Will We First Find Simple or Intelligent Life beyond the Earth?
Is there now a race to discover extra-terrestrial life? The search for life has gained greater momentum by the new knowledge that the Universe holds trillions of planets. Astrobiologists are beginning to search for chemical signatures — water, oxygen, hydrocarbons — far beyond our Solar System. But another search has been ongoing for over 50 years — the search for extraterrestrial intelligence. There is also the search for life elsewhere within our Solar System. Will it first be here — nearby, or in the spectral signature of ecosystems far away or realized through a signal from intelligent beings beyond Earth?
In Arthur C. Clarke’s novel “2001 Space Odyssey”, astronaut Dave Bowman’s final transmission before being pulled into the monolith at Jupiter was “Oh, my god! It’s full of stars!” Today with our great telescopes, our view is as wondrous but looking up into the vastness of space, we are now more apt to exclaim, “my god, it’s full of planets!” Look up to the night sky. Every point of light and in the voids, there are planets. The sky is full of planets.
The search for ET may not be much of a race at all. The Kepler space telescope has discovered over a thousand planets in a minute section of just our galaxy, the Milky Way. Statistically, with a very high degree of certainty, given the present definition of planet by the International Astronomical Union, there are hundreds of billions of planets. Revise the definition to include the likes of Pluto and then there are trillions. There are on the order of 400 billion stars in the Milky Way. Nearly all have one or more planets; an assertion also from the statistics. Planets far outnumber the stars in the Universe and it may quickly follow that with so many planets, there is life throughout the Universe.
Those searching for the signatures of biology-at-work beyond the Earth now have an ever increasing supply of good candidates. Pick a star and point a telescope and spectrometer and search. Its not that easy just yet. Planets are so much dimmer than stars — their light being a minute fraction of reflected starlight — astronomers need to mask out their star’s light and reveal the meager shred of light leftover — arriving as reflection off the planet. The best way this will be done is with space telescopes working above the obstructing atmosphere of the Earth.
For many people that follow astronomy and read science fiction, the search for E.T is all too well known. In formal terms the search began with a paper in 1955 by Coconni and Morrison, “Searching for Interstellar Communications.” However, the question of intelligent life beyond Earth was kicked around centuries before that but in 1950, Enrico Fermi blurted out, “Where are they?” in a conversation with his colleagues at Los Alamos who quickly grasped the gist of the simple question. We now know that for 20th century technology and know-how, the answer is not so simple.
Sixty-five years later, we do not have an answer yet for Enrico Fermi. Its become even more perplexing because we know now that there are billions, 100s of billions of candidate planets out there.
The third search is very local and has focused on Mars beginning with the Viking landers in 1976. The experiments were inconclusive at best [NASA page link]. One test was negative while the second showed activity that a few still believe is an indicator of metabolic processes from organisms on Mars. However, since Viking, other landers — Mars Phoenix and the rovers (MSL, MER) — have revealed a caustic chemistry in the soil that could mimic the activity of biological organisms.
Much more recently, continued studies of the Galilean moons of Jupiter and the moon Titan and Enceladus of Saturn have raised new possibilities. The gravity from their parent planets produce tidal stresses that are converted to heat inside the moons. It is an internal source of energy for the moons which is as old as the Solar System and for billions of years could have been supplying key ingredients for the making of life — liquid water and energy.
Whether life can develop and evolve in those environments is not known. Nonetheless, it is quite likely that at least one space probe in the next 30 years will attempt to pass through the geysers spewing out of these moons to test for organics and more elaborately, for life. Already, Cassini has revealed the presence of hydrocarbons in the geysers of Enceladus.
If ecosystems exist in the Jovian and Saturn systems, they have, on the most part, been hidden and trapped under tens and hundreds of miles of crust. They may be systems that do not lend the conditions to develop intelligent life forms such as we have on Earth. Nonetheless, it is still one possibility for discovery of extraterrestrial life within the next 50 years.
The Needle in a Haystack
The haystack in which we search for the needle — for ET — is four dimensional. It is space & time. Imagine also that if the Universe has, for example, 11 dimensions, such as some String Theories propose, and intelligent life uncovers paths into those dimensions, then the search is more than daunting and instead straddles the impossible.
