Many Minds

We egocentric humans have been reluctant to grant that any other creatures have minds like ours. Although that may be partly true—the human mind is the most complex one on Earth—ongoing research is demonstrating that most animals indeed have quite sophisticated minds. In fact, until the last several decades, many people did not believe that animals had a mind at all; but were more like automatons who also had no feelings. We can thank Rene Descartes for this idea, who, in the 17^th century, viewed animals as more like unconscious, stimulus-response machines.

Fortunately,  more and more of the solid barriers we once thought God had erected between us and other creatures are collapsing. For example, many recent clever experiments have demonstrated that animals make and use tools, recognize themselves in mirrors, have a sense of self, use symbolic communication, solve complex problems, and display other complex, cognitive abilities. Charles Darwin was way out in front of the effort to see similarities, when he wrote, “There is no fundamental difference between man and the higher mammals in their mental faculties.”

Despite these similarities in cognitive abilities, there is one barrier that we may never surmount: knowing what it's like to be another creature. Although our minds may work in roughly similar ways, the sensory inputs to minds are often very different. A dog's sense of smell is far greater than mine, so how its brain interprets its world will be heavily swayed by aromas that I am ignorant of. Our worlds will feel different. An eagle's eyes are for more acute than mine, so its visual world will be quite different from mine. Yet neither a dog nor an eagle can count to 10 or build a smart phone, so we likely will never be able to bridge the gap between us, to know what it's like to be the other. We are shut out from each others' imaginations and perceptions.

Current experiments in the field of ethology (animal behavior) are demonstrating that many animals respond to their environment in similar ways that we do. It's only reasonable to assume that they have comparable intentions and feelings. We can see that they also must represent their world internally, but because our senses are so different, we cannot know how it feels to them. Other research has shown that even plants possess sentience of some sort; even they have some kind of mind.

These findings will likely be very relevant, if we some day discover extraterrestrial life. If we can't imagine what it's like to be a bird or a bat on Earth, how will we fare when we meet aliens whose sensory inputs may be exotically different? Like Descartes once thought about dogs and cats, we may not even recognize that alien life possesses a mind, when in fact their minds may make ours appear quite primitive—like an amoeba.

Extraterrestrial Expertise

Regular readers of this blog know by now that I am fascinated by the possibility of life existing on other worlds. The more science learns about the broad spectrum of life here on Earth and some of its extremes, and the more exoplanets we discover, the more likely it seems that we may not be alone in the universe; that Earth is not the sole island of life, because life is so variable and planets are so abundant. This possibility of life elsewhere has captivated humans for millennia. While it remains conjecture, astronomers have embarked upon studies in recent decades that are revealing some fascinating aspects on the issue. 

We are currently engaged in various searches of the heavens, looking for a revelatory piece of evidence that we are not alone. These studies have continually evolved, as our technology has evolved. Most of these efforts have been driven by the technology that we possessed at the time we began them. What I have found fascinating, for example, is that our SETI (search for extraterrestrial intelligence) attempts have always been based upon what we could imagine alien technology might be like at the time these projects were initiated. They later became a bit outdated, as our technology advanced; so the SETI tools were accordingly updated. 

For example, many decades ago we looked into space for telltale flashes of light. Then we imagined that alien species might be sending out electromagnetic signals—radio waves. Recently, as more and more planets have been found (we have now discovered about 5000 exoplanets), some scientists maintain that we should be looking instead for how alien civilizations have altered the atmosphere of their home planets. They may have created biosignatures of gases as we have, such as oxygen and methane. 

Thus much of our search has been based on our guesses of the nature of alien technology that we had at the time. Given that our own technology has rapidly evolved and that extraterrestrial civilizations may be unimaginably advanced—how do we know that our current search methods are even sensible?

A recent question raised by some SETI researchers suggests a different approach. Rather than look for some sort of overt communication signal, might we instead seek what are called “technosignatures?” As life on Earth has evolved, our planet's atmosphere has changed (such as the increase of oxygen and methane mentioned above). Many millions of years ago carbon dioxide was the Earth’s dominant atmospheric gas, which later gave way to oxygen, with increasing touches of methane. As global warming is currently growing, however, carbon dioxide is once again increasing. We may soon be forced to choose to engage in planetary engineering, to control climate heating, since we lack the resolve to cut back on our consumption. Might we possibly be able to observe similar kinds of changes in the atmosphere of exoplanets?

As the field of SETI advances, we will likely continue to update our searches—based upon improved estimates of the possibilities and nature of advanced alien technology. Can we imagine the paths that other civilizations may have followed? If not, we may be looking down the wrong alley and missing the truth of alien technology. It's quite possible, for example, that they long ago decided to change direction, as they realized that their technology was leading them down a destructive blind alley; as we seem to be doing. Maybe they survived by moving other options higher up on their priority list—such as placing harmony and peace above technological advances.

Dismal Discovery

[Notice: The following story is fictional. I confess that I fabricated it. Nonetheless, something like it could happen some day—so maybe the reader could consider it as a science fiction warning to human beings: that they may be blithely headed toward catastrophe.]

In the year 2050 a spacecraft departed Earth for the planet Oasis, which orbits the star Alpha Centauri—a little over four light years distant. Back in 2025 Oasis was discovered, and it created great excitement, because it seemed almost like a twin of Earth. It was about the same size, in the same comfortable temperature zone, and exhibited an atmosphere very similar to Earth's.

