A Long Time Ago in a Galaxy Far, Far Away
Have you ever looked out on a damp and dreary January day and considered that everything you see around you — from the bare trees and the frost-fringed asphalt to the discarded newspaper tumbling on the breeze — is the culmination and product of nearly 14 billion years of cosmic history? The same is true of everything around us, from bacteria to buildings to our bodies.
I often take solace in the idea that the protons, neutrons and electrons that make up every atom in every molecule in my body were around, in some form or another, long before I existed. They will continue to exist long after I am gone. Their story is intertwined with the history of the Universe and the formation and evolution of galaxies.
Our solar system is about five billion years old, or about a third of the age of the Universe. Five billion years ago the Sun ignited in a spark of nuclear activity as a cloud of hydrogen gas gravitationally collapsed into a dense core. Temperatures and pressures in this core rose to a level that allowed pairs of protons (the single particle of which hydrogen nuclei are comprised), which are normally repelled by each —> Read More Here