NSCI 314 LIFE IN THE COSMOS 19 - LIFETIMES OF TECHNOLOGICAL CIVILIZATIONS Dr. Karen Kolehmainen Department of Physics, CSUSB

RECALL THAT THE LEAST WELL-KNOWN FACTOR IN THE DRAKE EQUATION IS L = AVERAGE LIFETIME OF A TECHNOLOGICAL CIVILIZATION

ESTIMATING L IS IMPORTANT BECAUSE: 1. IT ALLOWS US TO USE THE DRAKE EQUATION TO ESTIMATE HOW COMMON EXTRATERRESTRIAL CIVILIZATIONS ARE, AND, 2. EVEN MORE IMPORTANTLY, WE WOULD LIKE TO KNOW HOW LONG WE CAN EXPECT THE HUMAN RACE TO SURVIVE!

FACTORS THAT MAY LIMIT THE LIFETIME OF TECHNOLOGICAL CIVILIZATIONS IMPACTS BY ASTEROIDS, COMETS, OR LARGE METEORITES POPULATION GROWTH CLIMATE CHANGE (GLOBAL WARMING)‏ POLLUTION DISEASE WAR LOSS OF INTEREST IN COMMUNICATION

FACTS ABOUT THIS IMPACT MOVING AT 10 to 30 km/Sec PASSES THROUGH HOUSE IN 0.01 Sec at 10 km/sec ENERGY RELEASE = 1 KILOTON BOMB CRATER DIAMETER = 120 FEET (TYPICALLY AT LEAST 10x THE DIAMETER OF THE IMPACTING OBJECT)‏

CRETACEOUS-TERTIARY BOUNDARY BOUNDARY BETWEEN TWO GEOLOGICAL PERIODS 65 MILLION YEARS AGO ROCKS DEPOSITED BEFORE THE BOUNDARY CONTAIN DINOSAUR FOSSILS ROCKS DEPOSITED AFTER THE BOUNDARY CONTAIN NO DINOSAUR FOSSILS BOUNDARY MARKED BY THE EXTINCTION OF 80% OF LAND AND MARINE ORGANISMS (NOT JUST DINOSAURS)‏ RECOVERY, AS DOCUMENTED IN THE FOSSIL RECORD, TOOK AT LEAST 5,000 YEARS

EXTINCTION OF THE LARGE DINOSAURS LUIS & WALTER ALVAREZ DISCOVERED (1980): LARGE EXCESS OF IRIDIUM, A RARE-EARTH ELEMENT, LOCATED IN ROCKS DEPOSITED AT THE CRETACEOUS-TERTIARY BOUNDARY. THIS LAYER HAS BEEN FOUND WORLD-WIDE. IRIDIUM IS KNOWN TO BE PRESENT IN METEORITES AT MUCH HIGHER ABUNDANCES THAN IN EARTH ROCKS. TO SUPPLY THE ESTIMATED AMOUNT OF IRIDIUM WOULD REQUIRE A METEORITE 10 km ACROSS.

METEORITE ESTIMATED TO BE 10 km ACROSS (SOMETHING THIS SIZE IS USUALLY THOUGHT OF AS AN ASTEROID)‏ CRATER ESTIMATED TO BE km ACROSS PEMEX DISCOVERED A BROAD SUBTERRANEAN ARC OFFSHORE YUCATAN PENINSULA (1978)‏ SUBSEQUENT DISCOVERY OF 180 km CRATER AT CHICXULUB (STRUCTURE IS BURIED)‏ CRATER HAS BEEN DATED AND IS 65 MILLION YEARS OLD

99% of Atmosphere Below This Level Asteroid 10 km across moving at 30 km/sec Mt. Everest 8.7 km Ocean Floor 3 km

