WHERE IS EVERYBODY

WHERE IS EVERYBODY?

by Chris Boyce

The nature of the Paradox

The legend goes like this.

During the days of the Second World War, scientists of the Manhattan Project at Los Alamos in New Mexico worked on the development of the atomic bomb. Numbered amongst them was the Nobel laureate Enrico Fermi. During moments of rest, over lunch or at coffee breaks, Fermi would seek those who had newly joined the project. He would then engage them in conversation regarding the possibility of life elsewhere in the universe and let them build up their enthusiasm for the possibility of life and intelligence. Then he would enquire, 'So? Where is everybody?' In other words, if there are other intelligences out there why is there no evidence of them here on Earth?

Thus was born the Fermi Paradox.

When Fermi posed this question there was no public debate on ETs or SETI or even UFOs. Today when such debate is well aired by professional scientists and lay persons alike, his ‘Paradox’ is still one of the prime weapons in the sceptics' armour.

The Paradox is usually delivered in a number of different guises, like 'If there are aliens, why haven't they landed on the White House lawn?' and I'll take a look at these in a moment. But first let's take a look at the standard replies to the paradox.

There are no aliens and we are alone in the cosmos. This is the common assumption of the vast majority of people, although, interestingly, not in the scientific community. Most scientists who have had even a casual brush with the subject admit that life elsewhere is probable and ET civilisations possible. Others suggest that civilisations in the Galaxy may always wind up destroying themselves.
The ETs have evolved far beyond us. The phenomenon of evolution will apply to life everywhere. We can also expect any beings capable of traversing the distances between the stars to have gone through a long and rigorous process of natural selection. Natural selection may effectively cease when they have attained and passed out level of social organisation and medical achievement. This, however, will still leave them free to manipulate their own genes. The belief of those who hold to this answer is that such highly advanced beings would have no interest in us and would probably be quite undetectable. That said, a number of them would surely have expanded across the cosmos before they elected to become gods so there should be at least some evidence of their presence in the Solar System either today or in the past.
Space flight between the stars is an impractical method of exploring the cosmos. This is a particular favourite with a great number of astronomers. They cite the exorbitant costs associated with sending vehicles on interstellar journeys and the Himalayan enormity of the engineering problems to be solved. They favour telescopes, preferably radio telescopes, to look for evidence of ET presence in the heavens. None of them believes that there is any intelligent life in the Solar System other than humankind. There are however a considerable number of engineers and scientists who do not balk at the prospect of interstellar flight and actively research it.
Ours is a protected planet. ET protocols exist akin to Star Trek's 'Prime Directive' which bar any technologically superior beings from contacting any species below a particular level of technological capability - like manned interplanetary flight, for example.

So we can already see that there are clear answers to questions like 'How come no aliens have landed on the White House lawn?' There are, nevertheless, questions which these standard replies do not satisfy but they usually spring from a profound lack of understanding.

Let's look at these individually.

'If aliens have been visiting Earth for thousands of years how come they didn't gobble up all of our natural resources?' or The Greedy Grab-All Aliens:

Replying to them that the ET is a humane or even spiritually superior being cuts no ice with people who ask this question. They are quite right too. The nature of the ET is actually irrelevant here, greedy or benevolent. Beings capable of interstellar travel are unlikely to have any proprietorial interest in our world.

Biologically our world will have taken a profoundly different route from theirs; there is no common biological history so we can assume that although the mechanisms and perhaps even the materials of life will be similar in general they will differ in the detail. And life as we know it is in the detail - specifically the detail of the amino and nucleic acids. Earth will be at best a wilderness to them but more likely a bio-hell.

As far as energy resources are concerned they would have no interest in our natural reserves.

Our oil, coal and uranium stocks would be safe. Any species which developed interstellar flight would first require technologies which allowed them to harvest energy in the depths of space. They could not depend on the reserves to be found on those rare worlds where there were fossil fuels. Furthermore it is unlikely that reserves of carbon based fuel, as found on Earth, would appear attractive when compared with the much more bountiful resources to be found in the Outer Solar System.

So we know why they don’t steal our energy resources. Essentially, from an ET point of view, there's simply nothing in it for them.

'But surely if there were extraterrestrial beings around they'd show us how to conquer disease and famine and teach us how to live in harmony with one another?' or The Cuddly Kissy Touchy-Feely Aliens:

Again we should turn this around and ask `What's in it for the ET?'

