Eavesdropping on E.T. and the possibility of interstellar travel

Gabriel Popkin as an article at Inside Science about a study that looks at the possibility of intercepting communications between other alien civilizations.  The idea is that communicating across interstellar distances is best done with lasers.

So far, the optical search for extraterrestrial intelligence has focused mainly on the hope of receiving—and recognizing—an intentional, laser-encoded message. Researchers use dedicated telescopes or mine astronomical data collected for other purposes, like the Sloan Digital Sky Survey, to search for light pulses that could not be produced by any known object like a star. So far, no one has reported a light pattern that suggests an extraterrestrial intelligence.

But rather than look for light beamed directly at us, astronomers could also try to intercept signals sent between two distant civilizations. If advanced beings have existed for millions of years, they may well have found each other and started talking. Eventually many light beams would penetrate the intergalactic darkness, creating a criss-crossing network of communication beacons. As our solar system revolves around the galactic center, could we meander into the path of one of these beams?

While an interesting idea, the study largely concluded that this is unlikely to happen.

Unsurprisingly, he found that the chance of intercepting another civilization’s messages increased as more civilizations joined the communications network. He also found that the interception probability increased dramatically as the angle through which the beams spread out increased.

But the probability of accidentally wandering through a beam remained small as long as the beams were narrow, or collimated, like a typical laser. The beams would have to spread out about 1,000 times more widely than a standard laser pointer—in other words, more like a flashlight beam—before we have a decent chance of intercepting them, Forgan says. Sending out such a wide beam would require far more energy than emitting a tightly collimated one.

This isn’t too surprising.  Interstellar space is vast, and solar systems are (relatively) tiny.  As the article discusses, the aliens would have to go expensively out of their way to increase the odds of being detected by a third party.

One thing I find interesting about these studies, is that they have an implicit assumption: that interstellar travel or exploration is impossible, even robotically.  Because if it is possible and there are indeed hundreds of civilizations in the galaxy, then there would likely already be a communication relay in every solar system, and a vast interstellar communication web network.  If so, then our system would almost certainly have multiple beams interacting with other nearby stars.

If the aliens don’t want to be detected, it is possible that they could keep their relay stations in the Oort cloud, the region of comets and other icy bodies extending for a couple of light years out from the sun.  Of course, avoiding detection would have to be a major priority for them to keep their facilities so far away from the free solar energy of the sun.  But they could have decided to do so as soon as they noticed a tool using species developing on the third planet.  And if staying  hidden is a priority, we’re unlikely to find them for a while.

But, is the assumption that interstellar travel is impossible a valid one?  Or are SETI and other astronomers being overly pessimistic?  Most people are aware of the speed of light limitation, that nothing can travel faster than light.  But lamenting that issue is actually a bit of sour grapes, since we don’t even have the foreseeable technology to get to a significant percentage of the speed of light.  Just getting to 10% of c (the speed of light) will require astounding amounts of energy.

But it’s hard to imagine that in the centuries and millennia ahead, that we won’t be able to cobble together some method of getting to at least 1% of c.  There have been designs around for decades, such as the Orion Project, which would use nuclear explosions to propel a craft up to a high speed.  And there are many more speculative designs out there that could conceivably improve on that.

The problem is that Orion would still take centuries to reach the nearest star.  It’s easy enough for science fiction writers to wave their hands and imagine robotic probe machinery working that long, but engineering it is a different matter.  Still, Voyager 1 is four decades out and is expected to work at least another decade, albeit in a very low power mode.  Building a probe that could work for centuries would be difficult, but it remains an engineering challenge, not a fundamental limitation of physics.

And I think that’s why I remain optimistic that interstellar exploration will ultimately be possible, at least with robots.  Because the issues to be overcome are engineering ones, not fundamental scientific ones.  It’s hard to say whether those engineering challenges will be overcome in a century, a millennia, or farther out, but insisting that they never will seems unnecessarily pessimistic.

But as soon as we reach that conclusion, we’re back to wondering where everyone is (the Fermi Paradox).  Either they (or more likely their robotic representatives) are already here in the solar system, and hiding, as described above or in some other way, or they’re simply not there.  Or perhaps more accurately, the nearest neighboring civilization is millions of light years away in another galaxy, far enough away that they haven’t had time to reach us yet, if they ever will.

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xkcd: AI-Box Experiment

Click through for full sized version and yellow caption.

via xkcd: AI-Box Experiment.

I do keep saying that AIs won’t want what we want.

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The number of senses, free will, and productive reality

Christian Jarrett has an interesting article at BBC Future on the number of senses that we have.

The principle of five basic human senses is often traced back to Aristotle’s De Anima (On the Soul), in which he devotes a separate chapter to vision, hearing, touch, smell and taste. Today, the five senses are considered such an elementary truth that it is sometimes used as a point of consensus before writers embark on more mysterious or contentious topics. “What do we actually mean by reality?” asked the author of a recent article in New Scientist magazine. “A straightforward answer is that it means everything that appears to our five senses.”

