The cosmological arrow of time points in the direction of the universe's expansion. Time is not reversible. Once the elementary particles and forces created in the Big Bang found stability in the element hydrogen, there was no turning back. Gravitational attraction forged hydrogen into helium in stars, stars forged the elements, the elements formed molecules, molecules stored energy, information, and do work. Energy, information, and work inside a membrane became a life form. Life forms diversified........... Join this massive open online class to collaboratively help string the milestones of time into a collevitve understanding of the unfolding of the universe.
