Why Haven't Aliens Contacted Us?
By Lenny Everson
rev 3
Copyright Lenny Everson 2015
This free ebook may be copied, distributed, reposted, reprinted and shared, provided it appears in its entirety without alteration, and the reader is not charged to access it.
Cover design by Lenny Everson
Chapter 1: Introduction
The whole process should be fun, since nobody has a real clue why aliens haven't contacted us, and if there's a subject in which nobody knows anything for sure, there will be lots of people who are adamant to the point of violence on their own opinions.
I wrote the original in 2011. Now, in 2015, there’s sufficient new information to warrant an update.
I’ve also added some links. Someone complained about lack of references in the first edition of the booklet, and I thought, “Jeez; what does that person want for free?” But, anyway, at the end of this version are some links. You might have to cut and paste the URLs, or Google the titles, and by that time the sites may have vanished, but at least I tried.
Chapter 2: SETI, the Fermi Paradox, and The Great Silence
Which is a rather long title, some of which I got from an article on the WEB. SETI is “Search for Extraterrestrial Intelligence.” The “Fermi Paradox” goes back more than half a century when a guy named Fermi figured that if there were advanced civilizations somewhere, they’d be easy to find. Wrong, it seems. The paradox is that all our searching has turned up nothing. “The Great Silence,” some call it now.
Assuming that aliens would be broadcasting to us, the SETI (search for extraterrestrial intelligence) project was set up. At first they were looking for radio signals near the hydrogen band. Not getting any signals on the first try, the project has expanded until now they're checking for signals on tens of millions of channels at the same time, trying to guess how and from where signals would come to us.
No luck so far.
Another group came up with a novel idea. “Advanced civilizations need more energy,” they said. Eventually, they’ll get this by enclosing stars in metal spheres to make use of all the energy of those stars. All that will be visible is infrared light coming from the spheres. After checking some 100,000 galaxies, this group announced that they didn’t find anything like that, and announced, “the more we look, the more natural everything appears.”
The Great Silence continues. If you're wondering why, then you're in the same boat as I am, and this little booklet may help.
So let’s let the others keep listening and searching; meanwhile, we’ll casually try to come up with reasonable reasons that alien civilizations haven’t got in touch.
Chapter 3: Are There Other Solar Systems?
When I was a kid, people tossed around the Drake Equation, which went something like this: if only one in ten stars has planets and only one in then of those planets is in a habitable zone and….” Well you get the drift. There would still be millions of Earthlike planets in our galaxy alone. Only a few years ago, the number of stars that had planets circling them was a total out-of-thin-air guestimate. The sun, our own star, had a nice little family of planets, and the theory said that this might be likely, if other stars formed out of disks of gas and dust like the sun was supposed to have done. But a planet around another star was just too far away to detect in any way, unless the planet was huge enough to make the star wobble significantly.
The rest was just guessing, there was no way of knowing if any stars had any small rocky planets (like Earth) at all. That all changed recently.
Planets still are too far away to see, but science and technology has advanced enough to make some reasonable guesses. Every planet makes its star wobble a bit, and we’ve learned to detect smaller wiggles all the time. Better yet, some planets pass in front of their star (relative to us) and that dims the light a very tiny bit, but enough to make a measurement.
As telescopes got better, the measurements have gotten better, too. In the first edition of this booklet, I could honestly say, “Maybe there are no other planets around other stars.” Can’t do that now; it looks like most stars have planets around them. So cancel that as a reason that aliens haven’t contacted us.
A Wikipedia article says that our The Milky Way galaxy contains between 200 and 600 billion stars, and most stars have planets, so people get quite excited adding up all those planets and figuring some of them must have advanced civilizations.
And a fellow named Seth Shostak (a “senior astronomer at the SETI Institute in California”) figures there are lots of habitable planets in our galaxy. One in five planets is habitable, he says. "The number of habitable worlds in our galaxy is certainly in the tens of billions, minimum, and we haven't even talked about the moons. You know, moons can be habitable, too.”
And yet we still haven’t heard that, “Hello; how are you?” from any of those tens of billions of habitable planets and moons. Odd….
A recently updated estimate is that our galaxy is about 50% larger than previously estimated. It’s not that the diameter has been changed, but that the disk is rippled, corrugated, rather than being in a flat plane. This only means that there are likely even more planets and more chances for intelligence to form.
Chapter 4: Maybe No Other Life Ever Popped Out
Fundamentalists sometimes compare a living cell to a church. You can have all the building materials (bricks, glass panes, mortar, hard wooden pews) around, but they aren't going to spontaneously assemble themselves into a building, complete with sound system, urinals, and pictures of Jesus on the wall. Which is why fundamentalists usually believe in a divine power.
Now, a living cell is a collection of enzymes, amino acids, nucleotides, and other chunks of organized matter. Many of these are found drifting around in space, so, in terms of the church, a lot of the bricks and panes of glass are already made; the problem is in getting them assembled.
Isaac Asimov and others pointed out that many of these spontaneously assemble themselves into more complex structures. It's as if bricks had a tendency to group themselves into walls, for example.
