The Omnipresent Terror: A Science Fiction Story

Linda Tyler always hated Halloween, because she had suffered from a fear of ghosts since the time she was a little girl.

It had started in her childhood. While lying in her dark bed at night, she was often kept awake by a strange knocking sound on the roof above her. The knocking was merely caused by a tree branch being moved around by the wind, but Linda didn't know this. She imagined that there was some ghost who lived on top of the roof, a ghost who knocked on the roof as a harbinger of doom before coming in to destroy little girls like her.

Tonight was Halloween night, so Linda had ready a bag of candy to dole out to trick or treaters who knocked on her door. When she heard the first knock, she opened the door and saw two little children, one dressed as a witch and the other dressed as a ghost.

Linda grimaced, tossed the kids some candy, and quickly shut the door. Even the sight of a little kid in a ghost costume was enough to distress Linda, and remind her of her scared days as a young girl lying in her dark bed while the strange knocking occurred above her.

Linda decided to watch some television. As it was Halloween, the channels were full of horror movies, but Linda couldn't stand to watch such fare. She settled on a nice romantic comedy.

After watching it for almost two hours, she suddenly saw something strange on her TV screen. It was a ghostly, eerie face, with its eyes and mouth open in a horrifying expression.

The face spoke some words in an eerie, creepy voice. The voice said, “We are here,” but the words were dragged out in a deep, spooky, slow-motion:

“Wwwwweeeeeeeeeee aaaaaaarrrrrrrrrrreeeeeee hhhhhheeeeerrrrreeeeeee.”

Linda was upset by this creepy sight, and she changed the channel. But on the channel she changed to, she saw the same face. She kept changing the channel, but on every channel there was the same face. And on every channel, the voice was saying the same words, in the same deep, spooky, slow-motion voice:

“Wwwwweeeeeeeeeee aaaaaaarrrrrrrrrrreeeeeee hhhhhheeeeerrrrreeeeeee.”

Linda turned off the television. Some cable programmer's idea of a Halloween joke, she thought. I'm gonna give those clowns an earful.

Linda went to her laptop computer, and decided to check her email. She saw there were ten email messages for her, each with a Subject of “We are here.” She opened up one of the messages, and saw the message had a photo attachment showing the same ghostly, eerie face she had seen on the television. The body of each email message repeated the same sentence ten times: we are here.

Linda felt a pang of dread building up inside her mind. She decided to call her boyfriend. She picked up her smartphone, and tried to begin dialing.

But then she saw a face appear on her smartphone screen. It was the same ghostly, eerie face she had seen before on her television. The face was saying the same words, in the same deep, spooky, slow-motion voice:

“Wwwwweeeeeeeeeee aaaaaaarrrrrrrrrrreeeeeee hhhhhheeeeerrrrreeeeeee.”

Linda turned off the smartphone.

“God, no!” she said. “A ghost! It's everywhere!”

Linda's boyfriend lived seven blocks away, and she wanted to go to him for comfort. But it was night, and she was too terrified to go outside in her current state of fear. So she jumped in her bed, pulled the covers over her head, and tried hard to get to sleep.

The next morning, she woke up and went to her boyfriend to tell him about what had happened.

“There was a ghost in my apartment!” Linda explained. “On my television. On all the channels. In my emails. And even in my smartphone.”

“The same thing happened to everyone all over the world,” explained Tim, Linda's boyfriend. “But that eerie face is not a ghost. It's an alien.”

“An alien?” said Linda.

“Yesterday astronomers detected that a giant extraterrestrial spaceship had entered the solar system,” explained Tim. “They came from the stars; they are visitors from another solar system. They started contacting us yesterday, on all of our media. Radio, television, email, even smartphone operating systems. So far they have only one message: we are here.”

“I was so afraid,” said Linda. “I guess there's nothing to worry about now.”

“Sure,” said Tim. “Instead of worrying that some ghost will say 'Boo,' all we have to worry about is that some creepy alien beings will now conquer us or enslave us.”

A New Space-based Plan to Minimize the Risk of Human Extinction

As discussed in my previous blog post Flavors of Doom: 11 Variations on the Apocalypse, mankind faces numerous risks to its survival. There is the threat of nuclear war, the threat of an asteroid collision, the threat of global warming, and the threat of a microbe that could wipe out all of us. There are also other more remote threats such as the threat that the Yellowstone volcano system may erupt in a way that might cover much of North American in ash, and leave human survival doubtful.

Many thinkers have long recognized that moving out into space offers a potential for lessening the risk that man may one day become extinct. The idea is that if we can create colonies in outer space, mankind will not have “all our eggs in one basket.” But discussion of space colonization tends to quickly become grandiose. People talk about colonizing a planet around another solar system (something that is very far in the future at best), or talk about terraforming Mars (which would take many decades). In this post I will take a very different approach. I will describe a new relatively low cost space-based plan to minimize the risk of human extinction, a plan that could be launched using only currently existing technology (with the possible addition of a few rather modest technical advances).

Recolonization Stations

At the heart of this plan is what I will call a recolonization station. A recolonization station is a space station that is capable of recolonizing planet Earth (re-establishing human life on it) after some disaster has wiped out all human life on it. About 30 people might live in each of these recolonization stations. A recolonization station might look something like the station depicted below. The flat gray surfaces are solar panels, which would provide energy for the station.

This is mainly the classic ring-shaped design for a space station. The station is ring-shaped so that it can be rotated to produce artificial gravity for the people living in it, using simple centrifugal force. It requires no new technology to produce such an artificial gravity. Space station designers back way back in the 1950's realized that a simple ring-shaped space station would produce artificial gravity if it were rotated.

The main thing that is different about this space station are the three transport devices positioned at 3 points on the ring. These 3 devices are what I will call recolonization modules. Each recolonization module consists of a recolonization capsule designed to re-enter into the upper atmosphere, and a modest rocket unit designed to take the capsule from the space station to the upper atmosphere of the earth.

Ideally a recolonization station would be a closed system that would completely recycle all of its wastes, allowing the station to exist indefinitely with no need for new supplies sent from Earth. But something less than perfect recycling would probably be acceptable, because the station would probably still serve its purpose if it did not last independently for more than 50 years.

During any time in which human civilization was still fairly healthy on our planet, a recolonization station could be visited by spacecraft from Earth at intervals of once a year or once every two years, during missions that would restock its supplies and rotate its crew.

Handling a Threat of Human Extinction

In the case of a drastic decline of the human population, there might be no more resupply trips. Then the job of the recolonization station would be to survive as long as it could, sending its recolonization capsules only when there seemed to be no more human life (or very little human life) left on our planet. The recolonization station would need to have a good telescope capable of scanning the surface below for signs of human activity.

