```Timothy L. G. van der Linden writes:
> I had seen you use these geometrized units and understood most of them. It's
> a bit tricky for me since I always used the conventional notation.
> Unfortunately you are one of the very few that use this notation.
> Where I made the mistake was that I had not translated the E to E/c^2.
> Thank you for the explanation.

The primary text I use is _Spacetime Physics_ by Taylor and
Wheeler.  They almost always use geometrized units, introducing
them almost immediately in the first chapter.  I find they are
much easier to work with for most purposes.
> >v = c * tanh(a' * t' / c)
> >
> >Perhaps you calculated the global frame time rather than the
> >spacecraft local time?
>
> No, I used the same formula you did and still get 1.277 years (a=9.8 c=3E8,
> v=0.866c).

Perhaps _I_ calculated the global frame time instead of the
spacecraft time.  I get 1.277 years of spacecraft time when I run
the calculation now.

> Do you know how efficiently energy can be transferred into anti-matter these
> days? Or to put the question in an other way, what are the input energies of
> these supercolliders and how many anti-particles can be isolated after a
> collision.
> It's hard to get accurate data, so I haven't a clue of the efficiency to
> create anti-matter.

I really don't know how you could make antimatter in any quantity
using conventional technology.  I doubt it would be very
efficient at all.

At best, you could make something like 2 million tons per second
if you could convert the total output of the Sun completely to
antimatter (and an equal amount of matter).

> The energy needed for the anti-matter creation probably has to come from
> solar power and fusion.

Umm, what's the difference? :-)

> The reason that I followed your derivation quite thorough is that about a
> week ago I had finished calculations which should give the same results. My
> approach is completely different from yours. My main goal was to calculate
> the energy needed for such a trip. I had planned to send it to SD soon. I'd
> appreciate it very much if you would look at it before I send it to SD. It's
> mainly formulas and about 10Kbyte long. If you are interested I will send it
> to you.

I am about to leave on a trip to Seattle, so I can't promise I'll
have time to look it over.  You are welcome to send it to me and
if I can find time to look it over I will; I'll still have email
access from there.

```