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This past Wednesday Col Maybury, host of the Australian radio show The Starlight Zone, interviewed Shawn and I about covering the far side of the Moon with mirrors as a remotely detectable technosignature.
Listen to the complete (~5 minute) interview at the Starlight Zone
This idea got far more press than either of us had anticipated, so we tried to use our air time to do some damage control and clarify the idea beyond the scope of a brief news write-up. We are currently in the process of drafting the manuscript for submission.
This work is unfunded: We came up with this idea following the Pale Blue Dot III meeting as a solution to particular problems with the SETI approach to finding intelligence; however, we are not funded to develop this idea nor do we have any intentions of proposing construction of mirrors on the Moon to any funding agency. (Our global society can’t even agree upon a consistent program to address climate change issues–I seriously doubt our ability to maintain a long-term signaling project.)
Our signal is omnidirectional: A targeted broadcast such as a radio signal or laser pulse is limited because of its directionality. Our scheme, though, covers the far side of the Moon with mirrors on pivots (with dark solar panels on the opposite side) so that the albedo of the Moon can be effectively changed from 0 to 1, resulting in a 20% change in luminosity for the Earth-Moon system. This change in luminosity will be observable from almost any direction at any time and will not require a targeted broadcast.
Our signal is broadband: Because the light reflected from the Moon’s mirrors comes from the Sun, the detected change in luminosity will span a large section of the electromagnetic spectrum (depending on the particular mirrors used). This further increases our chance of success because we make fewer assumptions about the preferred observational/communicative frequency of extraterrestrials (whereas conventional SETI presumes radio beacons or other narrow-band broadcasts).
This beacon requires current and near-future technology: The mirror/solar panel pivots can be constructed with current technology. Furthermore, we are detecting new extrasolar planets every day. In 2009, Kepler will launch in search of terrestrial planets around other stars, and in the next 10-20 years the Terrestrial Planet Finder will be able to observe these planets and take spectra of their atmospheres. In other words, within the century it will be within our technological grasp not only to build such a signal but also to detect a similar signal around a distant world.
ET’s may use a similar technique: Even if we never construct a technosignature using the Moon, it is conceivable that a technological extraterrestrial society may signal their presence using a similar method. If the Terrestrial Planet Finder were to detect an Earth-sized planet around another star blinking in the prime numbers, we would at least have a hypothesis to explain this seemingly deliberate signal.
NewScientist wrote a short article on an idea Shawn and I have been discussing:
Mounting mirrors on the Moon and using them to signal across space could let ET know we Earthlings are here.
Ever since radio broadcasts began we’ve been trumpeting our presence to nearby parts of the galaxy, so far without reply. To improve the chances of being found, Shawn Domagal-Goldman and Jacob Haqq-Misra of Pennsylvania State University in State College reckon we should cover half of the Moon with mirrors.
Read the full article at NewScientistSpace.
Last day of AbSciCon tomorrow. The conference has been useful and thought provoking, though I have almost reached my saturation level for absorbing new information from fifteen minute talks. I present my talk on the climate of the Archean Earth (2.8 billion years ago) tomorrow morning. I also didn’t realize this until I arrived here, but apparently I have my name on four abstracts at the conference!
A Revised, Hazy Methane Greenhouse for the Archean Earth, J. Haqq-Misra, S. Domagal-Goldman, P. Kasting, J. Kasting
Synthesizing Archean Models and Data: A Self-Consistent Evolutionary History, S. Domagal-Goldman, J. Kasting, J. Haqq-Misra
Sustainability and the Fermi Paradox, J. Haqq-Misra
TPF-SETI, S. Domagal-Goldman, J. Haqq-Misra
Compared to the other conferences I’ve attended, it’s quite rewarding to feel like I’ve contributed something to the astrobiology community. More on the conference when I get back this weekend!
I have my own opinions as to the prevalence of life in the Universe, but I’m curious to hear what the rest of you have to say.
What do you think: is the phenomenon of life on Earth a cosmological fluke, or is the galaxy littered with inhabited worlds? Perhaps microbial life is commonplace while multicellular structures are rare–or maybe the galactic empire is stealthily watching and waiting for us to cross a technological threshold. And, of course, there’s always the possibility of stumbling across an alien beacon.
Ready, go!
