Scientists believe the Universe began with a hot “big bang” about 13,600 million years ago. The Universe continues to expand today. Evidence supporting the Big Bang theory includes the existence of microwave background radiation and redshift. Stars don't stay the same, but change with age. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Scientists have collected a lot of evidence and information about the Universe. They used their observations to develop a theory called the Big Bang. The theory states that around 13.7 billion years ago all the matter in the Universe was concentrated in a single, incredibly small point. This began to expand rapidly in a hot explosion, and is still expanding today. Evidence for the Big Bang includes that all galaxies are moving away from us and the further away a galaxy is, the faster it moves away. Redshift You may have noticed that when an ambulance or police car passes by, its siren is loud. it is sharp as it comes towards you, then becomes severe as it moves away. This effect, in which a change in frequency and wavelength occurs, is called the Doppler effect. It happens with any wave source that moves relative to an observer. This also happens with light and is called "redshift". Our Sun contains helium. We know this because there are black lines in the Sun's light spectrum where helium has absorbed the light. This is called redshift. It is a change in the frequency of the position of the lines. Astronomers have discovered that the further away a star is from us, the more red-shifted its light is. This tells us that distant galaxies are moving away from us, and that the further away a galaxy is, the faster it is moving away. Please note: this is just an example. Get a custom paper from our expert writers now. Customize essaySince we cannot assume that we have a special place in the Universe, this is evidence of a generally expanding Universe. It suggests that everything is moving away from everything else. The Big Bang theory is an effort to explain what happened at the beginning of our universe. Discoveries in astronomy and physics have proven beyond any reasonable doubt that our universe actually had a beginning. Before that moment there was nothing; during and after that moment there was something: our universe. The Big Bang Theory is an effort to explain what happened during and after that moment. According to standard theory, our universe began as a “singularity” about 13.7 billion years ago. What is a “singularity” and where does it come from? Well, to be honest, we don't know for sure. Singularities are areas that challenge our current understanding of physics. “Black holes” are thought to exist at the center. Black holes are areas of intense gravitational pressure. The pressure is believed to be so intense that finite matter is actually squeezed into infinite density (a truly mind-boggling mathematical concept). After its initial appearance, it apparently ballooned (the “Big Bang”), expanded and cooled, going from very, very small and very, very hot, to the size and temperature of our universe today. It continues to expand and cool to this day, and we are inside it: incredible creatures living on a unique planet, revolving around a beautiful star clustered together with several hundred billion other stars in a galaxy soaring in the cosmos, which it's all within it. an expanding universe that began as an infinitesimal singularity that appeared out of nowhere for.