The face of first contact: What aliens look like
25 January 2010 by Stephen Battersby, New Scientist magazine issue 2744
Tentacled monsters, pale skinny humanoids, shimmery beings of pure energy … When it comes to the question of what alien life forms might look like, we are free to let our imagination roam. The science-in-waiting of extraterrestrial anatomy has yet to acquire its first piece of data, so nobody knows what features we will behold if and when humans and aliens come face-to-face. Or face to squirmy something.
Despite this lack of hard evidence, a blend of astronomy and earthly biology offers some clues to what is out there. A few bold scientists are even willing to make an educated guess at the nature of aliens that might exist on faraway worlds.
What these extraterrestrials will be like depends on where and how we expect to meet them. Barring the appearance of flying saucers, there are two broad possibilities: either we have a close encounter with our neighbours by visiting the planets and moons next door; or we make an interstellar phone call to creatures inhabiting much more distant planets that circle alien suns. These two options have different implications for the shape of what we find living there.
What extraterrestrials will look like depends on where and how we meet them
If first contact turns out to be within our solar system, then at least we have some prior knowledge about the available habitats. Several spots might be suitable for Earth-like life based on carbon biochemistry and using water as a solvent. The subsoil of Mars may be warm enough to host microbes akin to Earth’s bacteria, for example, and there could be larger beasts swimming in the watery oceans of some outer moons of the solar system – especially Jupiter’s moon Europa. There’s every chance that a deep aquatic ocean lies beneath Europa’s ice, stretching right down to the moon’s rock core, where volcanic vents pump out hot, nutrient-rich water.
Astrobiologist Dirk Schulze-Makuch of Washington State University in Pullman calculates that the energy supplied by these vents could feed a large population of microbes, which in turn could support a pyramid of predators. Europa’s top predator, the equivalent of our great white shark, would be a fearsome creature with a mass of – wait for it – about 1 gram. “Europa could support a shrimp-sized organism,” he says. There would not be enough prey to feed a viable population of predators bigger than that.
Shrimp-sized doesn’t have to mean shrimp-shaped, of course. “It is kind of difficult to say anything about how it would look,” says Schulze-Makuch. Even on Earth animals have evolved an astonishing diversity of shapes and body plans, but Schulze-Makuch is nevertheless prepared to speculate. “I would make a guess at something worm-like,” he says. “That is a pretty successful kind of organism on Earth.”
While the hypothetical ice worm of Europa would be swimming about in boring old water, a few astrobiologists are pushing the boat out and pondering the possibility of life that is not water-based. Most places in the solar system are too hot or too cold for liquid water to exist, but there are several other liquids that might host some kind of biochemistry, says Steven Benner of the Foundation for Applied Molecular Evolution in Gainesville, Florida.
The clouds of Venus hold droplets of sulphuric acid, and billions of years ago there may have been pools of the stuff on the planet’s surface. Though pretty destructive to bags of water like ourselves, it could be a refreshing draught for beings with the right biochemistry. These acid-dwellers would have to be formed of chemically resistant materials. “Multicellular Venusians living in liquid sulphuric acid could have veins made of glass,” Benner suggests, conjuring up visions of delicate, transparent glassware creatures, rolling carefully over the Venusian rocks. But glass is not the only option: more mechanically robust materials would also fit the bill. “There are flexible polymers that are acid-stable, such as Teflon, polyethylene and silicone,” Benner points out.
Elsewhere in our solar system, surface lakes and seas exist to this day – though not watery ones. On Saturn’s moon Titan, they are formed from a chilled hydrocarbon cocktail of ethane and methane, and Schulze-Makuch speculates about what forms of life they might harbour. “Things might be bigger,” is his unexpected conclusion. “Water has a high surface tension, which constrains the volume of single cells. That’s why bacteria on Earth are so small.” The surface tension in a methane-ethane blend is much lower, so single cells could be enormous, a possibility that Schulze-Makuch has explored in his novel Voids of Eternity. “I have boulder-sized microbes moving over the surface and guzzling up hydrocarbons,” he says. “That is science fiction of course, but there may be something in it.”
In our eyes, the Titanians might seem pretty laid back. At around 93 kelvin, Titan’s seas are very cold and that makes chemical reactions super slow. “Things could be very slow-moving and slow-growing,” says Schulze-Makuch. “The lifetime of such an organism may be 10,000 years, or perhaps as much as a million.”
Who’s there?