So, for example, here is one hypothetical timeline: a recolonization station is launched in 2030; it receives annual supply visits for 20 years until 2050; in 2050, a biological plague starts to wipe out mankind; after 30 years all humans are dead; then in 2085 the recolonization station (which existed independently for 35 years without being resupplied) finally decides there is no sign of human life below, and then launches its three recolonization capsules in an attempt to recolonize Earth.

The recolonization station would work well under this type of “rapid human collapse” scenario, but might not work well under a scenario involving a very long and slow decline and extinction of mankind.

The station's requirement for success can be symbolically described like this:

L > T

where L is the maximum length of time that the recolonization station could exist with dozens of crew members without being resupplied, and T is the length of time between the last time the station is supplied, and the time when human life no longer exists on Earth.

Admittedly there are many hypothetical cases under which this L might not exceed this T, but there are many cases in which it would. As the recolonization stations are a relatively inexpensive form of survival insurance for mankind, we need not worry too much about the fact that they won't work in every scenario. As the saying goes, some insurance is better than no insurance.

Recolonizing Earth

The recolonization capsules would be launched from the recolonization station in the event that human life had perished on Earth. Each recolonization capsule might carry about ten human beings, along with tools, seeds, and equipment needed for those humans to survive and begin reproducing once they arrived on the planet. The capsules would use parachutes to make sure they touched down safely on land or water. The Soviet Union often had astronauts return to Earth in capsules that used parachutes to land gently on firm ground. The entire population of the recolonization station (about 30 people) would be transported back to Earth in the three recolonization capsules, at which point the recolonization station would be abandoned.

The astronauts riding in the recolonization capsules would need to be mainly young and female, to assure that the population of a newly established colony would grow as quickly as possible. An ideal average age would be only about 21 years, to allow for a maximum number of child-bearing years. Such a young population would be possible if certain measures were taken. One such measure would be rotating the crew in the recolonization station (prior to any disaster putting mankind in danger) to assure a young crew. Another such measure might be having the station crew (after some disaster that put mankind in danger) mate onboard the station to add new station crew members who could one day serve as earthly colonists by traveling down to Earth in the recolonization capsules. In the latter case, techniques might be used to assure a great likelihood of female offspring, as the recolonization capsules would need to be populated mostly by young females.

To assure the rapid growth of the newly established colony on the surface of Earth, it would probably be necessary to abandon conventional reproductive habits. There would probably initially be only two or three males among the recolonization capsule crew of ten. After adequate shelter was established, each man would probably need to quickly impregnate three or four consenting females, to assure that the colony started to grow quickly.

To assure adequate genetic variation in the new colony, it might also be necessary for the colony to make use of frozen sperm and possibly also frozen embryos brought with them in the recolonization capsule. Each recolonization station could initially be supplied with a repository of frozen sperm and frozen embryos, consisting of the genetic material of hundreds of carefully selected people. Such a genetic bank (which would not weigh very much) could be split up among the recolonization capsules, and used in the newly established colonies on Earth. This might require sophisticated medical training for the crew, and might require that some sophisticated medical equipment be included in the recolonization capsules. The technology for artificial insemination (and the implant of thawed frozen embryos) has been around for a long time, so this aspect would require no technical breakthrough.

Once they had landed, how could there be shelter for the crew members who landed somewhere on Earth in these recolonization capsules? They could start out by simply living in their capsule. Under most apocalyptic scenarios (such as the death of everyone on Earth because of global warming or a biological plague or a comet collision or a small asteroid collision or nuclear fallout or a super-volcano) there would still be many surviving human houses and buildings all over the globe. So the most likely way for the crew to acquire shelter would simply be to find a previously built building, and make use of that. Only the most extreme apocalyptic event (such as the collision of a giant asteroid which buries everything on the planet) would destroy all human buildings.

Each recolonization capsule would also carry with it electronic storage devices that would store a huge amount of useful technical information, as well as a huge number of cultural, historical, and artistic treasures in digital form. We can currently store the equivalent of a 20-volume encyclopedia (including all its pictures) on a single small disk. It would not add much weight to the recolonization capsules to have them include digital archives that included items such as the 1000 greatest books in digital form, the 1000 most useful books in digital form, the 100 greatest movies in digital form, and the 1000 most useful instructional videos on www.youtube.com. Such an archive would help insure that the recolonization capsules would be the seeds of communities that would become technically proficient relatively soon, without having to pass through centuries of “re-inventing the wheel” in a thousand different ways. 

The Relatively Low Cost and High Feasibility of This Plan

Perhaps the main attraction of the plan discussed here is its low cost (compared to other space-based plans), and the fact that it requires few or no technical breakthroughs. The plan could be put in place for a small fraction of the cost of colonizing the moon or terraforming Mars. We already know how to build space stations. Although the International Space Station currently in existence does not have a ring shape that allows for artificial gravity, it would require no big technical leap to construct a station that had such a shape. The technology for re-entry capsules that land with parachutes has been around for decades, and we also have had reproductive technology using frozen embryos and artificial insemination for decades. Probably the one technical advance needed for this plan is additional closed-system and resource recycling technology, which would allow a recolonization station to exist for a few decades independently. But that would be a relatively easy hurdle to jump.

As for the cost of the plan, assuming a somewhat lower cost of space flight because of recent launch vehicle advances, I estimate that several recolonization stations could be built and maintained for an annual cost of about 100 billion dollars (which would need to be shared by the world community). That's a significant cost, but not much of a price tag for helping to insure the continuation of a civilization which has a current net worth estimated at 223 trillion dollars. Any insurance agent will tell you that an insurance rate of a tenth of one percent is a huge bargain (by comparison, homeowners routinely pay an annual charge of about 1 percent for homeowner's insurance).

As for when such a project should be launched, the answer would seem to be: the sooner, the better. If various types of apocalyptic threats were to suddenly arise, it might be too late to get started on recolonization stations that might take 20 years to implement. The safest situation would be to have some recolonization stations already in existence, ready to respond to any existential threat to humanity that rapidly developed.

Click and Transform: A Science Fiction Story

Jack Hooper woke up on a Saturday in the year 2130, and nuzzled against his wife, who was lying in bed with him.

Walking into his kitchen, Jack went his up to his 3D Printer, and printed out a big stack of perfectly cooked pancakes. It only took a minute, and was so much easier than shaking out pancake mix, breaking eggs, adding milk, pouring the batter, and then running a risk of burning one of the pancakes.

Jack decided to go shopping for some new clothes. Jack knew that most of his friends shopped for clothes at home. It was easy. You used your 3D wall screen to select the clothes you wanted. You then pressed a Dress button, and your wall screen showed you exactly how the clothes would look on you if you bought them. If you decided to buy the clothes, you then pressed a Print button, and the clothes would quickly print out on your 3D printer.

