Aliens
NASA
No one knows for sure if aliens exist, but most scientists think it’s probable due to the universe’s vastness, though definitive proof is missing, with current searches focusing on potential habitable spots like Mars’ moons (Europa, Enceladus) and exoplanets, finding signs but not conclusive evidence yet. While simple microbes are considered more likely, some believe intelligent life could exist, though no confirmed signals or visits have occurred, despite public interest and ongoing scientific investigation.
News stories about the likely existence of extraterrestrial life, and our chances of detecting it, tend to be positive. We are often told that we might discover it any time now. Finding life beyond Earth is “only a matter of time”, we were told in September 2023. “We are close” was a headline from September 2024.
It’s easy to see why. Headlines such as “We’re probably not close” or “Nobody knows” aren’t very clickable. But what does the relevant community of experts think when considered as a whole? Are optimistic predictions common or rare? Is there even a consensus? In our new paper, published in Nature Astronomy, we’ve found out.
During February to June 2024, we carried out four surveys regarding the likely existence of basic, complex and intelligent extraterrestrial life. We sent emails to astrobiologists (scientists who study extraterrestrial life), as well as to scientists in other areas, including biologists and physicists.
In total, 521 astrobiologists responded, and we received 534 non-astrobiologist responses. The results reveal that 86.6% of the surveyed astrobiologists responded either “agree” or “strongly agree” that it’s likely that extraterrestrial life (of at least a basic kind) exists somewhere in the universe.
Less than 2% disagreed, with 12% staying neutral. So, based on this, we might say that there’s a solid consensus that extraterrestrial life, of some form, exists somewhere out there.
Scientists who weren’t astrobiologists essentially concurred, with an overall agreement score of 88.4%. In other words, one cannot say that astrobiologists are biased toward believing in extraterrestrial life, compared with other scientists.
When we turn to “complex” extraterrestrial life or “intelligent” aliens, our results were 67.4% agreement, and 58.2% agreement, respectively for astrobiologists and other scientists. So, scientists tend to think that alien life exists, even in more advanced forms.
These results are made even more significant by the fact that disagreement for all categories was low. For example, only 10.2% of astrobiologists disagreed with the claim that intelligent aliens likely exist.
Optimists and pessimists
Are scientists merely speculating? Usually, we should only take notice of a scientific consensus when it is based on evidence (and lots of it). As there is no proper evidence, scientists may be guessing. However, scientists did have the option of voting “neutral”, an option that was chosen by some scientists who felt that they would be speculating.
Only 12% chose this option. There is actually a lot of “indirect” or “theoretical” evidence that alien life exists. For example, we do now know that habitable environments are very common in the universe.
We have several in our own solar system, including the sub-surface oceans of the moons Europa and Enceladus, and arguably also the environment a few kilometres below the surface of Mars. It also seems relevant that Mars used to be highly habitable, with lakes and rivers of liquid water on its surface and a substantial atmosphere.
It is reasonable to generalise from here to a truly gargantuan number of habitable environments across the galaxy, and wider universe. We also know (since we’re here) that life can get started from non-life – it happened on Earth, after all. Although the origin of the first, simple forms of life is poorly understood, there is no compelling reason to think that it requires astronomically rare conditions. And even if it does, the probability of life getting started (abiogenesis) is clearly non-zero.
This can help us to see the 86.6% agreement in a new light. Perhaps it is not, actually, a surprisingly strong consensus. Perhaps it is a surprisingly weak consensus. Consider the numbers: there are more than 100 billion galaxies. And we know that habitable environments are everywhere.
Alone in the Vast Universe?
Sir Bernard Lovell, one of the world’s leading radio astronomers, has calculated that, even allowing for a margin of error of 5000%, there must be in our galaxy about l 00 million stars which have planets of the right chemistry, dimensions, and temperature to support organic evolution.
If we consider that our own galaxy, the Milky Way, is but one of at least a billion other galaxies like ours in the observable universe, the number of stars that could support some form of life is, to reach for a word, astronomical.
