By Michio Kaku
Up until just a few hundred years ago most people thought that the Universe was a stable, static place that had been here forever and would continue forever. Today we know that nothing could be further from the truth. In reality, we know that the Universe is a violent and continually changing place that was born in a mere nanosecond of time in the spectacular event we call the Big Bang. You may have heard the Big Bang referred to as the mother of all explosions but it wasn’t an explosion so much as an expansion. From a space that was infinitely small, the entire Universe expanded and continues even to this day -13.7 billion years later.
Lots of people wonder how we even arrived at that number and how we originally calculated the age of the Universe in the first place. It started with some educated guesswork and later got refined through some sophisticated technologies. A remarkable astronomer, Edwin Hubble was really one of the very first to make a reliable calculation of the age of the Universe. When Hubble was at Mount Wilson in the 1920’s, astronomers still believed that the Universe was static and not moving. But when Hubble looked at the very distant galaxies through a large new telescope, he began to notice that light was a bit distorted. The yellow galaxies appeared to be slightly redish and he wondered if the color change might be due to something called the Doppler effect. According to Wikipedia, the Doppler effect is commonly heard when a vehicle sound a siren or horn approaches, passes and then recedes from an observer. The same Doppler effect happens with starlight which becomes distorted and changes color. Hubble was then able to estimate the distance to certain stars and soon realized that they were receding and moving away from us. This meant that the Universe wasn’t static at all and was in fact actually expanding and had been for billions of years. Hubble’s work was a monumental discovery and changed everyone’s view on the way they looked at the Universe.
As hard as this is to fathom, at the very beginning, just at the instant of the Big Bang, the entire universe was infinitely smaller than an atom and we call this infinitely tiny point a singularity. This also raises the question of what was going on before the Big Bang. The problem we have is that standard mathematics just don’t apply before the Big Bang. There are of course beautiful animations of what we think may have happened during this bang but the fact is that the explosion took place in a time that is so short that it simply cannot be comprehended. The Universe expanded not into space but as space. In other words, matter did not simply explode but space expanded. It grew from a dot infinitely smaller than an atom to an area billions of light years across in a mere fraction of a second.
The Big Bang expanded as it cooled and as it cooled different kinds of matter began to condense out. For example, atoms began to condense about 300,000 years after the Big Bang. We still have lots of questions and there is still lots to learn but machines like the Large Hadron Collider are bringing us closer than ever before. With every successful experiment - we are closer to understanding the birth of our Universe.
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