What Is Space?
We’ve all seen the traditional grade-school scale models of the solar system. Maybe you made one years ago in science class out of painted Styrofoam balls or colored construction paper.
Or maybe you've seen one of those giant models hanging from the ceiling of a science museum. Big colorful globes, some with rings around them, some painted swirly colors, others looking more like pitted rocks.
For most people, that’s their basic mental image of the solar system. Bright yellow sun in the middle with all the different colored balls circling around it. Neatly contained in an orderly lineup, like different-sized houses on a street.
One thing these models that we have become used to can’t show us is the actual scale involved.
We’ve all heard of “space.” It’s the place out there, where the guys with the Right Stuff got to go and eat rehydrated meatloaf out of a plastic bag. It's where our cell phone satellites are, and where sci-fi heroes drive around at warp speed visiting strange new worlds, like one might pop in and out of stores at the mall.
But how much space is actually in space?
That’s an easy question to answer — a lot — but a hard one to really understand. We’re just not made to comprehend sizes and distances like that. We don’t have to. We live here, on Earth, and always have. It’s a finite place, and even then we have a hard time comprehending the size of it.
We know about these other places beyond our planet, and we've all heard the numbers representing the miles from here to there … 240,000 miles (to the moon), 34 million miles (to Mars), 93 million miles (to the sun), etc.
Big numbers. But they're just that: numbers. The human mind just doesn't work well with those numbers.
We might know it’s five miles to work, we get 25 miles to a gallon of gas and Aunt Louise lives in Boca Raton, about 900 miles away. But 34 million miles? OK, that’s far … right?
Yeah, it sure is. And you know what there is to do in between?
No Applebee’s, no rest stops, no trees, no rocks, no air, no nothing. Just space.
Lots and lots and lots and lots and lots of space.
No kidding, right? I mean, that’s why it’s called space. It’s real, and it’s there, right now. But still, it's hard to picture and even harder to show with grade-school models.
Space is difficult to represent in print and unwieldy to replicate as a model, but on a Web page it can be captured fairly simply. This scrollable Web page accurately shows the sheer distance between the planets, in relative scale size too. Consider that the sun makes up 99 percent of all the matter in the solar system, and you see why it’s so big on the first page. Even big ol' Jupiter is inside that remaining 1 percent of matter (and a good-sized portion thereof).
At the bottom of the page, there should be a scroll bar. Use the right arrow to start your trip on a horizontal track across the span of space separating the planets. If you try to drag the bar with your mouse, you’ll be going too quickly, so be sure to use the right arrow. Just start scrolling.
Mercury. Closest planet to the sun. Not so “close,” is it? Keep going.
Second planet in. Venus. Nasty place. Very hot.
Wave hi. Earth.
Scroll, scroll, scroll … *Bink.*
Mars. There are the four “inner” planets. You’ve done a whole lot of scrolling but have only covered a 10th the space of the page. Keep going …
Jupiter. Big huh? Well, compared with Earth, yes, but probably not as majestic as you’d expected, based on the models you’ve always seen. The sun could eat it for a snack. (And someday it might.)
If you have a minute or two to burn, you can scroll all the way to Saturn, then Uranus, Neptune and finally little demoted Pluto. Then the page stops. It doesn’t keep going out to all the other icy little worlds that exist far beyond Pluto in the vast Kuiper Belt, or into the swarm of snowballs that sometimes become comets, way way out in the Oort Cloud, so very far away yet still held by the sun’s gravity.
Even out there, where it looks like just another extra-bright star in the sky and sheds slightly more heat than the pad of sticky notes on your desk, the sun still has the gravitational upper hand.
And that’s just our solar system. Our family of worlds. Our painted Styrofoam balls. There are a lot more solar systems out there even farther away. Many of the stars you see at night have their own — with their own planets, their own Jupiters and Neptunes, and maybe even their own Earths (named differently, of course) with their own little models of their solar systems and websites trying to demonstrate what it really means to talk about space.
Image credit: NASA