As to advanced forms of life-advanced by our own miserable earth standards-Dr. Frank D. Drake of the National Radio Astronomy Observatory at Green Bank, West Virginia, has stated that, putting all our knowledge together, the number of civilizations which could have arisen by now is about one billion.
The next question is, “Where is everybody?” The nearest neighbour to our solar system is Alpha Centauri, only 4.3 light years away; but, according to Dr. Su-Shu Huang of the National Aeronautics and Space Administration, its planetary system is probably too young for the emergence of life.
Two other heavenly friends, Epsilon Eridani and Tau Ceti, about 11 light years away, are stronger contenders for harbouring life. Nevertheless, if superior civilizations are abundant, the nearest would probably be at least 100 light years away; therefore, it would take 200 years for a reply to be forthcoming, a small matter of seven generations. This should, however, make little difference to us, in view of the enormous potential gain from our contact with a superior civilization. Unless we are terribly conceited (a very unscientific demeanour), we must assume that the “others” are far more advanced than we are.
Even a 50- year gap would be tremendous; a 500-year gap staggers the imagination, and as for a 5000-year gap … (By the way, if they are as much as 50 years behind us, forget it!) It is quite possible that “others” have satellite probes in space, retransmitting to “them” anything that sounds non-random to the probe.
But they have probably called us several thousand years ago and are waiting for an answer; or worse yet, they have given up; or, more probably, they have reached such impressive technological advances that they have destroyed themselves.
Exchange Messages with Whom?
These attention-getting signals would be followed by what amounts to early “language lessons,” interspersed with items of technical information to help bring us up to the level of our superiors, “them.”
It may be assumed that the sense of sight, or an equivalent, is possessed by all higher· forms of life; the problems of communication could thus be greatly simplified through the medium of a “raster” representation such as that of a television screen.
After a conference held at Green Bank in 1961 to discuss the possibility of communication with other planets, one of the participants, Bernard M. Oliver, made up a hypothetical message on the raster principle. The message, consisting of 1271 binary digits or “bits,” is shown in Figure 1.
Since 1271 has but two prime factors, 31 and 41, we would naturally be lead to write out the message in raster form, in 41 lines of 31 bits each, or in 31 lines of 41 bits each; the latter case reveals a greater no randomness in the patterns disclosed, indicating that these are the correct dimensions.
There are dots at the four corners of the pictogram as reference points, marking the outlines of the rectangle. At the upper left is a representation of the sun; directly underneath in a column are dots representing 8 planets, identified by the appropriate binary coding to their left, preceded by a binary point as a marker.
The erect, two-legged beings illustrated are obviously bisexual and mammalian; one hand of the male figure points to the fourth planet where they apparently reside. At the top of the pictogram may be seen representations of hydrogen, carbon, and oxygen atoms, indicating that the chemical structure of life on their planet is like ours.
From the third planet there emerges a wavy line, showing that it is covered with water; the fish shows that they must have visited us and therefore have space travel. One hand of the female figure points to a six (preceded by the usual binary point), perhaps implying that there are six fingers on each hand; we could therefore assume that their number system is probably to the base 12.
At the tight of the female figure may be seen a bracket, in the middle of which is eleven in binary form (preceded by a binary point): this implies that the beings are 11 units high. A reasonable interpretation is that the unit is 21 cm., the wavelength of the transmission, making them about 7 Y2 feet tall, which ·should be all right for average Martians.
In 19 5 2 the British scientist Lancelot Hogben delivered an address before the British Interplanetary Society entitled “Astra glossa, or First Steps in Celestial Syntax.” Hogben pointed out that number is the most universal concept for establishing communication between intelligent beings, therefore mathematics forms the basis for the first steps in extraterrestrial communication; he then illustrated how he could transmit pulses representing integers, and distinctive signals or “radio glyphs” representing “+’ ‘, “-“, “= “, and so on.
