(This column was first published in the July 28, 2003 issue of The Buffalo News.)
A few days ago Jim Pawlicki and I spent several hours looking for breeding birds in Amherst's Nature View Park. Most of our attention was focused on nearby bushes and trees, but occasionally I couldn't help but look up beyond the canopy that shaded us.
It was one of those perfect mornings: no cloud marred the lovely blue sky and I was humbled once more by the immensity of space.
I thought again about that experience when I opened Michael Gross's interesting new book, Light and Life (Oxford University Press). In it he talks about visiting that university's Natural History Museum and finding there a model of our solar system.
He tells us, "High above the dinosaurs and other treasures of the courtyard, is a shiny brass globe slightly bigger than a basketball, with a little label underneath. Reading the label we learn that this is part of an accurately scaled model of the Sun, Earth, and Moon with the appropriate distances between them, and that the rest of the model is on the opposite side of the court."
Gross has to walk across the courtyard to find tiny spheres representing the Earth and Moon.
"Our planet," he adds, "is a lot smaller than the Sun, and quite far away from it, but both these concepts are difficult to imagine on their own, and even more so in combination. The drawings in books tend to either show the right sizes, or the right distances between the Sun and its planets, never both."
Because Gross's measures are in metric units, I decided to create my own scale model to visualize some of our Solar System sizes and distances. My first attempts didn't work out well. Making Earth the size of a baseball or even a ping-pong ball didn't serve because the distances got completely out of hand. I finally hit on making the Earth pea-sized, a quarter inch in diameter. That is, of course, a major shrinkage. The Earth is over two billion times as large. We're not just talking here about the scale of "Honey, I Shrunk the Kids."
Eight inches away in my model I would locate a sixteenth-inch diameter pinhead-sized sphere representing our Moon. That's a little small, but at least the moon is quite close.
But what's next? The center of our Solar System, the Sun, is over 80 yards away. That's a long fly ball in baseball or even a home run in some ballparks. And that Sun is quite a bit larger than our pea-sized Earth. It is almost 28 inches in diameter, bigger than most beach balls.
The planets nearest us would appear, like Earth, looping around that star. Mercury would be closest to the Sun, 30 yards away, Venus next at 60 yards, and the Mars that our spacecraft have already visited, at 120 yards.
Those planets are at least near our pea size: Venus's diameter very close to that of Earth, Mars and Mercury only half as thick, more like BBs.
The biggest planets, the quarter-mile distant Jupiter and half-mile distant Saturn, would be almost baseball-sized. At the other extreme, Pluto, would be only the pinhead size of our Moon. At near the limit of our Solar System, it would be almost two miles away.
And the stars? Quite a bit further. The nearest, Proxima Centaurus, would be 12,000 miles from us. That's a plane ride to Australia.
What is difficult to convey in this model-building is the sense that these objects would be in otherwise all-but-empty space. Even in this tiny-scale model the distances are awe-inspiring.-- Gerry Rising