One report, Origin of life: Chemistry of seabed's hot vents could explain emergence of life, says, “the surfaces of mineral particles inside hydrothermal vents (at the bottom of our oceans) have similar chemical properties to enzymes, the biological molecules that govern chemical reactions in living organisms. This means that vents are able to create simple carbon-based molecules, such as methanol and formic acid, out of the dissolved CO2 in the water….What our research proves is that these vents also have the chemical properties that encourage these molecules to recombine into molecules usually associated with living organisms."
The hydrothermal vents on the ocean floor are pretty unusual, when compared to life on the surface. But, as the report says, some of the complicated items life on Earth needs are formed right out of the chemicals there. It’s a start.
In another report, Meteorite Chemicals May Have Started Life on Earth - and Space, a group “synthesized sugars, amino acids and nucleobases with nothing more than formamide, meteorite material and the power of a simulated solar wind, replicating a process they believe cooked up a prebiotic soup long before life existed on Earth….The chemical has been detected in galactic centres and stellar nurseries, as well as comets and satellites. These latest experiments show that formamide, irradiated by the solar wind—simulated here by a proton beam—and in the presence of powdered meteorites, gave rise to amino acids, carboxylic acids, sugars and nucleosides—the building blocks of DNA and RNA.”
The longer we go on, it seems, the more likely it is that the “building blocks” are common. Building Blocks For Life Discovered In
Distant Star System says an article. “Astronomers have found complex organic molecules -- the chemical building blocks for life -- in the planet-forming disk of gas and dust around a young star, according to a new study….. Now we know we're not unique in organic chemistry," Karin Oberg, an astronomer with the Harvard-Smithsonian Center for Astrophysics and the study's lead author, said in a written statement. "Once more, we have learned that we're not special. From a life in the universe point of view, this is great news."
So there you have it; from the bottom of the ocean and from meteors in outer space, researchers have been detecting some of the “building blocks of life.” The biggest of these, enzymes, can contain ten thousand atoms in the order we see in life as we know it. It’s like discovering that bricks and glass formed by themselves.
But nobody yet as built a working cell from the basic materials. Ten thousand atoms may sound like a lot, but there’s a big gap between that and a fully self-replicating cell, which may have millions or billions of atoms in the correct order. We await further studies to see if scientists can close this gap. They're trying, of course, and many scientific groups think it's only a matter of time. Other scientists are a bit more pessimistic.
So there's still the possibility that getting a living cell going from the materials available on a planet may be just one heck of a difficult job, a really unlikely happening (without either divine help or an awful lot of luck).
Chapter 5: The Bad Neighbourhood Problem
It’s one thing to say there are a lot of ‘building blocks” of life drifting around the star clouds and popping up underwater. It’s a different thing to keep life going. Living molecules (so far as we know) are very long, carefully constructed chains. When you heat food in the oven, you break the large constructions into small, easier-to-digest pieces; that’s called cooking. Heat rips life’s molecules apart. When food hits your stomach, the acid there rips life’s molecules apart; that’s called digestion. Strong acids (or bases) rip life’s molecules apart.
Many kinds of radiation simply act as tiny bullets, knocking needed chunks off a living molecule’s construction.
And cold slows life’s operations a lot. Perhaps extreme cold may slow life’s evolutionary processes to the point where the life exists, but hasn’t got very far. Not far enough to send messages, anyway.
In other words, unless life evolves in the so-called “Goldilocks zone” (not too close to its star nor too far away) it can have trouble evolving. And, given the three or four billion years that we took to evolve enough to send signals to space, that zone has to stay reasonably constant during that time. Relatively small things (such as a chunk of rock a millionth the size of the planet) might set the whole process back a few squares, and larger thing may set everything back to square one again.
On the other hand, as many may point out, there’s a good chance life started its evolution on earth in the thermal vents of the ocean bottom, in an oxygen-free environment, near the boiling point of water. Whether this life could ever have evolved enough to call us on the phone is a good question. Surface life, such as humans and green beans, are not much helped by boiling water or a lack of oxygen, regardless of where we started.
Let’s look at some of the things that make what seems a perfectly fine planet one of those places you wouldn’t want your ancestors to grow up in.
Just last week, on Quirks and Quarks, Canada’s radio science show (the show is online and you may be able to listen to the segment), there was a short segment about this issue. It was called, “Jupiter Attacks” and the premise went like this:
- Studies have shown us that thousand of stars have solar systems with planets
- Generally, these solar systems have many large planets much closer to their star than our solar system does. Not only are there large gas planets where we have small rocky ones (Mercury, Venus, Earth, and Mars), but it’s common to have such large planets even closer to their star than Mercury is to the sun.
- Planets like Jupiter (in size and location) are fairly uncommon in other systems.
- A reasonable scenario is that Jupiter, early in our solar system’s history, ran amok, diving much closer to the sun than it currently stays. In doing so, it attracted or absorbed most material there. What wasn’t absorbed by Jupiter was scattered and made into a cascade of debris that collided and spiraled into the sun, leaving just enough for a few rocky planets.