ENERGY OF A MOVING BODY DEPENDS ONLY ON THE MASS (M) AND VELOCITY (V)‏ (BELOW EQUATION CORRECT ONLY IF V<< c)‏ KINETIC ENERGY = (1/2) MV² FOR A 10 km DIAMETER ASTEROID M = 2 TRILLION METRIC TONS = 2,000,000,000,000,000 kg V = 30 km/s = 30,000 m/s KE = JOULES OF ENERGY = ONE TRILLION TRILLION JOULES (EQUIVALENT OF 95 DAYS OF SOLAR RADIATION ABSORBED OVER ENTIRE EARTH)‏

ENERGY RELEASE ON IMPACT UPON IMPACT, ALL ENERGY EVENTUALLY TURNS TO HEAT. IMPACT PRODUCED A FIREBALL 200 km ACROSS AND WITH A TEMPERATURE OF 100,000 K RESULTS: GLOBAL EFFECTS FIRES POSSIBLE TRIGGERING OF EARTHQUAKES POSSIBLE TRIGGERING OF VOLCANIC ERUPTIONS CLIMATE CHANGES EXTINCTION OF MANY LIFE FORMS

EFFECTS OF LARGE IMPACT FIRESTORMS ~ DAYS TO WEEKS FIREBALL INDUCED FIRES UP TO SEVERAL THOUSAND KILOMETERS FROM IMPACT SITE GLOBAL FIRES DUE TO SECONDARY IMPACTS IMPACT WINTER ~ 1 YEAR GLOBAL CLOUD COVER, ACID RAIN, SALT RAIN, HIGH LEVEL OF DUST, REDUCED TEMPERATURE EXTINCTION OF NUMEROUS LIFE FORMS, ESPECIALLY LARGE ONES MANY PLANTS DIE DUE TO FIRES AND DARKNESS MANY ANIMALS DIE DUE TO INTERRUPTION OF THE FOOD CHAIN ULTRAVIOLET SPRING ~ 1 - ? YEARS DESTRUCTION OF OZONE LAYER UV INTERRUPTS PHOTOSYNTHESIS UV INCREASES MUTATION RATES, EVEN IN OCEANS FURTHER EXTINCTIONS

MASS EXTINCTIONS HUMAN- CAUSED DINOSURS ETC. SMALLER ASTEROID ? MOST LAND & SEA MOST FISHES MANY INVERT. MARINE SPECIES MILLIONS OF YEARS AGO

ASTEROID IMPACTS EARTH-CROSSING ASTEROIDS – ASTEROID’S ORBIT INTERSECTS EARTH’S ORBIT. ONE OF THEM HITS EARTH EVERY 50 TO 100 MILLION YEARS ON THE AVERAGE. ORBITS ARE NOW BEING MAPPED, SHOULD BE DONE IN 10 YEARS. THEN WE WILL BE ABLE TO PREDICT FUTURE IMPACTS. HUMANS MUST THINK ABOUT PROTECTION FROM IMPACTS! BEST METHOD – USE EXPLOSIONS NEAR ASTEROID TO ALTER ITS ORBIT SLIGHTLY. DON’T BLOW IT UP!

POPULATION GROWTH THERE ARE CURRENTLY 6.7 BILLION HUMAN BEINGS ON EARTH. HUMAN POPULATION IS GROWING AT A RATE OF: –1.4% PER YEAR –88 MILLION PER YEAR –7 MILLION PER MONTH –240,000 PER DAY –18,000 DURING OUR CLASS PERIOD TODAY IF YOU ARE 20 YEARS OLD, THE WORLD’S POPULATION HAS GROWN BY 1.8 BILLION SINCE YOU WERE BORN. THE MAJORITY OF ALL HUMAN BEINGS WHO HAVE EVER LIVED ARE ALIVE TODAY!

HOW WILL WE FEED EVERYONE? THE EARTH IS NOT INFINITE! IF GROWTH CONTINUES, AT SOME POINT IT WILL BECOME IMPOSSIBLE TO FEED EVERYONE, EVEN IF FOOD IS DISTRIBUTED EQUALLY TO EVERYONE. 17 MILLION CHICKENS THEY EAT 40% OF THE WORLD’S GRAIN HUMANS “CONTROL” ABOUT 90% OF ALL LARGE ANIMALS 4.3 BILLION LARGE DOMESTICATED ANIMALS IN ADDITION TO FEEDING HUMANS, WE MUST ALSO FEED: BY MORE SENSIBLE USE OF EXISTING RESOURCES (BETTER LAND USE, VEGETARIAN DIETS, DEVELOPMENT OF NEW CROPS), WE CAN DELAY THE PROBLEM, BUT NOT SOLVE IT!