Subsequent examinations of Oasis, with new telescopes and analysis tools, confirmed the theory that it was likely to harbor life. Yet no electromagnetic signals or other signs of advanced technology were detected coming from the planet. If life existed on Oasis—and all indicators suggest it might—maybe it was in a more primitive stage, and had not yet evolved very far.

By 2050 the climate of Earth had become very dangerous for its biological inhabitants. Humans had thoughtlessly continued their damaging behavior, until it was too late to rescue the planet from incurring atmospheric tipping points that flipped the environment into severe conditions. It was like returning to a climate situation of millions of years before, when hellish circumstances would have made life miserable for most of Earth’s current animals.

The spacecraft that left Earth in 2050 had no humans aboard, because their presence would have called for a much larger and complex craft—in order to include enough provisions for the 50-year journey. Thus, it was a robotic mission that arrived at Oasis in 2100. It orbited the planet, to confirm the data that had been acquired from Earth (which it did), then sent down a lander, to examine conditions on the ground.

The findings were shocking. Oasis had once been inhabited by technologically advanced beings, but all signs of that developed life had vanished ten million Earth years before. It became obvious that something on Oasis had caused all advanced life to become extinct, and now the only life forms there were extremely simple—and appeared to be once again evolving towards more complex life. Something catastrophic had happened long ago on Oasis.

When these findings were transmitted back to Earth, in 2100, it caused much anguish and soul-searching. Many decades previously, a few cautionary scientists had registered their concern that humans were transforming Earth into a polluted place that could cause many species to expire—including Homo sapiens—and that it would require millions of years for the planet to recover. Conditions on Oasis seemed to substantiate that fear. Was it now too late to rescue Earth and save many of its species—including humans?

If so, the dismal truth that had been shown by Oasis could occur on our precious planet: our damage could be complete and decisive. Earth's life forms could take a ruinous hit, and it would require millions of years for life to recover and begin again. That was devastating news for humans in 2100... they were staring into annihilation. 

For Earth-the-planet, however, the prospect was of minimal threat. The planet had been through several previous extinctions and would endure the current nasty conditions and eventually recover. There were yet hundreds of millions of years over which Earth would continue to evolve—quite likely without presence of destructive Homo sapiens.

Contamination Conundrum

Ever since we began sending humans and spacecraft to some of our solar system’s planets and moons, we've been concerned about the possibility of cross contamination—either contaminating those heavenly bodies with earthly microbes, or returning home from the Moon, after having picked up some alien microorganisms and spreading them around our planet. We note that many kinds of earthly invasive species get transported to new locales on Earth and then subsequently overrun native species, because there is nothing to check their proliferation in their new environment.

Could alien microbes (either from Earth, transported to other bodies, or from space to here) run amok and annihilate native species? This was the plot of H.G. Wells's novel War of the Worlds, which described the impending destruction of humans, until the invading monster Martians fell prey to earthly microbes and expired. The first three NASA astronauts returning from the Moon in 1969 were quarantined for three weeks, until it seemed unlikely they had picked up some Moon bugs.

These experiences have caused NASA to become increasingly concerned about contaminating any possible life on Mars or various solar system moons, where life might be harbored. It would be tragic to discover past life on one of these bodies, only to realize later that we'd inadvertently caused it to become extinct by introducing our germs. The problem has become increasingly challenging, since we've recently found many so-called extremophiles on Earth that have been shown to be able to survive the severe conditions of space, so we now know that we may have been sending invasive bugs throughout the solar system for a few years. 

NASA is fully aware that its past sterilization techniques were far less effective than today's meticulous methods. The Viking spacecraft that landed on Mars in the 1970s were most likely carrying a few Earth microbes, because they were not disinfected as thoroughly as is done today. What is the chance that those landers planted microbes that have had nearly 50 years to multiply and flourish? We are currently conducting quite sophisticated tests on Mars by rovers, to see if life might exist (or did exist) there. Could we possibly end up discovering the presence of our own bugs that have since mutated into Martian species?

But wait: there's also the possibility that all life on Earth originated not on this planet, but on Mars (or even elsewhere). Rocks have been found in Antarctica that were long ago blasted off the surface of Mars by an asteroid impact. They floated through space and were much later captured by Earth's gravity. Some of those Martian rocks appear to have microbial life (although that's controversial) enclosed in them. If so, could Mars have contaminated our planet? Might are we all really Martian immigrants?

Like many results in science—the more we come to know, the more we are shown our ignorance. So we continue looking for life elsewhere. Will we ever find it? If we do, can we be certain it is really alien? It's sort of like the old saying, “We have met the aliens, and they are us!”

Aliens Around Us?

I have posted several times on this blog about the possibility of life existing elsewhere than just on Earth. It's a subject that fascinates me and one for which we inch closer to an answer, each year. One important development in the search is that scientists are increasingly broadening the definition of life. Recent discoveries of strange life forms right here on Earth have pushed scientists to ponder the possibilities of alternative kinds of life. NASA's current definition of life is “a self-sustaining chemical system capable of Darwinian evolution.” That's much broader than the thinking was, just a few years ago.

In fact, some microbiologists have proposed an even broader definition of what they have dubbed “lyfe”—trying to become more open to alien possibilities. Lyfe has been proposed by them to have four qualities: it (1) draws on energy sources in its environment, (2) grows through replication, (3) can adapt to a changing environment, and (4) learns and remembers information that it acquires from that environment. Gone are the former criteria that life must be carbon based or even require liquid water.

