Cosmology Bus

Murmurs of Earth

In my last post I wrote about the twin Voyager spacecrafts, still hurtling through the heliosphere some 10 billion miles from Earth, and still communicating daily with a handful of engineers affiliated with NASA/JPL’s Deep Space Network. That's impressive enough, but so is that fact that if any of those engineers are under the age of 32, they weren’t even born when Voyagers 1 and 2 launched in 1977.

 

This stop is also Voyager-related, and specifically about the Voyager Golden Record or simply the Gold Record: the gold-covered phonograph record attached to the side of both crafts. Embedded in each disc are sounds and images from Earth -- artifacts essentially about ourselves collectivley comprising a message to possible extraterrestrial civilzations that might one day discover them. As was also mentioned earlier, the story of how they were proposed, created, and permitted to travel on the probes at all is as interesting as the content itself.

 

A Voyager spacecraft showing the record affixed to a panel of the instrument housing. Credit: NASA.gov 

 

The definitive source describing the origin and content of the record is Murmurs of Earth: The Voyager Interstellar Record, co-authored by Carl Sagan, F.D. [Frank] Drake, Ann Druyan, Timothy Ferris, Jon Lomberg, and Linda Salzman Sagan. The original edition was published by Random House a year after the launch, but copies of it and later editions are still available from Amazon and AbeBooks at an affordable price. We are fortunate that they are, because the authors -- an accomplished group of astronomers, artists, writers, and educators -- gave very serious thought to what the discs might contain.

 

But first things first. The initial gathering to discuss the Voyager message took place in Honolulu at a meeting of the American Astronomical Society in January 1977, between Carl Sagan, his soon-to-be wife Linda Salzman, Frank Drake, and possibly others. Drake's account is in the book and makes for interesting reading because he also supplies helpful context. Before Voyager 1 and 2 there were messages sent with NASA's Pioneer 10 and 11 spacecrafts (launched in 1972 and 1973, respectively) and from the Aricebo Observatory in Puerto Rico (in 1974). Sagan, Salzman, Drake, and others were involved in these, too, and they benefited from the experience.

 

Among the lessons learned by the group responsible for the Pioneer message content: never engrave a naked man and woman on a gold anodized aluminum plate bound to leave the solar system. It became abundantly clear after the launch that many Americans don't especially like the idea of their tax dollars being used to send "porn" into space.

 

The backlash had far-reaching effects. As the group meeting in early 1977 soon found out, NASA was committed to avoiding further public scorn (and political problems) with Voyager. Not only did pre-launch photos of the spacecrafts purposefully show them from angles that hid the records from view, the agency also nixed an embedded photograph of a nude male and female (a silhoutte was substitued on the sly). But the real shocker came later: NASA conveniently rejected the disc on a technicality after it was completed. In an editorial to the New York Times commemmorating the 30th anniversay of the Voyager program, project member Timothy Ferris explained why:

 

"Late one night in a New York sound studio, when we’d finished cutting the master, I inscribed the words, 'To the makers of music — all worlds, all times,' in the 'takeout grooves' next to the label. (The Voyager record is a metal version of the 33 1/3 vinyl records of the day, recorded at half-speed to double its data content. Etching an inscription between the takeout grooves was a trope I’d picked up from John Lennon.) A NASA quality-control officer checked the record against specifications and found that while the record’s size, weight, composition and magnetic properties were all in order, its blueprints made no provision for an inscription.

So the record was rejected as a nonstandard part, and the space agency prepared to replace it with a blank disc. Sagan had to persuade the NASA administrator to sign a waiver before the record could fly."

Critics and bureaucrats aside, many appreciate Sagan's success. Each record includes 118 images; the first two bars of Beethoven's Cavatina from the String Quartet No. 13 in B flat, Opus 130; greetings from the President of the United States (Jimmy Carter); greetings from the Secretary General of the United Nations (Kurt Waldheim); greetings from 14 UN delegates; greetings in 54 human languages, "greetings" from a Humpback whale; the names of many U.S. senators and representatives (more on this below); a 12-minute audiory essay consisting of 19 "Sounds of Earth;" and 27 musical selections.

