“Enjoy yourself, it’s later than you think.” I keep this quote, usually attributed to an old song by Guy Lombardo, on a post-it note taped to the inside of my daily planning notebook.  It helps remind me to enjoy life’s surprises and to remember that life is short and tenuous, so make the most of it while you are able. My recent birthday, the historic Artemis II space mission, and my own aging parents have got me really thinking about timelines, the passage of time, and how we experience time. Life has been very busy for me lately, and it has been hard to find time to write. The irony of this, as it relates to the topic of time, is not lost on me.  

We know time passes, right? We can see the evidence on our faces and feel it in our bodies. We can cross off days on our calendars and mark milestone events with celebrations and remembrances. We notice the rhythmic passing of the seasons, tides, and moon phases. But is our experience of time the same as what we witness around us? Science offers us some interesting ideas about what time really is and how we humans experience time. Chronoception (also called subjective perception) is how we humans measure the passage of time internally through our psychological experiences. This concept explains why we sometimes experience time passing at different speeds, especially when we are bored or in heightened emotional states.  For eons, philosophers have debated whether the passage of time is even real or simply a human construct. Even though we work to construct our own timelines, we don’t really, truly control them. Perhaps we construct them just to give ourselves some comfort or semblance of control. Physics suggests that time doesn’t actually move, at least not in the way we sense it.  It posits that all events are arranged in relation to one another, and those relationships are what we experience as time. This idea explains how our own timelines intersect and bump into other timelines, like marbles rolling across a surface. Neuroscience offers my favorite idea about how we experience time: neural mechanisms in our brains anticipate future events, giving us the sensation of time as a genuine psycho-biological experience, even if it is not a physically independent movement. And if we want to visit an even deeper level of scientific thought, the Second Law of Thermodynamics, entropy,  presents us with the concept of the Thermodynamic Arrow. Here, the universe, an isolated system, moves over time from order to disorder. Time moves in a one-way direction away from order and toward total entropy (disorder). It is this pathway that distinguishes the past from the future, with time flowing from low-entropy states to high-entropy states. Heavy stuff, I think, but interesting to ponder. Perhaps our experience of time is explained by parts of all these ideas.

The passage of time is certainly a funny thing for me. Not funny as in humorous, but more funny as in oddly not linear and often unpredictable. I am very calendar-driven and very linear in how I organize and approach my life and everything in it, at both the granular and bird’s-eye level. Usually, this serves me well, but sometimes it makes me too rigid and inflexible when unexpected things pop up. Being a planner means I am always aware of the linear passage of time, but time frequently passes in non-linear ways. We can mark the linear passage of time on a calendar, noting birthdays, anniversaries, appointments, etc., but the actual human moments of time passing are much more subjective, nebulous, and meandering. Some moments in our lives can seem to stretch on forever, while others feel much more fleeting. When I was young, I felt as if time moved at a glacial pace. I feared I would never reach “old enough” to do anything fun or exciting. Now, as a grandparent, time feels like it moves at the speed of light, and if I blink, I might miss something magical. I often wish I could hit the pause button on certain moments in the hopes of savoring them for a little longer.

We each have our own ever-changing timelines. We are also impacted by the timelines of our families, friends, and the larger world around us. I like to envision all of these timelines connecting and interacting much like a complex highway system with twists, turns, on- and off-ramps, etc. Like busy roads at rush hour, our timelines can affect each other in small and big ways. When we are too focused on our own timelines, we forget to see the timelines of those around us. Recently, I have had a few big reminders of the passage of time and the importance of keeping an open mind about changing timelines, both our own and others’. These events remind me that, as much as I plan, I am really not completely in control of my timeline. It’s an illusion, and that is OK as long as I don’t get too attached to a particular moment or expectation. Many things, big and small, cause hiccups in our timelines; some are amazing, some can feel awful, and everything in between. The simple ones can be more annoying than upsetting, ie, running into road traffic that makes you late to an appointment. Others can still be small but fun, ie, you had plans to hit the gym but an old friend invites you to dinner instead. Still others can rock our worlds, i.e., the sudden death of a loved one. I am increasingly aware of the passage of time with my aging parents. Their timelines are different from mine, and it is later than I think it is with them. Sometimes big events in our loved ones’ lives force us to recalibrate our timelines to support them. When this happens, I find it helpful to remember that they are also recalibrating their timelines, which can be hard. We can forget that our loved ones have expectations about our timelines, and we also have expectations for them, too. Although we have our own timelines, we must be aware that we are also part of other people’s timelines.

As I mentioned above, the passage of time has been on my mind. We can’t stop time or even really control it. I think it is best to let that idea go. But we can choose to be truly present in our timelines and in the timelines of those around us. We can witness the wonder of being human and the privilege of being in each other’s lives. I felt this wonder in the astronauts on Artemis II when they saw the moon and Earth through their tiny ship’s window. I know it is a privilege, though sometimes a bit painful, to be alongside my dear parents as they age and move through their own timelines. It really is later than you think, so make the most of every minute and moment on your timeline. Move with grace when other timelines unexpectedly bump you. Slow down if you can and always look for the magic, wonder, and love. After all, these are the things that make us beautifully human.