• About

Sacred Cow Chips

Sacred Cow Chips

Tag Archives: Fermi Paradox

Our Stardust Scrutiny, A Reverie Thus Far In Vain

01 Friday Jul 2016

Posted by pnoetx in Extraterrestrial Life

≈ Leave a comment

Tags

Drake Equation, Evan Solomonides, Fermi Paradox, Goldilocks Zone, Mediocrity Principle, Milky Way, Sphere of Communication, Yervant Terzian

smbc_klingons

The Fermi paradox juxtaposes the fact that we’ve heard no signal from extraterrestrial life against claims that life must be common in the universe. The paradox, named after physicist Enrico Fermi, is not so inscrutable given 1) the immense distances in interstellar space; 2) the likelihood that few civilizations have survived long enough to attain a high level of advancement; and 3) the slim chance (until recently, perhaps) of detecting messages from a distant civilization.

These points are addressed in recent paper by Evan Solomonides and Yervant Terzian of Cornell University entitled “A Probabilistic Analysis of the Fermi Paradox” (the full PDF is available for download on the upper right at the link). The authors note that the first broadcast from Earth that could be detected beyond the planet took place roughly 80 years ago. Unfortunately, it was Hitler’s commentary on the superiority of arian athletes at the 1936 Olympics. That seems a shame, but then it’s unlikely that the recipients can interpret the signal at all. Still, the authors estimate that by now, that broadcast will have reached over 8,000 stars and over 3,500 earth-like planets within an 80 light-year sphere around the Earth. That might sound like a lot, but it is an infinitesimal fraction of the Milky Way galaxy. There is roughly a zero chance that an advanced civilizations exists within a population of potentially habitable planets that small.

How Common Is Life?

Solomonides and Terzian extend their analysis using a version of the so-called Drake equation, which relies on a series of assumed probabilities to calculate the number of of active, intelligent civilizations in the galaxy, call it N. However, the authors assert that their version of the Drake equation yields an estimate of N for the entire history of the galaxy, but it looks very much as if they’ve simply redefined the equation’s terms. They use the equation to specify a relation between 1) the average length of communication history for all intelligent civilizations; and 2) the total area of all spheres of coverage, which is dependent on N. They assert that as of today, this combined area must encompass less than one-half of the galaxy because that implies that we are less likely to have heard a signal from extraterrestrials than not to have heard one. And we haven’t. However, this seems like a thin foundation from which to draw implications, and it is based on an expectation. Even if those spheres covered 90% of the galaxy or more, it would not rule out the silence we’ve “heard” to date. Nevertheless, the authors use this inequality to derive a lower and upper bound on the number of intelligent, communicating civilizations in Milky Way history.

Expanding Broadcast Spheres

Again, Solomonides and Terzian define “spheres of communication” extending into space as far in light years as the length of a civilization’s broadcasting history in earth-years. Earth’s sphere of communication now extends outward by 80 light years. But imagine that a long-extinct civilization on the other side of the galaxy sent messages about 30,000 years ago. The signal might be reaching us just now. But if that civilization’s broadcasting history lasted 1,000 years before an untimely extinction, its broadcast sphere would be like a hollow, expanding dumpling, now almost as wide as the galaxy itself but with dough walls a constant 1,000 light-years thick. Only the walls contain broadcast information, so the areas of spheres like these are not simply additive. The hollow “inner spheres” must be subtracted to get the total broadcast area.

Revisiting the Duration of Broadcasts

The communication spheres defined by Solomonides and Terzian are “disks” rather than spheres, because collapsing the galaxy into two dimensions simplifies the analysis. They do not appear to allow for the sort of hollowness implied by an older, advanced civilization with a limited survival time. That matters in terms the history relevant to our failure to detect signals thus far. If a civilization’s broadcasting history is of short duration relative to its distance from Earth, then its communication sphere has thin broadcast walls. If that now-extinct civilization originated signals on the other side of the galaxy more than about 35,000 years ago, the signals would be irrelevant to “our” Fermi paradox because by now, Earth is almost certainly inside the wall of its expanding broadcast “dumpling”. The signal passed us by before we were advanced enough to have thought about it. So the relevant history of the galaxy, for purposes of identifying the broadcasting histories of civilizations we might have heard from by now, goes back a bit farther than the total width of the galaxy, which is roughly 32,600 light years. The relevant history might be 35,000 years, give or take, not the 13 billion years since the galaxy’s birth. At least that limits one dimension of the problem.

