Looking Out on a Cosmic Aegean

Herbie Hancock’s Maiden Voyage is one of my favorite CDs, as definitive a statement of Hancock’s jazz artistry as, say, A Song for My Father is for Horace Silver’s craft, or Giant Steps for John Coltrane’s. But Maiden Voyage, particularly the title track, has that sense of relentless, questing motion that energizes me about all journeying. It’s restlessness mixed with inevitability, an Odyssean fling with great events in a vast and unknowable sea.

Such thoughts come to mind this morning because I’ve been paging through Giulio Magli’s Mysteries and Discoveries of Archaeoastronomy (Copernicus, 2009) while listening to Hancock’s work. It’s a lively and amusing book, amusing because Magli (Politecnico of Milan) enjoys taking swipes at colleagues as well as earlier scholars, and it plumbs the depths of sites around the world where our ancestors either did or might have aligned their structures with celestial objects. Some of these places remain controversial, because there are a lot of ways you can impose such alignments, not all of them necessarily in agreement with the ideas of the builders.

The ‘Knowability’ of SETI

I’m largely skeptical about much in this field, but I’m still curious to know more about it, and I want to talk more about Magli’s book when I’ve finished the last three chapters. But for today, I’ll focus on a particular chapter that struck me in light of our recent discussions on SETI. Just how ‘knowable’ would a signal from an extraterrestrial civilization be? In Magli’s terms, that relates to a question we can ask right here on Earth. How knowable are the ancient cultures whose intentions we now hope to divine from their ruins?

This is no easy matter to resolve, but in looking at it, Magli has recourse to a novel that Larry Klaes has mentioned in these pages before. It’s Roadside Picnic, by Arkady and Boris Strugatsky. The novel assumes an alien visitation of the Earth, one in which the visitors have absolutely no interest in human beings. These advanced creatures doubtless have an agenda of their own, but it’s not one that anyone can figure out. Behind them, in the area they visited, which is now known as ‘The Zone,’ people find artifacts that seem to make no sense. Two disks, for example, that always remain at the same distance from each other, but have no other obvious purpose.

No purpose understandable to us, that is. A substance like jam can trap a human like an insect in flypaper. Batteries that never run out of energy turn up. In other words, the relics of the encounter between humans and extraterrestrials are in some ways enigmatic, in other ways dangerous, and only some seem remotely useful to humans.

Perspectives on Pre-History

The characters in the novel are something like ants rummaging through the remains of a human picnic. Magli uses this perspective to consider the human ancestors who built the structures he studies in his book, places like Newgrange in Ireland, where a central shaft allows a bright arrow of sunlight to penetrate deep into the eighty-meter mound only on the morning of the winter solstice. Places like the Mayan pyramids that were aligned with the Sun’s position at the equinox, the earthen mounds of the Ohio and Mississippi valleys in the US, or, of course, the pyramids of Egypt.

It’s worth keeping in mind the values we bring to our investigations. Let me quote from this interesting book:

Our predecessors were not extraterrestrials, but humans who lived and suffered and loved and thought. But to a builder of Stonehenge, a Mayan astronomer, an Anasazi engineer, an Incan architect, or to the designer of the Great Pyramid, our technology, our little conceit of considering ourselves to be evolved, our way of counting, reasoning, recording data, our way of constructing theoretical schemas would be about as useful as a chocolate teapot. Our way is not absolute. It is not the way, it is but one way.

How difficult, then, to piece together the shards of the past and attempt to understand from them what people thousands of years ago were thinking as they built their structures. With the Strugatsky’s in mind, Magli goes on:

We are like those ants at the aftermath of the picnic. The picnickers did not leave instructions explaining in ant language what had happened or why. We have fragments and traces of evidence. We have what has been left behind, which is at best partial and mostly just mute. But it is not only that. It is that they would not have been interested in how we saw them anyway. They had their own way of thinking, reasoning, and studying that was not like ours, but that was just as effective. If we want to understand their ways, we must give up our schemes and embrace theirs; through respect comes understanding. But this is not easy to do.

This is a considerable understatement. Here is an example Magli uses to make the case: In September of 1991, at the edge of the Similaun glacier in Italy’s Val Senales (this is up near the Austrian border), the remains of a human body turned up. Precise dating showed it to be the body of a man who had died some five thousand years ago. He was dressed in a cloak of woven grass, a bearskin cap with chin straps, an overgarment in goatskin, goatskin trousers, and shoes with leather soles. He carried a calfskin haversack that contained a copper axe, a longbow made of yew wood, a quiver, about a dozen arrows, and a dagger. He also carried a grass net, perhaps for catching birds.

Making Sense of an Ancient Death

Was this man a ‘primitive’? Magli won’t call him that. His clothing encompassed the hides of five different animals and the wood and fiber from eighteen different trees and plants, all chosen carefully to match material properties with function. A contemporary of the megalith builders of northern Europe, he is perfectly equipped for his needs, and the technology he uses is suited to the environment he moves in. Magli will argue that we should not presume from his technology that he was less intelligent than us, merely that he worked with a different set of tools adapted for what was possible in his time.