Additional open-minded possibilities about lyfe are that—other than on Earth—its pace might be far slower or faster than life forms as we know them; thus making it difficult to even notice that it could be lyfe. Furthermore, could lyfe use energy sources that life does not? For example, bacteria have been discovered in deep Earth mines that do not use the sun's energy, but get their energy from radioactivity. Could there even be something that might be called “sub-lyfe,” which doesn't have to meet all four of the above criteria? Or even “super-lyfe,” which surpasses the four criteria? It's possible, furthermore, that a form of super-lyfe might look upon us humans (and all our fellow Earthly life forms) as we do upon crystals; or viruses, which are a form of not-quite-life, (requiring a living biological cell to invade and hijack its life functions).

When pondering the possibilities of life (or lyfe), other interesting questions come to mind. Are there ways to store information, other than by DNA? Where is the boundary between lyfe and non-lyfe? Must lyfe possess sharp, physical boundaries?

This past July, three missions left Earth for Mars—from China, the United Arab Emirates, and the US. They are all aimed at the next step of characterizing the nature of our fellow planet Mars—one that long ago had oceans and an atmosphere somewhat like Earth. The US and Chinese missions are both landers that will seek signs of current or past life there. Should we redefine their quest as one of looking for lyfe?

For future projects NASA is planning missions to Europa—a moon of Jupiter—and Titan—the largest moon of Saturn—both of which have the best chance of nonEarth life (lyfe?) in our solar system. By opening up to the definition and possibilities of lyfe, those undertakings may be more successful and unambiguous.

SETI Reset—Part 3: Simulation Hypothesis (11/19/19)

There is yet another possibility that might explain why our SETI searches have so far been unsuccessful. The lack of contact could be the result of what’s been dubbed the Simulation Hypothesis, which has been proposed in recent decades. It results from our spectacular advances in computer technology. The basic idea is that our technological innovation seems to be leading towards a point in time when we will be able to create, not only artificial intelligence (AI), but artificial life as well!

This is a bizarre thought that I will attempt to sketch out here, in a simplified form. There is a concept called Moore's Law—which was proposed some 50 years ago by Gordon Moore, a computer geek. It suggests that computer power doubles every couple of years—yielding smaller and smaller computer chips using less and less electrical power. Over recent decades Moore's Law has held. If it continues to hold, we may reach a point, in something like 50-60 years, where our computers will be complex and fast enough that we'll be able to simulate the human brain in the digital world. We already have created deep-learning software programs that have badly beaten the world's human geniuses in chess, Jeopardy!, and Go. The next leap is to mimic the capabilities of the human brain. It's only a matter of time. 

The huge advantage of creating artificial life is that we'd be able to produce and employ an entity as smart—or smarter—than our brain, at a tiny fraction of the required energy. This is due to a byproduct of Moore's Law: as we continue to multiply computing power, it comes at decreasing needs for energy. To keep a human being going requires a lot of energy. We need calories to fuel our big bodies and our brain is an energy hog. If we could develop the equivalent amount of brain power at a tiny fraction of the energy cost, how could we refuse such a bargain?

Our haste to expand computing power also posits an alternative, though much less desirable outcome of our technological race into the future: the strong likelihood that we'll destroy ourselves, before we reach the technological maturity of being able to simulate life. Many philosophers and scientists think that in our headlong rush to develop our technological prowess, we may well make ourselves go extinct. We seem to insist on playing with dangerous machines, with minimal ability to rein ourselves in. We've already perched at the edge of nuclear annihilation, several times.

Thus the Simulation Hypothesis brings up the possibility—if we survive—that we may someday be able to create a non-biological world that will mimic intelligence. It will be contained wholly within the confines of a digital simulation. In fact, what we are convinced is our real biological existence may simply be that we've been living in such a simulated world all along. Those advanced civilizations that SETI is looking for may have arrived long ago and programmed us. We may be nothing more than artificial entities in some highly-intelligent superbeing's game. The movie “The Matrix” suggests such a possibility.

This thought of our living out some kind of virtual digital life seems preposterous to us. Do we not know that we are flesh-and-blood critters? But how do we know that? Some of the sharpest scientific minds have suggested the virtual possibility. Stephen Hawking and Alan Turing pondered it. Plato suggested something similar in his “allegory of the cave,” 2,500 years ago. Nick Bostrom of Oxford University formally presented the Simulation Hypothesis, nearly two decades ago.

Here’s yet another question: If we are not an electronic simulation, but real, flesh-and-blood beings as we think we are, could our current biological existence be just a step on the way to a post-biological type of digital life? That possibility may become proven or denied in just a few decades. Whatever we learn, our current SETI communication attempts may continue to go unanswered, until a deeper understanding arrives. We are yet infants in the advanced technological world. We have a lot to learn and a lot of control to develop, if we wish to stick around to see.

SETI Reset—Part 2

In the last post I began to describe a few possible reasons why our Search for Extraterrestrial Intelligence (SETI) has as yet not found any signals arriving from outer space. Here are a few more suggestions I offer.

(2) Other alien civilizations may not have chosen to pursue a similar technological path as we have. Our technology too often has led to weapons that harm living beings. I can conceive of a civilization deciding to have taken a more sensible and peaceful approach and thus avoided technology’s harmful side effects, by avoiding much of our problematic technical inventions, such as the many types of weapons we’ve created. Would it not have been possible for Earth’s humans to have decided to put its energies into a spiritual society, rather than a high-tech and dangerous existence?