Morrison later carried out the basic idea a little further, using different pulse shapes to represent elementary mathematical symbols. An entirely different approach was developed by Hans Freudenthal, Professor of Mathematics at the University of Utrecht, who in 1960 published a book entitled Linces: Design of a Language for Cosmic Intercourse.
“Linces,” an acronym of “lingua cosmic,” tries to establish a communication of ideas through symbolic logic, but the consensus of those who have taken the trouble to study his book is that his plan is too difficult. After all, the object of the exercise is getting ideas across to another party, whose thinking processes may be entirely different from our own.
In other words, what we need to develop is an “inverse cryptography,” or Soil OFFICIM: USE ONL1 communication symbolism specially designed, not to hide meaning, but to be as easy as possible to comprehend. Cleverness on the part of the sender is then the important factor, not reliance on ingenuity of the recipient.
The inverse cryptographer-somehow, this term doesn’t sound quite right-must make his meaning clear to the recipient, even if the latter does not possess a cosmic equivalent of the Rosetta Stone.
As an illustration of how much information could be conveyed with a minimum of material, and as an example of facile inverse cryptography, let us consider a message I have devised to be typical of what we might expect of an initial communication from outer space.
The punctuation marks are not part of the message, but here represent different time lapses: adjacent symbols are sent with a short pause (1 unit) between them; a space between symbols means a longer pause (2 units); commas, semicolons, and periods indicate pauses of 4, 8, and 16 units, respectively. Between transmissions (numbered here for reference purposes) there is a time lapse of 3 2 units.
Transmission
( 1) A. B. c. D. E. F. G. H. I. J. K. L. M. N. 0. P. Q. R. s. v. w. x. Y. z. * &. $. ¢ . #. @. A. B. C. D. E. F. I. J. K. L. M. N. o. P. Q. R. S. T. U. v. w. x. Y. z. * ¢ . #. @. ( 2) A A, B; A A A, C; A A A A, D; A A A A A, E; A A A A A A, A A A A A A A, G; A A A A A A A A, H; A A A A A A A A A, A A A A A A A A A A, J. (3) A K A L B; A K A K A L C; A K A K A K A L D. A K A L B; BK AL C; CK AL D. BK CLE; EL BK C; F K D L J; J L D K F. EL K E; K E L E. (4) C MA LB; D MAL C; G ME LB; EM G L MB. (5) D KN L D; GK N ~ G; F M F L N; EM E L N. (6) J L AN; J K A L AA; J K B L AB; AA K A L AB. J K J L BN; J K J K J L CN; INK C L IC. (7) B 0 C L F; D 0 B L H; E 0 B L AN; D 0 AN L DN. (8) F P C L B; H P B L D; J P B L E; J P E L B. (9) AP J L Q J; AP ANN L Q ANN; Q J, P J L Q ANN. (10) Q J LR A; Q J 0 BL RB; ARE MAL REL E 0 Q J. Q ANN L R NA; Q ANN 0 B L R NB. (11) H L H; GS C, C S G. DK A L C K B; DK C S EK A; E K A S D K C. (12) D T A; D T B; D T C; D L D; D U E; D U F; D U G. J T I; J U AA. (13) FIRII V GN; ANNN K C V ANNN; AN P C V CRC. T. u. G. H. &. $. F· , I; (14) W E K AX L E KA; B W E K AX L W B 0 EX KW B 0 AX L B 0 F. (15) C YB L I; E YB L BE; B Y E L CB; W DK AX Y BL BE. (16) BE Z BL E; FD Z B L H; BG Z C L C; ABE Z C L E. W AI K F X Z B L E. BE Z B L M E; MABE Z C L M E.
