It is only by recognizing one's mistakes and correcting them that science can evolve. A scientist should always remain modest and criticize his own theories. Without imagination, Newton would never have found the theory of gravity, when he saw an apple fall from a tree and wondered why the moon wasn't falling too. The Universe is believed to have been created between 10 and 20 billion years ago. . One of the most stubborn 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 with the advent of the Big Bang theory, this belief was no longer correct. The universe was forced to take on the properties of a finite phenomenon, with a history and a beginning. About 15 billion years ago, a huge explosion occurred that began 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 upon. The Big Bang basically involved an explosion of space within itself, unlike the normal bomb explosion where fragments are thrown outward. The Big Bang then began to lay the foundation for the universe. The first stars form 100-200 million years after the Big Bang and reionize the Universe. Subsequently, 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 that occurs in space, radiating as much energy as the sun should radiate in its entire life. The solar system therefore formed 4.6 billion years ago. But this essay is not just about the big bang theory and the signal... middle of paper... d before detection. Another special feature of COS is its maximized efficiency, which means that every bounce of a light beam along its path leads to a loss of signal strength. The COS has a single bounce when the beam is fed into the appropriate channel. The Doppler effect (or Doppler shift) is the change in the 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 screaming, the sound of the siren gets progressively louder as it gets closer. Then, as it passes, the noise suddenly drops 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.