(3) Life may indeed be common out there, but the chances of it progressing beyond a single-celled state to a multi-cellular, more complex phase, may be quite low. Life on this planet stayed at a microbial state for about three billion years, before favorable conditions evolved to allow it to grow large enough to build things like cars and computers. Those propitious conditions were not inevitable. Life on Earth could still today easily be simple, single-celled critters, waiting patiently to grow more complex. 

(4) It took 4.5 billion years for “intelligent” life to evolve on Earth, so there's a low probability that life elsewhere (at the present) is at a similar stage of technological development to us. They may not reach that stage for a few billion years yet, or have long ago passed through it. I say “pass through it,” because an argument can be made that if life is to survive in the long term, it may have to get past dabbling with hazardous technological toys.

And finally, (5) Life anywhere in the universe may be doomed to evolve into a technological stage, after which it inevitably extinguishes itself. We on Earth seem to be headed towards what is often called an “omega point”—a time where we dramatically transform from civilization’s chaotic and exponential path, towards a sustainable way. It may be that that omega point could be the arrival of a completely different kind of intelligent life on Earth… if we survive to that time.

So the search for SETI will go on. We are curious creatures, and we want to know if there are others like us out there. It appears increasingly likely that extraterrestrial life might well exist, given our recent discoveries of extrasolar planets and Earth-bound extremophile-kinds of life. If the discovery of life in the vastness of the universe comes about, it would be an incredible discovery.

We cannot yet travel to the many distant worlds and directly observe life there... and maybe we never will—given the immense distances. So we continue look out there, building receivers to apprehend any EM signals flying through our region of space; which could prove that we are not alone. But is the presence of an “intelligent” species out there really going to be detected only by our reception of a technological signal they emit? Could there be other kinds of contact that we’ve not yet imagined? We'd best keep our minds open.

Next time I will describe yet another, rather weird possibility, for reconsidering the SETI issue… that we may already have been contacted and absorbed into a super intelligent civilization’s domain.

SETI Reset—Part 1

I have been taking an online course on astrobiology from the University of Arizona—where robust astronomical research has been the norm. I have taken a couple of previous courses from the university's astronomy team and appreciate their teaching abilities. This course blends their preeminence in astronomy with some of the latest discoveries of thousands of Earth-like planets around other stars and the potential for these planets to harbor life in some form; maybe similar to Earth.

Here is a question that has repeatedly arisen in the human mind: Is planet Earth alone in the universe at harboring life, or might there be other life-sustaining worlds? Is life common, rare, or nonexistent elsewhere in this cosmos? Does intelligent life exist out there—say, critters as smart as we think we are?

We are getting closer and closer to finding answers to these questions. As I have posted here several times, our search is being aided and abetted by the recent discovery of thousands of planets circling local stars. Without planets, you can't have life elsewhere.

A consistent search process for extraterrestrial life was begun a few decades ago—dubbed SETI—the Search for Extraterrestrial Intelligence. Its premise is that intelligent civilizations “out there” would have reached a technological capability at some point—as we have—and would have transmitted electromagnetic signals (EM) into space; signals that could eventually arrive at Earth. If so, might we receive them and verify that we're not alone? After all, we've been inadvertently transmitting EM signals from our planet for decades. Old TV episodes of “I Love Lucy” are currently flying through interstellar space, just waiting to be captured by some alien technology; maybe to the amusement of otherworldly beings.

So SETI was established decades ago—having been designed to receive some of those alien civilizations' equivalent TV programs, or, hopefully (and more likely) signals consciously sent out to inform beings like us that we're not alone. Yet my online course professor made the point that, although we're searching for outer space life, SETI is not really designed to locate outer-space intelligent life, but to discover extraterrestrial technology that is similar to ours.

We haven’t yet detected a signal, let alone determined the presence of either intelligence or the existence of life elsewhere. At best we currently can register the presence of EM signals that would indicate some sort of advanced technological civilization. One issue in our search for ET that possibly is being dealt with inappropriately is, Would intelligence “out there” display itself anything like what on Earth has evolved?

Furthermore, there is another key question that was posed many decades ago, by a prominent physicist/astronomer: If there are other advanced civilizations in outer space, where are they? Why haven't we already heard from them? This is a troubling question for many cosmologists. Again, we're not yet able to determine if there is or is not intelligence out there—we're asking if they have evolved technologies like ours, and, if so, where are the signals?

I can imagine several reasons why we've yet to capture a signal that we can confidently say came from outer space (and maybe never will): (1) The distances are simply too vast; signals from even the closest stars take many years to reach us; so, were we to detect a more distant signal, it may have been transmitted thousands of years ago. Any signal we might receive could be from a distant past, from a civilization that is no longer even existing. Where might our technology be, in another thousand years? Would our current primitive way of interstellar communication even be useful then? 

Other possibilities next time…

Clandestine Colossus

Recent research conducted over a span of 10 years by 1200 scientists from 52 countries (that's one hell of a collaboration!) has discovered a vast subterranean ecosystem that is almost beyond belief in its size and mass. It is in the form of microbes that likely weigh somewhere between 10 and 25 billion tonnes. That's several hundred times the combined weight of all of us human beings! Just try to wrap your head around the fact that all these tiny, one-celled critters outweigh Homo sapiens several hundred times over—and they are all below the planet's surface, out of sight! We like to believe that we surface creatures are what it's all about, as we walk, swim, and fly across the crust of Earth.

