The Big Bang Theory Explained
The Big Bang theory describes how our universe began expanding about 13.8 billion years ago from an incredibly tiny point called a singularity. This wasn't an explosion in space - it was space itself expanding!
Here's what happened step by step: First, the universe started as a singularity containing all space, time, matter, and energy. Then it expanded rapidly through a process called inflation. As it grew, it cooled down significantly.
During this cooling, nucleosynthesis occurred - nuclear fusion created the first atomic nuclei. Finally, electrons joined with these nuclei through recombination, forming the first actual atoms in the universe.
The evidence is rock-solid. Scientists like Vesto Slipher observed galaxies moving away from Earth using redshift measurements. Edwin Hubble calculated distances between galaxies, while Wilson and Penzias discovered cosmic microwave background radiation - basically the leftover energy from the Big Bang still humming through space today.
Amazing Fact: The universe is only 5% ordinary matter - the rest is mysterious dark matter and dark energy!