FROM GREGORY BENFORD, UNIVERSITY OF CALIFORNIA/IRVINE
TO JIM POWELL, RICHARD TUNA, ISAAC ASIMOV, JILL TARTER
FEBRUARY 12, 1987

YOUR THINKING STILL SEEMS A BIT NARROW. CONSIDER SEVERAL BROADENING IDEAS:

1. SURE, RELATIVISTIC BOMBS ARE POWERFUL BECAUSE THE ANTAGONIST HAS ALREADY INVESTED HUGE ENERGIES IN THEM THAT CAN BE RELEASED QUICKLY, AND THEY’RE HARD TO HIT. BUT THEY ARE COSTLY INVESTMENTS AND NECESSARILY REDUCE OTHER ACTIVITIES THE SPECIES COULD EXPLORE. FOR EXAMPLE:

2. DISPERSAL OF THE SPECIES INTO MANY SMALL, HARD-TO-SEE TARGETS, SUCH AS ASTEROIDS, BURIED CIVILIZATIONS, COMETARY NUCLEI, VARIOUS SPACE HABITATS. THESE ARE HARD TO WIPE OUT.

3. BUT WAIT—WHILE RELATIVISTIC BOMBS ARE READILY VISIBLE TO US IN FORESIGHT, THEY HARDLY REPRESENT THE END POINT IN FORESEEABLE TECHNOLOGY. WHAT WILL HUMANS OF, SAY, TWO CENTURIES HENCE THINK OF AS THE “OBVIOUS” LETHAL EFFECT? FIVE CENTURIES? A HUNDRED? PERSONALLY, I’D PICK SOME RAMPAGING, SELF-REPRODUCING THINGY (MECHANICAL OR ORGANIC), THEN SNEAK IT INTO ALL THE BIOSPHERES I WANTED TO DESTROY. MY POINT HERE IS THAT NO PARTICULAR PHYSICAL EFFECT—WITH ITS PLUSES, MINUSES, AND TRADE-OFFS—IS LIKELY TO DOMINATE THE THINKING OF THE GALAXY.

4. SO WHAT MIGHT REALLY AGED CIVILIZATIONS DO? DISPERSE, OF COURSE, AND ALSO NOT ATTACK NEW ARRIVALS IN THE GALAXY, FOR FEAR THAT THEY MIGHT NOT GET THEM ALL. WHY? BECAUSE REVENGE IS PROBABLY SELECTED FOR IN SURVIVING SPECIES, AND ANYBODY TRULY LOOKING OUT FOR LONG-TERM INTERESTS WILL NOT WANT TO LEAVE A YOUTHFUL SPECIES WITH A GRUDGE, SNEAKING AROUND BEHIND ITS BACK.

FINALLY, WE CAN’T GET OUT OF OUR OWN CULTURAL/ BIOLOGICAL MATRIX IN DISCUSSING THIS.BE PREPARED FOR SURPRISES, NO MATTER WHAT STRATEGY YOU PURSUE.

FROM RICHARD TUNA
TO GREGORY BENFORD
FEBRUARY 20, 1987

I AGREE WITH MOST PARTS OF POINTS 2, 3, AND 4. AS FOR POINT 1, IT IS CHEAPER THAN YOU THINK. YOU MENTION SELFREPLICATING MACHINES IN POINT 3, AND WHILE IT IS TRUE THAT RELATIVISTIC ROCKETS REQUIRE PLANETARY POWER SUPPLIES, IT’S ALSO TRUE THAT WE CAN POWER THE WHOLE EARTH WITH A FIELD OF SOLAR PANELS ADDING UP TO BARELY MORE THAN 200-BY-200 KILOMETERS, DRAWN OUT INTO A NARROW BAND AROUND THE MOON’S EQUATOR. SELF REPLICATING ROBOTS COULD ACCOMPLISH THIS TASK WITH ONLY THE COST OF DEVELOPING THE FIRST TWENTY OR THIRTY MACHINES. AND ONCE WE’RE POWERING THE EARTH PRACTICALLY FREE OF CHARGE, WHY NOT LET THE ROBOTS KEEP BUILDING PANELS ON THE LUNAR FAR SIDE? ADD A FEW SELFREPLICATING LINEAR ACCELERATOR-BUILDING FACTORIES, AND PLUG THE ACCELERATORS INTO THE PANELS, AND YOU COULD PRODUCE ENOUGH ANTIHYDROGEN TO LAUNCH A STARSHIP EVERY YEAR. BUT WHY STOP AT THE MOON? HAVE YOU LOOKED AT MERCURY LATELY?

FROM PROF. LESLIE WELLS, PACIFIC TECH.
TO JILL TARTER, NASA/SETI
MAY 5, 1987

POWELL AND TUNA ARE SICK. SICK. SICK. SICK. I FIND MYSELF IN COMPLETE DISAGREEMENT WITH EVERYTHING IN THEIR THESIS BUT THE PHYSICS. THE LEAP FROM THE UNSTOPPABILITY OF RELATIVISTIC BOMBS TO THE RATIONAL REQUIREMENT TO DESTROY ALL OTHER TECHNOLOGICAL SPECIES IS MOST DISTASTEFUL. THOUGH I DO AGREE THAT IT IS FAIRLY IDIOTIC OF SAGAN ET AL. TO WANT TO SHOUT OUR PRESENCE FROM THE INTERSTELLAR ROOFTOPS, IT IS NOT, TO MY MIND, PROVED THAT WE LIVE IN A VIOLENT UNIVERSE. IT IS ONLY FAIR TO WARN YOU THAT A COPY OF THIS LETTER IS GOING TO CONGRESSMAN AXFORD. SETI INDEED! YOU ARE THE ONLY “SCIENTISTS” IN THE WORLD WITH THE PECULIAR DISTINCTION OF NOT YET HAVING PROVED THAT YOUR SUBJECT MATTER EVEN EXISTS! I INTEND TO PERSONALLY SEE TO IT THAT NOT ONE RED CENT MORE IS SPENT ON THIS QUEST FOR LITTLE GREEN INVADERS FROM MARS!