(17) D * L D 0 C 0 B 0 AL BD; E * LE 0 D 0 C 0 B 0 AL ABN; H * L DNCBN. (18) & P D LAM Q C K Q EM Q G K Q I M. & V CRADAEI. (19) $LA K Q WA * X K Q W B * X K Q W C * X K Q W D * X K. $ V BRGAHBH. (20) ¢ E K A # L W E K A X; B ¢ E K A # L B W E K A X; B ¢ E K W D K C X # L B W E K G X. ¢ B # ¢ D # L W B X W D X L B 0 D. (21) SY ¢ & 0 WM AX Z B #KA L N
(22) B K C L ¢ @ NNA #; B K C L E. C 0 D L ¢ @_) NNA #; C 0 D L AB. D Y B L ¢ @ NNA # ; D Y B L AF . ( 23) B K C L E; ¢ @ NNB #. B K 0 L E; ¢ @ NNC #. E Y B L BE; ¢ @_) NNB # . F Y B L C E ; ¢ @_) NNC # . I T E ; ¢ @ NNB # . H U C ; ¢ @_) NNC # . & V BRGAHBH ; ¢ @ NNC # . ( 24) B L ¢ @ NND #. C L ¢ @ NND #. E, G, AA, AC, AG, ¢ @ NNO # . ANA ¢ @ NNO #. ( 25) ¢ @ NNE # L B 0 & ¢ @ A #; ¢ @ NNF # L & ¢ @ A # Y B . ¢ @ A # L ¢ @ NNG #. ¢ @ NNE # L B & ¢ @ NNG #; ¢ @ NNF # L & ¢ @ NNG # Y B. ( 26) ¢ @ NNH # L 0 0 Q C 0 & ¢ @ NNG # Y C . (27) Q B K Q 0 K Q H K Q AF K Q CB V A; Q B K Q 0 K Q H K Q AF K Q CB K ¢ @ NNI # L A. ( 28) C K ¢ @ A # L G; ¢ @ A # L 0. I K ¢ @ A # L AB; ¢@ A#LC. FDZ¢@ A#LH; ¢@ A#LB. ¢ @ A # L A, R GG, M R GG, J P C , & , K, M, ¢ @ NNI # . ¢ @ B # L A, R GG, M R GG, J P C , & , K, M, ¢ @ NNI # . ¢ @ C # L A, R GG, M R GG, J P C , & , K , M, ¢ @ NNI # . ( 29) ¢ @ NNE # L B & ¢ @ B #; ¢ @ NNF # L & ¢ @ B # Y B . ¢ @ NAN # LB ¢ @ C # K B ¢ @ 0 #; ¢ @ NAA # L ¢ @ C # 0 ¢ @ D # . ( 30) ¢ @ NNE # L ¢ @ NAB #, ¢ @ NAC #; ¢ @ NNF # L ¢ @ NAO #, ¢ @ NAC #. ¢ @ NAN # L ¢ @ NAB #, ¢ @ NAE #; ¢ @ NAA # L ¢ @ NAO #, ¢ @ NAE #.
Theories
Let’s say there are 100 billion habitable worlds (planets or moons) in the universe. Suppose we are such pessimists that we think life’s chances of getting started on any given habitable world is one in a billion. In that case, we would still answer “agree” to the statement that it is likely that alien life exists in the universe.
Thus, optimists and pessimists should all have answered “agree” or “strongly agree” to our survey, with only the most radical pessimists about the origin of life disagreeing.
Bearing this in mind, we could present our data another way. Suppose we discount the 60 neutral votes we received. Perhaps these scientists felt that they would be speculating and didn’t want to take a stance. In which case, it makes sense to ignore their votes. This leaves 461 votes in total, of which 451 were for agree or strongly agree. Now, we have an overall agreement percentage of 97.8%.
This move is not as illegitimate as it looks. Scientists know that if they choose “neutral” they can’t possibly be wrong. Thus, this is the “safe” choice. In research, it is often called “satisficing”.
As the geophysicist Edward Bullard wrote back in 1975 while debating whether all continents were once joined together, instead of making a choice “it is more prudent to keep quiet, … sit on the fence, and wait in statesmanlike ambiguity for more data”. Not only is keeping quiet a safe choice for scientists, it means the scientist doesn’t need to think too hard – it is the easy choice.
