Chronology of the universe

The Chronology of the Universe: A Journey Through Time

Imagine peeling back the layers of time, like an onion, to uncover the history of our universe. The chronology of the universe describes its history and future based on Big Bang cosmology. Research from 2015 estimates that the earliest stages occurred 13.8 billion years ago with an uncertainty of around 21 million years. How can we possibly grasp such vast stretches of time?

The Very Early Universe

The very early universe, a mere picosecond to 370,000 years after the Big Bang, is shrouded in mystery. It includes cosmic inflation and the emergence of fundamental interactions. Can we even begin to fathom what happened during these infinitesimal moments?

The Early Universe

As time progresses, around 370,000 years after the Big Bang, particle formation, neutrino decoupling, and nucleosynthesis occur. The universe transitions from a dense plasma to a state where photons can travel freely. How did these processes shape the early cosmos?

The Dark Ages

The Dark Ages and large-scale structure emergence span from 370,000 years to about 1 billion years after the Big Bang. During this period, the universe is opaque plasma, with clouds of hydrogen slowly forming stars and galaxies. The cosmic microwave background is formed during this time as well. What was it like in those early days when the universe was just a vast sea of light?

The Formation of Stars and Galaxies

Around 200-500 million years after the Big Bang, the first stars and galaxies begin to form. These early structures draw towards dark matter filaments, marking the beginning of large-scale structure formation in the universe. How did these early stars and galaxies come into existence?

The Emergence of Large-Scale Structures

After 1 billion years, matter dominates the universe’s behavior, and photons can travel far without being absorbed by hydrogen atoms. Galaxy clusters and superclusters emerge over time, leading to reionization between 250-500 million years ago. The universe gradually transitioned into its current form by 1 billion years. What does this tell us about the evolution of our cosmic neighborhood?

The Modern Universe

Galaxies have been observed since just 329 million years after the Big Bang. To derive the age of the universe from redshift, numeric integration or a special Gaussian hypergeometric function is used. The universe has looked much as it does today for about 12.8 billion years and will continue to appear similar for many billions of years. How do we measure such immense periods?

The Expansion of the Universe

The expansion of the universe is accelerating due to dark energy, an unknown form of energy that makes up about 68% of the universe’s mass-energy density. The Standard Model of cosmology is based on the Friedmann–Lemaître–Robertson–Walker (FLRW) metric, which describes the expansion of the universe since the Big Bang. What does this mean for our understanding of the cosmos?

The Future of the Universe

Beyond 100 billion years of cosmic time, we are less sure which path the universe will take. The future evolution of the universe is uncertain and depends on various physical constants and laws. If the universe continues to expand, it will eventually be limited to our local galaxy cluster, and stars will cease to form. What does this imply for the ultimate fate of our universe?

The chronology of the universe is a fascinating journey through time, from the earliest moments after the Big Bang to the present day and beyond. As we continue to explore and understand our cosmic origins, the mysteries of deep space remain ever-present, inviting us to ponder the vastness and complexity of it all.