If only it were that simple. Simply defining what we mean by a “sense” leads you down a slippery slope into philosophy. One, somewhat vague, definition might argue that a human sense is simply a unique way for the brain to receive information about the world and the body. If that is the case, then we can claim with confidence that there are certainly more than five human senses.

Jarrett goes on to discuss a number of additional senses such as proprioception (our sense of where our body and body parts are), our sense of balance, hunger, thirst, as well as the fact that the five “classic” senses could be split into many additional ones.

Of course, you could also be reductive about this:

At the other extreme, you could restrict our definition of discrete sense to the physical categories of incoming information. We can simplify the human senses down to just three – mechanical (which takes in touch, hearing and proprioception); chemical (including taste, smell and internal senses); and light.

You could be even more reductive and insist that there is only one sense, that of touch.  This would include what we traditionally mean by touching such as something coming into contact with your arm, but also the touch of photons hitting the receptors in your eyes or the touch of gas molecules to the smell receptors in your nose.

However, a strong case could be made that being so reductive isn’t really productive.  All of our senses may reduce to receiving electrical signals caused by matter or energy connecting with our body, but that certainly isn’t the way we perceive things.  For purposes of studying the senses, it makes more sense to categorize the ones that we perceive differently, even if that perception ultimately amounts to illusion.

This reminds me of the perennial debates on free will.  Once we decide that the mind is simply a logical construct of the physical brain, is there any room for free will?  Many insist no.  Our thoughts are driven by the laws of physics and therefore we must simply learn to live in that universe.

But most of those who make that insistence are also careful to clarify that they’re not endorsing fatalism.  Our decisions ultimately are controlled by physics, but we still have to make those decisions, and it’s not productive to simply not decide, to do nothing and consign our fate to the laws of nature.  Indeed, many of them would argue that we have a responsibility to gather the facts and make the best, most informed decisions that we can, particularly on ethical decisions such as whether or not to fight global warming, vaccinations, or faith healing.

The compatibilist position is simply to call the above “free will”, that it remains a useful concept, that insisting that it is an illusion is akin to insisting that the distinct senses are illusions, or that the game of football is an illusion, or the Mac OS X software on my laptop, or even this blog post.  None of these things can be physically pointed to.  They all only exist as patterns that we’ve given labels to.

A strict reductionist could insist that there is nothing but space, fermions, and bosons, and that all else are merely patterns built on top of these entities.  It’s possible that even these elementary particles are patterns of lower level realities.  It’s even possible that there is no base reality, that everything is patterns all the way down.  Ultimately, it may all be emergent.

We continue to regard things like Mac OS X, a table, a tree, and many other concepts as existing in their own right, because it is productive to do so.  And we regard ourselves as having several senses, because it is productive to do so.

But we continue to argue whether it’s productive to regard free will as real.  Given that most of us agree that fatalism is not a productive outlook, I often wonder if a term like “volition” was used instead of the theologically loaded “free will”, whether it wouldn’t make this debate moot.

The problem, of course, is that “free will” is a term heavily embedded in law, philosophy, and much of society.  The opponents of free will, who are often atheist activists, usually assert that the intuitive version of free will is the theological version involving a separate soul, and that because of this, the term needs to go.  However, empirical studies have not backed up those assertions.

Most people, it seems, intuitively regard “free will” as more or less synonymous with volition.  Although, to be honest, other studies have shown that most people are also intuitive dualists, and if explicitly asked if these concepts were related, they would say “yes”.

How many senses do we have?  Does free will exist?  Is there a reality above fermions and bosons?  Is there any one true answer?

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A cute video, at first, before getting into the darkness of addiction

I consider myself to be lucky that I’ve managed to only acquire one real addiction: caffeine.  I’ve given it up several times over the years, but always slid back into its clutches.  Given that, I have complete sympathy with those caught in the clutches of much more serious addictions, like nicotine, alcohol, prescription painkillers, or any of the illegal drugs.

This video gives a quick summary of the addiction experience.  It’s worth watching, and remembering the next time you find something that is intensely pleasurable.

via IO9

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Meditations on Canonicity


Michelle Joelle ponders the evolution of fictional (and mythological) stories, which I found particularly interesting given some of the discussion on the previous post.

Originally posted on Stories & Soliloquies:

I originally intended to write a post about the hyper-rigidity of fantasy and science fiction fans. I’ve read my fair share of theoretical analyses of fictional works, and generally speaking, all theories are beholden to a canonical standard in their analysis – no suppositions can be made outside of what is officially accepted and sanctioned by the author – the creator. The text is fixed with copyright laws, and the story is fixed by the veneration of a fandom. Movie adaptations are harshly judged on their adherence to the canon, and anyone who takes up a story element without explicit credit is derailed for “stealing” from the canon, as though the derivation constituted heresy.