POPULATION GROWTH GOVERNED APPROXIMATELY BY “EXPONENTIAL GROWTH” – THIS TERM HAS A PRECISE MATHEMATICAL MEANING. EXPONENTIAL GROWTH OCCURS WHENEVER THE RATE OF GROWTH DEPENDS ON HOW MANY ARE ALREADY THERE - THE MORE PEOPLE ARE ALIVE, THE MORE OF THEM THERE ARE TO REPRODUCE. EXPONENTIAL GROWTH IS CHARACTERIZED BY A “DOUBLING TIME”, i.e., THE TIME NEEDED FOR THE NUMBER TO DOUBLE ALWAYS REMAINS THE SAME.

DOUBLING TIMES DOUBLING TIME Example: You have $5,000 in savings earning 5% per year. You will have $10,000 in 14 years. Example: Inflation is running at 1.5% annually. In 47 years, the average cost of products will have doubled. ~ ~ 70 % GROWTH RATE Example: The world’s human population is growing at a rate of 1.4% per year. The current population is 6.7 billion. In 50 years the world population will be 13.4 billion.

HISTORY OF HUMAN POPULATION YEAR 200AD DOUBLING TIME (YRS)‏ POP. 200 M 400 M 800 M 1.6 B 3.2 B 6.0 B ANNUAL GROWTH 0.06% 0.16% 0.47% 0.93% 1.4% IT TOOK ABOUT 1 MILLION YEARS FOR EARTH’S HUMAN POPULATION TO REACH 1 BILLION. THE NEXT BILLION TOOK ONLY 100 YEARS. THE LAST BILLION TOOK ONLY 12 YEARS.

POPULATION GROWTH DOUBLING TIME IS NOT CONSTANT, BUT RATHER DECREASES WITH TIME! THEREFORE, POPULATION GROWTH IS EVEN FASTER THAN EXPONENTIAL GROWTH!

PAST AND FUTURE? YEAR 200AD POP. 200 M 400 M 800 M 1.6 B 3.2 B 6.0 B 12 B 24 B 48 B 96 B WHAT IS EARTH’S CAPACITY? ASSUMING A 50 YEAR DOUBLING TIME FROM 2000 ONWARD

SOLUTIONS TO POPULATION GROWTH POPULATION GROWTH WILL BE HALTED. THE ONLY QUESTION IS HOW WILL IT BE HALTED. BY OUR INTENTIONAL ACTIONS (i.e., BIRTH CONTROL), OR… BY EVENTS BEYOND OUR CONTROL (FAMINE, POLLUTION, DISEASE, WAR). THESE HAVE BEEN THE “TRADITIONAL” METHODS OF POPULATION CONTROL THROUGHOUT MOST OF HUMAN HISTORY. THE ANSWER IS UP TO US!

CLIMATE CHANGE GLOBAL WARMING DUE TO THE GREENHOUSE EFFECT HUMAN INDUSTRIAL ACTIVITY AND BURNING OF FOSSIL FUELS ADDS GREENHOUSE GASES TO THE ATMOSPHERE. –CARBON DIOXIDE –METHANE –WATER VAPOR THE EVIDENCE THAT GLOBAL WARMING IS OCCURRING AND IS CAUSED LARGELY BY HUMANS IS OVERWHELMING. THE VAST MAJORITY OF SCIENTISTS AGREE ON THIS. EVEN IF WE STOP ADDING GREENHOUSE GASES NOW, WARMING WILL CONTINUE FOR A THOUSAND YEARS.‏