I find the following sentence somewhat troublesome because Solomonides and Terzian seem to focus on the length of broadcasting histories only with reference to the present time:

“The planar area of the galactic disk reached by communication from any intelligent civilization (assuming such civilizations are uniformly dispersed throughout the galaxy) can be modeled as the area of N disks with radius Lh (average length of broadcasting history in years)…“

Some of those N disks are probably hollow. The idea that civilizations are commonplace may not mean that they all exist contemporaneously, and while the authors must understand that point, the description above implies that all disks are saturated with broadcasted information from center to outer rim rather than hollow.

Solomonides and Terzian then attempt to place the radius of earth’s own minuscule broadcast disk within the hypothetical distribution of all such discs within the galaxy:

“… we know that humanity was almost certainly not the (or even one of the) first species in the galaxy to develop broadcasting technology, nor one of the last. Put statistically, it can be said with a high degree of confidence that humanity is somewhere in the median 90% of the population of galactic species as far as broadcasting history is concerned. That is to say, we are not among the first nor last 5% of civilizations to develop this technology. … Taking a very conservative estimate, we posit that we have been broadcasting for 5% as long as the average communicative species has been, and as such this upper limit on the average is approximately 1600 years. This can be substituted back into the inequality derived previously to give an idea of the frequency of life that our apparent loneliness suggests.“

A couple of notes on this statement: First, it assumes that the lengths of broadcasting histories are distributed uniformly from 0 to 1,600 years. Second, it seems to preclude any history of broadcasts prior to 1,600 years ago. If that is the case, then the number of civilizations they consider are what I’d call “near contemporaneous”. The authors do not seem to be accounting for all history after all.

Few Neighbors Or Many?

The authors go on to calculate lower and upper bounds on the number of communicating civilizations in the Milky Way, but again, in light of the quotes above, the implied existence of civilizations seems to be near-contemporaneous. Perhaps that’s okay for arriving at a lower bound. Again, Solomonides and Terzian assume that our 80 years of communication history puts us below 95% of all other communicating civilizations. Therefore, the longest history among such civilizations would be just 1,600 years. Because we have heard nothing, there must be great distances between relatively few civilizations: only about 210, according to Solomonides and Terzian.

In light of the relevant history of the Milky Way, 1,600 years seems outrageously short for the longest communication history. To my way of thinking, broadcast histories, whatever their number, must be distributed over the entire galaxy and over a time span of about 33,000 years. If extinctions shorten the duration of those histories, then it is possible that we’ve simply missed the outer walls of a number of broadcast disks that have already reached us. In that case, civilizations must be sparse both spatially and over time. Unfortunately, the authors’ lower bound for the number of communicating civilizations must be taken as an estimate for civilizations whose existence is near-contemporaneous with our own. However, that does not fit as neatly into an explanation of the Fermi paradox as the authors would like.

For an upper bound on the number of communicating civilizations, the authors assume that we are on the verge of hearing from another civilization in response to our initial communication. If so,  then we have a very close, neighboring civilization about 40 light years away, which implies an outrageously high frequency of civilizations in the galaxy: about 78 million, according to the authors. The upper bound relies on an assumption that it’s necessary for Earth to receive a response to our communication, as opposed to receiving an independent communication from afar. Perhaps the signal/response requirement is imposed for reasons of estimating a more densely populated galaxy for the upper bound.

The lower and upper bounds imply that life is either rare or ubiquitous; the authors claim that either is an unreasonable violation of the so-called “mediocrity principle”, which posits that our civilization is “run-of-the-mill”: the first is a violation because we are rare; the second is a violation because we’ve somehow managed to avoid hearing anything despite the denseness of communicating civilizations in the Milky Way.