These microbes live in conditions that we deem hostile to life, yet they prosper in extremely hot locations (up to 122^o C or 250^o F, like inside an oven), with no light, under intense pressures, and with minuscule nutrition. Some of their life spans are measured in geologic times, their pace is so slowed down. They are alive and do metabolize, but use such little energy that they live for millennia and appear to be in stasis. Their movement can be measured in centuries—triggered by tectonic plate shifts, earthquakes, or volcanic eruptions. At first glance, they would appear not even to be alive. We already know that microbes—bacteria and archaea—dominate on the Earth's surface, but these findings show that less than 30% of all the planet's microbes live on the surface—the vast majority is hidden.

The scientists who made this discovery did so by creating boreholes up to 5 km (3 miles) deep. The latest types of microscopes were also employed. Since the underground microbes are buried so deeply, they live in a pristine world—as yet uncontaminated by humans. As we foul the planet's surface, they continue to live beyond the reach (so far) of our harmful technologies.

These findings raise some intriguing questions about life on Earth—and possibly elsewhere. Where and how did life begin on our planet? Did it originate at the surface and later migrate downward or did it start at depths and later move upwards? What do we make of critters whose metabolism is so slow that they endure for millennia? Maybe these microbes could be identified by this study as living, because all life on Earth has similar properties and the scientists recognized some familiar features. 
 
What might this discovery say about examining possible life forms on another planet or even moons of our solar system, where life there may be of a very different chemistry or live a much slower existence—so slow that we may not even recognize them as living? If humans continue their reckless ways, the environment on Earth's surface may become unlivable for most species. If that happens, are these underground microbes—this clandestine colossus—waiting to surface one day and reinhabit our planet?

There are undoubtedly many other questions that could arise, as we continue to explore and characterize this vast underground ecosystem. We keep making discoveries that broaden our understanding of the various forms and conditions of life. It is opening us up to possibilities that we recently had no idea existed. What new discoveries await us—here on Earth or out there?

No Phone Home—Part 2

Some SETI researchers have asked an intriguing question: If there are civilizations out there, why haven't we received a message by now? In other words, where are they? Well, a mismatch in technology could well be one reason. How do we get in touch with a civilization that may be thousands of years behind or ahead of us? What chance would intelligent creatures on Mars 2500 years ago have had of talking to the ancient Greeks by EM signals from that planet?

I believe that the lack of contact may be explained in a different way, however: simply due to the vast distances involved. I have written a couple of times on this blog about the enormous distances of stellar space. (As a reminder, one of my analogies was to collapse our solar system into something the size of a basketball. On this scale, the nearest star would be five miles away and the nearest galaxy—Andromeda-- would be 360,000 miles away!) It is a huge challenge for us to fathom the actual interstellar distances. 

For example, Andromeda is 1.5 million light years away. To send and receive an EM signal from any creatures in that closest galaxy would require three million years round trip! That's just too long a time span to “phone home” and wait for an answer.

Thus, there may indeed by “life out there”, but it could likely be just too far away for us ever to discover—let alone communicate with. We indeed may not be alone in the universe, but we may never find that out. The universe is simply too big. Would an ant in my back yard have any chance of finding out about similar critters in the rain forests of Brazil?

Let's face it: Earth and its life forms are but the tiniest blip in the universe—in both time and space. We do not amount to much in the grand scheme of things. We are not the center of the cosmos. We are a flash in the pan that will most likely soon be gone.

I think the more relevant question is: Does it matter whether or not there's life out there? We would love to know, but we may well remain ignorant. It matters to some people, because if we were to discover some kind of civilization beyond Earth, it would surely rattle some cages—especially those which contain anthropocentric people, or people tightly attached to religious beliefs that would have us at the center of it all. It's a fascinating question to ponder, but don't hold your breath for an answer any time soon. Maybe in three million years.

No Phone Home—Part 1

One of humankind's enduring questions is whether or not Earth is alone in the universe in harboring life. Are we the only—and therefore exceedingly special—example of animation in the vast cosmos, or might there be others out there? This very question has evolved as our understanding of the universe has grown. The ancients may have wondered about life existing on the other shore of the sea, and people a couple of hundred years ago speculated on beings living on the Moon and Mars.

Today, however, we know much more about the vastness of the universe (even though we may not be able to wrap our heads around how truly vast it is), so now our imaginations extend way beyond our solar system, even our own galaxy, to the billions of galaxies out there. Yet the same question still poses itself, but the potential territory has gotten immensely greater, and thus the possible answers far more manifold.

We also now know much more about how life may have arisen on Earth and the extreme forms that it can assume here. We know that the presence of humans, along with all the other planet's creatures is the result of a long and torturous path that could have taken countless other directions. Some of those other alternatives could easily have resulted in the final termination of life on Earth (it could have come to a dead end and may still), or brought about life forms quite alien to what we know today.

So back to that perennial question: Is there life out there? What chance is there that it bears any resemblance to Earth's critters? Would we even recognize it as life, if we were to encounter it? More to the point, are the distances so vast that we'd ever encounter it? Movies like “ET” offer us fascinating and bizarre creatures who come to visit, and then “phone home,” to return to their world. But any kind of life out there may be simply too far away for us ever to come in contact with, or simply be unable to phone home, because of the tremendous distances.