The biological gulf lying between us and the ET is far greater than the billion year wide abyss which separates us from the social insects. Despite the fact that they are incredibly accomplished creatures with complex societies and astounding technologies - some even in advance of our own - we do not regard them equals nor are we ever likely to. From our viewpoint they are barely conscious. They are accomplished, undoubtedly but they are also very deeply different. What is in it for them or ourselves to attempt opening a dialogue? Neither of us seems interested.

Few people would, out of the kindness of our hearts, open a large jar of honey directly below a failing wasp colony just to help them out.

Again, there's simply nothing in it for the ET. The 'Contact Equation' is all one way in this instance.

'Surely aliens would have wiped us out before we developed spaceflight and a nuclear arsenal?' or the Galactic Genocidal Gang:

ETs in the Solar System, as pointed out above, would find life much more comfortable in its outer reaches of the Solar System and there's very little chance of us posing a threat to them there. We can also anticipate them having reached our level of technological expertise a very long time ago – probably many millions of years in the past. They are likely to be less alarmed by our weapons than any of our nations would be if the news got out that a tribe in the Surinam rain-forests had developed a cross-bow.

Yet many people would say that the Fermi Paradox is no paradox at all. These are the proponents of the Extraterrestrial Hypothesis, those who believe that some of the truly unidentified UFOs are ET spacecraft.

This hypothesis is not wholly inconsistent with the 'What's in it for ET?' response to the Paradox. If there are ET craft visiting us, their occupants seem to have little more than an academic interest in matters terrestrial.

But, as mentioned above, many astronomers tell us how difficult and vastly expensive interstellar flight would be.

Well, this is true but only in part. Let's take New York City as an example. Most of the inhabitants come from European and African stock but they don't commute across the Atlantic to work in the city. They live there.

If we are not the first intelligences, then colonisation of the Galaxy took place in the remote past - not in the historic past but the past as measured in geological or cosmic timescales. That one or more settlements of ET origin may have been present in the Solar System for many millions of years is not an unreasonable assumption in this case.

Where then is the evidence for these ancient colonies?

There is no more evidence than there is for the basic principles of the Search for Extraterrestrial Intelligence, SETI: it is reasonable to assume that intelligent life has arisen elsewhere in the universe, perhaps many times over during the past billions of years.

Few people, and those who do are mainly axe-grinding politicos, consider SETI to be unscientific. The only fly in their ointment is Fermi's frustrating question 'Where is everybody'.

The answer could be this simple: 'They're here!'

Des. Res. - Solar System Real Estate

Any ET dropping in on the Solar System from interstellar space would almost certainly decide to avoid the inner system, that is to say Mercury, Venus, Earth and Mars, for a number of reasons.

The resources are so far down the Sun's 'gravity well' that extensive travelling to and from to the outer system, where most of the material resources are to be found, would be energy expensive.
The inner system's resources are mainly to be found on planets, high gravity environments, and these, again, are energy expensive both to work in and to leave.
The inner system is particularly vulnerable to bursts of intense radiation from solar flares. The Earth's atmosphere protects us from these but they do pose a serious danger to space travellers. The strength of this radiation drops off with distance from the sun and flares would pose little threat to anyone moving in the environs of the outer planets.
There are no material resources found amongst the inner planets which are not found in greater abundance or with easier access beyond the orbit of Mars.

So avoiding the inner system simply makes good sense.

Beyond Mars lie three potential habitats for would-be colonists intent on settling the Solar System.

1. The cometary halo.

2. The asteroids.

3. The gas-giants' moon systems.

1. The cometary halo.

Two 'clouds' of comets encompass the Solar System, the Kuiper Cloud extending from 100 ~ 10,000 AU(1)and the Oort Cloud which starts some 40,000 AU out stretching as far as 60,000 - perhaps with some cometary orbits going out as far as 100,000. There are literally billions of comets and all are rich in water, minerals and hydrocarbons.

Most of them are less than 10 miles across and rotate at a moderate speed, normally somewhere between 5 hours and 5 days. They are believed to be composed of a very light porous aggregate of volatile gas ices imbued with clathrates - compounds where one material is trapped within the crystal lattice of another. Cometary material is probably as dense as water and with the consistency of wind-blown snow.

The big drawback about living out there is the temperature, 10 degrees above absolute zero.

