Time has fascinated the human mind for millennia. Through the vantage points of culture, physics, timekeeping and biology, we have compiled a special timeline organizing some of the efforts that humans have made to understand time. (thread) quantamagazine.org/what-is-time-a…
Western culture tends to emphasize a linear conception of time, but the ancestors of today’s Australian aboriginal peoples embraced a timeless view of nature. In Asia, followers of Hinduism and Buddhism adopted a cyclic view.
Some of the best evidence for how ancient cultures viewed time can be found in artifacts of timekeeping mechanisms, like Egyptian sundials and circular Mayan calendars.
In physics, Aristotle’s definition of time as “the calculable measure of motion with respect to before and afterness” dominated Western conceptions of time until the work of Einstein in the early 20th century.
In 1729, the astronomer Jean-Jacques d’Ortous de Mairan placed mimosa plants in a darkened room for several days and noticed that their cyclic opening and closing persisted “as if the plants could feel the sun.”
In 1905, Albert Einstein’s special theory of relativity showed that there can be no “master clock” for the universe, as Isaac Newton had previously imagined. Later, in his general theory of relativity, Einstein showed that space and time can be warped by gravity.
Later in the 20th century, the Big Bang model of cosmology implied that the universe — and possibly time itself — had a beginning. The radiation known as the cosmic microwave background has since been described as the echo of the Big Bang. 
In 1972, two groups of scientists discovered a brain region that governs circadian rhythms by using information about light and darkness. In 2018, scientists uncovered a region of the brain that plays a crucial role in connecting time to memory formation. quantamagazine.org/how-the-brain-…
To explore the Arrows of Time timeline in greater detail, and for ongoing reporting on physics, mathematics, computer science and biology, visit quantamagazine.org.