My NaNoWriMo novel is finished, and I am quite pleased with the result. The story Inhabitants of Eternity is a journey of philosophical and spiritual ideas set in the context of near-future scientific discoveries. In particular, the Terrestrial Planet Finder mission will be capable of observing terrestrial planets around other stars, which includes the ability to determine the gases present in the atmosphere. It is conceivable, then, that in the next century we will observe a planet that, at a distance, looks nearly identical to our own life-filled world. Though we have continually been pushed into mediocrity by the discoveries of astronomy and cosmology, Earth is still the only inhabited planet that we know of, and so the uniqueness of Earth’s phenomenon remains a steadfast truth for many people. Set in the near future when this mission first starts surveying the skies, Inhabitants of Eternity explores the implications of such a discovery on both religious and secular thought.
The story takes place through a series of dialogues that explore our conception of knowledge, the implications of biological evolution, the likelihood of extraterrestrials, and the relationship between religion and science. The main character is also a dreamer, which provides a unique setting for his own exploration of these personal and profound ideas. I have written several essays that touch on some of the themes in this story, but I until now I had not outlined the totality of these thoughts into a single work of discussion. I certainly learned a lot from this process, and I am looking forward to what the eventual finished work will look like. I like to give my writings time to ripen, so I will likely not start revisions until January or February; revision seems most beneficial with a fresh look at the manuscript.
For thus says the high and lofty one
who inhabits eternity, whose name is Holy:
I dwell in the high and holy place,
and also with those who are contrite and humble in spirit,
to revive the spirit of the humble,
and to revive the heart of the contrite. (Isaiah 57:15)
I’m not usually a huge fan of YouTube blog entries, but I couldn’t resist posting this gem from my childhood. I saw this music video/PSA (which apparently is the Barenaked Ladies) while watching Saturday morning cartoons one day, and I was never able to find it again until now! What could be more perfect than the combination of racial tolerance and extraterrestrials?
Last night in Seattle before heading back to State College.
SETI initiatives and other projects to search for intelligent life often assume they are looking for a single intelligent species–perhaps similar in some ways to our own–that has achieved mastery over their home planet. The modern global civilization views itself as separate from the biosphere, and as a result has continued a self-destructive pattern of increased consumption and growth. This civilization views itself as the masters of the world, the single most important and dominant species on the planet. Search for life initiatives implicitly assume any contact they make will likewise be a single “superior” species.
This notion is relatively recent, though, compared with the duration humans have existed on Earth. No species is an island, since life cannot exist outside of the community. Although the global human civilization views itself as separate from the community of life, this pattern of thought is ignorant and ultimately self-destructive. Likewise, any long-lived extraterrestrial intelligence (at least that resembles what we know in some way) will be part of a community of life. If we ever make contact, we will reach an entire community–not just a single species.
I keep meaning to get to some posts on evolution, but I keep getting distracted by end-of-the-semester work (and winning money at poker). This is the concluding paragraph from a paper I just finished on the Fermi Paradox for a class. I’m pretty happy with how it turned out, and I’m interested to see what my advisor thinks of it.
The Fermi Paradox cannot logically conclude that humans are the only advanced intelligence in the galaxy, but the absence of evidence for ETI colonization of the galaxy is suggestive that no ETI has successfully formed a galactic civilization. This is not because no sufficiently advanced intelligence has developed technology, but it is because civilization itself is an unsustainable mechanism. SETI assumptions often imply that civilization is a necessary consequence of intelligence—but even if this were true, the ecological instability of civilization would render any galactic civilization short-lived. A galactic civilization may arise in the Milky Way, but its limited duration will make it nearly impossible to detect. The absence of ETI civilization does not preclude the search for life, since missions such as TPF and DARWIN are not dependent on the presence of intelligence. Additionally, there is always the possibility that a sustainable extraterrestrial intelligence exists in the galaxy—perhaps even in the solar vicinity. Detection of such life may prove difficult, though, since it has always been a challenge to conceive of the life we do not know.
Awhile back I asked myself a question: millions of years from now, when dolphins, whales, chimpanzees, gorillas, or other creatures develop further in intelligence, will they have any form of spirituality or religion? Alternatively, will an extraterrestrial intelligence have any form of spirituality or religion?
I think I finally know how to begin answering this question.
One of my favorite jokes, I figured it should be immortalized here.
At some point in the future, humanity’s exploitation of Earth’s resources renders the planet completely devoid of any materials. The moon does not last long either, so the next logical choice is Mars.