Great Filters

It’s reasonable to question the assumption that an advanced civilization’s broadcast history would be of relatively short duration. The galaxy is a hazardous place, however, presenting extreme natural threats to any planet finding itself in a “Goldilocks zone” near its host star and capable of harboring life over an extended period. Threats range from interloping space rocks to variations in a planet’s exposure to radiation. Then, there are hazards to life arising from natural conditions on the planet itself, such as extreme volcanic activity and perhaps natural toxins. Finally, the development of technology brings hazards as well, including the possibility of chemical, biological and nuclear calamities. All of these constitute “Great Filters” that may prevent civilizations from reaching a stage of advancement sufficient for interstellar travel and colonization of other worlds.

Can such hazards be expected to put a halt to a representative civilization’s broadcasting, and within how many earth centuries? In some cases, it’s likely to be as few as 10 or 20 centuries, but even if extinction is common, there are also likely to be a few civilizations making it to the far right tail of the survival distribution. Those few civilizations, or even one, could have begun broadcasting so long ago that their communication spheres are much larger than the galaxy itself. We might just hear them if they exist, but perhaps that argues that they do not.

Detection and and Understanding

Beyond the limits of communication spheres, another compelling reason for our failure to detect signals from other civilizations is signal degradation over great distances. According to Solomonides and Terzian, signal strength weakens with the inverse square of distance. Even today, messages of extremely distant origin might be impossible for us to discern, let alone understand.

“Though a handful of these signals have been designed to be picked up by extraterrestrial intelligence (…. i.e. Fibonacci, the prime numbers, the squares, all broadcast in binary), the vast majority would be indecipherable. This is because an alien civilization would need to first decode binary into sound (and figure out our tone encryption method) or video (with very specific, inconsistent formats), and if they could somehow do that, they would then need to decode the resulting 3,000 human languages … into something they could parse successfully.“

Given sufficiently well-equipped listening centers here on Earth, detection becomes something of a mathematical exercise. Over the past 10-15 years, there have been advances in developing algorithms to extract signals from an otherwise noisy background.

Conclusion

With plausible assumptions, the Drake equation yields the conclusion that the galaxy may be populated with a large number of intelligent civilizations, larger still if we count those existing at any time over the past 35,000 years. The Solomonides and Terzian paper shows that the lack of detection on Earth is not very surprising, but in a limited context. The silence might be even less surprising if many of the historical civilizations had a broadcasting age of limited duration, generating hollow broadcasting spheres, because the walls of many of those spheres would have passed us by long before our own radio age. Therefore, the Fermi paradox does not seem to be such a paradox after all.

 

 

Will ET Be a Socialist?

19 Wednesday Aug 2015

Posted by pnoetx in Capitalism, Socialism, Space Travel

≈ Leave a comment

Tags

B.K. Marcus, Capitalism, Carl Sagan, central planning, Colonizing Mars, Elon Musk, Enrico Fermi, Extraterrestrials, F.A. Hayek, Fermi Paradox, Huffington Post, Interstellar Travel, io9, Large Hadron Collider, NASA, Neil deGrasse Tyson, Planned Society, Private Space Exploration, Public goods, Self-Replicating Machines, SETI, Socialism, SpaceX, The Freeman, The Great Filter, Tim Urban

image

If we are ever visited or contacted by agents from an extraterrestrial civilization, what kind of society will they come from? The issue is given scant attention, if any, in discussions of extraterrestrial life, at least according to this interesting piece in The Freeman by B.K. Marcus. The popular view, and that of many scientists, seems to be that the alien society will be dominated by an authoritarian central government. Must that be the case? Marcus notes the negative views taken by such scientific authorities as Neil deGrasse Tyson toward laissez faire capitalism, and even Carl Sagan “… could only imagine science funded by government.” Of course, Tyson and Sagan cannot be regarded as authorities on economic affairs. However, I admit that I have fallen into the same trap regarding extraterrestrial visitors: that they will come from a socialist society with strong central command. On reflection, like Marcus, I do not think this view is justified.