Getting the balance right
What we probably want is balance. On one side, we have the lack of direct empirical evidence and the reluctance of responsible scientists to speculate. On the other side, we have evidence of other kinds, including the truly gargantuan number of habitable environments in the universe.
We know that the probability of life getting started is non-zero. Perhaps 86.6% agreement, with 12% neutral and less than 2% disagreement, is a sensible compromise, all things considered.
Perhaps – given the problem of satisficing – whenever we present such results, we should present two results for overall agreement: one with neutral votes included (86.6%), and one with neutral votes disregarded (97.8%). Neither result is the single, correct result.
Each perspective speaks to different analytical needs and helps prevent oversimplification of the data. Ultimately, reporting both numbers – and being transparent about their contexts – is the most honest way to represent the true complexity of responses.
Do aliens exist? This is an interesting question and one that NASA has been trying to understand, explore, and figure out for a long time. We have not yet discovered life on any other planet, and we have not seen any scientifically supported evidence for extraterrestrial life.
But if we think about life on this planet, beyond the big things — the elephants, the whales, redwoods trees –– and focus on the tiny things, nearly everywhere on Earth that we’ve looked, we’ve found microbial life.
Our definition of habitable environments continues to expand. Off the Earth we’ve only begun to look. NASA has sent five rovers and four landers to the surface of Mars. Additionally, orbiters have been outfitted with some amazing cameras to take pictures of the whole surface of the Red Planet. But we’ve only explored a tiny fraction of Mars. And that’s only one of the promising bodies to look for life in our solar system.
There are icy moons in the outer solar system like Saturn’s moon Enceladus and Jupiter’s moon Europa that look like they may have subsurface oceans that could be habitable. And that’s just what’s in our solar system. The more exoplanets we find around other stars, the more we learn about how many different environments could exist for life.
We can’t yet say for sure whether aliens exist. To quote Carl Sagan: “The universe is a big place. If it’s just us, it seems like an awful waste of space.” So, NASA will keep looking.
We are not alone in the universe. A few years ago, this notion seemed farfetched; today, the existence of extraterrestrial intelligence is taken for granted by most scientists. Even the staid National Academy of Sciences has gone on record that contact with other civilizations “is no longer something beyond our dreams but a natural event in the history of mankind that will perhaps occur in the lifetime of many of us.”
Connection?
In this connection, Professor Iosif Shklovsky, Russia’s greatest radio astronomer, has cited the profound crises which lie in wait for a developing civilization, any one of which may well prove fatal:
1960 in Project Zoma, an attempt to detect possible intelligent signals from outer space. The frequency selected for listening was 1420.4057 52 megacycles per second, or a wavelength of 21 cm.
This frequency, postulated independently by two professors on the faculty of Cornell University, Giuseppe Cocconi and Philip Morrison, happens to be the radiation frequency of atomic or free hydrogen which permeates space in great clouds; moreover, this frequency is within the range of radio frequencies able to pass through the earth’s atmosphere.
Presumably, the significance of this frequency would be known to other intelligent beings in the universe who understand radio theory. We are still talking about radio waves as the communication medium; other possible media might be masers, lasers, or the as yet undiscovered and unnamed “readers.”
A technology superior to ours might even have learned how to modulate a beam of neutrinos (weightless, uncharged particles that physicists on earth find it difficult even to detect); if so, “they” may have to wait a century or two before we learn how to build a neutrino receiver.
The growing presumption that life exists in other worlds led, in 1971, to a six-nation multidisciplinary conference held in Soviet Armenia on Communication with Extraterrestrial Intelligence.
The U.S. delegation of about two dozen scientists was headed by Dr. Carl Sagan of the Centre for Radio physics and Space Research at Cornell University. The report of this conference, published in 197 3 by MIT, deals with such subjects as the evolution of intelligence, the lifetimes of technical civilizations, and the number of advanced galactic civilizations.
