The universe is a big place. Most physicists say it is infinite, and estimates of our observable universe fall around 93 billion lightyears across. Fortunately, math and science give us the tools to unravel what we cannot see, such as last week’s breakthrough discovery of the “echo” from the Big Bang.
The Big Bang theory posits the universe burst from a single point some 13.7 billion years ago. In a fraction of a second it underwent staggering expansion, growing exponentially at speeds faster than light. Early phases of the universe contained plasma so “dense” (high-energy) that photons could not escape. About 380,000 years later, the plasma cooled enough to let light push through, giving the universe its first moment of transparency. This theory is widely accepted by the scientific community and explains many properties of our universe, such as cosmic background radiation, large-scale structures, and the large presence of light elements (more on these in future posts).