Freeman Dyson envisaged bio-engineered tree-like structures growing on comets, completely engulfing the cores and extending out tenuously to a vast globe of light catching leaves. These would supply the settlement with energy. The tree roots, buried deep inside the comet would seek out, process and provide minerals and bio-materials for the colonists. The 'trunk' of the tree - a banyan-like complex most probably - would act as home for the settlers.

The centre of such a structure would most likely be assembled over time from a few dozen to a hundred comets with materials from a few hundred others mined to supply materials for the tree. During the construction phase power would probably be obtained from fusion processes burning either the millions of tons of deuterium found in virtually every comet or simply from ordinary hydrogen using the proton-proton process which takes place in the stars themselves.

By the time the spherical comet-tree was complete, the settlement would be self sustaining with a closed ecology and harvesting energy directly from starlight. Say we decide to supply a settlement of 500 beings with the equivalent of, say, .05 Megawatts each. This is more than 20 times the per capita consumption rate in the USA today. For this the gossamer structure would have to be in the region of some 35,000 miles across - more than four times the diameter of the Earth but with only a vanishingly small fraction of its mass(2).

These structures would be ideal not only for cometary life but also for journeying between the stars. If our ETs travel in this manner, living like this in the Oort cloud would be perfectly natural for them.

2. The asteroids.

Lying principally between the orbits of Mars and Jupiter, the asteroids form a cornucopia of natural resources and potential habitats for space voyagers.

Asteroids are rocky bodies measuring between a few hundred yards and a few hundred miles across. The largest of these, Ceres (640 mi), Pallas (300 mi) and Vesta (240 mi) are approximately spherical but most of the others are either roughly cylindrical or irregular. Water ices are found on the vast majority along with complex hydrocarbons, minerals and metals. They rotate gently, taking between 5 and 20 hours to complete a revolution.

Two types of asteroid are most common C-type and S-type. The C-type are so described because they appear similar to chondrite meteorites. These contain chondrules or ball-like masses of material which have quickly cooled from a molten state. S-types, correspondingly, are stony like the stony-iron meteorites. Lying in the main much closer to the Sun at just under 2 AU to slightly over 3 AU, solar energies would be a real possibility for processing substances and fabricating structures.

There are two possibilities for creating asteroidal settlements. The first is to mine for various materials and live in the excavated chambers. The second is to surround the asteroid with a greenhouse bubble membrane. With either of these solutions in place the settlers would then be ready to set up a functioning ecology.

Carving out sets of caverns and tunnels would require serious power but then a society of beings capable of interstellar travel should have mastered the finer points of fusion. They may well be able to make use of the hydrogen found in the water-ice for this purpose. Marshall T. Savage(3) has pointed out that by removing a substantial amount of material from the interior of a large asteroid a staggering amount of living space can be created.

Take Vesta as an example. If half of Vesta were mined or architecturally excavated, some 4 million cubic miles of living space could be established. Divided into areas with an average ceiling height of 100 feet this would transform into about 215 million square miles of living space - far greater than the total land surface area of Earth!

Perhaps of even greater interest, there are literally millions of asteroids only a few miles wide. If we run the same calculations on these, we find that an asteroid some five miles across can provide a territory of some 3.5 thousand square miles, almost enough room to encompass London and all its metropolitan boroughs five times over.

The idea of hollowing out asteroids is not new. It was suggested by J.D. Bernal in The World, the Flesh and the Devil back in 1929 and more recently by Arthur C. Clarke in his novel 1974 novel Rendezvous with Rama. This, in turn, was inspired by the work of Cole and Cox(4) ten years earlier on making asteroids habitable and used as interstellar arks.

Savage also came up with the idea of encasing smaller asteroids in membrane bubbles(3). He points out that it would be possible to extract a small amount, less than two percent, of the water on a six mile diameter asteroid and place it around the asteroid as a bubble within a constraining membrane. This water would provide a radiation shield and a greenhouse environment for the contained ecosphere.

3. The gas-giants' moon systems.

The principal drawbacks of both the cometary halo and the asteroids are that they are very widely dispersed. Travel from one comet to another can be time consuming and energy expensive, likewise travel from asteroid to asteroid. The principal advantage of the gas-giants' moons over the other real estate systems is precisely that they are all within comparatively easy reach of one another.

The one main drawback to such an environment is Jupiter. Close to Jupiter, at the distances of the inner three Galilean moons, Io, Europa, and Ganymede, Jupiter's radiation belts could prove life threatening.

Callisto, further out and quite safe, is more than twice the diameter of our own Moon. This might prove attractive to colonists wishing a noticeable surface gravity but closer to that of Mars than Earth's.