But Jack liked to shop for clothes the old fashioned way. He wasn't quite sure why – maybe it was because he liked to touch all the different textures of clothing. There were still a few old-fashioned clothes stores left, and Jack enjoyed going to them.

He got dressed, and walked out towards his black car parked on the street. Jack paused for a second, and stared at the car.

“Nah,” Jack said aloud.

Jack took out a little remote control unit from his pocket, and fiddled with its interface for a while. Then he clicked a little button marked Change.

Suddenly his car transformed itself. The car changed from a box-shaped vehicle to a much more slick and sleek vehicle, and the color changed from black to red.

“Cool,” Jack said calmly.

He jumped in the car, and drove to the clothes store. After buying the clothes, he spread them out on the hood of his car, taking another look at them.

“Nah,” he said.

Jack took out the little remote control unit from his pocket, and fiddled with its interface for a while. Then he clicked a little button marked Change.

The clothes on the hood of the car changed their colors to a new look Jack had selected. Jack then put them into his car, and drove off.

Jack drove back to his house. He parked the car a few houses away. When he approached the house, he took a good look at it, and began to stroke his chin.

“Nah,” he said.

Jack took out the little remote control unit from his pocket, and fiddled with its interface again. Then he clicked a little button marked Change.

Jack's house then transformed its appearance. The shiny steel exterior suddenly became an exterior that looked like elegant redwood. The windows became much larger, and a chimney grew out of the roof. It took only five minutes for this transformation.

“Cool,” said Jack. Gonna enjoy that new fireplace, he thought to himself.

He walked into his house, and saw his wife.

Jack's wife was actually a robot wife. But she had soft flesh that no one could tell was not human flesh. She was also bright, pleasant, and a great cook and housekeeper.

Jack realized that he was tired of making love to the same old dark haired thin woman. He wanted to try a different type of mate. So he took out the remote control from his pocket, and fiddled with its interface. Then he clicked a little button marked Change.

Suddenly Jack's robot wife transformed so that it no longer looked like a thin woman with dark hair. Now it looked liked a younger blonde woman with a much fuller figure.

“Cool,” said Jack. He printed out himself some lunch, and began watching 3D television.

On the television, the news announcer reported the death of a famous person.

“The world mourned the death today of Cyril Rodgers, the inventor of programmable matter,” said the announcer. “Rodger's amazing invention led to the creation of countless thousands of products that can instantly change their appearance, through the wonder of molecular re-materialization. Rodgers' invention transformed our world in countless ways.”

“Duh, tell me about it,” chuckled Jack.

Why You Are Not Living in a Computer Simulation

In 2001 Nick Bostrom created something of a sensation with his provocative paper “Are You Living in a Computer Simulation?” Bostrom argued that super-advanced extraterrestrial civilizations might be able to create computer simulations that mimic the type of experience humans have, and that we might all be living in such a simulation. I would guess that such an idea may have come from the appearance two years earlier of the popular film The Matrix, which depicted people living in a reality that they thought was normal life, but was really just a computer simulation.

I will now discuss some reasons why such a possibility is extremely unlikely.

Reason 1: The technical feasibility of such a simulation is very low.

Bostrom's paper glosses over the many huge technical hurdles of creating a computer simulation in which the end result is many conscious minds who think they are living on a planet when they really are just living in a computer.

Bostrom's first gloss is to ask us to suppose that in his alien-generated simulation of human experience “these simulated people are conscious (as they would be if the simulations were sufficiently fine-grained
and if a certain quite widely accepted position in the philosophy of mind is correct)." We have no idea whether it is actually possible to produce human-like consciousness in a computer, so this is a very questionable assumption.

Bostrom estimates that all of human consciousness could be simulated in a computer that performs between 10³³ and 10³⁶ operations per second. He estimates that an alien civilization could handle this, because it could build a planet-sized computer capable of 10⁴² operations per second. Of course, the idea of a planet-sized computer is very farfetched. We have no experience with any computer a trillionth that size, and there may be all kinds of technical reasons why you can't build a computer even as large as twenty miles in width (such as the fact that the combined heat from all the circuits would cause everything to get messed up, the fact that the speed of light may slow down the communication between internal parts, and the fact that it may be impossible to properly cool a computer of that size).

There is also reason to think that Bostrom has vastly underestimated the required number of operations to simulate our existence in a computer simulation. Bostrom gets his number of between between 10³³ and 10³⁶ operations (for a simulation of all of human consciousness) by naively taking an estimate of the number of operations in the human brain per second, and multiplying that number by the number of humans and the lifespan of a human. But a simulation that allows for free-will and branching possibilities would seem to require vastly more computing power – probably far more than the operations of Bostrom's hypothetical planet-sized computer (or even a star-sized computer).

It requires a relatively small number of bits to display the famous film The Godfather. But imagine a computer generated virtual experience in which you are Michael Corleone, and you can make any choice at any point in the film – you can kill the guy in the restaurant, or kill any other person you see; you can marry the woman in Sicily, or marry any other woman in Sicily, and so forth. Every possible choice involves a combinatorial explosion which vastly and exponentially increases the computer operations needed for a free-choice simulation in which any agent in the simulation can do whatever he wants.

Bostrom seems to have made the mistake of calculating the computing cost of a passive human experience (one in which we are like roller coaster riders without any branching options), rather than computing the infinitely higher cost of a free-will human experience (in which we are like car drivers who can drive anywhere and get out of the car anywhere and interact with people anywhere).

In fact, the likely computing cost of a simulation creating something like the consciousness of all human beings (with complete free will and a full range of choices) would in all probability greatly exceed the maximum capability of a computer that had all of the mass in a solar system (the sun, all the planets, and all the asteroids). And forget about interstellar computers – there is no reason to think that computers spanning multiple solar systems are practical (because of the years it takes for light to travel from one star to another).

It short, it would not be technically feasible to create a computer simulation of all of human consciousness using any technology we can imagine.

Reason 2: Aliens would have no motive to create a computer simulation that consisted of lives like ours, having experiences like we now experience.

The question of motive is one that Bostrom doesn't even address. If extraterrestrials had the ability to create a computer simulation that could include our current experience, why would they go to all the trouble of doing that?

Let's imagine some possible motives. We can imagine a malevolent motive. We can imagine very evil aliens who get pleasure from creating pain for others, like a sick boy who enjoys sticking a lit cigarette on a caged mouse. But our human experience (with usually more pleasure than pain) doesn't correspond to the type of computer simulation that such beings would create, which presumably would be something more like one of Dante's depictions of hell.

Consider the opposite motive. We can imagine benevolent, loving extraterrestrials who create our lives in a computer simulation just so that there can be some more happiness in the universe. But presumably beings with such a motive would create a computer simulation in which there was more pleasure and less pain than we see in human experience.

