Sara Walker and Lee Cronin write:

A timeless universe is hard to imagine, but not because time is a technically complex or philosophically elusive concept. There is a more structural reason: imagining timelessness requires time to pass. Even when you try to imagine its absence, you sense it moving as your thoughts shift, your heart pumps blood to your brain, and images, sounds and smells move around you. The thing that is time never seems to stop. You may even feel woven into its ever-moving fabric as you experience the Universe coming together and apart. But is that how time really works?

According to Albert Einstein, our experience of the past, present and future is nothing more than ‘a stubbornly persistent illusion’. According to Isaac Newton, time is nothing more than backdrop, outside of life. And according to the laws of thermodynamics, time is nothing more than entropy and heat. In the history of modern physics, there has never been a widely accepted theory in which a moving, directional sense of time is fundamental. Many of our most basic descriptions of nature – from the laws of movement to the properties of molecules and matter – seem to exist in a universe where time doesn’t really pass. However, recent research across a variety of fields suggests that the movement of time might be more important than most physicists had once assumed.

A new form of physics called assembly theory suggests that a moving, directional sense of time is real and fundamental. It suggests that the complex objects in our Universe that have been made by life, including microbes, computers and cities, do not exist outside of time: they are impossible without the movement of time. From this perspective, the passing of time is not only intrinsic to the evolution of life or our experience of the Universe. It is also the ever-moving material fabric of the Universe itself. Time is an object. It has a physical size, like space. And it can be measured at a molecular level in laboratories. [Continue reading…]