Introduction: DIY Planet Walk

About: During the COVID-19 crisis, all of the Unitarian Universalist Fellowship's religious services moved into an online-only format. I generally organize Sunday school activities for the children of the Fellowship …

In today's story, we learned about Unitarian Universalist scientist Clyde Tombaugh, who discovered Pluto in 1930. It's kind of crazy that we've only known Pluto existed for less than 100 years! But that's because Pluto is very, very small and very, very, very far away. Just how small and how far away? It's hard to visualize.

So let's go on a fun, outdoor adventure to help us do just that!



-pen or pencil


-1 large ball, like a soccer ball

-2 pinheads

-2 small beads or peppercorns

-2 coffee beans

-1 chestnut or chestnut-sized rock

-1 acorn or acorn sized rock or bead

-1 sprinkle

Step 1: Assemble Your "planets."

You've probably seen a picture of the solar system at school or in a book. Because those pictures have to fit on a page or a poster, they can't really show how far away everything is! In these pictures, the planets always look really close together. That's really not the case, though! This activity will help you understand just how BIG our solar system really is!

First, you'll need some planets. It doesn't really matter what you use, as long as they have some size differences. You could use objects similar to what I've used, or a variety of differently-sized rocks, or different sizes of clay balls you make yourself, or even just little dots and circles you draw!

Here's what I used (actual planetary diameters are approximate):

-A bowling ball for the Sun. You can use a soccer ball or a basketball -- really any large ball. My partner likes to bowl, though, so I borrowed his bowling ball. (The real Sun is about 800,000 miles in diameter.)

-Two pinheads for Mercury and Mars. (Mercury is 3,000 miles in diameter, and Mars is 4,000.)

-Two beads for Venus and Earth, slightly bigger than the pinheads. (Venus is 7,500 miles in diameter and Earth is 8,000.)

-Two coffee beans for Uranus and Neptune. (Uranus is 32,000 miles in diameter and Neptune is 30,000.)

-A bead larger than all of the other planets but Jupiter for Saturn. (Saturn is 75,000 miles in diameter.)

-A pebble larger than all of the other planets for Jupiter. (Jupiter is 90,000 miles in diameter.)

-The smallest sprinkle I could find in my sprinkle jar for Pluto. (Pluto is 1,400 miles in diameter.)

Once you have all of your planets, put them together on your table. Look at how small they are compared to the Sun! The Sun is really, really big!

Step 2: Tape Your Items to Pieces of Paper.

The "planets" are really small and really easy to lose just sitting on your table, let alone while you're on an adventure. Cut a piece of paper into 9 cards (or just use index cards if you have them), and tape each planet to a card. Label the planet so you know which is which.

Step 3: Note the Distance Between "planets" on Each Card.

On your adventure, you'll be counting paces between each planet to get an idea of how far apart they are. To make this easier, I put the number of each paces from the planet before on each card, as follows (actual distances are also approximate):

-Mercury is 10 paces from the Sun. (36,000,000 miles)

-Venus is 9 paces from Mercury. (31,000,000 miles)

-The Earth is 7 paces from Venus. (26,000,000 miles)

-Mars is 14 paces from Earth. (49,000,000 miles)

-Jupiter is 95 paces from Mars. (342,000,000 miles)

-Saturn is 112 paces from Jupiter. (403,000,000 miles)

-Uranus is 249 paces from Saturn. (896,000,000 miles)

-Neptune is 281 paces from Uranus. (1,011,000,000 miles)

-Pluto is 242 paces from Neptune. (872,000,000 miles)

Step 4: Place Your "Sun" at Your Starting Point.

I started from my porch, so I set the bowling ball right outside my door. Onward to Mercury!

Step 5: Walk 10 Paces to "Mercury."

Mercury's just at the end of my half of the porch.

Step 6: Walk 9 Paces to "Venus."

Venus was just on the other side of my neighbor's side of the porch, halfway down the driveway.

Have I mentioned that my neighbors think I'm pretty weird?

Step 7: Walk 7 Paces to "Earth."

Earth is right at the end of my driveway. Onward to Mars!

Step 8: Walk 14 Paces to "Mars."

Earth can still easily be seen. But now we're leaving our "close" neighbors. Of course, metaphorically, we've already traveled 142,000,000 miles! But now buckle in for a longer ride to Jupiter.

If you're doing this walk with your family, make sure to assign someone to count steps!

Important Note: Now that we're getting out into farther reaches of space and traveling much longer distances, it's likely that at least one of your step counts could put you in the middle of a road. Make sure to look both ways before you cross any intersections, and finish crossing any street before you lay down your planet!

Step 9: Walk 95 Paces to "Jupiter."

A little over a block later, we arrived at Jupiter. It's even further to Saturn, now!

Step 10: Walk 112 Paces to "Saturn."

A little over a block further on. You can still almost see my driveway, where Earth is, but you certainly can't see Earth itself. Now we're really in the far reaches of the Solar System. It only gets further out from here!

Step 11: Walk 249 Paces to "Uranus."

We definitely can't see Saturn or my driveway from here! Now, onward even father to Neptune!

Step 12: Walk 281 Paces to "Neptune."

Uranus is off in that direction somewhere. Now: on to our last stop!

Step 13: Walk 242 Paces to "Pluto."

Wow! We've walked over half a mile to make this scale model of our Solar System. That half mile walk represents the 3,666,000,000 miles that it actually is from the Sun to Pluto.

Our Solar System is HUGE. And our system is just a tiny system in a tiny corner of our galaxy, which is one of many galaxies. I hope this walk has made you feel a little bit of wonder about the enormity of our universe, because that's exactly what our UU scientist friend Clyde Tombaugh felt every day.

Note: On your way back, pick up your planet cards so they don't blow off in the wind and become litter. Always gotta respect the 7th Principle and take care of this planet!