- Eventually, Saturn pulled Jupiter back to the place where it is now.
- Had Jupiter not done this, small rocky planets like Earth would not have been possible. Had Jupiter had not cleared out a lot of gas, the small planets would have had atmospheres too thick to be habitable.
It’s a theory that implies that, without Jupiter, there would have been no place like Earth, with its thin and useful atmosphere.
I was barely finished typing in the above hypothesis, when I read more on the subject in a NY Times, May 16, 2015 piece. The article included the bit about Jupiter and Saturn, being driven outward, unleashing a cascade of asteroids known as the Late Heavy Bombardment. But it included the concept that the heat of these rocks hitting the nitrogen in the Earth’s atmosphere, formed hydrogen cyanide. And, the author goes on, “cyanide is the ancient pathway for inert carbon atoms to enter the chemistry of life.” Some of these “chemistry of life” chemicals included “lipids, nucleotides, and amino acids, the three significant components of a living cell.”
(You’ll notice in this booklet that I don’t deal in depth with the chemicals of life. That’s because this poet doesn’t understand the biochemistry involved.)
So, perhaps, had Jupiter not made its excursion towards the inner solar system, there would have been no genuinely “earth-like planet” and perhaps not the first chemicals of life. If so, that could, once again, mean that Earth is so much an exception that the existence of other planets with chatty life forms could be doubtful. On the other hand, I have to remind myself of Shostak’s claim that there are “certainly in the tens of billions” of planets in our galaxy, minimum. That’s a lot of planets and a lot of chances for other Jupiters to run amok and create other Earths.
And then there’s Saturn. Astronomers find that planets in most solar systems are in orbits more eccentric than those in our solar system. The planets are often in very oval orbits, spending part of their year either too close to or too far from their star for life to evolve steadily and easily. Oh, it might be possible, but extreme temperatures for part of the year may slow down development.
Models of our solar system that have Saturn ten percent closer to the sun show that this would put Earth into a very eccentric orbit. Models that have Saturn in a tilted orbit show that this would also push Earth into some very bad orbits.
What I’m trying to say is that there may have been conditions under which many a planet either:
- couldn’t get an environment suitable for creating life, or
- couldn’t get an environment suitable for a sufficiently rapid advancement of life (only a too-slow evolution was possible, or the local space environment kept returning life to square one)
I’ll return to these several times, of course.
Then there’s the moon. Scientists are pretty sure the moon formed from an odd collision of a Mars-size planet into Earth. Had the collision happened at a more direct angle, a single planet would have resulted from the debris. Had it happened at a more glancing angle, more of the debris would have gone into space and been lost.
But it didn’t, and what we ended up with something that as close to a twin-planet system as it is to a planet-and-its-moon system. There’s nothing like it in the other three inner rocky planets. Mercury and Venus have no significant moons, and Mars has a couple of iddy-biddy rocks that drifted in from the asteroid belt.
Isaac Asimov speculated that, without the moon, Earth would have had very little evolution from its pond-scum origins. He wondered if the moon’s tidal forces kept the Earth’s deep magmas shifting. This, in turn, brou
ght radioactive materials to the surface, and this radioactivity produced the mutations in DNA that boosted evolution into high gear. With no big moon, evolution would proceed, using only the lesser radiation from space, at a much slower pace. Perhaps without the moon, intelligent beings wouldn't evolve in four billion years (the age of the earth) but in 20 billion years, which is longer than the age of the universe. Lots of planets, maybe, with very primitive life.
I include a link at the end of this booklet to an article called “Can Astronomical Tidal Forces Trigger Earthquakes?” You’ll find, in the article that if there’s a link between the moon and volcanoes, it’s a small one, perhaps less than enough to support Asimov’s theory.
So a planet with enough volcanoes to produce evolutionary radiation but not so many as to sterilize life may be necessary. That might require a moon just big enough to keep the continents moving without being so big as to haul out magma in too large quantities. At the right distance, too. And going around its planet in the same direction (I'm told that if the moon circles the planet opposite to the planet's direction of rotation then the moon will eventually spiral into the planet).
Furthermore, the pull of the moon on the ocean helps spread the sun’s heat more evenly across the planet. And tides produce tidal zones at the edges of oceans. Tidal zones may (or may not) be prime areas for stimulating evolution.
Scientists point out that, without a stabilizing moon, earth would slowly rotate onto its side at regular intervals, and that this might be hard on evolution. (Then again, it might just stimulate evolution.)
I’d like to stress that this “the moon is necessary for life” concept has recently come under attack. Google “was the moon necessary for life on earth?” for more details.
There may be Earth-sized, rocky planets within the habitable zone of a star, and yet, if that planet’s orbit is even moderately eccentric, the planet may be unsuitable for advanced life – or maybe for any life. The tidal forces that such an orbit produces within the rocks of the planet can heat those rocks to the point where water can’t form into oceans, and is spouted out of volcanoes and kept in the atmosphere. This in turn, can turn a potentially good planet into a Venus-style greenhouse. Eventually, the water may be lost to space and the planet forever without the materials most essential for life.
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