The Terrible Secrets of Space, Part One: Let's Get Small

In honor of Just Science 2008, I'll be posting a series this week called "The Terrible Secrets of Space" (named for this). Not everything (or anything, perhaps) I discuss in these posts will qualify as cutting-edge science. Rather, I'll be posting about some of the freakier things about the universe and its various bits and pieces, and the stuff that motivates my interest in backyard astronomy. I figure it gels well with the nascent nature of this here blog.

We'll start off with a relatively straightforward, and hopefully none-too-boring, perspective on how small we are in the overall shootin' match.

First up, we have a highly simplified Total Perspective Vortex:

I've seen some nitpicking online about whether the exact sizes and scales or correct, but you certainly get the idea. Our planet is tiny compared to the sun, and our sun isn't all that big either. What the video doesn't show is the galactic scale, in which stars barely resolve into individual dots, and, of course, the universal scale, for which I just happen to have another handy dandy visual aid:

What you're seeing here in this NASA chart is the composition of the universe (bearing in mind the duality of matter and energy -- E=mc^2, in case you ever wondered what that equation actually means). Of the small portion of the universe comprised of visible matter, an extremely small percentage is comprised of stars, and a smaller still percentage is comprised of the heavy elements that make up planets. This chart deals in composition rather than volume, but the message is similar: We're extremely small not only in terms of the space we take up relative to the total available space to be taken up, but also in terms of the percentage of the universe devoted to materials that make our lives at all possible. Dig?

Bringing this exercise closer to home, we have this famous monologue from Carl "Billyouns and Billyouns" Sagan:

I don't endorse all of the philosophical extrapolations in the video, but, again, you get the point: we are very, very small.

(I should add here that Bill Nye the Science Guy did a really cool demonstration on one of his shows in which he demonstrated the relative scales of the solar system by placing (very small) scale models of planets at their proper distances around a scaled-down sun. The first few planets were relatively close -- though not as close as you might expect -- but the outer planets required vehicles to reach. There's a re-creation of sorts available on YouTube that's altogether unwatchable. I won't link to it here because I don't want you to blame me when you claw your eyeballs out.)

You can play this game with time, too, though unfortunately I don't have any visual aids. The universe, so it's reckoned, is about 14 billion years old. Earth has been around for about 4.5 billion years. Humans (at least the ones on earth) have been around for 200,000 years. Let's say a human life is about 100 years. If the entire age of the universe were condensed into a single 24-hour day, the human race would have shown up at around 11:59:59 p.m. A human would live for about six ten-thousandths of a second.

So, there you go. Keep this in mind as we continue our tour of the freaky universe through out the week.