Image 111, "Page from a Book," from The System of the World (1687), by Isaac Newton. Credit: NASA.gov 

The variety of images and sounds is impressive. Jon Lomberg assembled the pictures of Earth. Linda Salzman acquired the greetings in human languages. Timothy Ferris selected the music. Ann Druyan was responsible for the Sounds of Earth essay and served the project as creative director. (Druyan later co-wrote the Cosmos television series and co-produced the film Contact. She and Carl Sagan married in 1981.) Each part of the production had its own challenges and drama, which are chronicled by the authors in chapters titled "Pictures of Earth," "A Voyager's Greetings," "The Sounds of Earth," and "Voyager's Music." Within them the actual images, sounds, and music are described in the order they appear on the disc, often with behind-the-scenes anecdotes.

Not surprisingly, Carl Sagan guided the entire project. This was no small feat; the spacecrafts launched in August and September 1977, giving a window of only seven months to get the job done. His own contributions to the book -- "For Future Times and Beings," "The Voyager Mission to the Outer Solar System," and an Epilogue -- are gems placing the record project and the mission in helpful perspective. He also provides anecdotes that instruct and sometimes amuse. Here's one about what happened after President Carter decided to add a greeting:  

" . . . NASA officials were concerned that the separation of powers in the U.S. Constitution might imply that if the President could greet the stars, so must the representatives of the legislative branch of government. After weighing the matter for about a day, NASA decided it was essential to include on the Voyager record at least the names of a large number of senators and representatives, especially those whose committees had cognizance of NASA activities. As a result, four additional pictures were added at the very last moment . . . I was at least pleased that NASA did not insist on including the names of the members of the U.S. Supreme Court, as the logical conclusion of the separation-of-powers argument. This part of the Voyager message is without doubt a signal to down here rather than to up there."

Today you can sample almost the entire interstellar record on the NASA/JPL Voyager Interstellar Mission site. (The chimpanzee track on the Sounds From Earth page makes me laugh out loud every time I hear it but, hey, I'm easily entertained.) The Golden Record Flash page is worth a visit, too.

Murmurs of Earth ends with Carl Sagan's words describing a possible encounter between one of the Voyager crafts and intelligent life in the vicinity of star A + 79 3888, which, at the time the book was written, appeared to be the closest star either craft would pass after leaving our solar system and traveling perhaps 60,000 years:

"They would wonder about us. They would know that 60,000 years is a long period of time in the hisory of civilizations. They would recognize the tentativeness of our society, its tenuous acquaintence with technology and wisdom together. Had we destroyed ourselves or had we gone on to greater things? Some of the Voyager music intentionally expresses a kind of cosmic loneliness, which would perhaps communicate itself across the expanse of light-years and the differences in evolutionary histories. We, too, were time-capsuling, searching the skies and seeking another civilization with which to communicate.

But one thing would be clear about us: no one sends such a message on a journey, to other worlds and beings, without a positive passion for the future. For all the possible vagaries of the message, they could be sure that we were a species endowed with hope and perseverence, at least a little intelligence, substantial generosity and a palpable zest to make contact with the cosmos."

The Voyager mission and the message attached to each spacecraft are all of this, and more. They are symbols of human culture reflecting the idea that the cosmos evolves and includes life -- what historian Steven Dick calls the "biological universe as a cosmological worldview."

Clearly, when we listen to the sounds or look at the images embedded in the discs, one does not have to be an astronomer or engineer to tap into those human traits expressed by Sagan, or imagine an encounter one distant day ahead.

That we can do this so easily suggests the biological universe, our current worldview of the cosmos in the extraterrestrial life debate is, for many, as pervasive as star dust.

Next stop: Worldviews 

Banner bus photo credit: Dorothy Delina Porter

 

Voyagers

If you visit NASA's Missions Finder page and scroll down, you'll see that Voyager is one of only two entries listed under the letter v. That's 119 missions deep in the space agency's use of the alphabet, and more than a generation away from its launch in 1977.

Actually, more than a generation away from both Voyager launches. You have be of a certain age or a farily serious student of space exploration history to recall there were two unmanned Voyager spacecraft. Voyager 2 launched first, in August 1977, taking advantage of planetary alignments to study Uranus and Neptune. Voyager 1 followed in September, arriving at Jupiter and Saturn ahead of its twin. The discoveries made by both crafts greatly expanded our knowledge of these four outer planets and their moons.