As strange and marvellous as it would be to encounter these beasts, they are probably not going to be very interesting to talk to. For aliens on our intellectual level – or indeed far above it – we will almost certainly need to look beyond the limits of our own solar system. In the search for extraterrestrial intelligence, a few astronomers have been straining Earth’s radio ears for the sound of alien transmissions. SETI researchers are now debating whether to become more proactive and start sending out messages (see “We’re over here!”). If we do make contact, what kind of creature is going to be on the other end of the line?
Even without knowing the details of their chemistry or habitat, it is possible to hazard a few guesses. For a start, they may have a taste for flesh. “Predators tend to be more intelligent,” says evolutionary biologist Lynn Rothschild of NASA’s Ames Research Center in Moffett Field, California. “They have to do more moving around to outsmart the other guy. You don’t have to be terribly intelligent to grab a leaf of lettuce.” If that applies to alien ecosystems, we can expect to be talking to carnivores – or at least omnivores like ourselves.
And then there is the fact that in order to contact us, ET must be able to send and receive radio waves or laser beams, or use some other medium to reach across the light years. So either they are vast creatures that have evolved natural radio-wave organs to talk and listen to each other, or they have developed technology. For that, intelligence alone is not enough. “The thing that advances us as a species is that we are social,” says Schulze-Makuch. “One of us alone is not very smart – I’m so dumb I can’t even build a radio. It is by working together that we got on the moon.”
So message-sending aliens will probably have some form of society. It need not be anything like human societies, however. “There are meta-intelligences in the societies of bees and termites. I can imagine something like a termite or ant colony that gets really intelligent,” says Schulze-Makuch. This does not tell us, however, whether they will be furry, scaly or slimy. Even on Earth, clever brains come in a wide variety of packages: dolphins and primates, parrots and crows, sea otters, honey badgers, octopuses and squid.
The principle of convergent evolution could give us some ideas, though. “Some things have evolved many times on Earth such as hearts, eyes and jointed limbs, and the four “F’s – flight, fur, photosynthesis and sex,” says Jack Cohen, a reproductive biologist who has helped science fiction authors design plausible aliens for their books. “They happened independently in different branches of the tree of life. If you ran Earth again from the start, you’d likely get these again.”
So if our aliens come from a planet with a range of habitats not too different from those on Earth, they might well have some of the same characteristics. A well-lit world like ours would probably produce beings with eyes – so maybe a recognisable face after all. And our cosmic correspondents would presumably need some manipulating organs to fiddle with the nuts and bolts of their technology. They might even have hands, but then again why not a prehensile tail or a trunk instead? “Maybe it’s an antenna, maybe a tentacle,” says Rothschild. “Maybe an octopus would look at us and think ’How can you expect this organism to develop technology with its two clumsy front limbs?’”
Whether such creatures would be aquatic, like Earth’s octopoids, is questionable, however. Much of our technological development, from curing meat to smelting metal, is based on fire, and learning to use fire is likely to prove an insurmountable obstacle even for very clever water dwellers. Far better for the talented, tentacled monsters to slither onto land before building their interplanetary empire.
Putting it all together, the daring astrobiologist might be prepared to make a very small bet that SETI-type aliens will be social multicellular predators with eyes, sexes, and sticky-out bits of some sort. Unless, of course, the aliens were usurped by smart machines or decided to modify themselves using biotechnology. In that case, we might find tentacled monsters, pale skinny humanoids, shimmery beings of pure energy …
http://www.newscientist.com/article/mg20527441.400-the-face-of-first-contact-what-aliens-look-like.html
Exolanguage: do you speak alien?
20 January 2010 by Stephen Battersby, magazine issue 2744
The cosmos is quiet. Eerily quiet. After decades of straining our radio ears for a whisper of civilisations beyond Earth, we have heard nothing. No reassuring message of universal peace. No helpful recipe for building faster-than-light spacecraft or for averting global catastrophes. Not even a stray interstellar advertisement.
Perhaps there’s nobody out there after all. Or perhaps it’s just early days in the search for extraterrestrial intelligence (SETI), and we’re listening to the wrong star systems or at the wrong wavelengths.
There is another possibility, says Douglas Vakoch, head of the Interstellar Message Composition programme at the SETI Institute in Mountain View, California, which ponders the question of how we should communicate with aliens. “Maybe everyone’s listening but no one is transmitting. Maybe it takes an audacious young civilisation like ours to do that.”
So should we start sending messages into the void? And if so, how can we make ourselves understood to beings we know nothing about?
One astronomer has already stepped up to the challenge. Alexander Zaitsev at the Russian Academy of Science’s Institute of Radio Engineering and Electronics in Moscow has sent four interstellar messages since 1999, each beamed to no more than a handful of nearby sun-like stars. Zaitsev’s efforts are pretty small scale, however, and so far his group is more or less alone except for some low-power operations offering to send your message to the stars for a fee.
