GP 25 Web Book

Day 14
Little Green Men

In the 1930s, a radio show on a Martian invasion brought panic to the eastern United States.  With space exploration, Martian movies are now comedies or period pieces. Aliens need to purchase tabloids to read about themselves.  So far the tabloid clientele is Earthlings.

The fictional aliens of my youth were green.  I think this came from the belief that food is scarce on Mars so that plants would also function as animals. They were little, I think for the same reason. Alien invasion stories provided a politically correct enemy for a war, just like modern tabloids do not fear alien libel suits.  They provide a nice venue for social commentary.  The 1898 book War of the Worlds by H. G. Wells centers on British society, especially the irrelevancy and impotence of their clergy in the modern technological world. The then-new concepts of germ theory of disease and evolution by natural selection play a major role.

It is not productive to discuss the sociology of unknown aliens at great length.  Science fiction writers are better than scientists at it anyway. I will return to what aliens might be like after I discuss how our own intelligence evolved and how it may aid our survival. I will then get on to finding ET.

Street smarts.  We are intelligent but what does that mean? Microbes and plants respond to their environments but in a programmed way.  Animals have programmed instincts.  We are born with the fear of heights and the fear of snakes.  Darwin defined intelligence as the ability to learn from the environment and modify one’s behavior to one’s advantage. As Darwin showed, this degree of intelligence exists in earthworms.

I will up the bar some to the ability to learn from the environment and teach one’s offspring. This widespread ability is the seed for technological intelligence.  Two clades of animals held lottery tickets to becoming a machine-making organism. The cephalopods (like squid and octopus), and the vertebrates.  The cephalopods did poorly in the Cretaceous-Tertiary mass extinction.  Squid and octopi have large brains and dexterous arms.  Octopi take care of their young but are solitary.  Squid are social but do not care for their young.  The pre-adaptation of social technology just did not arise.

Numerous vertebrates show the seeds of technological intelligence.  Our close relatives chimpanzees and bonobos (pigmy chimpanzees) have some tool making and abstract communications ability.  So does our more distant relative, the gorilla. This is not surprising in that the common ancestor dates back only 5 to 10 million years.  More distantly related carnivores use tools.  The sea otter is famous for this in California. The raccoon and black bear probably belong on the list, but it is not clear whether they picked up the habit by watching humans.  Elephants, dolphins, crows and seagulls have complex learned behavior.  These organisms will require millions of years of evolution (with the right selective pressures) to reach machine making. No one would try to teach any non-human terrestrial species calculus.

Evolution to the point of chimpanzees did not trouble Alfred Wallace, but the next step to a conscious human did.  The problem is obvious.  Our language and machine making abilities make us far too fit.  We need not be able to discuss the philosophy of Kant to organize a zebra hunt.  Grunts and pointing would serve to get the hunters in the right places. Sticks and stones would work perfectly well once a zebra was cornered.  Wallace was not a racist like many Europeans of his day. He knew that so-called savages did perfectly well when exposed to Western learning, but he thought that savage peoples did not need to think to live. That is, the intelligent brain evolved before there was any use for it.  Natural selection could no more do this then cause a mushroom to become intelligent.

Wallace did not understand a savage life style. Real savages live by their wits. They spend much time learning and transmitting acquired information. For example, it takes a lot of knowledge to survive in the Arctic.  How long would you last without modern technology?

In fact, humans are highly adapted to learn and transmit acquired knowledge. Our long infancy provides time for learning and our prolonged adulthood provides the teachers. In detail, our stone-age evolution was akin to sexual selection, but might better be called cultural selection.  The human with good communication skills and imagination got to breed more often than did the boring dullard.

The genes that code for conscious action and communication are recent modifications of older genes, probably in the last hundred thousand years. Civilization then took off quickly.  We have gone from starting to plant crops to landing on the Moon in the last 10,000 years.  There is only one intelligent species on the Earth because once cultural selection kicks in evolution is fast.  The transmission and improvement of learned technology is even faster.  The chance of two species in one solar system reaching this stage at the same time is miniscule.