Artist's conception of Voyager 2 passing Jupiter, by ElChristou, 2007. Source: CelestialMatters.org 

From where I sit, one of the best brief descriptions of their journeys appears in David Grinspoon's Lonely Planets: The Natural Philosophy of Alien Life, hands-down the most entertaining and thought-provoking book on the subject of life beyond Earth written to date. Here's his take:

"During the 1970s and 1980s our eyes were opened to the rest of the solar system by the epic travels of the Voyagers. Launched in 1977, the year after the Viking landings, the two Voyagers flew by Jupiter in 1979 and Saturn in 1980. One craft, the indomitable Voyager 2, made it to Uranus in 1986 and Neptune in 1989. These missions took decades of hard work and intense planning, but the excitement was distilled into brief, manic 'encounters' lasting only several days each, as one of the Voyagers would race past one of these giant planets, feverishly snapping pictures of its cloudy surface and its entourage of moons. Then, having safely radioed the bounty home, the spacecraft would quickly recede into the lonely depths of interplanetary space, heading for the next new world. During each encounter, multiple worlds were transformed instantly from obscure telescopic subjects into concrete, detailed places. The stunning pictures from these bursts of revelation will be treasured by humankind forever."

Grinspoon writes so well about it because he was directly involved:

"For planetary scientists the Voyager encounters were peak, formative experiences, and the trajectories of those two spacecraft through the outer reaches of our solar system became entwined with the trajectories of our lives. When Voyager 2 reached Jupiter, I was a nineteen-year-old undergraduate assisting the team of scientists who retrieved and analyzed the photos beaming back from deep space. At the Uranus enounter I was participating as a twenty-six-year-old graduate student, and at Neptune I was a postdoc pushing thirty."

Good stuff. But now, another thirty-plus years later, relatively few people besides planetary scientists remember what the Voyager craft accomplished, despite some brief media coverage in 2007 marking the 30th anniversary of the launches. Perhaps fewer still know of these additionally remarkable and inspiring aspects of their story: each craft is, of course, still traveling through space and communicating daily with scientists on Earth, and each carries an identical gold-plated record designed to inform any intelligent beings in our galaxy that might discover them by chance one day more about planet Earth via recorded sounds and images.

These days Voyagers 1 and 2 are traveling through the heliosphere, a kind of bubble in space where the Sun's solar wind meets the winds of other stars. As of May of this year, Voyager 1 was about 10.2 billion miles from Earth, Voyager 2 about 8.2 billion. (But for both, the total distance traveled since launch was then nearly 13 billions miles.) It takes signals traveling at the speed of light -- 186,000 miles per second -- more than 15 hours to reach either craft, and vice versa. Only NASA/JPL's Deep Space Network (DSN) antennas are capable of communicating with the probes now.

Given their distinguished history it's not surprising that Voyager discoveries are still being made. Now called the Voyager Interstellar Mission, five instruments on board each craft are today investigating a variety of magnetic field, cosmic ray, and plasma phenomena. Last year data from Voyager 2 confirmed the heliosphere has a "squashed" shape; it's pushed inward closer to the Sun due to an interstellar magnetic field. Knowing this improves our understanding of how solar and interstellar space interact.

And the gold records?

The Voyager "Golden Record" and its cover. Credit: NASA/JPL 

The identical discs deserve at least one post of their own (next stop) but for now, I like thinking about them attached to the side of each craft in their mirrored jackets, hurtling along at somewhere close to 10 miles per second on their respective trajectories toward the interstellar medium. How they were proposed, created, and eventually permitted to travel on the probes (it almost didn't happen) is to me just as interesting as the content embedded in the discs themselves. 

Space exploration is an expensive, tricky business. And always, a highly complex activity that requires a unique combination of circumstances before any project literally gets off the ground. Harris Schurmeier, Voyager Project Manager from 1970 to 1976, describes this in a special way:

"There were and still are many remarkable and amazing things about Voyager but to me the most remarkable was the timing. The planetary alignment that occurs only once every 175 years occurred at the time we were ready and able to do the mission. The necessary technologies were developed -- communications, navigation, power, electronics, attitude control, instruments. The scientists were experienced. There was strong public support. We could not have done it 5 years earlier and 5 years later the politics would not have supported it."

Right place. Right time. Bold ideas.

Next stop: Murmurs of Earth 

Banner bus photo credit: Dorothy Delina Porter