And the distances are what matters. Humanity has for a few decades been engaged in space communication efforts, in which various researchers have scanned deep space, looking for electromagnetic (EM) signals that distant civilizations may have broadcast to the universe—signals that announce their existence. These projects are labeled Search for Extraterrestrial Intelligence (SETI). The premise is that distant technological civilizations (if they exist) would likely emit EM transmissions, in an attempt to notify other civilizations of their presence. 
 
But is this assumption justified? The SETI project surmises that distant technological species would choose to send out some kind of “I am here” signal, but is this true? Stephen Hawking wrote that this can be a risky process for Earthlings, if we engage in this game, because some life forms that may be far superior to us could thereby discover we are here and subsequently launch space ships to come and dominate Earth.

Another point to consider is that our SETI projects have evolved dramatically, in the last few decades. As our technology has advanced, we come up with progressively better methods of searching. But the civilizations we hope to contact may be centuries or millennia ahead or behind us. They may have developed communication schemes that we either once rejected or have yet to discover. We may be way out of temporal sync with these creatures and miss connecting, simply because our technologies do not match. It could be analogous to Europeans in the 19^th century looking for radio wave emissions from Tierra del Fuego, when the inhabitants there preferred smoke signals.

More on extraterrestrial life next time...

Anybody Out There?—Part 2

Getting back to intelligent life out there, civilizations on other worlds could be billions of years older than ours, or have yet to develop. If humans have come so incredibly far in a few thousand years, what may have happened on planets where life originated several billion years earlier? If life evolved there anywhere like it did here, we can't begin to imagine how advanced they've become.

And those questions (or speculations, because we yet do not have any evidence that intelligent life has arisen elsewhere) lead yet to another fascinating and significant question: If intelligent life is far ahead of us someplace out there, why have we not yet had it knocking on our earthly door? Where is it? Humans have played with the concept of space travel for at least a couple of hundred years. We've even begun taking baby steps to the Moon and Mars. “Star Trek” and other science fiction tales describe interstellar and intergalactic space travel, but is such travel really possible?

Distances across vasts spans of space are difficult to wrap our heads around. Even at the speed of light—which we may never approach—the length of time required to negotiate these distances is daunting. “Star Trek” engineers could shift the Enterprise into “warp” speeds: faster than light, but those speeds may forever remain fiction.

That said, how about considering an intelligent species on the other side of the galaxy that is a mere million years ahead of us? Couldn't they have reached cosmic speeds and brought transit times down to within maybe hundreds of thousands of years? Or where might we be in space a million years from now? Such transit times are incredibly long, but not beyond the reach of a civilization that may have been around for a few million years.

So where are these intelligent, advanced space travelers? Why haven't we heard by now, if they're so much more developed than we are? Couldn't a super-advanced civilization have spanned the universe by now—or at least the galaxy? Once again there may be no answer to these questions... they may even be the wrong ones to be asking. I'm sure that in another decade or so (a cosmic instant) we'll come up with a better set of questions. Until then, these are the ones we ask.

Some people suggest that the absence of any contact can be explained by the fact that there are no intelligent civilizations out there. Maybe so, but that is no reason to stop looking. What's more, humans were once inclined to believe that we were special, that Earth was the only source of life in the universe. As more and more planets and life possibilities are found, our specialness may not be true.

One rather disturbing answer brought up by some researchers as to why we're still unaware of other intelligent civilizations (if they're out there) is that there might be a limit as to how long a technological civilization can endure. The dinosaurs lasted something like 150 million years. We humans have been around only a couple of hundred thousand years. We have a long way to go, before we demonstrate our longevity. There are many informed prognosticators who raise the possibility that we may not last that much longer. Our technology races forward, with little thought to its dangers, virtually out of control. We tend to do things that we later regret—such as create an atomic bomb or pesticides that are subsequently shown to cause human birth defects and diseases. So far, most of the dumb things we have done have been small and on a local scale, but we are now playing with fire on a planetary scale, via global warming, habitat degradation, nuclear arms, etc. If we keep up our pace, we could render Homo sapiens extinct.

Our extinction is a real possibility. If so, it would terminate Earth's current experiment of evolving “intelligent” life. Of course, not all life forms on our planet would be eradicated—many of them are far tougher and resilient than we are. (Think of ants.) The evolutionary clock for the development of intelligent life on planet Earth would simply be reset. There's at east another billion years or two for the experiment to be rerun, before our sun expands and cooks all life on the planet.

So many questions. So many possibilities. Most are beyond the imagination of our minds. It's an exciting—as well as a sobering—time in our evolution. We are yet infants in the cosmos. We have time to correct our dangerous ways and see where evolution may take us in the far future. It'd be nice if we do, and are able to join other forms of intelligent life in universal kinship.

Addendum

Here's a neat way to get a feeling for the extraordinary length of time the Earth has been around and how short a time we've been here. (The following simile comes from an online course I'm currently taking: “Astronomy: Exploring Time and Space,” from Arizona Sate University, offered by Professor Chris Impey.)

Let a 1,000 page book represent the age of the Earth; thus each page of this massive tome represents 45 million years. Here are a few fascinating facts about this hypothetical book:

• For the first 10-20 pages of the book, no life is present on Earth. It's a barren planet.
• Fish first appear on page 500; half way through the book.
• The dinosaurs become extinct on page 985. (Only 15 more pages to reach to today!)
• Our ape-like ancestors appear halfway down page 1,000.
• Modern humans enter the scene on the book's very last line.
• Everything we humans pride ourselves on, everything from 40,000 year old cave paintings to the recent discovery of the Higgs boson, is contained within that last word on page 1,000.