CLIMATE CHANGE WARMING ISN'T UNIFORM - SOME AREAS GET WARMER, SOME GET COOLER PRECIPITATION PATTERNS WILL CHANGE – SOME AREAS GET WETTER, SOME GET DRIER. RISE IN SEA LEVEL AS GLACIERS MELT –COASTAL AREAS WILL BE FLOODED MORE SEVERE STORMS SOME SPECIES WILL BECOME EXTINCT AS POLAR ICE MELTS, MORE SOLAR HEAT IS ABSORBED, INCREASING WARMING EVEN MORE. AS OCEANS WARM, MORE WATER EVAPORATES, INCREASING THE GREENHOUSE EFFECT FURTHER. (WATER VAPOR IS A GREENHOUSE GAS.)‏

POLLUTION HUMANS ARE POLLUTING: –AIR –WATER –FOOD SOURCES MANY POLLUTANTS PERSIST IN THE ENVIRONMENT FOR VERY LONG TIMES. OVERPOPULATION EXACERBATES THE PROBLEM: –MORE PEOPLE PRODUCE MORE POLLUTION. –POPULATION PRESSURE FORCES PEOPLE TO MOVE INTO MORE POLLUTED ENVIRONMENTS.

DISEASE MANY DISEASE-CAUSING BACTERIA HAVE EVOLVED RESISTANCE TO ANTIBIOTICS. –THE BIGGEST CAUSE OF THIS IS ANTIBIOTICS THAT ARE ADDED TO ANIMAL FOOD. –ANTIBIOTICS ARE ADDED IN ORDER TO INCREASE THE EFFICIENCY OF PRODUCTION OF FOOD ANIMALS. –OVERPOPULATION INCREASES THE PRESSURE TO ADD ANTIBIOTICS IN ORDER TO INCREASE FOOD PRODUCTION. THERE ARE DISEASES THAT KILL ESSENTIALLY EVERYONE WHO GET THEM AND ARE HIGHLY CONTAGIOUS (EBOLA, FOR EXAMPLE). NEW DISEASES APPEAR OCCASIONALLY (AIDS, FOR EXAMPLE). –CAN MOVE FROM OTHER SPECIES INTO HUMANS

DISEASE OVERPOPULATION AND POLLUTION INTRODUCE NEW DISEASES AND MAKE EXISTING ONES WORSE. –OVERPOPULATION FORCES PEOPLE TO MOVE INTO AREAS WHERE THEY'VE NEVER LIVED BEFORE, EXPOSING THEM TO DISEASES CARRIED BY ANIMALS. –OVERPOPULATION DECREASES THE AVAILABILITY OF MEDICAL CARE TO MANY PEOPLE. –POLLUTION CAN DAMAGE PEOPLE'S IMMUNE SYSTEMS, SO THAT THEY BECOME MORE SUSCEPTIBLE TO DISEASE.

WAR HUMANS HAVE ALWAYS ENGAGED IN WAR, BUT... UNTIL RECENTLY, THIS WAS NOT A THREAT TO THE ENTIRE HUMAN SPECIES. WE COULD WIPE OURSELVES OUT VIA ANY OF THESE WEAPONS OF MASS DESTRUCTION: –NUCLEAR WEAPONS –BIOLOGICAL WEAPONS –CHEMICAL WEAPONS

WAR NUCLEAR WEAPONS –THE WORLD INVENTORY OF NUCLEAR WEAPONS IS SUFFICIENT TO KILL EVERYONE ON EARTH MANY TIMES OVER. –IF A SUFFICIENTLY LARGE NUMBER OF NUCLEAR EXPLOSIONS TOOK PLACE, IT WOULD TRIGGER GLOBAL EFFECTS, INCLUDING A “NUCLEAR WINTER.” –SINCE THE END OF THE “COLD WAR,” WE HAVE REDUCED THE NUMBER OF NUCLEAR WEAPONS FROM ABOUT 65,000 TO ABOUT 20,000.