The outer moons are much smaller and well supplied with water ices and likely to have all of the essentials for setting up a working settlement. These are to be found from about 7000 miles on out to the edge of the gravity well, eight satellites in all.

Saturn actually has the look of a system which just might have been thoroughly settled for some time, heavily worked and with much of the debris now drifting in rings about the giant planet.

Satellites in this system range in size from some of the recently discovered objects only a few miles across to more substantial properties like Tethys, Ipaetus and Rhea many hundreds of miles across. Then, of course, there is one of the most interesting moons in the entire Solar System, Titan. This would again prove attractive to any colonists looking for a substantial but low gravity environment rich in hydrocarbons and possessing a dense atmosphere.

Other substantial outer system moons which could prove similarly attractive would be all five of Uranus's major satellites and all eight of Neptune's - particularly Triton, again, for those who prefer a gentle but definite gravity field.

At these distances from the Sun the use of solar collectors would probably be impractical. The most obvious source of energy would be mining the gas giants themselves for energy. Their resources are, after all, quite spectacular.

Consumption of energy for our entire planet is estimated at 13.6 TW (terrawatt=1 million MW) for 1997. Using the helium-3 present in the atmospheres of the outer worlds to power fusion generators, the entire population of the Earth could theoretically go on consuming energy at the present rate for over a billion years before exhausting supplies(5).

If we estimate a population of one hundred million ETs amongst the moons of the outer system, all consuming at our present rate, they would use roughly a fiftieth of what we presently do on Earth. The energy resources of the outer system could last them for 50 billion years. Even if ETs have been helium-3 mining in the outer moon systems for millions of years they've barely scratched the surface of the reserves out there.

However, we should bear in mind that any ETs who have crossed the void between the stars in something similar to the comet-ships or asteroid-arks described above, would in all likelihood be very much more energy conscious than we are today.

The argument that aliens do not exist because there is none here can thus be seen as parochial and strongly anthropocentric. There is no reason why there might not be a major ET presence of some form in the Solar System right now. Of course even if they arrived ‘yesterday’ in terms of cosmic time that means they have probably been here for at least millions or, more probably, tens - even hundreds - of millions of years.

Considering a society or societies millions of years ahead of us in terms of technical development and deeply different in their cultural history, the ‘What’s in it for them?’ question clarifies their position on contact with humanity. Studying our world is probably only one of numerous activities and studying Homo sapiens will certainly be a part of that but considering the deep divide in maturity that separates us, they may leave it up to us to find them and initiate the communications process ourselves.

Then where should we start?

Look here!

Gregory Matloff is an Adjunct Professor of Physics and Astronomy at a number of colleges in and around New York. His suggestion(6) is that astronomers studying small objects in the solar system, like comets and asteroids, should build up a catalogue of their infra-red profiles. This is because any astronomical body supporting life as we know it will have to shed heat. This will manifest itself as an anomalous IR reading once investigated.

Such curiosities are already known to exist amongst the asteroids of the Kuiper Belt extending far out beyond the orbit of Neptune. Matloff proposes these be more closely observed and searches for further IR curiosities be mounted.

ET may turn out to be closer to home – and closer to discovery – than we ever dared imagine!

Notes.

1. AU - an Astronomical Unit, representing the distance of the Earth from the Sun, is roughly 93,000,000 miles or something over 8 light-minutes.

2. Astrophysicist Eric Jones and anthropologist Ben Finney worked out the requirements for comet settlers harvesting starlight; see "Interstellar Nomads" in Space Manufacturing, Advances in the Astronautical Science, 53, 1983, pp 357- 374 and "Interstellar Migration and the Human Experience", Berkeley, University of California, 1985.

3. The Millennial Project, by Marshall T. Savage, Little Brown, 1994.

4. Islands in Space: The Challenge of the Planetoids, Dandridge M. Cole and Donald W. Cox, Chilton, 1964.

5. These estimates are based on calculations to be found in "Colonising the Outer Solar System" by Robert Zubrin, Chapter 5 of Islands in the Sky, eds S. Schmidt and R. Zubrin, Wiley, 1996.

6. The Reenchantment of the Solar System: A Proposed Search for Local ET's, by Dr. Gregory L. Matloff, Adjunct Professor of Physics & Astronomy, New York University, CUNY, Pace Univ., The New School, USA. National Institute for Discovery Science Essay Winner 1999: http://www.accessnv.com/nids/essay.shtml