One explanation for the default view that extraterrestrial visitors will be socialists is that people uncritically accept the notion that an advanced society is a planned society.  This runs counter to mankind’s experience over the past few centuries: individual freedom, unfettered trade, capitalism and a spontaneous social order have created wealth and advancement beyond the wildest dreams of earlier monarchs. Anyone with a passing familiarity with data on world economic growth, or with F.A. Hayek, should know this, but it Is often overlooked. Central planners cannot know the infinitely detailed and dynamic information on technologies, resource availability, costs and preferences needed to plan a society with anything close to the success of one arranged through the voluntary cooperation of individual actors.

Many of us have a strong memory of government domination of space exploration, so we tend to think of such efforts as the natural province of government. Private contractors were heavily involved in those efforts, but the funding and high-level management of space missions (NASA in the U.S.) was dominated by government. Today, private space exploration is a growth industry, and it is likely that some of the greatest innovations and future space endeavors will originate in the private sector.

Another explanation for the popular view is the daunting social challenges that would be faced by crews in interstellar travel (IST). Given a relatively short life span, a colonizing mission would have to involve families and perhaps take multiple generations to reach its destination. There is a view that the mini-society on such a ship would require a command and control structure. Perhaps, but private property rights and a certain level of democratization would be advantageous. In any case, that carries no implication about the society on the home planet nor the eventual structure of a colony.

A better rationale for the default view of socialist ETs involves a public goods argument. The earth and mankind face infrequent but potentially catastrophic hazards, such as rogue asteroids and regions of strong radiation as the sun orbits the center of the Milky Way galaxy. These risks are shared, which implies that technological efforts to avert such hazards, or to perpetuate mankind by colonizing other worlds, are pure public goods. That means government has a classic role in providing for such efforts, as long as the expected benefits outweigh the costs. The standard production tradeoff discussed in introductory economics classes is “guns versus butter”, or national defense (a pure public good) versus private consumption. IST by an alien civilization could well require such a massive diversion of resources to the public sector that only an economically dominant central government could manage it. Or so it might seem.

As already noted, private entrepreneurs have debunked the presumed necessity that government must dominate space exploration. In fact, Elon Musk and his company SpaceX hope to colonize Mars. His motives sound altruistic, and in some sense the project sounds like the private provision of a public good. Here is an interpretation by Tim Urban quoted at the link (where I have inserted a substitute for the small time-scale analog used by the author):

“Now—if you owned a hard drive with an extraordinarily important Excel doc on it, and you knew that the hard drive pretty reliably tended to crash [from time to time] … what’s the very obvious thing you’d do?
You’d copy the document onto a second hard drive.
That’s why Elon Musk wants to put a million people on Mars.”

Musk has other incentives, however. The technology needed to colonize Mars will also pay handsome dividends in space mining applications. Moreover, if they are successful, there will come a time when Mars is a destination commanding a fare. Granted, this is not IST, but as technology advances through inter-planetary travel and colonization, there is a strong likelihood that future Elon Musks will be involved in the first steps outside of our solar system.

While SpaceX has raised its capital from private sources, it receives significant revenue from government contracts, so there is a level of dependence on public space initiatives. However, the argument made by Marcus at the first link above, that IST by ETs is less likely (or impossible) if they live under a socialist regime, is not based primarily on recent experience with private entrepreneurial efforts like Musk’s. Instead, it has to do with the inability of socialist regimes to generate wealth, especially the massive wealth necessary to accomplish IST.

Discussions of ETs (or the lack thereof) often center around a question known as the  Fermi Paradox, after the physicist Enrico Fermi. He basically asked: if the billions and billions of star systems, even in our own galaxy, are likely to harbor a respectable number of advanced civilizations, where are they? Why haven’t we heard from them? My friend John Crawford objects that this is no paradox at all, given the vastness of space and the difficulty and likely expense of IST. There may be advanced civilizations in the cosmos that simply have not been able to tackle the problem, at least beyond their own stellar neighborhood. No doubt about it, IST is hard!

