>>11658294>>11661824continued...
I'll just give you a bit of backstory for the "Kzinti lesson", this is from the "Known space" series of books by Larry Niven.
At the time (some years in the future, 2100-2200 humanity was colonizing the solar system in slower than light craft. The kzinti, a race of "cat people" who were very warlike, had slave empires, gravity manipulation and faster than light ships, set its sights on conquering earth.
The kzinti's psychics told them that humanity didn't have any warships, so the invasion went ahead. As the kzinti warped into the humans home system (sol), they found out the true depth of their mistake.
Human space ships had one of two propulsion methods.
One was a beam core fusion torch, pumping out terawatts of power.
The other was a gigantic array of near mercury orbit solar platforms, powering truely staggering laser beam "pushers" for pushing solar sails up to fractions of light speed.
about 15 minutes after warping into the sol system, the kzinti fleet was utterly vaporized by these solar sail pushing lasers, and the rest of the fleet was sliced to ribbons with the beam core fusion drives used as weapons at close range.
The kzinti lesson is as follows: "A reaction drives efficiency as a weapon is proportional to it's efficiency as a drive"