The evolution of a second intelligent species on the Earth will occur only if we let it.  Science fiction stories, like The Planet of the Apes, have already alerted us to the danger of breeding or genetically engineering another intelligent species as slaves.  If we have squid slaves, we will soon have squid rebellion with much human support.  We will have to share the planet with them or perish.  Having squid study oceanography is efficient and intriguing.  The real danger comes in that wisdom is dearer than knowledge.  Millions of years of evolution for social behavior have not freed humans from wars. I tremble with what an engineered species would do.

Scaffolding.  So far intelligence does not seem that difficult.  Given time several extant clades on the Earth would achieve it.  Humans just happened to hold the first winning lottery ticket that was drawn.  A higher hurdle was going from microbial to complex multicellular life. This happened just once.

I retreat a bit to the discovery of DNA and the genetic code.  All the cells in our body have the same chromosomes and genes (except red blood cells that lack them and the germ cells that have half a set), but the cells in your big toe are a lot different from the cells in your liver and your eye.  Studies of fruit flies showed that control genes make eye cells grow in the eye.  Further work showed that this biological innovation occurred just once.  The control genes in plants, fungi, and animals are all related.  There have been many gene duplications, but the genes are highly conserved.  Squid genes sometimes function in fruit flies.

The control genes allow the body to grow indirectly.  We start to grow gills that will be no use, but the control genes redirect this growth later on.  The butterfly is vastly different from the caterpillar.  The control genes tell the right structures to grow at the right time.  Cell death is often planned.  Our hair and fingernails are dead cells. Oak leaf cells die in the fall.

The control genes are highly conserved because their failure is disastrous, like an organ growing in the wrong place or not at all.  Fruit fly breeders have legs growing on antennae and eyes in the wrong place, which would be lethal in the wild.  A gross failure of the control genes is teratoma, several forms of cancer with a melange of cell types in the tumor.

Control genes were a difficult biological innovation.  Complex cell types are far different than just getting cells to join in filaments. All that is needed then is a mutation where the cells remain attached after dividing or regroup in a consortium.  Control genes did not evolve quickly once oxygen was in the air and ocean (Figure 1).  The vacancy sign on the niche for plants, animals, and fungi hung out for over a billion years.

Figure 1: The trilobite Elrathia kingii hung out in Utah about 500 million years ago. Specimens are available in many rockshops. It lived in very oxygen-poor water at the bottom of a shallow sea. Other species have inhabited similar environments since that time indicating that abundant oxygen is unnecessary for animal life. However, oxygen-poor environments are rare and transient, an evolutionary dead end for animals on the Earth. We breathe abundant oxygen because we are a wide-ranging successful species that evolved in a common persistent environment. Animal-like organisms may have evolved intelligence in oxygen-free or oxygen-poor environments on other planets. Small sulfate "breathing" animals called oligochaetes exist in the ocean. They have microbes within their cells that do the chemical reaction, but or not fully independent of oxygen. Photo by the author.

If your feet are cold put on your hat.  Thermoregulation is certainly necessary for our brain to function intelligently.  We get delirious from a fever or hypothermia.  Cold woodsmen and mountain climbers perish when they are too cold to act rationally.  Evolutionarily, it was efficient for a brain to work at a single temperature.  Maintaining this temperature is costly.  We need to eat far more food for our weight than a “cold-blooded” animal.  We are prone to head injury. Our large brain makes childbirth dangerous.  Evolution has reached a compromise where the baby’s head just fits through, but the mother hips are still usable for walking, and the time taking care of the helpless baby is not too large.  An intelligent egg-laying organism would find other follies with the live birth of a large baby.

Thermoregulation by a warm-blooded body is easy.  It evolved at multiple times in mammals, birds, large sharks, and large tuna.  It even occurs in the skunk cabbage, which heats itself to bloom in the early spring.  But thermoregulation is unnecessary in the deep ocean.  The water temperature stays the same and the organism need not expend any energy to keep its brain at a constant temperature.  An intelligent organism living in this environment would come up with lots of reasons why warm-blooded organisms cannot be smart.

