100-Year Starship some way off

--- In spacesettlers, "William" wrote:

> Here's another alternative:
>
> It is 1500 years from now, the solar system has
> been settled throughout by humans. The problems
> of keeping humans alive in settlements, of
> setting up self-supporting settlements on
> different planetary surfaces or in space, have
> been solved (they had to be in order to expand
> out into the Solar System in the first place).

So far, so good. I'm with you.

> The population of this Solar-System-wide human
> civilization is literally millions of times what
> is it now. Because of this, its economy is also
> millions of times what the world economy it now.

Makes sense.

> Because of this, that civilization can afford,
> with *no* problem, ways of getting *large*
> numbers of humans to Alpha Centauri *fast*,
> with accompanying infrastructure, however
> extravagant these ways might be *to us*. Things
> that would be hopelessly costly to us, won't
> be to them; THINK BIG. Whether it's laser-arrays
> the size of the moon, tankers full of antimatter,
> starships hundreds of miles long, or whatever
> else, they can.

You know, a Saturn V launch probably used more
energy than the entire human population used in the
year 1492. Suppose you had explained to Christopher
Columbus just how much energy such a launch requires,
and then tried to tell him that a single nation would
do this a dozen times or so in the course of ten years.