Imagine stepping from the Sun to Earth in less than a minute—that is, much faster than the speed of light. Not possible, right? In fact, it is, if you are traversing a model with a scale of 3.4 billion to 1.
Next to the Chippewa River, in downtown Eau Claire, Wisconsin, is the epicenter of the solar system: our Sun, and the beginning of Eau Claire’s Planet Walk. I went on the journey, so let me share my experience and some other thoughts on perspective and our solar system.
The Sun is a 16-inch diameter metallic sphere atop a pavilion in Phoenix Park, grand on its perch and shiny in the light of the real Sun. Mere steps away is Mercury, represented at twice its actual size due to its diminution.
Venus is also a few steps, and then Earth. This little neighborhood of rocky planets is what exists between us and our home star. On one hand, it’s not much space, considering how much further the walk goes (a total distance of 1.1 miles). On the other, looking at the tiny size of the inner planets—smaller than a pencil eraser—it’s a vast amount of empty space already. But we’re just getting started.
Mars is a bit further out. The last of the rocky planets, it rests comfortably within the inner solar system and still well under the Sun’s influence. I can still clearly see the star and its pavilion throne from here.
The space between Mars and Jupiter is the first proper walk of my experience. It is not empty but filled with flowers, blooming periwinkle and pink and yellow and white and overwhelmingly green. Such a contrast: all this life completely fills up what in reality is just pure emptiness.
Save for the asteroid belt, of course. Near where it would be, there is, perhaps fittingly, a field of smooth gray and tan boulders.
Jupiter rests, stately and proud, near the bridge across the Chippewa River. The orbit lines of its moons are striking: imagine how large and looming Jupiter must be to Europa, the moon within which slumbers a cold ocean and perhaps life.
I continue across the bridge over the Chippewa River. It’s a distance at least as far as I’ve traversed so far, and I am battered by winds. I imagine the solar winds streaming from our Sun, blasting its planets with radiation and ionized particles. Jupiter, in particular, has a massively powerful (and massively enormous) magnetic field to protect it from this.
I reach Saturn across the bridge. This is the last time I can look back and see my starting point before it’s lost from view. The Sun, itself, is hidden, but I wouldn’t be able to distinguish it anyway. The fact that our telescopes can pick up Saturn and its moons so well from Earth is astonishing with this in mind. With modern telescopes, this is minor league stuff.
Now for the first actual work-out of the walk. Uranus is quite a ways off, further south along the river and past a well-maintained neighborhood of what must be pricey houses.
Neptune is worse. It’s sunny and bright, and midday, so I’m feeling my body strain a little with the heat. I can’t see our starting point, or even Saturn, anymore. It’s incredible to think how far the Sun’s sphere of influence extends. Gravity, while relatively weak on close scales, has a gargantuan range. Our model Sun, 16 inches wide, is (hypothetically) keeping this marble-size planet in a stable elliptical orbit at about three-quarters of a mile out. I set out for Pluto.
With the huge distance yet to cover, I’ve been walking faster, lingering to observe the view less. It’s as close to empty space as I’ll come in this scaled-down solar system. Just a rhythmic tapping of my feet on concrete, eating up the 3.7 billion tiny miles between Phoenix Park and the lawn near UW Eau Claire’s Haas Fine Arts Center. New Horizons, the probe that just got those gorgeous images of our tiny dwarf planet neighbor, took nine years to travel a distance that I crossed in about half an hour. My mind sparks, working to scale up my speed and time. I am faster than light.
Pluto is represented at four times its actual size. Like Mercury, it’s just too minuscule for this scale to capture it properly (but if the scale were any bigger, the walk would be much less neat and manageable).
I am fascinated by the last bit of information on Pluto’s plaque. On this scale, the Alpha Centauri star system would be somewhere in Hong Kong. Let’s push my brain a little again, and contemplate the scale of it. If I were able to continue at an average walking speed of 3 miles per hour, I would reach Hong Kong in about 104 days. Consider: I’ve been traveling at many times the speed of light on the scale. This recognition seems to help me grasp the fact that spacecraft cannot realistically ever reach Alpha Centauri in a reasonable amount of time (that is, measurable in human lifespans). The distance is just too great. Conventional physics and conventional engines just won’t cut it. Sobering.
Perspective is an incredible thing. I highly recommend taking “planet walks,” if one is available to you. On the subject of our solar system’s vastness, here are some other wonderful scales:
This one is a website where you have to scroll to get through our system. (It’s pretty tiring—I gave up at Mercury.)
This is a scale in the Nevada desert which includes orbits and must be driven across, and it’s a beautiful video besides.
To the reader: what are your thoughts on perspective, and on the enormous scale of our solar system (if not our universe)? What other similar activities or resources would you recommend?