In their recent paper, “On the role of GRBs on life extinctions in the Universe”[link], published in the journal Science, Dr. Piran from Hebrew University and Dr. Jimenez from University of Barcelona explained that not only are there Goldilocks zones around stars, there is also a zone on a Cosmic scale. This zone has been dictated by the time for the Universe to expand and form a space-time that is tranquil — lacking frequent destructive gamma ray bursts that would repeatedly snuff out complex life leaving only simpler forms.
While we have not found anyone, the boundaries and conditions of the search are becoming more clear. There are millions if not billions of earth-like planets in our galaxy but most have had only the same amount of time to flourish and develop life as ours. The conjecture that in a 14 billion year old Universe where our Solar System is a mere 4.5 billion years old, there must be many biological systems much older than ours may not, well, hold water so well.
However, advanced intelligence may need just a few hundred years, or less, to be far more advanced than our present state. If intelligence elsewhere involves technology leading to artificial intelligence and control of their own evolution, then any intelligent life that exists out there could quickly be far beyond our capabilities.
The greatest unknowns are how intelligent life evolves beyond a state similar to ours. We do not know our own fate let alone the fate, nay, the existence of any others. Even with feeble technology, in a long standing struggle of subsistence, we have contrived answers to the greatest and oft most fearful questions that beset us. However, at the level of a species we persist and have grown but realize that we do not know where it takes us. How we will respond and evolve with a rapid expansion of knowledge and know-how, is not known. It is a fate likely besetting all intelligent lifeforms. Could it explain why we seem alone?
The answer of “Where are they?” could be completely so dark and ominous, the tinder that has fueled many science fiction stories. However, it could be far simpler than this. Our passage through the 20th Century that is responsible for setting our present vision of the Universe, has indeed provided the imagination and thoughtfulness to commence a search but by no means has provided the technology that is needed to truly make connections with the many intelligent beings out there. The 20th century could be just a venturi that has accelerated us into a fast approaching era where our technology will begin to touch upon the full capabilities that intelligent life can have to manipulate the Cosmos.
Why can’t we see any form of such massive modification of the Cosmos or signatures of intelligent life well beyond our means? Would every single one choose to withhold their whereabouts to lesser intelligence? We began our search with radio waves, listening for signals in conspicuous parts of the electromagnetic spectrum (21 cm). We have looked closer to the spectrum of our natural vision, the infrared. We searched for heat signatures and continue to do so. There may be “exhaust” signatures from the use of stellar power sources. On the other hand, the expulsion of waste products might only be on the calling card of young technological civilizations such as ours that develop then quickly advance or disappear.
The distances for communication are so daunting that great civilizations would have to harness nearly the power of whole stars to transmit to a sizable audience. Stephen Hawking and others worry that we shouldn't raise attention to our presence but on the other hand, with time, does intelligent life discover a harmony with Nature — the Cosmos — so grand that it transcends any need to say hello and shake hands with other “intelligent” life forms? Ultimately, we all seek understanding and harmony and without it, there is eventual disintegration.
So the problem has become much more clear in the last 20 years. There are plenty of planets to say the least. Simple life could thrive even without a nearby star or residence in an Earth-like Goldilocks zone. However, recent research is showing that living conditions have emerged across the Cosmos only in the second half of time in the Universe. And it appears imminent for us and therefore likely for other technologically-oriented intelligent beings that knowledge and power achieve a sudden and rapid expansion, one that quickly far exceeds our own present state. Lastly, there are questions that would be much more suited for Freud. Fermi’s question, “Where are they?” is anchored in the pinnings of our own psyche. Is curiosity universal? Is fear of the unknown and is the quest to understand embedded deeply in the evolution of all creatures? Is it a first derivative of our survival instinct that is likely a common denominator of life throughout the Cosmos? If the answer is ‘yes’, then where is everybody?
The search for intelligent life is also considering more sophisticated signals, for example, beings using light amplification by stimulated emission of radiation- lasers. Matter of fact, any discovery of laser light would be a sure indicator of life elsewhere no matter if it carries a signal — information — or not. Also, a search for very brief pico-second digital signals has commenced. Only our leading edge technology has permitted these new searches to begin. It underscores how we are still technologically feeble in attempting a full and comprehensive search for intelligent life.