I have argued to Crawford that there should be civilizations covering a wide range of development at any point in time. In only the past hundred years, humans have increased the speed at which they travel from less than 50 miles per hour (mph) to at least 9,600 mph. The speed of light is approximately 270,000 times faster that that! At our current top speed, it would take almost 50% longer to reach our nearest neighboring star, Alpha Centauri, than the entire span of human existence to-date. With that kind of limitation, there is no paradox at all! But I would not be surprised if, over the next 1,000 years, advances in propulsion technology bring our top speed to within one-tenth of the speed of light, and perhaps much more, making IST a more reasonable proposition, at least in our “neighborhood”. There may be civilizations that have already done so.

Answers to the Fermi Paradox often involve a concept called the Great Filter. This excellent HuffPo article by Tim Urban on the Fermi Paradox provides a good survey of theories on the Great Filter. The idea is that there are significant factors that prevent civilizations from advancing beyond certain points. Some of these are of natural origin, such as asteroids and radiation exposure. Others might be self-inflicted, such as a thermonuclear catastrophe or some other kind of technology gone bad. Some have suggested that the Large Hadron Collider in Switzerland could be a major hazard to our existence, though physicists insist otherwise. Another example is the singularity, when artificial intelligence overtakes human intelligence, creating a possibility that evil machines will do us in. The point of these examples is that some sudden or gradual development could prevent a civilization from surviving indefinitely. These kinds of filters provide an explanation for the Fermi Paradox.

More broadly, there could be less cataclysmic impediments to development that prevent a society from ever reaching an advanced stage. These would also qualify as filters of a sort. Perhaps the smart ETs lack, or failed to evolve, certain physical characteristics that are crucial for advancement or IST. Or their home planet might be light on certain kinds of resources. Or perhaps an inferior form of social organization has limited development, with inadequate wealth creation and technologies to transcend the physical limitations imposed by their world. On a smaller than planetary scale, we have witnessed such an impediment in action many times over: socialism. The inefficiencies of central planning place limits on economic growth, and while high authorities might dictate a massive dedication of resources toward science, technology and capital-intensive space initiatives, the shift away from personal consumption would come at a greater and greater cost. The end game may involve a collapse of production and a primitive existence. So the effort may be unsustainable and could lead to social upheaval; a more enlightened regime would attempt to move the society toward a more benign allocation of resources. Whether they can ever accomplish IST is at least contingent on their ability to create wealth.

Socialism is a filter on the advancement of societies. ETs capable of interstellar travel could not be spawned by a society dominated by socialism and central planning. While government might play a significant role in a successful ET civilization, one capable of IST, only a heavy reliance on free-market capitalism can improve the odds of advancing beyond a certain primitive state. Capitalism is a relatively easy ticket to the wealth required for an advanced and durable civilization, and conceivably to the reaches of the firmament.

Unfortunately, there is absolutely no guarantee that capitalistic ETs will be friendly  toward competing species, or that they will respect our property rights. They might be big, smart cats and find us mouse-like and quite tasty. Their children might make us perform circuses, like fleas. In any case, if ETs get this far, it’s probably because they want our world and our resources. My friend Crawford says that they won’t get here in any case. He believes that the difficulty of IST will force them to focus on their own neighborhood. Maybe, but on long enough time scales, who knows?

I would add a caveat to conclusions about the strength of the filters discussed above. A capitalistic society might reach a point at which it could send artificially intelligent, self-replicating machines into space to harvest resources. Those machines might well survive beyond the end of the civilization that created them. Conceivably, those machines could act autonomously or they could take coordinated action. But we haven’t heard from them either!

For a little more reading, here is SETI‘s description of the Fermi Paradox, and here is a post from io9 on the Great Filter.

Follow Sacred Cow Chips on WordPress.com

Recent Posts

  • Long COVID: a Name For Post-Viral Syndrome
  • Cash Flows and Hospital Woes
  • Let’s Do “First Doses First”
  • Fauci Flubs Herd Immunity
  • Allocating Vaccine Supplies: Lives or “Justice”?