All of modern humanity's accomplishments are enclosed within the very last word of a 1,000 page book! We humans may consider ourselves the “last word,” but we sure are the Johnny-come-latelies on the planet! I hope that our story does not end there. I hope that we find a way to put out a new edition some day that far exceeds 1,000 pages.

Stalwart Life

Over the last few decades scientists have discovered life thriving in environments that were once considered to be too hostile and barren. For example, dozens of miles under the sea surface, where it's inky black and noxious fumes vent from smoky fumeroles, organisms thrive in water as hot as 200^oF. Deep in underground mines (some 2 ½ miles down), far from the sun and its life-giving rays, microorganisms feed on minerals and soak up heat from radioactivity, in lieu of any photosynthetic processes. In extremely acidic water, near its boiling point (such as in Yellowstone National Park), other organisms prosper. Only a few decades ago scientists would have been convinced that life (as they then knew it) could not survive in such harsh environments.

These discoveries of life's robustness have forced biologists to revise the conditions under which they believe life could survive. The very definitions of what constitutes life and what life requires to take root and thrive have been dramatically amended.

A recent example of another unlikely site for life has been the discovery of robust creatures deep under the Antarctic ice shelves, far from sunlight, in a location that was expected to be dark, cold, and lifeless. After having drilled a half-mile deep hole through the ice shelf, 500 miles inland from the open ocean and that far from any sunlight, researchers found microbes and small fish—in a completely dark location. How did these critters get there? How do they survive? I won't go into the details here, but the scientists were dumbfounded, when they lowered an underwater robot and photographed creatures. It blew their minds.

These recent discoveries have caused scientists to revise their theories about what life requires to survive, as well as to recognize the new kinds of life they've found in these hostile environments. The requirements for life on Earth have been significantly broadened. Maybe life doesn't require water—once thought to be absolutely necessary. Maybe it doesn't require photosynthesis of the sun's energy—which most every life form must have. Maybe it can use the energy and heat emitted by radioactive decay deep underground. Indeed, these are all true.

We are thus expanding our understanding of the extremes under which life can survive. We are getting past our myopic view that life must be very much like us, in order to exist. Microbes have been proven to be incredibly robust. Some have even been attached to the exterior of the International Space Station, where they have been exposed to high radiation, extreme temperature changes, and a total lack of atmosphere for over a year... and they survived!

What fascinates me is the implications that these discoveries have had on our guesses about the existence of extraterrestrial life. Earth offers very cordial conditions for life, compared to the harsh environments found elsewhere. Life thrives on our planet, in countless forms and in many pleasant ecosystems. Until these recent discoveries of life existing in harsh locations, scientists were inclined to discount the possibility of life other than on Earth. Many people thought that our little planet could be the only place in the universe where life arose. This is turning out to be a narrow-minded viewpoint.

Now we are thinking differently. In fact, right here in our solar system life may have gained a toehold in places other than Earth. Mars is looking more and more likely that it may have had life, a few billion years ago. Europa—an ice-covered moon of Jupiter—is thought to harbor an internal ocean of water; in conditions not that much different from Antarctica. Researchers are making plans to visit Europa and run experiments to see if life may be found there. Other moons in our solar system may have conditions where life may be able to survive. Farther out in space, thousands of planets have been discovered orbiting their stars. Preliminary findings suggest that some of them may be conducive to life. Life almost seems simply to be waiting for us to find it.

The existence of extraterrestrial life has, until the last couple of decades, either seemed doubtful or was confined to the realm of science fiction. Humanity is beginning to realize that life just may be abundant in our universe. Stay tuned... the answer may come in another decade or two.

Lunar Life

To date, NASA's Kepler mission has discovered over 1000 planets circling other stars. This is humanity's first confirmation that planets do exist “out there,” and are thus very common in our galaxy. Therefore, we are gaining confidence that life may well be found on planets other than Mother Earth, if even only a tiny fraction of those planets may be inhabitable. (Since we now know there are so many of them, the odds of habitability proportionately increase.)

The discovery of these planets has required the ability to detect incredibly faint changes in the light levels of these stars, such as when a planet passes in front of its star (between us and the star) and ever so slightly (ever so slightly) dims the light that reaches us.

Even so, the incredible-but-still-modest sensitivity of our current instruments has permitted us thus far overwhelmingly to detect giant planets. The instrumentation techniques are getting constantly more refined, so smaller planets—more Earth-sized orbs—are being discovered and more will soon be found; but so far it's primarily large, gaseous planets (like Jupiter and Saturn) we've been able to observe. Life, as we know it, however, could not exist on these giant planets, both because they have no solid surface and because their strong gravity would crush any forms of life.

OK. So we've very recently found over a thousand planets, but for most of them, life is very unlikely to be able to exist. Does that possibly diminish the chances of our finding extraterrestrial life, even though we now have demonstrated that these uninhabitable planets are common? Not necessarily, because these giant planets may well have moons circling them (just as Jupiter and Saturn have dozens of moons), and some of those moons are likely to be Earth-sized, and thus possibly able to harbor life.

