The Big Bang Theory was invented by astronomers, who used mathematical calculations along with observations to come up with the idea of how the universe begin. The mathematical part of the Big Bang theory is a combination of Albert Einstein’s general theory of relativity and theories of fundamental particles. Today the National Aeronautics and Space Administration also known as NASA, has the Hubble Space Telescope and the Spitzer Skace Telescope measuring the expansion of the Universe. It’s said that one day the Universe will stop expanding and turn around, then collapse just like when it was born. The theories of physics say if we looked at the Universe one second after the Big Bang, we would have only seen a ten billion degree of neutrons, protons, electrons, anti electrons, photons, and neutrinos. After a while, the Universe would cool. The neutrons would start decaying into protons and electrons or they would combine with protons to make deuterium. The Universe would cool and reach the temperature where electrons combine with nuclei and form neutral atoms. Before they recombination, the Universe would be opaque because of the free electrons that had caused light to scatter like sunlight from the water droplets in clouds. When the free electrons got absorbed from the neutral atoms, the Universe became transparent. This created the afterglow of the Big Bang also known as cosmic background radiation. It can still seen today.
NASA has had two missions to study the cosmic background radiation, taking pictures of the Universe 400,000 years after it was born. The first mission was the Cosmic Background Explorer also known as the COBE. In 1992, the COBE Crew declared that they mapped the hot and cold spots in cosmic background radiation. The hot and cold spots are part of the gravitational field in the beginning of Universe. The spots formed giant clusters of galaxies that go on from hundred million light years all over the Universe. Dr. John Mather and George Smoot, from the University of California, helped NASA earn the 2006 Nobel Prize for Physics with their work on cosmic background radiation. The second mission sent to explore the cosmic background radiation was the Wilkinson Microwave Anisotropy Probe, also known as the WMAP. The WMAP overlooked the whole sky. It measured the different temperatures of microwave radiation, that is equally spread all over the Universe. What the WMAP saw in the sky was hot regions (in red color) and colder areas (in a blue color). Combining this information with theory of how the Universe looks, scientists think that the Universe is flat. That means the geometry of the Universe fits the rules of Euclidean geometry.
Planck was the third mission by the European Space Agency with help of NASA, it took off in 2009. The Planck mission resulted in the most realistic maps of the microwave background radiation so far. It had tools sensitive to temperature variations of a culpa millionths degree. Mapping the whole sky, over 9 wavelength bands. Planck can measure the changes of the temperature of Cosmic Microwave Background radiation. The Big Bang theory was bulletproof and made everything seem clear, but in 1996, the examination of distant a supernovae completely changed whole theory. Many scientists thought that the Universe and everything in it would move slowly as it expands. The supernovae showed that the expansion of the Universe was not moving slowly like they thought, but faster as it accelerated. Something unknown that’s not matter or ordinary energy is pushing the galaxies apart from the each other. This is called dark energy, whether it’s formed dynamically or it’s an ability the vacuum of empty space has. Maybe one day scientists will find out exactly what dark energy is, cracking the Universe’s hidden secret right open.