Archives

  • January 2021
  • December 2020
  • November 2020
  • October 2020
  • September 2020
  • August 2020
  • July 2020
  • June 2020
  • May 2020
  • April 2020
  • March 2020
  • February 2020
  • January 2020
  • December 2019
  • November 2019
  • October 2019
  • September 2019
  • August 2019
  • July 2019
  • June 2019
  • May 2019
  • April 2019
  • March 2019
  • February 2019
  • January 2019
  • December 2018
  • November 2018
  • October 2018
  • September 2018
  • August 2018
  • July 2018
  • June 2018
  • May 2018
  • April 2018
  • March 2018
  • February 2018
  • January 2018
  • December 2017
  • November 2017
  • October 2017
  • September 2017
  • August 2017
  • July 2017
  • June 2017
  • May 2017
  • April 2017
  • March 2017
  • February 2017
  • January 2017
  • December 2016
  • November 2016
  • October 2016
  • September 2016
  • August 2016
  • July 2016
  • June 2016
  • May 2016
  • April 2016
  • March 2016
  • February 2016
  • January 2016
  • December 2015
  • November 2015
  • October 2015
  • September 2015
  • August 2015
  • July 2015
  • June 2015
  • May 2015
  • April 2015
  • March 2015
  • February 2015
  • January 2015
  • December 2014
  • November 2014
  • October 2014
  • September 2014
  • August 2014
  • July 2014
  • June 2014
  • May 2014
  • April 2014
  • March 2014

Blogs I Follow

  • TLCCholesterol
  • Nintil
  • kendunning.net
  • DCWhispers.com
  • Hoong-Wai in the UK
  • Marginal REVOLUTION
  • CBS St. Louis
  • Watts Up With That?
  • Aussie Nationalist Blog
  • American Elephants
  • The View from Alexandria
  • The Gymnasium
  • Public Secrets
  • A Force for Good
  • ARLIN REPORT...................walking this path together
  • Notes On Liberty
  • troymo
  • SUNDAY BLOG Stephanie Sievers
  • Miss Lou Acquiring Lore
  • Your Well Wisher Program
  • Objectivism In Depth
  • RobotEnomics
  • Orderstatistic
  • Paradigm Library
  • Scattered Showers and Quicksand

Blog at WordPress.com.

TLCCholesterol

The Cholesterol Blog

Nintil

To estimate, compare, distinguish, discuss, and trace to its principal sources everything

kendunning.net

The future is ours to create.

DCWhispers.com

Hoong-Wai in the UK

A Commonwealth immigrant's perspective on the UK's public arena.

Marginal REVOLUTION

Small Steps Toward A Much Better World

CBS St. Louis

News, Sports, Weather, Traffic and St. Louis' Top Spots

Watts Up With That?

The world's most viewed site on global warming and climate change

Aussie Nationalist Blog

Commentary from a Paleoconservative and Nationalist perspective

American Elephants

Defending Life, Liberty and the Pursuit of Happiness

The View from Alexandria

In advanced civilizations the period loosely called Alexandrian is usually associated with flexible morals, perfunctory religion, populist standards and cosmopolitan tastes, feminism, exotic cults, and the rapid turnover of high and low fads---in short, a falling away (which is all that decadence means) from the strictness of traditional rules, embodied in character and inforced from within. -- Jacques Barzun

The Gymnasium

A place for reason, politics, economics, and faith steeped in the classical liberal tradition

Public Secrets

A 93% peaceful blog

A Force for Good

How economics, morality, and markets combine

ARLIN REPORT...................walking this path together

PERSPECTIVE FROM AN AGING SENIOR CITIZEN

Notes On Liberty

Spontaneous thoughts on a humble creed

troymo

SUNDAY BLOG Stephanie Sievers

Escaping the everyday life with photographs from my travels

Miss Lou Acquiring Lore

Gallery of Life...

Your Well Wisher Program

Attempt to solve commonly known problems…

Objectivism In Depth

Exploring Ayn Rand's revolutionary philosophy.

RobotEnomics

(A)n (I)ntelligent Future

Orderstatistic

Economics, chess and anything else on my mind.

Paradigm Library

OODA Looping

Scattered Showers and Quicksand

Musings on science, investing, finance, economics, politics, and probably fly fishing.

Cancel