Good story telling involves overcoming obstacles. In sci-fi, those obstacles often include aliens, robots, various anomalies in space or time… We forget that every cubic light-year of space is full of danger even before we start making stuff up.
Pictured above: our galaxy, the Milky Way. Part of the image is obscured. You see those dark clouds? That’s dust. Cosmic dust. Vast clouds of it—enough to block out the stars behind. Our galaxy is a very dirty place.
If you want to travel anywhere near the speed of light, that dust becomes a huge obstacle. A collision with a particle smaller than a grain of sand—at high enough velocity—would punch a hole through your ship. Passing through a cloud of such particles would be like walking into a spray of bullets.
Find that hard to believe? Think about hitting a deer. At ten miles per hour, it’s not so bad. At thirty-five, it’ll probably leave a dent. At seventy, your car is lucky to be alive. The greater the speed, the more damage the deer will do. Now imagine hitting a deer—or anything—at the speed of light, 10 million times faster than any car can go.
With so much dust in our galaxy, the navigators of any interstellar spaceship will spend a lot of stressful hours dodging particles too small to even see. That, combined with the cosmic radiation from yesterday’s post, makes “empty” space as dangerous as any alien, robot, or space-time anomaly.
Click here for the Iris Nebula, a place where clouds of cosmic dust are clumping together to form new stars.
Click here for some computer simulations of what cosmic dust particles look like at the molecular level.
Click here for a glossary of terms related to cosmic dust and other things found in “empty” space.