The Solar System In Scale -
Walking The First Nine Planets
In 1:10,000,000,000 Scale
You've seen diagrams of the Solar System in textbooks, and they all look so... compact. There they are, the nine principle planets, in their orbits, neatly fitted to the book's page. Thing is, that's a little deceptive.
The reality is another matter. Our Solar System is actually made up of a lot of space, all of it empty. Trying to get this point across is difficult enough. There are a number of large scale models out there (Talcott Mountain Science Center's in Avon, Connecticut comes to mind through personal experience). In order to make these large models work, though, the distances have to be really stretched. For instance, if you have a Sun that is 200 inches (5 meters) across, the planet we call Earth (you're standing on it... I hope. If you're not, please contact me) works out to be 2 inches (50 mm) in diameter. It sits over 1785 feet (545 meters) away; not a big deal. Pluto, which measures roughly 1/4 inch (6 mm), on the other hand, sits over 13 miles (almost 21 km) away. Not exactly visible, and very hard to walk in a single classroom session. These models are still impressive, though, and really convey the emptiness between the worlds.
I chose a smaller scale, 1 inch = 186,000 miles (1cm = 100,000 km). In this scale, light takes one second to travel that inch (or 25 mm). Walking along at a modest clip, you can easily beat the starship Enterprise. If you really must stick to the speed of light, however, this walk will take a real long time.
This model was setup alongside Huffman Boulevard next to the South Campus of the Florida Community College at Jacksonville. We'll start with the inner Solar System out to Jupiter.
(image edited from "Google Maps" )
The Inner Solar System and The Terrestrial Planets
In our chosen scale, the Sun works out to 5.6 inches (142 mm) in diameter...
Starting near the entrance to the northeast corner of FCCJ's parking lot, we begin to build our model.
We start with the Terrestrial planets, so called for their rocky nature, in other words, Earth-like.
The planet nearest to the Sun, Mercury, sits 19.5 feet (5.91 meters) away; 36,000,000 miles (58,500,000 km) in this scale. In this model, it is a mere speck, .0195 inches (.4 mm) in diameter.
We've not travelled that far at all. The Sun, though, contrary to what you see in a lot of science fiction, does not dominate the sky. It is, however, around three time the size it is when seen from Earth.
Next, we arrive at the hottest planet in the Solar System, Venus (yes, it is generally hotter than Mercury).
Venus is larger than Mercury, in fact very close to the size of Earth. Here, it is .0487 inches (1.2 mm) in diameter. The Sun is roughly 1 1/2 times the size we see it from Earth. It lies 36 feet (10.97 meters) from the center of our Solar System, 66,960,000 miles (108,000,000 km).
Now, we reach our home planet, Earth.
We've travelled 50 feet (15.24 meters) from the Sun. In this scale, Earth is .0512 inches (1.3 mm) in diameter. Imagine, everything you love, everyone you know, all of history, all crammed into that tiny blue dot (tip of the hat to the late Carl Sagan). By the way, if you look closely, you'll see that there are two dots. The one on the right is our Moon, highlighted for visibility (it would be virtually invisible otherwise).
Since we've arrived at Earth, we can now talk about the way planetary scientists refer to distances within our own Solar System. Since the space between the planets is so enormous, talking about miles or kilometers gets overwhelming. So, the "cosmic yardstick" (or "meterstick" for our metric friends) is the average distance of the Earth from the Sun, which is approximately 93,000,000 miles (150,000,000 km). This is an astronomical unit, or AU. While I still mention our model's distance in feet (and meters), I will also give the distance in scale AU.
The infamous red planet Mars is next.
Mars is less than half the size of Earth, in scale .0217 inches (.6 mm). It has two moons, Phobos and Deimos, which would be microscopic here. We've travelled 76 feet (23.16 meters), 1.52 AU, and have reached the end of the Terrestrial planets. The next planet lies much further and marks the beginning of a realm of giants, Jupiter.
Jupiter, King of the Planets, and the Beginning of the Outer System
When compared to the Terrestrial planets, Jupiter marks a stark contrast, and even on this model it is notable.
Jupiter marks the first of the Gas Giants, and in our model sits 260 feet (79.2 mm), 5.2 AU from our Sun. It is also huge compared to the smaller, inner planets; .5613 inches (14.2 mm) in diameter. We include it here as our boundary marker. To get a true idea of how far we've travelled, let's step back a little and locate the Sun -
You don't see our mighty Sun? Well, it's at the end of that arrow, that faint little yellow dot. In reality, from this point on, the distances will be getting longer and the temperatures much, much colder (unlike the day this image was taken; yes, that is a water bottle, mute testimony to the heat.).
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