Robert Park is an emeritus professor of physics at the University of Maryland, College Park and a former Executive Director of the American Physical Society, well known in scientific circles for his critical commentaries on alternative medicine and other pseudoscience, as well as his opposition to space travel and space development. He is the author of Voodoo Science: The Road from Foolishness to Fraud, and Superstition: Belief in the Age of Science. While many scientists voice doubts about the feasibility of doing so, Park flatly states that we will never have human beings actually get to another star system.

Not next century. Not next millennium. Never.

He says in his various writings, (and I’m paraphrasing here), that more-or-less permanent outposts on the Moon, Mars, some of the larger asteroids, and maybe a few of the outer planets’ moons, is pretty much going to be the extent of actual human space travel, and that the vast majority of even that will be unjustified and unnecessary, with no benefit anywhere near worth the cost and the risk of sending human beings there, except in the realm of human ego. He says by the time it’s anywhere near feasible to do it, there will be not the slightest advantage to sending humans over the machines that we’ll have then; they will not be able to do anything that the machines can’t do, at a fraction of the cost.

As for interstellar travel? He says forget it. Won’t happen. He dismisses as pseudoscience fiction all notions of ‘ways’ to circumvent the speed of light, mostly believed in by people who got their education in physics from Star Trek and Star Wars, or, (in the case of real scientists), simple irrational wishful thinking. And “tachyons”, if you’re wondering, are every bit as much of a fairytale fantasy as unicorns and talking snakes. We not only have absolutely NO evidence for them, we have no observations of anything in the Universe that would so much as indicate their possibility. (Nor has anyone come close to giving any explanation of exactly what it would mean in the real world to have the value of a mass be an imaginary or complex number). He says there may well be some way, some how, for a photon or an electron to occasionally get around the speed of light- but not a spaceship, and certainly not a living organism. He believes we will definitely explore other star systems, first with our ever-increasing observational capabilities, and eventually with a physical presence; but it will be our machines we send there, not ourselves.

For anyone who disagrees with him, Professor Park recommends the following calculation:

Choose the nearest star (that you wish to get to); decide
how long you're willing to travel, calculate how fast you will need to go to get
there in that time, what you will have to take with you, and how many
should be in the crew. Make it a one-way suicide mission if you wish. As
a final step, calculate the kinetic energy that must be imparted to the
spaceship to get you there in that time (one half the mass times the
velocity squared.) I suggest you stay away from the relativistic limit; it
complicates the calculation and won't help you anyway. The good news is
that you will then sleep secure in the knowledge that UFOs from elsewhere
in the galaxy are not subjecting humans to hideous experiments. – from his weekly newsletter “What’s New” at bobpark.org

The nearest star system is Alpha Centauri, a trinary system 4.3 light years away, and expressing it in light years does no justice to the scarcely imaginable distance that is. And that’s the very nearest one, right next door in stellar terms.

I too was raised on Star Trek and Star Wars, but I have a B.S. in physics, and I’ve always been uncomfortably aware that science fiction never did anything but gloss over the incredible problems involved in interstellar travel with glib terms like ‘warp drive’, ‘hyperspace’, and ‘wormholes’, etc. I’ve always believed it would happen, eventually, somehow, some way, because I always wanted it to be true. But Professor Park’s assertions are very hard to argue against. And sure- you can say: oh, there were lots of people who said we’d never have instantaneous communication, that we’d never be able to fly, that we’d never break the sound barrier, that we’d never get to the Moon, etc- but none of those things seemed to be actually physically impossible, even when we had no idea how to do them. As for what is physically possible: our technology will eventually allow us to attain some significant fraction of lightspeed, but this swiftly reaches a point of greatly diminishing return. The faster you go, the greater energy increase is needed to go any faster because more and more of the energy increase goes into increasing the mass rather than the velocity. How big a chunk of your life would you be willing to spend to go somewhere that we’ll easily be able to observe from Earth by that time, just to say you went there? And this is only possible at all, timewise, for the dozen or so very nearest stars; for all the rest, even lightspeed is insignificant for the distances involved.

I’m not sure why this is so depressing to me. It’s not like I was ever going to live long enough to travel on a starship to a Galactic Conference of the United Federation of Planets or anything. It just seems ignominious somehow that we may well never leave our own star; never have any of those interstellar federations or alliances or empires I read and watched and dreamed about. Never meet any other civilizations face to face. To me, this is far more depressing than the realization that there’s no ‘God’ or anything ‘supernatural’ and such.

As Rationalists and followers of the Scientific Method, we have to face the facts squarely, however unpleasant they seem, wherever they lead. And, while there’s always the possibility that Professor Park is wrong, the simple fact is that we have no rational reason to believe that.

And that’s damn depressing.