How Things Work: Space Travel
You lay back in the seat, stare at thousands of switches, and pray that no tiles fall off. Two solid booster rockets generating over six million pounds of thrust are strapped to your butt, and once ignited, they can?t be turned off. You smile weakly at your comrade and listen as the ignition sequence is counted down. There is a demonic roar underneath; g-forces are building, the cockpit is shaking like the San Andreas faultline, and you?re already feeling nauseous. The g-forces build as you accelerate to 17,400 mph, and as the tiny cockpit window fades from sky blue to pitch black. You see your vomit bag floating away: welcome to space.
Unfortunately, given our chemical means of propulsion, we aren?t going too far. Science has given us multiple alternative means of propulsions, but none seem to be as safe or simple as chemical propulsion. While it would only take 100 milligrams of antimatter to equal the propulsive thrust of the Space Shuttle, it currently costs $62.5 trillion to make just one gram of antimatter. While nuclear fission once seemed highly feasible, it was ultimately deemed unsafe. Physicists have yet to produce a self-sustaining nuclear fusion reaction. Finally, an ion thruster is simply too slow. Plasma rockets sound cool, but they also probably would require a nuclear reactor onboard, and thus are still unusable.
But never mind that ? we can still go to Mars. Yet there are other problems, and I don?t mean just having to drink your own recycled urine. Space travel leads to a great deal of radiation exposure for the astronaut, especially beyond the Earth?s protective magnetic field. Continuous muscle disuse leads to dystrophy, while continued lack of gravity leads to osteoporosis. Mysteriously, astronauts seem to lose their hearing rapidly, even though the noise levels in a spaceship aren?t above safety standards on Earth. Finally, given the constant worry that a dust speck might pierce your spacecraft, you might go mad, and it wouldn?t be much fun touring Mars in a straitjacket.
Let?s face it: space travel is cold, lonely, and dangerous. With advanced propulsion systems, it would take us 70,000 years to reach Proxima Centauri, the closest star outside the solar system. Even if we could travel at the speed of light, it would still take 4.4 years to reach this star. Clearly, we need a wormhole!
Imagine that the universe is draped over the skin of an apple, and a worm is traveling on its surface. The shortest conventional way from one side of the apple to the other is around the circumference. However, if the worm digs a ?wormhole? through the apple, the distance is less. Wormholes in 4-D space work the same way. Theoretically a person could travel vast distances across the universe by falling into a convenient wormhole and tunneling through spacetime. Of course, you never know where you might end up!
Regardless of what type of propulsion is powering your rocket, it?s still just a thin wall of metal separating you from the cold, black vacuum of space. Enjoy your flight.