That could be about to change. Perhaps bored with spending so long hearing nothing, the wider SETI community is starting to consider a more active approach. They will get together to discuss whether to go for it at a meeting in April in League City, Texas. Vakoch, who will chair these sessions, is all in favour. “I have long held the position that after broad-based international consultation, we should be doing active SETI,” he says.
It’s an approach that worries ex-astronomer and science fiction author David Brin, who was a member of the International Academy of Astronautics SETI panel until 2006. He resigned when the committee backtracked on the wording of a protocol that called for discussion before deliberately broadcasting into space. “I dislike seeing my children’s destiny being gambled with by a couple of dozen arrogant people who cling to one image of the alien,” says Brin. Since then three other members have quit for similar reasons. Vakoch has some sympathy with Brin’s point of view. “These issues are much too important and too complex to be resolved after only a few days of discussion.”
If the enthusiasts for active SETI get their way and there is a real effort to send a message, the next question is: what should we say?
Some early attempts to communicate with aliens – including the plaques attached to NASA’s Pioneer 10 and 11 spacecraft, and the phonograph records on the Voyager probes – were really only symbolic efforts. More likely to be received one day is the powerful radio broadcast devised by SETI pioneer Frank Drake and sent from the Arecibo telescope in Puerto Rico in 1974. We have a long wait for contact if we rely on this, though: the message won’t reach the distant star cluster it was aimed at, M13, for 25,000 years. It was also a very brief message, containing only 210 bytes of information.
“These are greeting cards,” says Seth Shostak, who is a senior astronomer at the SETI Institute. “It is nice to get a greeting card, but hard to decipher if it’s in a language you don’t understand, because the amount of material is so limited.”
Interstellar geek speak
Although the Arecibo message is cunningly constructed, it is difficult even for a human to understand. The signal contains a series of 1679 bits, a number chosen as it is equal to the product of two prime numbers – 23 and 73. The hope is this will prompt an acute alien recipient to arrange the 1s and 0s into a 23-by-73 rectangle. Doing so reveals a rather complicated picture, which is supposed to give some basic information about our chemical and biological make-up, our civilisation and the solar system (see illustration).
To me it looks a bit like a small person with a big head, four eyes and eight bushy eyebrows. So the only bit I’ve got right is the “person,” and there I had a big advantage. “It is much worse if you don’t have lot of context, if you don’t even know about Homo sapiens,” says Shostak.
So where might we find some common ground with ET? Perhaps in mathematics. This idea goes back about three centuries, when it was suggested that we could hail beings on the moon by cutting a diagram of Pythagoras’s theorem into the forests of Siberia.
In 1960, Dutch mathematician Hans Freudenthal proposed an interspecies language called Lincos that starts with simple mathematical statements – a series of beeps to represent 1 + 1 = 2 for example. It then uses these to define logical relationships, eventually building up to more complex concepts of time and space.
More recently in the 1990s, mathematician Carl DeVito and linguist Robert Oehrle, both then at the University of Arizona in Tucson, made an attempt to speed up this process by assuming that respondents have some knowledge of physical concepts. In DeVito’s scheme, once some mathematical and logical symbols have been defined, we would launch into a description of the periodic table, and then discuss energy in terms of specific heats of the elements and so on. They argue that any civilisation capable of receiving our radio signals must have some knowledge of physics to build radio receivers.
While interstellar geek-speak might be fine for sending details of your solar system and the latest technology, it’s not so easy to move on to more abstract ideas, such as human nature and culture. How would you convey a simple sentiment like “we come in peace”?
How do you convey a simple sentiment like ’we come in peace’ to an alien species?
“It seems that sooner or later one must fall back on pictures,” says DeVito. Images might be the only way to convey to an alien what we’re talking about, and to show them what our world is like. They wouldn’t need to have vision like ours, merely some way to understand spatial patterns in at least two dimensions. Then they could attach symbols to meanings, like a child with a picture book.
And we can do better than “cows go moo.” Paolo Musso, a philosopher at the Pontifical Urbaniana University in Rome, Italy, has outlined one way to combine mathematics and images to tell a moral tale using the process of analogy. First, arithmetic is used to establish signals that mean right and wrong, defined by sums that are right and wrong. These can then be applied to cartoons showing what we consider to be good and bad actions.
