Our news sweeps have turned up nothing worth blogging about. The creationists seem to be in hibernation. No problem, we can always think of something to say — even if it’s a bit off topic.
That graphic above this post is typical of the illustrations we’ve all seen in our textbooks. But did you know that you have never seen an illustration of the Solar System drawn to scale?
We’ll ignore the obvious fact that the Sun is so much larger than any of the planets. Using very approximate figures, the sun is about 860,000 miles in diameter, which is more than 100 times larger than the Earth. That can’t be accurately shown in a simple diagram, so we’ll have to forget about the relative sizes of the Sun and the planets. Instead, let’s talk about the distances of the planets from the Sun.
The Earth, as every school child learns (in the non-metric US), is 93 million miles from the Sun — one Astronomical Unit (or AU). That means the Earth is over 100 times as far from the Sun as the Sun’s diameter. For convenience, shrink the Sun to a one-inch circle. Earth would be 100 inches away from the Sun — over 2.5 meters. No graphic in a school book can show that to scale.
Okay, let’s scale that down by a factor of ten. Now Earth is only 10 inches from the Sun. That’s nice, but Mars is over 1.5 AUs from the Sun — 15 inches in our textbook drawing. Jupiter is more than five AUs from the Sun, which is 50 inches in our severely scaled-down drawing. Saturn is almost 10 AUs away — that’s 100 inches, and once again our graphic is over 2.5 meters wide, with more planets still to go. Uranus is nearly 20 AUs from the Sun, Neptune is 30 AUs away, and Pluto is 40 — that would be 400 inches from the Sun, more than 33 feet, or more than 10 meters for our non-US readers. (All figures are approximate.)
Scale it down some more — by yet another factor of ten. Earth is now a tiny dot only one inch from the Sun, while Pluto is 40 inches away, and your drawing is over a meter wide. How can those distances be shown on one page — or even a two-page spread? It can’t be done, which is why you’ve never seen an accurate drawing of the Solar System.
While you’re pondering that, we now declare this to be an Intellectual Free Fire Zone. We’re open for the discussion of pretty much anything — science, politics, economics, whatever — as long as it’s tasteful and interesting. Banter, babble, bicker, bluster, blubber, blather, blab, blurt, burble, boast — say what you will. But avoid flame-wars and beware of the profanity filters.
The comments are open, dear reader. Have at it!
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