What about the possibility that we were created in a computer simulation by extraterrestrials who are doing some big experiment, to find something out? This motive also doesn't work. Psychological or sociological experiments would be done by relatively ignorant beings with a whole lot to learn, not by godlike beings powerful enough to create computers the size of planets or suns (such beings would have presumably already learned whatever knowledge might be received from such an experiment).

In short, we have no plausible motive for why extraterrestrials would create a computer simulation consisting of minds like our minds, and lives like our lives.

Reason 3: If we were part of an extraterrestrial computer simulation, we would probably see “realism imperfections” in the simulation that we do not see.

Because of the combinatorial explosion problem described above, the computing cost of a fairly realistic computer simulation of human experience (with less than perfect detail everywhere) would be many, many orders of magnitude less than the computing cost of making such a simulation perfectly realistic, with perfect detail everywhere. So according to the principle that slightly imperfect things (and vastly easier things) should be far more likely than perfect and incredibly difficult things, we should expect that if we were living in a computer simulation, we would occasionally see signs of imperfection in the simulation: what we can call “realism imperfections.”

One can easily imagine the type of things you would be likely to sometimes observe if your life was part of a not-quite-perfect simulation. For example, you might look at a distant point in the sky, but see no further detail when you looked at it again with a telescope much more powerful. Or you might dissect an organism, and find only a featureless mass when you looked inside it, instead of all the realistic details. Or you might go to a randomly selected distant library and start opening books, and find that they had only white pages in them. But we never see anything like such “realism imperfections” in our universe. There are various strange, paranormal things that people sometimes claim to see or experience (UFOs, ghosts, and the like), but nobody sees anything like these types of “realism imperfections.” That's not what would be likely if we lived in a computer simulation.

Moral Issues

The reasons above are good intellectual reasons for not believing that our lives are part of a computer simulation. There is also a powerful moral reason. If you believe that your life is part of a computer generated simulation produced by extraterrestrials, then the logical next step is to suspect that none of your fellow humans exist. Because if the extraterrestrials are simulating in their computers the sky, the ground, the trees, and the rocks that you see, you might as well assume that they are simulating all of the humans (except you) also. This is because doing a computer simulation with just one observer is so much easier than doing a computer simulation with billions of observers. So if you believe in Bostrom's simulation hypothesis, the next stop on the train is the belief that you are the only human that exists. Such a belief (which would give you a license to murder and rape as you please, since you're not really hurting anyone else) is morally suicidal.

In short, the simulation hypothesis is both intellectually untenable and morally disastrous.

Taboo Seductress: A Science Fiction Story

Rod Roberts had a well-earned reputation as the horniest man in the galaxy.

In had started back in the Starflight Academy, where Rod had sweet talked his way into the dormitory room of half of the female star cadets. It had continued during Rod's first tour of duty at Stargate Three, where Rod's amorous exploits had made him something of a living legend.  On the ship to Tau Ceti, Rod had enjoyed many an erotic tryst in tiny cramped places that the ship's designers could never have imagined would allow such activity. Rod had the nickname of the Cosmic Casanova.

But now Rod had a problem. He was stuck on the third planet of Tau Ceti, on a 30-day mission to gather biological samples and mineral samples. He was  part of a landing party of four people, but it consisted only of men. For someone with Rod's raging hormones, this was a temporary hell.

“Me and Jaworski are taking the 4-wheeler to explore to the west,” said Rod's boss Cy Wilson, talking to Rod and another astronaut named Ted Ferello. “We'll be back in a day or two. You guys stay here and gather more samples. And whatever you do, don't make any contact with any intelligent life forms you may come across. We know there are some intelligent beings here, but our policy towards them is non-interference.”

Rod and Ted kept up the job of gathering the life samples and mineral samples. They ate and slept in a landing craft that had taken the astronauts from their interstellar starship to the surface of the planet. On their first night alone in the landing craft, Ted saw something while looking out of the window of the landing craft.

“Look at that!” Ted said. “It's one of this planet's intelligent life forms.”

Rod looked ahead. The creature did not have a monstrous appearance at all. Instead it looked like a woman – a very beautiful woman. The creature had long flowing blonde hair, full red lips, large luminous eyes, abundant breasts and buttocks, and a thin waist.  The creature was scantily clad in a minimal piece of clothing.

Ted started talking about the marvel of convergent evolution on two different planets, but Rod could only think of one thing: how sexy the alien creature was. In situations like this, Rod's libido always trumped his higher thinking processes.

The next day while Ted and Rod were gathering samples, Rod saw the alien woman in the distance. Rod drew closer to the woman. He began to smell an alluring scent, like nothing he had ever smelled before. The woman was smiling at Rod, and she seemed to have a seductive look on her face.

Rod thought for a moment: should I take the risk of defying a taboo, by trying to mate with an alien woman? But then Rod gave into temptation. He was not one to let a taboo come between him and his next sexual conquest.

Rod approached the alien woman and began kissing her. The woman seemed to giggle with delight. One thing led to another, and before long the two of them found themselves lying on the greenish-blue grass of the alien planet, locked in a tight embrace.

At first Rod thought it was the best and most exciting romp he had ever had. 
But then, all of a sudden, the physical bliss turned into physical agony.

Rod pulled away from the woman, and shrieked in pain. The pain was from one particular part of his body. He ran back to the landing craft, looking for
something that would ease his pain.

Jaworski and Wilson returned in the 4-wheeler vehicle, and with great embarrassment Rod explained what happened.

“You idiot!” shouted Wilson. “I told you to stay away from the intelligent life forms here.”

The men got back in the landing craft, and blasted off, returning to the starship that was orbiting the planet. Rod went immediately to the ship's doctor, asking what could be done about his medical problem.

“Pull down your pants, and let me take a look,” said Dr. McKinney.

“How could this have happened?” asked Rod.

“If you had bothered to fully read your briefing book,” said Dr. McKinney, “you would have read about the unusual biology of the intelligent life forms on this planet. During sex the female secretes an acidic liquid from her reproductive organs. It does no harm to the males that the females normally mate with. But that acidic liquid is what has put you in the sorry shape you are now in.”

“Can't you fix it?” asked Rod.

“No,” said Dr. McKinney. “The acid zapped you between your legs. Look at how burned and damaged that thing is. We'll have to amputate it.”

“Amputate it?” said Rod. “No, no, anything but that!”
---------------------------------------------

Jaworski and Wilson sat glumly in the starship's main cafe.

“It's a pity about Rod,” said Wilson. “He's like a bird who had his wings cut off.”

But Rod then came into the cafe, grinning from ear to ear.

“I thought they had to do that surgery,” said Jaworski, surprised. “You know – the last surgery in the world any man wants.”

“They did it,” said Rod. “Snip and cut. But with the wonders of stem cell technology, the doctor grew me a new one in the lab, and attached it to my body.”

“So you're as good as new?” said Wilson. “The Cosmic Casanova is back in business?”

