We reached the Moon in a tin can, built a humble space station, and have a plan to reach Mars in a bigger tin can. But we need to reach the stars. And we will.
Yes, I know what you are thinking: "It's impossible."
And right now, you are right. Our current propulsion engines are, simply put, pathetic. We are still in the Stone Age of space travel. As cool as they are, rocket engines—which eject gas at high speeds through a nozzle on the back of a spacecraft—are extremely inefficient, requiring huge volumes of fuel runs out faster than you can say "Beam me up, Scotty."
We have cleared the tower
Solid boosters, hybrid, monopropellant, bipropellant rockets... all these would be impossible to use in interstellar travel, with maximum speeds going up to a maximum of 9 kilometers per second. Rockets won't work even using the effect of planetary gravity to gain impulse. Voyager—the fastest man-made spacecraft out there racing at 17 kilometers per second—would need 74,000 years in deep space to reach Proxima Centauri, the red dwarf star located at 4.22 light-years in the Alpha Centauri system, the closest to our Sun.
But even if we were able to build a massive spacecraft with today's experimental—but feasible—propulsion technology, it will still take thousand of years to reach Alpha Centauri. Using nuclear explosions—like the ones proposed in the Orion project—would be more efficient than rockets, achieving a maximum of 60 kilometers per second. That's still a whopping 21,849 years and a couple months.
Using ion thrusters—which use electrostatic or electromagnetic force to accelerate ions that in turn push the spacecraft forward—would only reduce that amount marginally. Even theoretical technology—like nuclear pulse propulsion, with speeds up to 15,000 kilometers per second—won't cut it. And that's assuming we can find a way for these engines to last all that time. And let's not even get into the resources and engineering needed to create a vessel capable of sustaining life for such a long period of time.
All to reach a stupid red dwarf with no planets to explore. We may as well not go, really. You know, let's just save Earth from our own destruction and colonize Mars or Titan or Europa (if the aliens let us do that.)
Our ignorance is our only hope
It gets even worse. Our current understanding of physics—which says that nothing can travel faster than light—basically establishes that we will never be able to achieve space travel in a way that is meaningful to Humanity. In other words, even if we are able to discover a propulsion method that could get a spacecraft close to the speed of light, it will still take hundred of years to reach an star system with planets similar to Earth. By the time the news get back to us, we all will be dead.
And that's precisely the key to our only hope to reach the stars: Our ignorance. As much as we have advanced, we are still clueless about many things. Physicists are still struggling to understand the Universe, discovering new stellar events that we can't explain, and trying to make sense of it all, looking for that perfect theory that will make everything fit together.
That fact is that, since we don't know how everything works, there still may be something that opens the way to faster-than-light space travel. Discovering the unknown—like physicists have been doing since the Greeks—and harnessing new math and theories into new technology is our only way to spread through the Universe in a way that makes sense to Humanity as a whole. You know, like Star Trek or Battlestar Galactica or Star Wars: Travel across the Universe in hours or days, not in centuries or millennia.
I'm giving her all she's got!
One of those yet-to-be-unraveled things is the Big Bang, the origin of the Universe itself. Our origin, the final question that we have been trying to answer since we came out of the cave and looked up the night sky. We still don't know exactly what happened, but the observation of the Universe from Earth and space probes have caused some physicists to propose many different models. One of these models says that, during the initial inflation period of the Universe, space-time expanded faster than light. If this turns out to be the case, it would make possible the creation of warp drives.
Yes, the warp drives.
Warp drives were first proposed in a logical way by Mexican physicist Miguel Alcubierre. He theorized that, instead of moving something faster than the speed of light—which is not possible under Einstein's relativity theory—we could move the space-time around it faster than the speed of light itself. The spacecraft will be inside a warp bubble, a flat space that will be moved by the expansion of the space behind it and the contraction of space in front of it. The spacecraft won't move faster than light, but the bubble will. Inside the bubble, everything would be normal.
A way to understand the effect, as Marc Millis—former head of the Breakthrough Propulsion Physics Project at NASA's Glenn Research Center—explains, is to look at the way a toy boat reacts in the tub when you put some detergent behind it. The bubbles will expand the space behind the boat, impulsing it forward. In the same way, a spaceship with a warp drive would be able to do the same thing.
But while there have been already experiments in the laboratory that suggest that this may indeed be possible, we are still far, far away from developing the technology that would make warp drives a reality. To start with, the amount of energy necessary to bend space like this is way beyond anything we can produce today. Some scientists, however, suggest that antimatter may be the fuel that will make this possible.
Again, there are a lot of question marks surrounding antimatter, but this is precisely part of our only hope: Somewhere, still hiding, is the breakthrough that will make interstellar travel possible. The possibility is still there.
Why should we go to the stars?
So call me an optimist if you have to. It may be all this sun shining in New York right now. Or maybe it is because I saw Star Trek yesterday (and it was as good as I hoped it to be and then some more.) The fact is that I'm convinced that interstellar travel will happen. You and I will probably not see it, but if Humanity can survive self-annihilation, I'm sure we will achieve it.
No, "will we reach the stars?" is not the question to answer. We will. The more important question is why do we need to go?
The answer to this is the reason why we have celebrated humans in space all this week, now coming to its end. As I said when we started Get Me Off This Rock, space exploration is the most epic and most important adventure Humanity has ever embarked upon. When we travel to space we are opening the way to the preservation of Humanity. We are trying to contact other civilizations. We are trying to answer the biggest questions of them all: Who are we? Why are we here? How did we get here? Are we alone in this rock we call Earth?
But there is more. A lot more. Ultimately, the most important thing will not be getting the answers to these eternal questions. The most important thing will be the process of reaching for the stars. Because if we manage to get there, it would mean that we managed to survive as a species. That is the only way we can develop the engineering and the resources needed to build something like the Enterprise. Survive self-destruction, solve the problems we have here, collaborate, work as species, not as countries or corporations.
That's what space exploration and interstellar travel is all about. Only if we manage to go beyond our petty fights and stupid wars, only if we work together towards a better future, we will be able to go where no one has gone before. And be back to tell about it before dinner gets cold.