A Mars exploratory team is driving around the surface, searching for new mineral deposits, promising geologic features, and even signs of past life. As they turn a corner around a hill, the team gasps in amazement at what they see: in front of them is a tremendous, colossal, 50-story statue of a human-like figure sitting down. And even more amazing is that every single test they run on the statue indicates it is alive–yet the figure appears no more than a stone sculpture. All the great minds of the world begin to search for a solution to this paradox, but no successful theory emerges.
One day, a young post-doc is pacing back and forth beneath the statue when he breaks down: “How can something like this exist? It just doesn’t make sense!” The moment he speaks those words, the sky darkens, the wind begins to howl, and the statue slowly stands up, looking down at the post-doc. In a thundery, booming voice the statue says, “It can’t exist. It’s impossible!” “Oh, of course,” says the post-doc. “It only stands to reason.”
Artists, engineers, soldiers, and kings are not a result of extra time due to the benefits of agriculture. Rather, the Mesopotamian culture was accelerated through a path of technological development because of the large populations they generated. Non-Mesopotamian cultures have developed technology, but the pace of development is much slower. They do not have less free time; there are simply fewer people and therefore less combined free time. The population explosion in the Mesopotamian culture resulted in a greater number of people doing science/art/etc., but this was not because each person had extra time. Thus, totalitarian agriculture (or any agriculture, for that matter) is not a prerequisite for technology. Technology may develop at a slower rate, but agriculture is not a prerequisite.
With regard to life in the Universe, it may be that a lifestyle akin to totalitarian agriculture does not develop very often. This does not mean that no communicable civilizations exist, though. The Mesopotamian culture’s worldview (that humanity is above Nature) is a destructive one, akin to a self-annihilating civilization as SETI describes (one with a low value of L in the Drake Equation). Therefore, the detectable, communicating civilizations will take similar paths to the non-Mesopotamian cultures; this will provide ample time for the civilization to adapt and gradually incorporate technology into their lives, avoiding unfortunate consequences. These types of civilizations will be long-lived (high value of L in the Drake Equation) and able to develop communication projects similar to SETI and other efforts.
In other words, the Mesopotamian-worldview may accelerate the pace of technological development, but it will ultimately lead to the demise of the civilization. Conversely, non-Mesopotamian-worldviews will lead to steady technological development and eventually result in stable (not necessarily perfect) civilizations capable of communicating.
Life in the Universe lives on.
This was pointed out when I attended the Pale Blue Dot III meeting and has certainly been mentioned by others as well.
In the movie Contact, Ellie Arroway remarks, “If just one in a million of those stars has planets, and if only one in a million of those has life, and if just one in a million of those has intelligent life, then there are millions of civilizations out there.”
By current estimates there are ~1022 stars in the Universe. Thus, by the above statement there would not be millions of civilizations but rather 1022/(106)3 = 10,000 civilizations in the Universe. The Contact filmmakers suggest that we might very well be alone in our own galaxy (although I doubt Carl Sagan shared this sentiment).
I think the odds are better than that, anyhow. And, always thinking optimistically, I think there is a chance that we will be able to touch upon this question within my lifetime. Contact with extraterrestrials may be far off, but missions such as the Terrestrial Planet Finder may give us some clues to this age-old question.
Arr, I be at th’ Pale Blue Dot III workshop on National Talk Like a Pirate Day!
In th’ search fer extraterrestrial intelligence, a deliberate signal received from another civilization would be a clear signal that we be nay alone. Th’ problem becomes more difficult, however, when we consider th’ possibility o’ an extinct civilization, an’ we can only detect the’r “graveyard” from a distance. Technological artifacts may remain fer a short time, but weatherin’, plate tectonics, an’ convection smartly eliminate any traces o’ past intelligent life. E’en if a civilization constructed a monolith t’ the’r existence, ‘t would be nearly impossible t’ detect at a distance.
Thar be nay simple solution t’ this problem (at least, nay yet). Me idee involves th’ use o’ a relatively inactive (geologically speaking) satellite orbitin’ th’ planet o’ interest (such as Earth`s moon). Perhaps a technologically advanced civilization altered th’ atmosphere o’ one o’ its satellites such that th’ signal persists long after th’ life has gone extinct. An atmospheric signal would be detectible at a distance, an’ if we could determine properties o’ th’ satellite (such as mass, size, an’ orbital radius) ‘t may be possible t’ identify an artificially generated atmospheric signal. O’ course, thar be nay guarantee that any o’ these factors be present, but nay one spake graveyard huntin’ would be easy.
