Let's look at the continental United States for a moment. Imagine if it didn't have its highways. If you went out traveling on a full tank on gas, you likely wouldn't even leave your state. Sure, you'd know the general "east" and "west" direction, but considering all the mountains and hills, who's to say you won't change course? Who's to say you won't get lost?
Our highway systems are successful for the following reasons:
- Gas stations, restaurants, and motels are essentially checkpoints.
- Even if you could not read signs at all, almost every town has a motel, gas station, and checkpoint
- Signs that show miles, destinations, and routes are paths.
- Even if you ran out of fuel, you could just call highway patrol. Possibly even some random stranger could help you out.
- The highways are constantly cleaned and inspected.
Now let's compare the universe to the continental US highway. Well, there certainly aren't signs to tell you where you're going. There are no checkpoints to refuel your body and vehicle. It's mostly desolate, so if you get stuck in a part of the universe where there's literally
nothing, you're all alone. By the way, some solar systems and galaxies may not even have a source of light. Can you imagine the possible amount darkness?