang then began to lay the foundations of the universe. The first stars formed 100 to 200 million years after the Big Bang and reionized the Universe. After that, the first supernova exploded and spread nitrogen, oxygen, silicon, magnesium, carbon and iron through uranium throughout the Universe. A supernova is the explosion of a star, it is the largest explosion to take place in space, radiating as much energy as the sun is expected to do in its entire lifetime. The solar system was then formed 4.6 billion years ago. But this essay is not only about the big bang theory and the... middle of paper ......d signal before detection. Another special feature of COS is its maximized efficiency, meaning that each bounce of a light beam along its path results in a loss of signal strength. The COS has a single bounce when the beam is introduced into the appropriate channel. The Doppler effect (or Doppler shift) is the change in frequency of a wave for an observer moving relative to the source of the wave. For example, if someone is on a street and an ambulance approaches with its siren blaring, the sound of the siren gradually gets louder as it gets closer. Then, as we pass, the noise suddenly diminishes noticeably. This is an example of the Doppler effect: the change in the observed frequency of a wave as the source of the wave moves toward the viewer. The Doppler effect occurs in both sound and electromagnetic waves, including light waves..