Space is as incomprehensible as it is awesome. Its true magnificence can be difficult to understand, even for an astrophysicist. Maybe that's why we often resort to simplified explanations and easy-to-understand pictures when discussing it. Maybe that's why basically everything we picture about space ranges from wildly incorrect to pants-on-head idiotic. To start with ...
6 Our Perspective Of Space Is Out Of Perspective
When most of us think about the solar system, we think of this:
Can you guess what's wrong with it? That's right: everything. First: Earth is actually really tiny. Really, unbelievably, curl-into-a-ball-and-pee-a-lot tiny. Here's a sense of our mighty, life-carrying planet's place in our solar system's pecking order:
Lsmpascal via Wikipedia
It's OK to feel a little insecure.
Can you see Earth? Of course you can't. It's the pixel below the ever-so-slightly larger blue-green dot that is Neptune, which is below the slightly bigger dot that is Jupiter. To put that in numbers: There are approximately 11.21 Earths across the diameter of Jupiter. The sun is about 109.7 Earths across.
Now that we've established we're roughly the size of a hair follicle on the giant flaming testicle that warms us all, let's talk about planetary orbits. Most classic solar system charts present orbits as perfect circles, with the planets hanging out fairly close to each other at respectable, yet aesthetically pleasing distances. Reality, on the other hand, is a mess of slightly elliptical circuits, as per Kepler's First Law of Planetary Motion. Also, they're really far apart from each other:
And let's not even discuss Sedna, the moody teenager of the solar system, only showing up for dinner before sulking away to its gloomy bedroom.
If you want to play with the abject terror that is the vastness of our own solar system, here's an interactive scale model. Or, hell, you can just watch these guys build one:
Note that they need the freaking Nevada desert to do so.
5 Comet "Tails" Don't Actually Tail The Comet
Quick: Which way is this comet going?
RIGHT TOWARD US.
If you said, "Toward the bottom right of the picture," you are wrong. In fact, if you said anything but, "I have no idea. I am a total dipwad. Please stop asking me things about space," you are also wrong.
We tend to assume the comet is basically a giant galactic hadouken, and its tail follows the main fireball-lookin' bit. But comets are essentially big hunks of ice and stuff, and every other thing we see about them -- the lights, the tail, everything -- is just the sun working its magic.
This is a comet:
Not pictured: the alien mothership following it to destroy us.
At around five astronomical units (one unit = 93 million miles, or Earth's average distance from the sun), the sun starts heating the comet with enough force to sublimate some of the ice straight from solid to gas, and the gas mixes with dust to form a halo around the comet called a coma. The tails (yeah, there are in fact two) grow from this. One of them is the plasma tail of ionized gases, and the other is just plain ol' dust.
The plasma tail forms when solar wind hits the coma and ionizes the gases, making it point directly away from the sun. The dust tail tends to curve toward the comet's orbital path, true, but it also gives in to the sun's radiation pressure (way worse than peer pressure) and steers away from the sun. You would too, if you were a celestial body. The sun is a bit pushy.
"I give you cancer. No reason; I'm just a dick."