“Not only that,” said Rod smiling happily, “while the doc was growing me a new one, he made mine three inches longer.”

The Significance of an Accelerating Universe

A few years back scientists made a surprising discovery: the finding that the expansion of the universe is accelerating. This came as quite a surprise, because before this cosmic acceleration was discovered, not many cosmologists predicted that the expansion of the universe was speeding up. Most scientists thought before that the expansion of the universe was either occurring at an unchanged rate, or that it was possibly slowing down. The discovery that the expansion of the universe is accelerating resulted in the Nobel Prize in Physics in 2011 for Saul Perlmutter, Brian P. Schmidt, and Adam G. Riess.

There have been many articles and news stories about the acceleration of the universe's expansion, but fairly little analysis about the meaning or significance of this finding. A Google search on 10/23/2013 for the exact phrase “significance of cosmic acceleration” produces zero matches, as does a Google search for the exact phrase “significance of an accelerating universe.” Let's have a try at discussing the significance of this finding, and to do that we must look at the concept of a cyclical universe.

A cyclical universe theory is one that says that the universe passes through a series of phases or cycles, with each cycle being repeated over and over again. Depending on the theory, each cycle may last billions or trillions of years.

The main theory of a cyclical universe which prevailed around 1985 was the theory of an oscillating universe. To understand this theory, you must understand the concept of critical density. Scientists have long said that if the density of the universe in mass-energy is less than a particular density called the critical density, the universe will keep expanding. But if the density of the universe is greater than this critical density, the universe's expansion will one day slow down and then reverse. If that were to happen, the expansion of the universe (in which the distance between galaxies increases) would turn into a contraction of the universe (in which the distance between galaxies decreases). At the end of the period of contraction would be a Big Crunch in which all of the universe ends up crunched together in a very dense state.

The theory of an oscillating universe held that the universe's density was less than this critical density, and that the current expansion of the universe would one day slow down because of a gravitational attraction of the universe's mass-energy. The theory maintained that at some time billions of years in the future, the universe's expansion would turn into contraction, at which point galaxies would then start moving closer towards each other. The theory maintained that this contraction would eventually result in a Big Crunch that would consist of all the matter in the universe collapsing into a hot dense state (kind of a Big Bang in reverse).

But this theory of an oscillating universe did not maintain that this cycle of a Big Bang followed by Big Crunch would happen just once. The theory maintained that this cycle had been occurring forever, and would continue to occur forever.

If you were to express this theory of an oscillating universe as a piece of computer programming code, it would look like the loop below. The loop is what they call an endless loop, one that repeats endlessly (because 8 is always greater than 7).

While 8 > 7

      Big Bang();

      CosmicExpansion();

      CosmicContraction();

      BigCrunch();

End Loop

The theory of an oscillating universe is shown in the diagram below. Each of the semicircles is one of the imagined cycles of expansion and contraction. Each cycle begins with a Big Bang and ends with a Big Crunch. The red line shows the actual observed expansion.

The theory of an oscillating universe was very attractive to many people, because if it were true, it would eliminate the difficulty of explaining the Big Bang. Rather than being a strange one-of-a-kind event (with possible theological implications), the Big Bang would become just a “routine” event that had happened an infinite number of times before.

But even before the acceleration of the universe's expansion was discovered, there were big problems with this theory of an oscillating universe. One huge problem was that there was no good theoretical basis for predicting that a Big Crunch would produce a Big Bang – instead the more likely result would just be that a Big Crunch would cause everything in the universe to end up in a black hole or black holes. Another problem was that entropy would increase in each cycle of an oscillating universe. So instead of there being a possibility of an infinite number of cycles, there could actually only have been a few cycles of an oscillating universe. A cyclical theory that only allows for a few previous cycles is defeating its own rationale of avoiding problems of a beginning.

Despite these problems, many scientists clung to the theory of an oscillating universe, hoping that it would be confirmed. But the discovery of the acceleration of the universe's expansion has put the final nail in the coffin of the theory of an oscillating universe. Because the universe's expansion is accelerating, there will be no Big Crunch. The distance between galaxies will just continue to grow more and more.

Hence the discovery of the acceleration of the universe's expansion has wiped out the most popular theory of a cyclical universe. There has not emerged any widely held theory of a cyclical universe to replace the theory of an oscillating universe. The only remaining theories of a cyclical universe are basically ornate speculative edifices advanced by a single theorist, or a single theorist and a handful of colleagues. None of these theories has gained much traction, partially because none of them have the simplicity of the theory of an oscillating universe.

Anyone trying to come up with a theory of a cyclical universe has the deck stacked against him. You have the Big Bang, the unexplained one-of-a-kind event beginning the universe. You have the Second Law of Thermodynamics, which tells us entropy always increases over long time periods, and the fact that the current entropy level in the universe is vastly lower than it would be if the universe were many times older than 13 billion years. You have the acceleration of the universe's expansion, which tells us that there will be no further opportunities for an event like the Big Bang, when everything was densely packed. These are not facts that lend credence to any cyclical theory of a universe. Nature seems to be screaming at us that the universe is not eternal and cyclical, and it requires a huge amount of speculative imagination to come up with any theory that drowns out that message.

This, then, is the real significance of an accelerating universe. Its significance is that it indicates that we are living not in a cyclical cosmos, but instead the first and last edition of our universe.

Slavery, Version 2.0: A Science Fiction Story

Jill Bolton had made some bad mistakes in her young life which had begun in the year 2015. Jill had borrowed lots of money to go to a pricey liberal arts college.  Not able to decide on a career path, she had majored in history, a subject she found interesting. After graduating with a bachelor's degree, she was unable to find a job. It seemed no one wanted to hire a history major. She ended up taking on and off jobs as a waitress to help pay the rent.

But Jill had borrowed $60,000 to pay for college, and the interest rate was high. As Jill was only able to pay a tiny amount of the loan, the amount that was due kept growing higher and higher.  Jill also charged large amounts on her credit cards to make ends meet. Five years after leaving college, Jill added up her debts, and discovered that she owed a total of $117,890.  Bankruptcy was not an option, because you were not allowed to discharge student debt in bankruptcy, and new laws had made it all but impossible to get rid of credit card debt except by paying it off.

Jill was distraught by her debts. But one day she saw a web ad promising an easy way to get rid of all your debts. Jill filled out  a form online, and after a salesman called, Jill made an appointment to go see someone at a company called New Eon Debt Removal Services, Inc.

Jill arrived at their office, where she met a young man named Donald Black.
Donald promised to remove all of Jill's debts.

“We will destroy your debt!” said Donald enthusiastically. “We will burn it, vaporize it, and nuke it. Just sign right here, and your debt will be vanished history, just like the Roman Empire and the Third Reich.”