Making quick assumptions can be fatal to good science. The Similaun man was originally thought to be a shepherd, or perhaps a shaman or a hunter lost in a blizzard. But later analysis showed he died from an arrow wound, and it was found that the blood of four different individuals appeared on various parts of his gear. Was he a warrior? Perhaps. He also, in addition to the above equipment, carried a deerhorn tool resembling a jeweler’s hammer, perhaps used to sharpen flint but not well understood. His contracted right hand may indicate he died with a knife in it, a possibility not considered until researchers stopped considering him as a wandering hunter-gatherer.

And, of course, we may still not have him right. Muses Magli:

These people did not leave us manuals or explanations. All they left us are their works. And it is time that we recognize the possibility that there exist objects about which we understand nothing — objects that are as puzzling to us as those equidistant disks were for the characters of Roadside Picnic. It is time to admit that we do not know what they are for or how they work.

Humility and the Message

I like that sense of humility before artifacts and ponder how it would translate to the reception of a SETI message. My hunch is that if we do receive such a message, it will not be a targeted beacon but a bit of random traffic. No Encyclopedia Galactica here. What it is, who sent it, why it was transmitted, will remain as enigmatic as the Strugatsky’s artifacts, or islands barely visible through the midst in Odysseus’ Aegean.

I’m replaying Maiden Voyage, pleased at the driving percussion and brush work, which reminds me of the sound of sea against a hull. The relentless piano theme makes me think how much early terrestrial voyages and future interstellar ones may have in common, in the assumption of a destination all the more worthy for being sought when its contours are unknown. As a species, we seem to be destined for journeying. Where will others find our artifacts, and when?

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Herschel: Lighting Up the Interstellar Medium

Sometimes we’re reminded in a stunning way of how much material exists in the star-forming regions of the galaxy. Take a look at the image below, which comes from the Herschel Space Observatory. Herschel’s SPIRE camera, which works at wavelengths between 250 and 500 microns, is combined here with data from the observatory’s other camera, called PACS, which operates between 70 and 170 microns. The combination reveals detailed images in the far infrared, locating star-forming regions that would otherwise be difficult to detect at a single wavelength.

SPIRE_PACS

Image: Five-color composite image of a 2 x 2 degree area in the plane
of our Galaxy, combining the PACS and SPIRE observations. In this image the SPIRE and PACS images have been combined into a single composite; here the blue denotes 70 microns, the green 160 microns, and the red is the combination of the emission from all three SPIRE bands at 250/350/500 microns. Credit: ESA.

The infrared range these instruments cover should tell us much about interstellar material, including its mass, temperature and composition. What we learn about the interstellar medium is, obviously, a factor in the design of any future probes to the stars. Herschel, the largest telescope yet flown in space, is now undergoing performance verification, which involves tests of its data processing software and checks of its hardware’s operational modes until mid-October. The image above is part of the first trial run using both the SPIRE and PACS instruments at the same time.

And what a result. Here we’re looking at interstellar materials condensing in what this rather elegant Science & Technology Facilities Council news release calls “…a continuous and interconnected maze of filaments and strings of newly forming stars in all stages of development, unveiling a tireless Galaxy constantly forging new generations of stars. We see an intricate network of filamentary structures with surprising features indicative of a chain of near-simultaneous star-formation events, glittering rather like beads of water on a string in the sunlight.”

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Arecibo in Context: Watching for NEOs

Some things to keep in mind with regard to near-Earth objects: NASA is working with a Congressional mandate from 2005 that it discover ninety percent of all NEOs that are 140 meters in diameter or greater. The deadline for this task is 2020, and the interim report Near-Earth Object Surveys and Hazard Mitigation Strategies (written by a committee appointed by the National Research Council) says the surveys currently in progress are not capable of meeting this goal. The final report is to appear in December.

Now switch to Arecibo. The radio telescope there, run by Cornell University and the National Science Foundation, has run into serious funding questions. NSF must decide whether the current cooperative relationship between Cornell and NSF should continue, and whether the observatory itself should be funded. You may recall that an NSF panel recommended in late 2006 that Arecibo’s operating budget be reduced in a series of steps, ultimately taking it from $10.5 million to $4 million by 2011. Such reductions could close the observatory.

arecibo_asteroids

The role of Arecibo’s planetary radar in the NEO issue? That’s also spelled out in the interim report, which cites the observatory’s ‘unmatched precision and accuracy’ in detecting comets and asteroids that could hit the Earth. We still don’t know what’s going to happen with Arecibo, but the report certainly can’t hurt. Says Don Campbell (National Astronomy and Ionosphere Center):

“If the survey committee had not come out that strongly, it would have virtually ruled out any funding. [The report] was a necessary, but not sufficient condition to get funding from either NASA or NSF.”

Image: Arecibo Observatory radar images of asteroid 1992 UY4, which has a diameter of 2 kilometers, made from four days’ observation in August 2005. Credit: Lance Benner/Jet Propulsion Laboratory.

Short of sending a spacecraft to an NEO (itself a desirable outcome), the Arecibo planetary radar provides the best imaging and tracking for these objects that we have. We may argue about the likelihood of our planet being struck by any of these objects, but the idea that we would surrender this powerful tool for building and tracking the NEO inventory, now in place and functioning, seems incredible. We wait with guarded optimism to see how the funding picture develops for Arecibo. More in this Cornell University news release.

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