Many of these approaches start with counting, but what if the slimy ones don’t have our concept of arithmetic? “There is no guarantee that if ETs have mathematics it will be commensurable with ours,” says Vakoch. He and others have instead suggested a more creative channel of communication: sending examples of our culture. It is possible, Vakoch says, that aliens will develop a taste for Toulouse-Lautrec paintings or Meade Lux Lewis boogie-woogie numbers, and then we will have done something worthwhile. In 2008 NASA transmitted a song by The Beatles at the star Polaris, while artist Joe Davis has aimed other sounds and messages at two nearby stars.
Zaitsev’s longer messages – Cosmic Call 1 and 2, and Teen Age Message – combine several of these ideas. Each message consists of a beam of radio waves sent from the Evpatoria radio telescope in southern Ukraine, which encoded each bit of information by shifting the transmission frequency slightly up or down. A bit can represent a black or white square, and a number of them can be built up pixel by pixel into a series of pictures like the original Arecibo message. Some of them form a rather sketchy “bilingual image glossary” – a dozen hand drawings meant to show concepts including people, family, nature and games, with English and Russian words attached. Zaitsev has also included an excerpt of theremin music to soothe, or perhaps irritate, alien listeners.
Give them porn
But the main content was a series of 127-by-127 pixel images forming the “interstellar Rosetta Stone,” developed by astronomers Yvan Dutil and Stephane Dumas from Defence Research and Development Canada in Valcartier, Quebec. Like Freudenthal’s and DeVito’s approaches, the images start with arithmetic and build from there. They also include graphs to illustrate physics, as well as sketches of the solar system, Earth’s topography and the man and woman from the Pioneer plaque.
As well as these complex signals, Zaitsev has transmitted a more lightweight message. In “A message from Earth,” sent in 2008, contributions from users of social networking site Bebo were directed at a single planetary system around the star Gliese 581. If anyone there is listening, they can expect to receive it in 2029 – followed by 26,000 unsolicited text messages collected by Cosmos magazine and transmitted last year. At 50 to 60 kilobytes, there is more information in the Cosmic Calls than in the Arecibo message, giving alien cryptologists and linguists something to work with. To give them a helping hand, a lot of what has been sent is redundant.
“Redundancy really helps,” says Shostak, as it allows a recipient to make a guess about the meaning and then check it, like in a crossword. He suspects that all the polite efforts to be understood might be unnecessary. “A lot of people wonder what we should send. Music, mathematics or pictures? My first thought is it probably doesn’t matter,” he says.
Instead, Shostak suggests that we just gabble. “My conclusion is that you would just send them the Google servers. That’s an enormous amount of information, much of it redundant and pictographic. Much of it is pornographic too, but I expect they could handle that.” (Although it raises questions like, can Earth handle a trillion orders for Viagra?)
According to Shostak’s calculations, sending so much stuff becomes practical if we assume that ET is very good at listening and has the technology to pick up a faint, rapidly changing signal against the background noise of the galaxy. If they have truly vast radio dishes, then we can send them encyclopedias and even libraries in a sensible amount of time.
Shostak also points out that an interstellar message is quite likely to be a one-way deal: it may not even reach its destination until long after our civilisation has ended. So as this is probably the only chance of telling an alien world about humanity, we might as well say as much as we can.
Of course, it would be much better if we could actually chat, as this would allow us to gradually teach each other our languages and histories. But interstellar distances make that nigh on impossible unless we can somehow send a representative.
Sociologist William Bainbridge of George Mason University in Fairfax, Virginia, is trying to develop avatars, human personalities encoded in software. If he succeeds, we could send one into deep space, perhaps programmed into an interstellar probe. Or if we can find a way to tell receivers how our software works, we could even send avatars to them via a radio beam.
Whatever we decide, the next problem is where to aim our message. Broadcasting loudly to the whole sky would use ludicrous amounts of power, far beyond our capabilities today. Instead, active SETI would target promising star systems. A sun-like star is a start; planets are better. Space telescopes such as Kepler should be able to detect planets that are Earth-size, and future telescopes should eventually be able to pick out those with liquid water on the surface and oxygen in their atmospheres.
This still might not be a well-targeted address list, however, because civilisations may be very thinly spread. “Even if you found a list of 10,000 Earth-like worlds, that might not be good enough,” says Shostak. “We’ve had biology for 4 billion years, and radio telescopes for 40 years; that’s 1 in 100 million.” If the technological window for aliens is as short as ours then we might have to transmit to 100 million Earths before anyone hears us.
For practical reasons, Shostak thinks we should wait and listen. “The bottom line is that for the foreseeable future, the only decent targets are people that have contacted you. Let them do the heavy lifting.”
In the meantime, planning our own message could help to focus the minds of SETI experts on what kind of communication we should be looking out for. If Earth’s efforts are anything to go by, we can expect a basic maths lesson and some pictures of naked aliens.
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