Jill was given a contract with lots of small print. The contract was worded in thick, confusing legalese which was hard to read and understand. Buried somewhere in the contract was the phrase “agree to an indefinite period of servitude,” but Jill didn't bother to read every word in the contract. She just trusted Donald, and signed the contract, after briefly skimming over it.

“Congratulations,” said Donald. “You are now a slave.”

“Very funny,” said Jill in a chilly tone of voice. “You shouldn't joke about things like that.”

“I'm not joking,” said Donald honestly. “I mean you are now quite literally a slave. You just signed an agreement renouncing all of your legal rights. You agreed to an indefinite period of servitude. That means you agreed to become a slave.”

Donald took out a donut-shaped electronic collar out of his desk, and snapped it around Jill's neck. It was a type of collar that couldn't be taken off by someone once it had snapped around the neck.

“What the hell are you doing?” said Jill. “I'm getting out of here.”

She tried to leave, but as she reached the door, she felt an excruciating pain. She looked back at Donald, who was holding a remote control.

“We now control you, through that electronic collar I put on your neck,” said Donald. “Wherever you go, we'll know where you are. You won't be able to take the collar off. If I want to punish you, I just press this button, and you will feel the worst pain you've ever felt.”

“You pig,” said Jill. “I'll scream bloody murder. You won't get away with this.”

“Scream all you want,” said Donald. “It won't get you anywhere, because what we are doing is perfectly legal. Haven't you been following the news? Didn't you see all those news stories with titles like 'The New Slavery'? The corporations who control the country got the government to repeal the Thirteenth Amendment. Slavery is as legal as paying your income taxes.”

Jill was taken to a Slaves Orientation Center, where she was briefed on the new life she would face.

“Okay, newbies, life has dropped you at the bottom of the barrel,” said a harsh slave master named Andrew. “Those of you who are men will be shipped out to work underground at the shale oil sites. It's a dirty, exhausting job, but you'll get used to it.”

“Those of you who are women will be working as sex slaves, as part of the new Brothels division of the corporation,” Andrew continued. “Every day, buses filled with men will arrive, and then you have to do whatever they tell you. You'll have to put up with all kinds of disgusting stuff, but at least you'll have a good chance to rest when it's all over.”

“Don't try running away,” said Andrew, “or we'll just send an electronic signal that will cause your collar to zap you with the worst pain you've ever felt. And remember: once a slave, always a slave.”

Jill fumed. How could she have got herself into this mess? But while she was being trained as a sex slave, Jill got a lucky break.

Four men stormed into the Slaves Orientation Center, armed with shotguns. They had electronic devices that they used to disable the slave collars of all of the sex slaves, including Jill. They used another device to take the collars off of all the women.

“We are the Sons of Freedom,” said one of the men. “We have sworn to free every slave we can find.” 

“Thank you for saving me,” said Jill. “What is your name?”

“The name's Brown,” said the slave freer. “John Brown.”

Will Robots Make Us Sissies?

The period between 1870 and 1910 was a great age for rugged American masculinity. It was the age of the cowboys and the conquest of the American west, when a man might spend several hours on a horse, and spend most of the day wearing a holster with a gun, a period when a hungry guy might shoot himself a rabbit for lunch.  Perhaps the most representative figure of the age was the ultra-masculine Theodore Roosevelt, a guy who would have easily won a fistfight with any American president who came after him.  But a few decades in the future, we may have a very different type of age. It may be a pampered, prissy, pinker era in which most of the more masculine activities are not done by men but by robots.

Let's look at activities that we strongly associate with masculinity. One of them is fighting. Today we lionize the American fighting man who risks his life in combat. But we are already starting to replace the manned air force with robotic drones. So instead of a manly Top Gun dropping bombs from a plane while dodging enemy gun fire, it's more and more a guy sitting in a comfy headquarters sipping a latte while he controls a drone thousands of miles away. After a few decades, most ground troops may be replaced by fighting robots.  Once that happens, joining the military may not be regarded as any more manly a career choice than, say, becoming an office manager.

Another masculine activity is driving a car. In modern times the iconic image of the rugged cowboy sitting on his horse has been replaced by the image of the modern man sitting behind the wheel of his car, preferably a slick shiny  convertible which growls like a tiger when you are revving the engine. In the movies the masculine guy is always behind the wheel, and his less masculine friend is always sitting in the back seat.  But in the future none of us may be the drivers. Google and other companies are working on self-driving cars. Once they are introduced they may soon become a universal standard. Politicians could easily ask: why are we losing 30,000 people per year in auto accidents because of fallible human drivers? There could then be a phase-out of all human-controlled vehicles, with robotic self-driving cars replacing them.  By 2070 the masculine guy behind the wheel may be a thing of the past.

Another masculine activity is manual labor. It looks manly when you dig a ditch, shovel snow or move a big heavy object. But after a few decades all such work may become the job of robots. We can imagine a conversation of the year 2075:

Joe: I'll move this big heavy thing myself.
Dave: You're not actually going to lift that thing, are you? Be sensible, and ask our robot to do it.

Another masculine thing is risk taking that puts a person in danger. Nothing seems more masculine than an astronaut who blasts off into space on a risky space mission,  a rock-climber who scales a cliff, or a motorcyclist who makes a daring jump. But such activities may become rare in the future because of an expansion of the human lifespan caused by the smallest type of robots: nanobots.

Technological visionaries such as Ray Kurzweil predict that in the future doctors will be able to inject us with microscopic robots called nanobots that travel through our body, repairing our cell damage, rejuvenating our cells, and cleaning out our cell wastes. The result will be much longer lifespans.

Today a person who puts himself in danger may reason: at worst I'll only lose a few crummy decades of life. But imagine if nanobots extend our potential lifespans to many centuries. Then each time a person considers doing a risky thing, he may say to himself: this may cost me centuries of life. The result may be a great decline in any type of manly, macho risk-taking such as mountain climbing, parachute jumping, deep sea diving, and risky space pioneering.

In short, robots may lead mankind to a prissy, pampered, pinker era.    
  

Man of the Future?

Summaries of 50 Science Fiction Stories, With Links

You can access dozens of illustrated science fiction stories on this site by browsing through the story titles. But some people find it easier to select stories that interest them by looking through a list of story plot summaries. For the benefit of such people, I have compiled the list below. If you find a story that interests you, just click on the link to read the story.  You are guaranteed NOT to be annoyed by any advertisements or pop-ups.

• Long after Earth's cities are wrecked and covered in moss, alien visitors find one surviving remnant of American culture. Link.
  
• A woman on a slow-moving spaceship is the thirty-seventh clone of a woman who once lived thirty-seven lifetimes ago on Earth. Link.
  
• A future surveillance state requires everyone to wear electronic headbands that will help control behavior and monitor everyone's activities. Link.
  
• A man raises his IQ to be nine times higher than the average human intelligence. Link.
  
