The Experience of Time

Time is a mystery, and after this last year it seems more mysterious than ever. We exist in time, it is ongoing and seemingly changes with every experience, but we don't understand it or even know what it is. Stephen Hawking wrote books about time, and in the end still didn't understand what time is.

Will there ever be an end? Was there ever a beginning? How can we meaningfully measure time so that we can compare rates of change and frequency of events, and use that knowledge to predict future events? How does time leave its mark on the Earth and in the building blocks (atoms) of the Universe? Geologists study the passage of time by studying the marks of change in rocks, planetary features, and Earth chemistry. The task of unraveling the story of billions of years will never be complete, we will always be studying the planet and the Universe to better understand existence through all scales of time.

Earth Scientists refer to layers of evidence of planetary change as paleo-proxy records. These records are quite literally ancient representatives of past processes that left their mark on and in the materials of the planet, on unfathomably wide arrays of time scales. Consider the task of distinguishing between processes that overlap on the scales of seconds, days, seasons, centuries, millennia, and millions of years. The evidence of change is recorded in layers of glacial ice, sediments, fossils, and in the fluctuations of the chemistry within. Some paleo-proxy records can only be understood on the scale of deep time, when the divisions of millions of years on the Geologic Time Scale is the most appropriate measurement. Other records, like ice cores, convey higher resolution information about the annual patterns of Earth evolution.

At a single location, layered paleo-proxy sediment records can reveal shifting wind directions over hundreds of years, seasonal fluctuations in the annual flow of water, and a fossil record of biological adaptation and extinction over millions of years. The interpretation of paleo-proxy records is highly complex as natural processes overlap in space & time, and the culmination is picture of an ever-evolving planet that can experience rapid change that is challenging for life.

For me, the challenge of rapid change & uncertainty was the overarching theme of this last year. I felt like the rate at which time progressed constantly changed, and time became more mysterious & elusive. Before pandemic shutdowns descended, we tracked time through the consistent patterns of our daily lives, aligned with the Gregorian calendar and our clocks synced to precisely measured and standardized time. But those daily patterns changed and our perception of time changed in turn. The precise measurement of time is actually a very recent human innovation. The oldest evidence of time keeping dates back to 5,000 years ago, clocks were invented approximately 700 years ago, the novelty of watches arrived just over 400 years ago, and time was standardized using atomic clocks in the 1960s. Today, our time keeping is more reliant on atomic decay measurements than on observable cycles in nature. We have Gregorian months that are loosely connected to lunar cycles, & years that are imperfectly aligned with solar cycles. We often speak of time with no thought of seasons or nature in any other respect. We have quickly come to rely upon our measured, but otherwise imperceivable, divisions of time to mark the passage of our lives, and when our regular patterns of time are disturbed, so are we.