Spare change.  We expect macroscopic organisms to be multicellular. So much so that our chauvinistic term “higher organisms” is equivalent to multicellular organisms.  Yet there is considerable overlap in size between multicellular and one celled organisms.  We have already seen sand-sized formanifera that paleontologists used to date rocks.  They are bigger than small insects and mites. Even larger foraminifera lived on the ancient seafloor and large species continue to do so.  These one-celled organisms exceed the size of the smallest vertebrates.  Some eat small animals.

Rice-shaped fusilinids perished in the mass extinction of the end of the Paleozoic. They approached a centimeter in length.  They were locally abundant enough that some limestones are almost totally composed from their fossils.  The name refers to their resemblance to musket bullets.

Some nummulites were even larger, up to several centimeters across.  The name comes from the Latin word for coin.  It is descriptive. Some are larger than U.S. quarters (Figure 2).  They lived in the early Tertiary and were extinct by 23 million years ago.  As with fusilinids, they sometimes make up the bulk of a limestone.  Their fossils are common in the rocks used by the Egyptians to build the Pyramids.

Both fusilinids and nummulites show considerable complexity, as do extant giant foraminifera.  The spiral pattern in nummulites is intricate.  They did not evolve to the point that they had good senses, like vertebrates and squid.  Competition with already existing animals may have kept evolution in that direction in check.  These lineages arose after the seafloor already teemed with well-adapted animals.  The story might have been different if their lottery ticket for a large organism had been drawn before there were other animals around.

Figure 2: Nummulites were large one-celled foraminifera.  The species lived about 50 million years ago near what are now the pyramids of Egypt.  Herodotus recognized such specimens as fossils of marine organisms. Specimens from Jim Ingle.  Photo by the author.

Again an intelligent one-celled organism might come up with dead-end follies of multicellular organization.  Here ‘tis my try. Having a nucleus in each of a countless number of cells is a great waste of phosphorus in the DNA and nutrients in general. A multicelled organism risks mutation and cancer each time a cell divides.  A one-celled organism can keep its genetic material sequestered out of harm's way.  It risks division only to reproduce and need not partake in sexual reproduction in every generation. (Foraminifera have complex sexual practices; some analogous to fish spawning.) It might even be able to transmit its learned knowledge in the asexual generations.

Here is a link to a site about large foraminifera. It can be followed to several other sites. http://www.bowserlab.org/

Harbingers of doom.

Shine it like a comet of revenge,
A prophet to the fall of all our foes!

First Part of King Henry the Sixth, Act III. Scene II.

William Shakespeare (1564–1616)
The Oxford Shakespeare,  1914

I now switch from how we got here to how we may stay.  Any aliens we find have likely been intelligent for a geological period of time.  Statistically, we will see the successful cultures, not those that quickly bring about their own demise.  How can we survive for a geological time ourselves?  The big danger is at our own hand, and scientists are not much help with politics.  How do we avoid natural hazards for which science can help?

We need to keep the climate from going bad.  Global warming is real, but unless it triggers war it is not a threat to civilization.  It is correctable in that the excess CO₂ in the air would mostly enter seawater in a decade. A little global warming may even keep us out of an ice age.  I am not advocating a head in the sand approach. Rather, global warming and conservation in general are manageable if there is international cooperation.

Neither do mundane natural disasters, like earthquakes, tsunamis, and hurricanes, pose any global threat.  There will continue to be casualties but they will be local.  We need to be concerned about the disaster that befell the dinosaurs, the impact of asteroids.  Most dinosaurs that ever lived did not die from asteroids, but all the living dinosaurs died at the same time.  There were no dinosaurs to carry on.

Astronomers have made a good survey of the larger asteroids in the solar system.  Earth-crossing asteroids are complete down to a 10-km diameter.  None are heading our way.  We cannot relax and give the all clear sign, though.  The impact of a 1-km diameter asteroid would incinerate a continent-sized area and plunge the Earth into global winter.  It would not wipe us out but would put civilization at risk. Statistically this is the most dangerous size class.  Smaller objects have disastrous but more local effects, the danger drops off rapidly below 300-meter diameter.  Larger ones are quite rare.  We do not have to worry much about Tunguska and Meteor Crater sized projectiles. These are the smallest objects that can damage the surface. They hit every few hundred years, but most of the Earth’s surface is sparsely populated.  Technology will concentrate on them only when the larger objects are well in hand.