• An Olympic competitor mysteriously displays superhuman athletic abilities. Link.
  
• Astronauts find a planet offering boundless riches of sensual pleasure. Link.
  
• The rich flee to comfortable refuges in remote locations after civilization collapses. Link.
  
• The emperor of a dying solar system vows to become the one person who will survive the calamity. Link.
  
• Extraterrestrials try to conquer our planet by getting us all addicted to something more pleasurable than sex or heroin. Link.
  
• A husband and wife decide to electronically link their brains, so that they can always read each others' minds. Link.
  
• After man becomes extinct, robots live on, basing their way of life on our old television shows. Link.
  
• A little boy becomes the only one on our planet who can figure out a puzzle left by alien visitors from the stars. Link.
  
• A man freezes himself for decades, hoping that he will be a rich man when he defrosts. Link.
  
• A group of friends on another planet vow to walk on all the moons they can see in their sky. Link.
  
• Extraterrestrial visitors start to terraform Mars, making it become more earth-like. Link.
  
• An old man becomes young again, and gets a shocking surprise after he starts dating again. Link.
  
• An environmental disaster requires everyone on the planet to make a ridiculous-looking modification in their appearance. Link.
  
• Turmoil and tension erupts after astronauts from one planet find that the beings on their sister planet are superior in every way. Link.
  
• A man uses the Large Hadron Collider to help him steal loot and store it in another dimension. Link.
  
• When a huge group of protesters protests unemployment caused by robots, the sky above them becomes filled with menacing drones. Link.
  
• When a starlet uses stem cells to turn back the clock, she gets a nasty surprise at the Academy Award ceremony. Link.
  
• A country threatens the United States with a dark energy bomb vastly more powerful than a hydrogen bomb. Link.
  
• Astronauts from Earth discover the secrets of the eons from immortals on a distant planet. Link.
  
• The mother of the last family on Earth finds it necessary to tell a comforting lie to her son. Link.
  
• After global warming worsens, illegal immigrants flee a hot dusty United States trying to get to a green temperate Canada. Link.
  
• A superintelligent young boy faces bullying from the kids at his school. Link.
  
• A church of the future uses fancy technology to fleece the faithful. Link.
  
• A society of the twenty-second century prohibits all males from the island it controls. Link.
  
• A small group of trillionaires divide up the world's riches for themselves. Link.
  
• Almost everyone in the US uses a personable computer interface, making it the perfect target for foreign subversion. Link.
  
• An opponent of modern technology lets loose an amnesia plague, causing millions to lose their memories. Link.
  
• A young girl is puzzled by why everyone suddenly looks hideously ugly. Link.
  
• A daughter suspects that her father has been replaced by a sinister android. Link.
  
• A bloodless war of robots breaks out between the United States and Europe. Link.
  
• On an arid alien planet, a young man goes on a quest to find out if there is any truth to the legendary things called rain and clouds. Link.
  
• A gold-digging wife is frustrated when her very rich and very old husband uses high technology to extend his life far beyond his expected time of death. Link.
  
• Long after a passing rogue planet yanks Earth into a new orbit, a group of men explore a Manhattan buried underneath a glacier. Link.
  
• A woman defies a future society of immortals that bans parenthood. Link.
  
• Noticing that his mother's body below the neck looks newly young, a son suspects his mother of a horrible futuristic crime. Link.
  
• A person on a low-gravity planet performs a set of heroic deeds impossible on a planet like ours. Link.
  
• Two earthly nations use space-time wormholes as weapons against each other, fighting the weirdest war ever. Link.
  
• A young woman with superhuman intelligence is criticized by her fellow geniuses for falling in love with a man of normal intelligence. Link.
  
• A young man in a space colony orbiting Earth develops a plan to return to the planet that humans abandoned long ago. Link.
  
• Scientists unfreeze life frozen at the bottom of an Antarctic lake, unleashing a plague from millions of years ago. Link.
  
• A woman finds that powers high in the US government have used high technology to alter her memory. Link.
  
• A person devises an ingenious plan that will let people on his planet see the stars for the first time. Link.
  
• A collapsing volcano in the Canary Islands causes a super-tsunami that puts New York City underwater. Link.
  
• A man discovers that the woman he wanted to marry is being electronically controlled by another person. Link.
  
• After robots take over the world, humans are confined to pleasurable concentration camps. Link.
  
• The government offers a plan to freeze old people until a future age when they can be revived. Link.
  

The Rare Colonization Hypothesis

Here is a stock argument for the rareness or uniqueness of mankind in our galaxy: if an extraterrestrial civilization were to arise on another planet, it might destroy itself soon after developing atomic weapons; but if it were to survive long enough to develop interstellar travel, it would then spread throughout the galaxy. But no such civilization has come and taken over our planet. So extraterrestrial civilizations must be very rare in our galaxy. Perhaps we are the only civilization in our galaxy.

This argument involves a great fallacy. The fallacy is assuming that a successful extraterrestrial civilization would be likely to spread throughout the galaxy once it was advanced enough to do interstellar travel. There is no reason to think that such a thing would occur. In fact, it may be more likely that any extraterrestrial civilization would either confine itself to its own solar system or only colonize a few nearby stars.

I will call this thesis the Rare Colonization Hypothesis.  I may state the hypothesis as follows: the average extraterrestrial civilization capable of interstellar travel is likely to colonize no more than a small number of other solar systems.

Alien Rejecting Interstellar Colonization Plan

The Difficulty of Interstellar Travel

The main reason for adopting the Rare Colonization Hypothesis is the fact that judging from what we currently know about the laws of nature, interstellar travel is incredibly slow  and difficult.  According to Einstein's Special Theory of Relativity (which is currently regarded as established fact), it is quite impossible to travel faster than the speed of light.  Outside of dense star clusters (where the heavy metals needed for life are not very common), the average distance between stars is about five light years.  This means that even if you built the fastest space ship capable of traveling to another star, it would take you at least five years to get there.

In fact, there are astronautical and engineering reasons why it may well be impossible for any spaceship with living creatures to travel at more than 10% or 20% of the speed of light.  One reason is the need to gradually accelerate a spaceship without creating too high a g-force for the spaceship crew. Another reason is the need to gradually decelerate the spaceship so that it would not zoom too fast into any solar system it was visiting.  Another reason is that the more fuel you take along in the spaceship, the more energy it requires to accelerate the spaceship to a high speed. While there are proposals for starships that scoop up hydrogen between the stars, they don't result in speeds that are a high fraction of the speed of light.

There are all kinds of exotic proposals for faster-than-light travel involving wormholes and space warps, but they all assume that nature has a giant gift waiting for us to discover, a gift that will allow us to cheat on the law of nature saying nothing can travel faster than light. Since we haven't found that gift yet, we should assume that it probably isn't there.  Your mother may have hidden $10,000 in bearer bonds under your mattress, but until you see them, you should assume they aren't there.