WAR BIOLOGICAL WEAPONS –NATURALLY OCCURRING OR ENGINEERED ORGANISMS –OFFENSIVE WEAPONS ARE BANNED BY MULTILATERAL TREATY – THE TREATY ALLOWS DEFENSIVE WEAPONS –SOME COUNTRIES PROBABLY HAVE OFFENSIVE WEAPONS IN SPITE OF TREATY

WAR CHEMICAL WEAPONS –BANNED BY MULTILATERAL TREATY –48,000 TONS ARE ESTIMATED TO EXIST –ARE GRADUALLY BEING DESTROYED TO COMPLY WITH TREATY (ABOUT 1/3 ALREADY DESTROYED)‏ –SOME COUNTRIES MAY HAVE SECRET STOCKPILES

ARGUMENTS FOR SHORT L A STEROID IMPACTS OCCUR REGULARLY. HUMAN POPULATION CONTINUES TO GROW RAPIDLY, BUT THE RESOURCES OF THE PLANET ARE LIMITED. HUMAN ACTIVITY CONTINUES TO ADD GREENHOUSE GASES TO THE ATMOSPHERE. HUMANS CONTINUE TO POLLUTE THE PLANET AND POISON OUR OWN ENVIRONMENT. HUMANS CONTINUE TO KILL EACH OTHER IN WARS, AND VIA POLITICAL AND ECONOMIC DECISIONS. EXISTING NUCLEAR WEAPONS COULD DESTROY THE ENTIRE HUMAN POPULATION MANY TIMES OVER. MANY IMPORTANT WORLD DECISIONS ARE MADE BY POLITICAL, BUSINESS, AND RELIGIOUS “LEADERS” WHO DON’T TAKE THESE PROBLEMS SERIOUSLY.

ARGUMENTS FOR LONG L SOON WE WILL HAVE THE TECHNOLOGY TO PROTECT OURSELVES AGAINST ASTEROID IMPACTS. EDUCATION CAN HELP CONVINCE PEOPLE OF THE DANGERS OF OVERPOPULATION, CLIMATE CHANGE, AND POLLUTION. SCIENCE AND TECHNOLOGY CAN HELP US CLEAN UP POLLUTION, LIMIT GREENHOUSE GAS EMISSION, AND CURE & PREVENT DISEASE. INTERNATIONAL PRESSURE MAY HELP PREVENT WARS, OR AT LEAST LIMIT THE NUMBER OF DEATHS. WE HAVE ALREADY DECREASED THE NUMBER OF WEAPONS OF MASS DESTRUCTION ON THE PLANET THROUGH TREATIES, SO THIS CAN BE DONE. IF WE COMMUNICATE WITH ALIEN CIVILIZATIONS, WE MAY LEARN FROM THEM HOW TO SOLVE SOME OF THESE PROBLEMS.

CLOSING COMMENTS EITHER N = 1, AND HUMANS ARE THE ONLY TECHNOLOGICAL CIVILIZATION IN OUR GALAXY, OR… N > 1, AND OTHER (MAYBE MANY OTHER) CIVILIZATIONS EXIST. IN EITHER CASE, HUMANS ARE UNIQUE. IF LIFE DOES EXIST ELSEWHERE, IT WILL BE VERY DIFFERENT FROM US. THEREFORE WE ARE WORTH PRESERVING! WE WILL NEVER FIND OUT IF EXTRATERRESTRIAL LIFE EXISTS IF WE DESTROY OURSELVES (OR ALLOW OURSELVES TO BE DESTROYED) FIRST!

CLOSING COMMENTS BY OUR ACTIONS, WE DETERMINE OUR OWN LIFETIME AS A TECHNOLOGICAL CIVILIZATION, AND OUR CONTRIBUTION TO THE VALUE OF “L.” (L IS THE AVERAGE LIFETIME OF A TECHNOLOGICAL CIVILIZATION. EACH CIVILIZATION, INCLUDING OURS, HELPS TO DETERMINE THIS AVERAGE LIFETIME.)‏ LET’S CHOOSE TO MAKE THE LIFETIME OF HUMAN CIVILIZATION AS LARGE AS POSSIBLE!