I don’t put a lot of store in the sacredness of fictional canon. I don’t mind when movies alter the story to fit the medium of film (though I do mind when they alter the story…

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How Farming Almost Destroyed Ancient Human Civilization

Annalee Newitz has a fascinating article at IO9 on early neolithic societies: How Farming Almost Destroyed Ancient Human Civilization.

Roughly 9,000 years ago, humans had mastered farming to the point where food was plentiful. Populations boomed, and people began moving into large settlements full of thousands of people. And then, abruptly, these proto-cities were abandoned for millennia. It’s one of the greatest mysteries of early human civilization.

…The problem is that people in Neolithic mega-villages had inherited a system of social organization and spirituality from their nomadic forebears. Because nomadic life requires everyone in the group to share resources to survive, these groups would develop rituals and customs that reinforced a very flat social structure. Certainly there would be families that had more prominent positions in a hunter-gatherer group or small village, but if they ever started hoarding resources too much that would be bad for the entire group. So people would strongly discourage each other from ostentatious displays of social differences.

…But the ideology of these Neolithic people in mega-villages, Kuijt speculates, may have treated any kind of social differentiation as taboo. As soon as somebody took enough power to be a representative or proto-politician, other people would rail against them. He believes that major conflicts may have grown out of this tension between a belief in flat social organization and the need to create social hierarchies in larger societies. It’s an intriguing hypothesis, especially when you consider that when cities re-emerge in the 4,000s BCE, they have rigid social hierarchies with kings, shamans, and slaves. Plus, they have writing, which is primarily used to tally up who lives where and owns what.

The quotes above give a basic overview of the article, but the article is very well done with colorful images and informative diagrams, including a very interesting timeline.  If you’re interested, I highly recommend reading the full thing.  I learned some things from it, and I’m moderately well read in this area.  For instance, while I knew Çatalhöyük had been abandoned at some point, I wasn’t aware it was part of a general collapse.

As interesting as I did find this article, the basic hypothesis seems weak to me.  The reason is the vast time scales involved.  Remember that we’re talking about the period between when farming began, around 10,000 BC, until around 5000 BC.  That’s pretty much the same time span as recorded history.  Çatalhöyük, the main example Newitz discusses, flourished from c. 7500 BC until c. 5700 BC, almost two millenia.  No society in recorded history has managed to last that long (at least, not without creative historical interpretations of events).  In other words, it was a successful society for a very long time.

We also have to remember that these were pre-literate societies, so the people living in Çatalhöyük or similar settlements in 5700 BC almost certainly had no memory of how their hunter-gatherer ancestors had once lived.  Oral histories, and hence cultural traditions, just don’t survive intact more than a few centuries without evolving heavily.  (Literate societies generally have their core traditions in sacred documents that serve to limit that evolution, even if it doesn’t eliminate it.)  The idea that culture remained static from when hunter gatherers settled down until this late neolithic collapse millennia later seems implausible.

I don’t doubt that the neolithic settlements probably suffered from organizational problems.  They didn’t have writing yet, which had to limit how sophisticated their organizational structures could become.  But the idea that they held hunter-gatherer values for thousands of years, collapsed, and then figured out hierarchies to build civilization is probably too simplistic a view of what was more likely a complex evolution over thousands of years.

The timescales are interesting:

  • 200,000 BC: modern humans emerge in Africa
  • 90,000-60,000 BC: a portion of humanity migrates out of Africa
  • 12,000 BC: earliest settlements
  • 10,000-8000 BC: farming begins
  • 5500-5000 BC: the neolithic collapse the article discusses
  • 3000 BC: development of writing and the beginnings of record history

Sometimes I wonder if civilization isn’t just an aberration, a passing fad allowed by the current ice age interglacial period, that we may have to leave behind in the millennia to come.


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The RNA world

Originally posted on Why Evolution Is True:

by Matthew Cobb

I have just sent off the final version of my book Life’s Greatest Secret: The Story of the Race to Crack the Genetic Code (to appear in 2015 with Profile Books, and Basic Books in the USA). The book is mainly history, covering the period 1943-1961, but the final four chapters bring the story up to date, describing things like the sequencing of the Neanderthal genome, the development of genetic engineering, and epigenetics.

To celebrate, I thought I’d give readers a condensed version of one of the sections dealing with that exotic-sounding entity, the RNA World.


Proteins and DNA, which are so important to life today, have not always existed on our planet. The RNA machinery that exists in every cell of every organism on Earth, and the ability of RNA molecules to act as enzymes, catalysing biochemical reactions without the involvement of proteins, all indicate that…

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