Imagine what it might be like living on a moon that is the satellite of a giant planet in some distant solar system. Our Moon offers Earth only one face, because Earth's strong gravity field has forced it to rotate in lock step around us. The Apollo astronauts who walked on the Moon saw the Earth suspended above them, in the same place, Moon day after Moon day.

The same thing would happen if we were to stand on a moon orbiting a giant planet orbiting a star somewhere. One face of this moon would permanently point toward the planet. The planet would be this huge orb filling much of our sky—never changing its position. It would be frozen in our sky. When our star is behind us, it fully lights up the face of the planet (we might call it a “full planet”) and it would bask us in its reflected light. If the planet was purple, we'd be bathed in a purple haze.

When positions change and our star is now behind the giant planet above us, we'd be watching its dark side. In fact, it would appear as this huge black disc in our sky (blocking out the star's light), surrounded by a starry background.

This is just one of many bizarre scenarios that could be found on moons around giant planets elsewhere. Some day humans may arrive at some of these worlds and be able to watch some fascinating celestial sights—quite alien to anything we're used to... whether or not life has greeted us there.

Defining Life

A question that continues to pester science is: What is life? One of my dictionaries offers this definition: “the condition that distinguishes animals and plants from inorganic matter, including the capacity for growth, reproduction, functional activity, and continual change preceding death.” That seems to cover the topic quite well, but it has a problem: it may work well for distinguishing life on this planet, but how about other worlds in space? It also assumes that we know what an animal and a plant is—as well as being able to tell what “functional activity” means; and finally, death. These definitions depend on what we know about life on Earth; leading us to think that we will recognize life elsewhere when we see it, wherever it is.

But as we look out toward other bodies in the universe and wonder if we're alone or not—if life may have emerged elsewhere—could we even recognize it on alien worlds? In recent decades scientists have discovered here on Earth several species of what are now called “extremophiles”: microbes that live in habitats that we once thought were impossible for life; such as next to hot and toxic undersea volcanic vents; highly acidic pools of water; and deep underground locations, far from the sun and any source of plant nutrients. So our definition of life—and the conditions under which it can survive—has had to be widened.

Now we are on the verge of exploring other worlds in our solar system, upon which we know some of these extreme conditions exist: Mars, Jupiter's moon Europa, Saturn's moon Enceladus, and others. Scientists are eager to check them out, and we may well be able to do so, in another decade or so. An even greater stretch of our ability to detect life may come when we develop better instruments to evaluate the properties of planets orbiting nearby stars.

Our ability to tell whether life exists “out there” hinges on the adequacy (or breadth) of our definition of it. Researchers keep offering updated definitions, but for every one put forth, other scientists quickly come up with a counter example even here on Earth that nullifies it. Take the reproduction part of the definition of life given above: What if we found some entity on the moon Europa that seemed to be alive, but showed no evidence of reproducing? Maybe it just has a very long reproductive cycle. How long do we wait, in order to say yes or no? What might death mean on Enceladus? How do we judge whether something has “functional activity” on an alien world?

Our current understanding of biology is still a little too primitive to come up with a clean definition of life here on Earth, let alone on some outer-space planet. For example, in the late 1970s the two Viking spacecraft that landed on Mars had the explicit objective of determining if life could be found there. The limited design of the Viking experiments, however, did not allow a decisive answer. NASA may have even conducted the wrong kinds of tests.

We'd better keep our minds open and not try to nail down the definition of life, until we are able to get to an alien world and observe what conditions prevail there. It just might show us something beyond our wildest expectations, and even beyond our current ability to wrap our heads around.

Seeing Double—Part 1

I have posted several blogs here about stars; describing meditations that come to me, as I soak in the tub under dark winter skies, while becoming absorbed in the heavens. It is now late fall. The trees above my tub have dropped their leaves and the sky turns inky dark by 8 PM. This provides me with wonderful stargazing opportunities. Bring the winter on! I love my summer evenings in the tub, since I can watch the ever-morphing clouds and the graceful, leafy trees sway in the balmy breezes above me; but there’s something very special about cold weather’s dark, starry skies.

I lie back, floating in the hot water, and fix my gaze on one patch of sky, slowly becoming absorbed into its star field. Some stars are bright, some dim; some are farther away than others; some gather in clusters and nebula. The patterns (especially the constellation-like figures) mesmerize me. I become aware that I’m peering into a three-dimensional star field that has depth, rather than just viewing points of light which all seem to emanate from the same distant celestial sphere.

I sometimes ponder the fact that about half the stars I see are really binary systems: two stars that dance closely around each other, rather than standing as solitary suns like ours. I rarely can resolve the pair by naked eye, but astronomy’s large telescopes can do that, to show us that many of them are truly double stars. In fact, many of them are actually multiple star systems, where one or two additional small, almost invisible, minor stars add to the complex dance.

A recent issue of Scientific American magazine has an article on binary stars and their planets, titled “Worlds With Two Suns,” by two cosmologists. Until recently, some astronomers tended to doubt that binary stars could even have planets orbiting them—let alone that they would have a chance of harboring life on their worlds. This is because a planet attached to a double star system could randomly be jerked around by the competing pull of the two stars. Such planets would not settle into stable orbits, or, worse yet, could even get sucked into one of the suns, or flung off into deep space by the opposing tug of the double stars. The complex gravitational field a planet would be forced to negotiate would cause its orbit to be too chaotic—most certainly too disordered for life ever to be able to take hold.

More on double suns next time...