The final frontier

As the world -- or at least the corporate media -- seems enthralled by the spectacle of billionaires taking joy rides to the edge of space, I feel compelled to comment on the larger implications. There are no larger implications, other than the prospect that billionaires may continue to take joyrides to the edge of space until they get tired of it, then they'll find some other way to waste their ill-gotten gains.

 

This may seem a digression, but bear with me. Many people find it so compellingly obvious that we ought to have discovered other technological civilizations in the galaxy, and even be in contact with them, that they actually call the absence of detectable extraterrestrial civilizations a "paradox."  That is ridiculous. Would we be detectable to ET? Our feeble radio broadcasts are undetectable a couple of light years away, and since the nearest star is more than 4 light years away, that means nobody but Homo sapiens is watching I Love Lucy reruns.

Sadly, Einstein was right. It is impossible to travel faster than light. Physicists have had more than a century to chew over relativity and this conclusion is absolutely airtight. Star Wars, Star Trek, the C.J. Cherryh universe, Asimov's Foundation, Dune, the Hyperion Tetralogy, Buck Rogers -- all that is impossible. Actually, it's practically impossible to travel at even a substantial fraction of the speed of light. If you're going at 20% light speed and hit a grain of sand, it will be like an atomic bomb. The starship Enterprise has a deflector array but they never explain how it works, and that's because it can't.

But you're never going to get to that velocity anyway. It's also impossible to accelerate in a vacuum without throwing away reaction mass. They've had since 1687 to chew over Newton's conclusion on that subject and it's also airtight. That means you can't accelerate to anything like 20% of light speed without an immense store of fuel and you need to save more than half of it to decelerate and maneuver once you reach your destination. So while travel between stars is physically possible, it requires decades if not centuries. I'm not holding my breath until people invest in sending a robot to Proxima Centauri in the hope it may send a radio message to their great grandchildren, and I don't expect many extraterrestrials are particularly motivated to do that either.

If Elon Musk really wants to go to Mars, a rocket that shoots people up 69 miles and then falls back to earth is not a step in that direction. It's irrelevant. The journey would require a totally different technology.

 

I can't think of any particular reason to go to Mars in person. It's a very unpleasant place to say the least, the average temperature being -63 C which is -81 F and no breathable atmosphere. While we've gotten pretty good at sending robots, sending people is not possible with current technology because nobody has figured out a practical way of shielding them from radiation. (In low earth orbit we're inside the earth's magnetosphere, which gives us shelter from charged particles.) 

So it's fun to explore the solar system with robots, but there is no payoff to earthlings to traveling in space in the flesh. There is no conceivable economic payoff. Low earth orbit is a commercially valuable space, but even there humans have no useful role to play. So let's pay attention to the one planet that really matters to us.