It’s helpful to take a long-term view of your life – but it’s often difficult to think beyond the coming year, or even the coming day.
It’s inspiring to think of yourself connected to the vast web of nature – but that’s an awfully abstract idea to summon while you’re busy preparing your next meal or paying your next bill.
So allow me to propose a little dose of cosmic thinking that could help with both forms of perspective. To expand your sense of time, look up on a clear, dark night, and take a deep journey into the past. You can’t see your own past, but you can look directly into the past of the universe. In fact, you can’t avoid gazing into the past. Due to the limited speed of light, the light of every star you see at night is many years old. That is, the light you see right now has spent many years traveling through space from that distant star to your eye.
This is an odd but powerful concept. When you aim your eyes upward at night, you are gazing the stars as they were, not as they are. Every flicker of starlight is therefore anchored to a moment in history. When you look at the stars, you are unconsciously connecting with that earlier time. Why not connect with it consciously?
You can also flip things around, switching from backward to forward, to tap into another connection between you and the vast expanse of nature all around you. The future life of every star is written in beams of light that are currently on their way to Earth. That future is out there, streaming across interstellar space, full of yet-unseen meaning. If a star is 100 light years away, you are seeing it now as it was 100 years in the past. Meanwhile, the next 100 years of that star’s life story (whatever exotic drama may occur in the life of a star) is already streaming toward you.
Here is another odd but powerful concept: The future is not just an idea but an actual thing, waiting for us. In the case of the stars, the tale of what happens to them next is already set; that tale simply hasn’t reached us yet. Fortunately, the situation is different for us. Our future is contingent on the actions we take today, tomorrow, and the day after. Our future is out there, but it is not yet locked in.
If I may mangle Shakespeare: We humans are sometimes masters of our fates. Free will is not in the stars, but in ourselves.
Tripping across space and time
Am I geeking out too hard on this whole past/future perspective thing? Bear with me. I think it will be worth the journey.
The key to this altered view of reality is being aware that light may be fast, but it sure is not instantaneous. Light (or radio waves, or any kind of information-bearing signal for that matter) moves at a precise, finite speed: 299,792 kilometers per second, or 186,282 miles per second if you prefer, through empty space. As a result, everything you see – literally, everything – is taking place in the past.
The speed of light conveniently works out to be almost exactly 1 billion feet per second. You are probably looking at these words on a screen that is one foot(ish) away from your eye, which means that you are looking 1 billionth of a second into the past as you read. A typical conversation has a light lag of a few billionths of a second. That’s not enough of a delay that you could possibly notice it, but it is there. (If anyone ever accuses you of living in the past, you can now respond that it’s not your fault; the laws of physics force you to do it.)
When you shift to astronomical scales, the time-delays associated with the speed of light suddenly swell to more meaningful scales. The Moon is slightly more than 1 light-second away: Glance up at a smiling lunar crescent and you seeing it as it was a second ago. For the Sun, the lag is a little over 8 minutes. For Voyager 1, the most distant object built by humans, the lag is one full day. Troubleshooting a faulty onboard computer at that distance poses quite the challenge.
When you expand yet again to interstellar distances, you take another huge leap in time. The nearest star system, Alpha Centauri, is 4.3 light years away, meaning that you see it 4.3 years in the past. You are living 4.3 years in Alpha Centauri’s future. Arcturus, the bright orange star of the springtime sky, is 37 light years away. The stars of the Big Dipper range from about 80 to 120 light years away.
You might notice an interesting pattern in those numbers. By happy coincidence, many of the bright stars of the sky lie at distances where the travel time of their light falls within the range of a human lifespan. If you are 10 years old, there is a bright star whose incoming light is about the same age as you are. That’s true, as well, if you are 20, 30, 40, and so on. The oldest person on Earth is about the same age as the light from Dubhe, the star that marks the front tip of the Big Dipper.
No matter how old you are, there is a prominent star in the sky whose light is roughly the same age as you are…assuming you are more than 4.3 years old, that is.
Find your own star
This is what I call the “stars of your life” concept. You pick out a star whose distance in light years roughly matches up with your age in years, and anchor your sense of time to it. When you look at that star tonight, you are seeing light that was emitted right around the time you were born. All the time that you’ve been living your life, the light from that star has been traveling toward you, until the moment – now – when that light enters your eye and becomes visible to you.
To me, the resulting celestial connection is humbling but inspiring. It’s extremely difficult to visualize the spatial distances to the stars (trillions and trillions of miles!). It’s a lot simpler to imagine the time distances to the stars: the path marked out by a beam of light traveling as long as you have been alive, steadily racking up the miles. Covering the distance from New York to Tokyo twenty times a second, over and over.
You can easily identify the star that roughly matches your age. If you are around 10, try Sirius (8.7 light years), the brightest star in the sky. In your 20s, sparkling Vega is a good bet. In your 30s, go with Arcturus. In your 40s, the lovely northern star Capella. In your 50s, Castor, one of the Gemini twins. In your 60s, Aldebaran, the red eye of Taurus. In your 70s, Regulus, the paw of Leo the lion. In your 80s and above, you can hop around among the stars of the Big Dipper.
You can get more specific in picking out your own star by reviewing a list of the brightest stars, sorting it by distance, and looking for the number closest to your age. All the stars I’ve mentioned are bright enough that you’ll have no trouble seeing them even under light-polluted suburban or urban skies. You might just need to refer to a sky map, and perhaps wait until the right season for your star to come into view.
Note that, as time goes by, the star corresponding to your age keeps changing. You catch up with older and older starlight – that is, with more and more distant stars. Sure, you are getting older, but at least you are also reaching deeper into the universe.
And you don’t have to stop with your own lifetime. You can also view starry light that matches up in age with significant moments in human history. The prominent summer star Deneb is 2,000 light years away, corresponding to the time of the Roman Empire and the birth of Jesus. The globular cluster M4 (pretty through a small pair of binoculars in the constellation Scorpius) is 6,000 light years away; its light is the same age as the first written language.
The Andromeda Galaxy, at 2.5 million light years away, is the most distant object readily visible to the naked eye. Spot its diaphanous glow in the autumn sky, and you’re looking at light that began its journey around the time that the genus Homo emerged in Africa. All of our direct human evolutionary history is tethered to that little smudge of light. What will Earth be like 2.5 million years from now, when the next lap of light from Andromeda arrives? Will we, or anything like us, still be around?
I hope you find this kind of perspective elevating the same way I do. And if you enjoyed this far-out meditation on space and time – just wait until my next column, where I take the “stars of your life” concept one step beyond.