What do we do about 1-km class objects? Actually they are not hard to detect. In fact, NASA did not show much interest at first because only tens of million dollars are needed to set up a land-based network of telescopes.  Observations are now underway and we will have orbits for 90% of the (1400) 1-km diameter objects by the end of the decade. It is feasible to work down to the 50,000 300-m diameter objects.

Most likely we will not find any objects on a collision course.  1-km diameter objects hit statistically about once in a million years.  Unless we find an object coming our way in the initial survey we will have decades to centuries of warning time.  Asteroid orbits are very well behaved and quite predictable.  Asteroids jump out of their orbits like trains from tracks only in bad movies.  We will keep track of the asteroids we find and continually update orbit estimates.

What if we find an asteroid heading our way?  We will most likely have warning and time to act.  Shooting them down at the last moment is futile.  We would first land a transmitter on the asteroid to confirm its orbit. The Earth is small compared to the vastness of the solar system so only a nudge is needed.  Blowing it up with an H-bomb replaces one dangerous object with several.  Two practical suggestions are to set off a small nuclear explosion away from the asteroid to spall off a layer of rock.  The equal and opposite force on the asteroid accelerates it into a new orbit.  NASA has large ion-drive motors on the drawing board that have enough thrust to move a small asteroid.  This option can be tested on a safe asteroid before we really need it.

Comets are a more serious problem but only 1/10 of the risk.  We can get good orbits for periodic comets, like Halley’s, but comets come in from beyond the orbit of Pluto.  We do not have the technology to detect even several kilometer-sized objects in the region.  We detect most comets after they have started to flare.  We may have only months of warning.  We do not yet have a good way to deflect comets.

Break glass and open in case of danger in 400 million years.  The Sun is getting more luminous with time and plate tectonics will grind to a halt.  We do not know which will occur first, but the failure of the Sun is more ominous.  What will a high-tech civilization do about it?  It can do nothing with the Sun itself. The problem is like tweaking Venus to make it clement. At the start of the red giant phase over 5 billion years from now, the Sun will be only twice as luminous as now.

Our descendents may try to cut the flux of sunlight to the surface. We have already seen that volcanic dust and impact dust cools the surface.  The needed mass of dust is huge and it does not stay up more than a few years. Sulfur-burning planes at high altitude might do some good, as sulfur stays up longer than dust.  It might be possible to create a dust ring in orbit around the Earth.  Given the time available, mirrors in orbit seem more controllable.

We might get rid of the light after it comes in. One can increase the albedo of the Earth with large arrays of mirrors. Ice naturally increases the albedo of the Earth so this will work at first, given the millions years to get ready. Efficient solar cells could collect light and broadcast it to space as radio waves.

One can fight the water vapor part of the runaway greenhouse to some extent by covering the low-latitude ocean so it does not evaporate.  This would destroy much of the Earth’s biology, so it is really a last resort.

Changing the Earth’s orbit is not easy.  One could crash asteroids into the Moon so that the Earth-Moon system moves out from the Sun and the Moon moves toward the Earth enough to keep it at its present distance.  Many large asteroids or comets would be needed to have any effect.  The dust generated in Earth orbit might be more useful as already noted.

We could genetically engineer ourselves to withstand higher temperatures.  There is a limit to this unless we prevent the greenhouse from getting hotter than 100°C or so.

Our descendents may choose to retreat.  They will have to do this or die at the end. First to Mars as it becomes clement and then the asteroids, the satellites of Jupiter and out beyond Pluto in the red giant stage.  When the Sun becomes a white dwarf, its heat will cease to be a danger, but it will no longer be a source of light.  The technology will have to find another star or work out a way not to need one.