It is certainly possible that interstellar colonization could by done by using robots or suspended animation of a human crew or a multi-generational world ship. But, unless there is some surprising twist in the laws of physics that makes interstellar travel easy, any mission of interstellar colonization is going to take decades or centuries.

The Comparative Ease of Interstellar Radio Communication

Compared to interstellar travel, interstellar radio communication is very easy. Rather than spending trillions to launch a mission between the stars, a civilization could achieve radio and television communication across the stars for a millionth of the cost.  Any interstellar rocket expedition would not produce any results known to a home planet until decades or centuries in the future, but by building some powerful radio telescopes a civilization might get results immediately.

The relative ease of interstellar radio communication makes it much less likely that civilizations would engage in extensive interstellar colonization. Why spend trillions on dangerous, risky missions between the stars, when you can get knowledge about other civilizations more quickly at a millionth of the cost?

Would There be Some Natural Tendency Leading Extraterrestrials to Colonize Many Stars?

Despite the considerations mentioned above, it is sometimes argued that there is some natural tendency that would lead a civilization to expand aggressively across the stars. It is sometimes said that humans have a natural tendency to spread their genes to as many distant places as they can.  Some others argue that there is a natural human tendency to conquer everything that we can conquer. Therefore, it is argued, we should assume that alien civilizations should have a similar tendency.

But these imagined characteristics of humanity don't really exist to any extent sufficient to justify such assumptions about alien civilizations.

Do human being beings have any natural tendency to spread their genes to as many distant places as possible? Very few people actually show any such tendency.  Many millions of  young men have the opportunity in today's world to travel around the world, impregnating women around the globe, and spreading their genes all over the planet. Very few men do any such thing. For example, it is very rare to read about a man who has one daughter in Africa, another daughter in China, a son in South America, and another son in the United States.  It is therefore false to imply that we have a natural tendency to spread our genes to as many distant places as we can.

What about the supposed human lust for territorial conquest? Very few humans have actually shown any interest in controlling very distant territories. Even if one looks at the most aggressive conquerors in history, one virtually always sees only people interested in conquering neighboring countries. Even Adolf Hitler seems to have shown no serious interest in conquering anything outside of Europe.

Do we see much in the way of human lust for conquering or colonizing worlds beyond our planet? Consider these facts:

    Time when humans first landed on the moon: 44 years ago
    Number of humans currently on the moon: 0

We actually see fairly little desire in humans for colonizing other worlds or spreading our genes to every distant place we can put them. So there is no reason to assume that extraterrestrials would have such a tendency.

Colonization Not Needed for Worlds to Explore

Here is another reason for thinking that interstellar colonization may be rare:  any civilization capable of colonizing another star would have computer technology and virtual reality technology so advanced that it could create a huge number of breathtaking virtual worlds offering endless opportunities for virtual adventure and exploration. Imagine something like a video game, but with images as good as you see in the sharpest high-production movie, and with flawless computer-generated AI everywhere. It might be hard to get anyone to sign up for a long, risky interstellar expedition, when a person could satisfy all his lust for exploration and adventure and beauty in virtual worlds in his living room.  

Diminishing Returns from Interstellar Colonization

When colonization has occurred in human history, it has usually been because the country launching the colonies was gaining clear benefits that made the colonization worthwhile. For example, the Spanish got a steady stream of gold, silver, and crops from their New World colonies which made the colonies worthwhile to the Spanish.

It seems, however, that there would be very little trade benefit to be got from interstellar colonization. The distances are simply too far for trade to be economically viable. Any civilization capable of colonizing other solar systems would have incredibly sophisticated molecular assembly technologies. The cost of sending materials or treasures from another solar system back to another solar system would be many times greater than the cost of synthesizing such products on the home planet.

What type of benefit would come from interstellar colonization? There would be a kind of “insurance policy” benefit that would come when a planet created one or two interstellar colonies. The benefit would be that the civilization that created the colony in another solar system would no longer have “all of its eggs in one basket,” and would no longer be in a situation where the destruction of its home planet would mean its extinction.

However, such an “insurance policy” benefit would diminish greatly when a planet established its second or third interstellar colony, and this benefit would diminish still further when it created its fifth or sixth interstellar colony. Once any planet existed in two solar systems, it would no longer have a risk of extinction, and would no longer have “all its eggs in one basket.”  There wouldn't be any point in creating a fifth or sixth interstellar colony for an “insurance policy” benefit.

There would also be a diminishing “thrill return” from establishing interstellar colonies beyond the first or second colony in another solar system. It might be terribly exciting to create the first colony on another world, but the home planet would get a much smaller thrill from the creation of additional colonies. I'm reminded of what happened during the first few moon landings:

 Viewer of Televised Apollo 11 Moonwalk: Oh my God! They're walking on the moon!
 Viewer of Televised Apollo 17 Moonwalk: Not another stupid moonwalk! They're  interrupting my regular quiz shows and soap operas!

In short, after a planet created one or two interstellar colonies, there would be a much smaller benefit from creating additional colonies.

The Implausibility of Colonizing Von Neumann Probes

Some people argue that extraterrestrial civilizations would create robotic machines that would go from one solar system to another, always creating mass copies of the original machine. Such machines might then fill up all habitable planets in the galaxy with copies of themselves.

I am tempted to call such a proposal the Dumbest Idea Ever.  Colonizing self-reproducing robot expeditions would be like a cancer on the galaxy. Perhaps the greatest thing about a galaxy such as ours is its diversity, the fact that it presumably allows countless divergent civilizations and life forms and cultures to arise.  The idea of gobbling up all the available planets and filling them with copies of one particular robotic expedition would be like replacing every canvas in the world's museums with copies of one painting.  Any species capable of doing such a thing would presumably be wise enough not to do it.

Conclusion

The theory advanced here (the Rare Colonization Hypothesis) is a plausible hypothesis to help explain why we do not see extraterrestrials in our vicinity. There are other ways of explaining our current non-observation of extraterrestrials. It is quite possible that extraterrestrial colonization occurs very frequently, that there is some huge society of aliens, and that the Earth has been declared a kind of reserve area that is “hands off” for interference or colonization. Such an idea (sometimes called the Zoo Hypothesis) is fairly plausible, but it seems to require that there be some “controlling power” in our galactic vicinity (perhaps some empire or league of planets). The Rare Colonization Hypothesis is simpler and more plausible than this Zoo Hypothesis, because the Rare Colonization Hypothesis does not require any belief in some arrangement or law of conduct that is being followed by our galactic neighbors.  The Rare Colonization Hypothesis simply requires us to believe that extraterrestrial civilizations don't do very often something that is very, very difficult to do: to establish a colony many trillions of miles away.