The electromagnetic energy that reaches the Earth is a noisy blackbody-like spectra. On the other hand, E.T. could leave much simpler signals detectable from vast distances. Necklaces of geometric shapes could be orbiting safely around their parent stars blocking out their star light in periodically visible universal symbols of intelligence — solids or lattices of polyhedral shapes. We are looking but just like the search for simple signatures of distant ecosystems, our ability to detect many of these calling cards, stray or directed messages is just on the threshold of what is needed.
So the Fermi Paradox [@SETI Institute] remains just that and the search just as daunting but on the other hand there are 100s of billions of stars with planets and technology nearing implementation that will begin a straightforward examination for biological signs.
Concept illustrations of the NASA TESS space telescope (left) and the PLATO mission of ESA (right). The two telescopes will expand upon the search by Kepler and is likely to increase the number of known planets from the present ~2000 to over 20,000 planets many that will be orbiting nearby stars. Photo Credits: NASA, ESA
We have no idea how quickly or at all whether the spectral signatures of ecosystems beyond our Solar System will be found. We do not know how common life is, whether simple or complex. Astrobiologists are quick to say, we simply need more data — some data. The Earth’s system represents effectively one data point.
More data is coming. The groundbreaking work of William Borucki [bio] of the SETI Institute led to the study of 150,000 stars by the Kepler space telescope in search of planets. Over 1000 transiting planets have been confirmed from Kepler observations with still more to come. Next up will be two new space telescopes — NASA’s Transiting Exoplanet Survey Satellite (TESS) launching in 2017 and the ESO’s Planetary Transits and Oscillations of stars (PLATO) in 2024. TESS will search fr planets around 500,000 bright stars and 1000 of the closest stars, primarily small red dwarfs. PLATO will search up to a million stars for Earth-like planets with the potential for habitability.
PLATO and TESS is effectively part of the first of a two step program. The second step has commenced already from the ground. There are searches underway for spectral signatures of water and hydrocarbons and results are positive. However, they are crude measurements on the edge of noise levels and how they truly translate to real properties of planets, if at all, orbiting distant stars remains a question.
Engineers and scientists within NASA, ESA and several institutes are working on coronagraph concepts and designs that will block out the light of a star to leave the feeble reflected light of planets surrounding them. PLATO and TESS will first add to the results from Kepler and ground-based efforts but it will be the 2020s before any stellar coronagraph telescopes search for the spectral signatures of life.
Once stellar coronagraphic telescopes begin the search, dozens of good candidate planets will be checked within weeks or a few months. If life is common, then the first indicators of their presence should be discovered quickly. As time goes on and the telescope discovers nothing revealing life, some statistical work will be possible that sets upper limits. We will realize that life is more rare and uncommon throughout the Universe with each passing negative result.
However, discovery could come swiftly and the search would be over. ‘Life is out there.’ We are not alone and finding one other ecosystem quickly would be a sure indicator that we will find many, many more. The search and discovery would swiftly become a process of classification which has already been imagined by some scientists. And it cannot be discounted that ground-based efforts could advance sufficiently before the 2020s to reveal real signs of life — ecosystems beyond the Earth.
The night sky would be transformed. As our ancestors knew it as being full of stars and we begin to know it as full of planets, it could suddenly be seen as a vast veil of flora and fauna overhead. Parents will point to not just interesting stars — blue or super red giants — but also explain how this or that nearby star has ecological systems very similar to ours. At the same time, the Fermi Paradox — “Where is everybody?” could remain and continue to be raised by generations to come.
Other recent stories by T.Reyes:
The Prelude to the Singularity — our relation with past & present technology foreshadows what could become of us with emergence of artificial super-intelligence
The Singularity can explain why we seem alone in the Universe
By Boots or Bots? How Shall We Explore?
Ex Machina, Humanity’s Ultimate Blind Date
How We’ve ‘Morphed’ From “Starry Night” to Planck’s View of the Cosmos