Calling ET.  How do we call ET?  Either radio waves or lasers will work.  It is really easy to communicate between nearby stars with someone who knows that the message is coming.  The physics are like combining a lighthouse with a foghorn. The beam from the lighthouse rotates so the observer sees short intense pulses of light.  The amplitude of the pulses is far above the ambient light.  If the lighthouse sent out a signal in all directions, it would be weak everywhere.  The mariner would have trouble seeing it.  The foghorn broadcasts in all directions, which awakens landlubbers. It has pulses but they take up about half of the time. It has a single tone or a carefully modulated tone.  Our ears are good at recognizing tone, the vibration frequency of sound waves.  The mariner can hear the controlled tone above the din of crashing waves much easier than an uncontrolled signal.  Our eyes can tell the frequency of light, color, but they are not good at it.  Lighthouse technology (pharology for those who want a large vocabulary) evolved before lasers.  Modern navigation has rendered many lighthouses obsolete.

How do we communicate with someone on a planet around another star? First assume that the receiver knows that the signal will be coming.  We will first aim the signal at the recipient similar to how a lighthouse beam is pointed horizontally to be aimed at sailors (rather than birds). We then need to make the signal more intense than the ambient noise in space and probably our Sun.  We do this by pulsing the signal, like a lighthouse, so that our available energy arrives with large amplitude.  We will modulate the signal frequency, like a foghorn.  We need to be careful that enough radio or laser signal arrives so that it behaves like a macroscopic signal.  That is, we need to have a lot of quanta hit the receiver (for those with some physics).

What do we need for success?  A large radio telescope can communicate with another one anywhere in the galaxy.  A military laser for shooting down this or that can communicate with optical telescopes on other stars if the beam can be aimed within the other solar system.  A pointer laser would do if we could point it accurately enough to fall on an earth-sized planet.  ET will be able to phone if she knows we are here and really tries.

What about picking up a signal that is not aimed specially for us or a signal casually sent out to a vast number of stars, one at a time? By definition, ET’s intelligence here is limited to the ability to make radios or lasers. The SETI project has been doing this for a few decades, so far with no success. It is privately funded since the small item on NASA’s budget was a prime target for congressmen to get laughs.  The technology is improving to where the radio SETI can search much of the sky while ordinary radio astronomy goes on.  Given the low cost, the effort is well worth doing.  Optical SETI is much less advanced.

Radio waves from TV and radar have leaked out of our atmosphere for over 50 years.  Any ET with radio telescopes that periodically check nearby stars would have detected us.  The boring part of the task can be fully automated, even with our technology. A return signal could have come only from the modest number of stars within 25 light years of the Earth.  It will take centuries for the radio waves to reach millions of stars, with time to send a return message.

There is a way to speed things up if ET is not vigilant.  Astronomers observe supernova. Once they detect one, many of the radio telescopes and the optical telescopes on a planet will be pointed that way.  To get detected, we need merely broadcast a signal in the direction that the supernova light is heading after it passed us for a few days after we see it.  ET will have his eyes open and ears up.

Where may ET be chatty?  Around red dwarf and red giant stars.  The red dwarfs have planets and stars that last almost forever.  They may harbor several billion year-old civilizations eager to locate recently technological ones.  The inhabitants of red giant systems have had space travel thrust upon them.  They may be looking for greener pastures and trying to save their history if not themselves.  At the least, civilization spread out over icy objects far from the star will generate a lot of laser and radio traffic.

Thou shall not covet?  I have promised not to drone on at length about unknown aliens and their sociology.  We have seen that only two steps from prebiotic chemistry to humans seem hard; first getting life started and then getting complex multicellular life.  The anthropic principle keeps us from reading too much into either one.  ET needs only a semi-stable environment where large organisms can exist.  Moderate instability is actually helpful as it favors intelligent rather than programmed response.

What will ET not want from us? She is not likely to have a big demand for tabloids.  Neither will ET find us edible; both our organic chemistries are complex and different. She will not covet our technology except as antiquities that go back a geological time on her own planet.  She will not want our planet for living space; there are countless uninhabited ones.  Our air and water are not likely to be of her taste.

What do we have to give ET?  Information, which would be very difficult for her to obtain remotely or by space exploration.  We have a wealth of social information.  Their sociologists would not reject the history of a whole new planet.  Their geologists and biologists will grab additional new well-documented cases.  It will take some time to get the two-way communication on line, but both ends will share much of science.  It will take time to bring our science up to theirs. I leave further aspects of our reaction to science fiction writers.

Copyright Notice

back to top