Last November a group of scientists at Arecibo Observatory in Puerto Rico sent a three-minute message beamed at Messier 13, and this represented man’s first attempt to take the initiative in communicating with another civilization.
The project was conducted by the National Astronomy and Ionosphere Centre, which operates the Arecibo Observatory for Cornell University and the National Science Foundation.
Messier 13 is a cluster of 300,000 stars on the edge of the Milky Way, 24,000 light years away, so if the message is received and answered promptly, unless we happen to hit them on one of their three-day holidays we should have their answer in 48,000 years, give or take a day or two.
The main purpose of the experiment was to dramatize the capabilities of the world’s largest antenna at the Arecibo Observatory.
If another civilization were trying to establish communication with us, it would first embark on attention-getting signals of such a nature that we could distinguish them from random cosmic noise; once we receive a recognizable signal, we have a good chance of understanding the message.
For example, they could start with trains of signals corresponding to the natural number 1, 2, 3 …, followed perhaps by prime numbers.
They might continue with equal-length extended signals consisting of start and stop impulses, with occasional pulses in between; when these signals are aligned flush over one another, they would show a circle, the Pythagorean Theorem, or similar geometric design.
Transmissions
The first transmission, (I), is obviously an enumeration of the 32 different symbols which will be used in the communications; in transmission (2) is the clear implication that A represents the integer 1, B the integer 2, and so on to J being the integer 10. In transmission (3), the symbols K for a plus sign and L for “equals” are introduced; in (4), the symbol M stands for “minus”; in (5), the symbol N stands for the concept and sign for zero. In (6), the concept of decimal notation is introduced; in (7), the symbol 0 must stand for the multiplication sign; in (8), the symbol P must stand for _the sign for division.
in (9), the symbol Q must represent a sign for the reciprocal; and in (10), the symbol R must stand for a decimal point. In the next ten transmissions there are introduced the concepts and symbols for inequalities, approximations, nested parentheses and brackets, powers and roots, factorials, and infinite series defining pi and e. Transmission (21) adds nothing new to the 31 symbols recovered thus far, but it does quote one of the most beautiful concepts in pure mathematics, Euler’s identity, e;. + 1 = 0. With this they are telling us that, if they can teach us such a complex notion at this early stage, we will be staggered by what they will teach us by the 200th or 2000th transmission.
Beginning with transmission (22), words and word cluster concepts are introduced, so that by the time we come to transmission_ (30) we are now understanding, in a manner of speaking, pure Venereal sentences.
Furthermore, we can now see how we could recover the code they are using on us, and which. will obviously consist of thousands upon thousands of code groups with different meaning; this is easily appreciated by anyone who takes the trouble to fathom the meaning of all 30 transmissions in the foregoing example.
Even right after this first series of transmissions, if we are in direct communication with that planet, we shall have questions to put to “them”: the proof of Fermat’s Last Theorem, Goldbach’s conjecture, and many other unsolved problems in mathematics and the natural sciences.
Goldbach’s “notorious” conjecture is called by that adjective only because other mathematicians weren’t imaginative enough to make the conjecture themselves; it states that every even number greater than 2 can be expressed as the sum of two primes. It will not be difficult for “them” to demonstrate their intellectual and technological superiority (first, don’t forget it was they who were able to call us!).
If “they” but know the seventh digit of the “fine structure constant,” they are ages ahead of us (we know only the first five for sure, suspect the sixth). This number, 137.039 … , is the ratio, among others, of the speed of light to the speed of the hydrogen electron; it may take a century to calculate this constant to 9 digits.
And after we resolve our pressing scientific questions, it might be appropriate to make discrete inquiries as to how we could live in harmony and peace with our fellow man-that is, if we aren’t eaten or otherwise ingested by the superior civilization that had the good fortune to contact us.
But as far as the cryptologist is concerned, he (and generations of his descendants who might experience the supreme thrill of their lives when we hear from “them”) must keep a level head, not get excited, and be prepared to cope with problems the likes of which he has never seen-out of this world , so to speak.’
