Hi All

et I wouldn't want to argue over relativistic mass - I don't understand it well enough. To me it's a real thing because everytime protons wack together in an accelerator their relativistic mass becomes real, detectable particles. Is it "real" mass though? I really don't know.

Your answer to McFly was concise and accurate. That link you gave is pretty cool and it actually has the conversion equation between acceleration and time-distortion factor [gamma] ~ (1+aS/c^2), that's acceleration*displacement/cee^2 plus one, for our friend McFly.

Total elapsed time to get to that TD factor is a bit trickier...

in planet time... sqrt(4s/a + (s/c)^2) or v*[gamma]/a

which is similar to the Newtonian equations t^2 = 4s/a or t = v/a

in ship time it's c/a*arcosh[gamma]... which for high gamma factors is ~ c/a*ln(2*[gamma])

As an example say you push it to gamma = 10, v = 0.995 c. One year for you is 10 years back home, but at one gee it takes 9.6 years planet time and 2.9 years ship time to hit that speed. Crank it up to 30 gee, whilst floating in oxygenated fluorocarbons, and only 5 weeks pass for you, and about 16.5 back home - same 3.3 time factor, but achieved quicker. Robert Forward's "Time Master" does just that with the help of some friendly negative matter aliens. Then he tosses in wormhole time machines to complicate matters further...

Adam