There are an infinite number of lines that can be drawn through a point on a plane.
This is part of the problem when considering life in the galaxy and beyond: a sample size of one. But we won’t let that stop us now.
The Drake Equation, developed by Frank Drake and Carl Sagan, is a probabilistic method for estimating the number of communicative civilizations in the galaxy. It’s difficult when we only have one data point to work with, but here’s my [current] set of parameters for the equation, with explanations:
The Drake Equation: N = R * Fp * Ne * Fl * Fi * Fc * L
R = rate of formation of stars in the galaxy = 10 stars/year [~1011 stars in the galaxy / ~1010 years (for the age of the Milky Way)]
Fp = fraction of those stars with planets = 35% [about half of star systems are binaries, although even some of these may have planets; but not all single-star systems have planets either]
Ne = number of “Earths” per planetary system = 0.5 [many planetary systems consist of "hot Jupiters"; current detection methods are skewed toward these type of systems, so it is perhaps reasonable to assume that half of the systems have an "Earth"]
Fl = fraction of these planets where life develops = 80% [once the conditions for life are present, it may be the case that life will develop in some form]
Fi = fraction of these planets with intelligent life = 5% [is intelligence an automatic consequence of evolution, or is life common but intelligence perhaps less so?]
Fc = fraction of these planets where communicative technology develops = 50% [once intelligence is achieved, it seems likely that technology will eventually follow]
L = lifetime of communicating civilizations = 200 years [okay, so I'm a bit pessimistic; but I doubt the ability of humanity to progress 200 years past the radio era]
With these parameters, I get an estimate of the number of communicative civilizations in the Milky Way to be N = 7.
Last time I did this, I got N = 2, so perhaps the results of planet searches have increased my outlook. In any case, I certainly hope there’s more than 7 in the galaxy. And maybe humans are simply a poor example of a technologically advanced civilization, and L for the universe is really more on the order of a thousand years or so.
There are approximately 240 M dwarf stars within 10 parsecs of Earth. M dwarfs (small, cool, dim stars) are thought to make up about 75% of the stars in the universe, although they are too faint to be detectable by the naked eye. The expected lifetime of an M dwarf is >100 billion years–much longer than the current age of the universe, so there have probably been very few M star deaths thus far.
Given the age and number of M stars, if life exists elsewhere in the universe then the life around M stars might have a significant evolutionary advantage to us Earthlings. We only got in the game a little over 4 billion years ago (when the Sun formed), but these guys could have had up to 13 billion years of development! Assuming that they didn’t blow themselves to bits in some massive civil war, there could very well be a highly advanced M star civilization out there, simply given the amount of time they could have had. Of course, self-destruction of an “intelligent” civilization is a separate matter of speculation. Maybe tomorrow I’ll go through the Drake Equation for fun. But I still like to think that somewhere out there is an M star system teeming with life.
On Star Trek, the prime directive is a guiding principle of the Federation, dictating non-interference with the development of a primitive society. If memory serves me correctly, this was often invoked when the Enterprise encountered intelligent beings, but never on a planet that contained only single-celled organisms. But doesn’t the principle of non-interference still apply?
Suppose our exploration of Mars uncovered living subterranean organisms. Maybe it will “just” be single-celled organisms, but I would maintain that it is still “their” planet. I’ll admit that I would be torn between the notion of studying an extraterrestrial life form and non-interference. But in terms of non-interference, where does the line get drawn? Star Trek writers kept it simple by creating encounters with intelligent civilizations, but what if they encountered a planet full of, say, squirrels? The squirrels are not intelligent in the classical sense of the word, but they certainly are a complex life form that can develop further. What about an ocean world full of fish? Although I would have a hard time simply walking away from Mars were life to be discovered, I am still not satisfied with non-interference being limited only to those encounters which we consider to be “intelligent”.
It’s all over the Earth, and now it’s around Saturn! A NASA press release today announed that liquid water has been discovered on Saturn’s moon Enceladus, in the form of erupting geysers. Joining Europa and Titan, we now have several targets within our own Solar System to search for life, or at least learn more about favorable/disfavorable conditions for the development of life. Of course, water does not automatically imply life, but it’s a great start. After all, on Earth wherever we find water, we find life. But life or no life, a satellite with active vulcanism is still exciting in its own right.
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