Centauri Dreams
Imagining and Planning Interstellar Exploration
Possible Planet in Nearby Brown Dwarf System
Has astrometry finally bagged an exoplanet? A new study from Henri Boffin (European Southern Observatory) and colleagues has found compelling evidence that the nearest pair of brown dwarfs to the Sun — WISE J104915.57-531906, otherwise known as Luhman 16AB — is home to a hitherto undetected companion. It’s interesting news not only for the astrometry angle but because Luhman 16AB is no more than 6.6 light years away, making it the third closest system to the Sun after Alpha Centauri and Barnard’s Star.
Image: Luhman 16AB, two brown dwarfs in the Sun’s neighborhood, now considered home to a possible planet. Credit: NASA / JPL / Gemini Observatory / AURA / NSF.
I give prominence to astrometry here because the European Space Agency’s Gaia mission was launched this morning, chartered with creating a three-dimensional map of the Milky Way, but also with finding exoplanets using astrometry as its primary method. While radial velocity measures tiny motion in stars induced by unseen planets, it does so by analysis of the Doppler shift in light from the star. Astrometry actually measures the positions and movement of the stars. It’s all about measuring angles and deriving astrophysical data from the result.
The Hubble Space Telescope used astrometric methods in 2002 to study a planet around Gliese 876 that had already been discovered, but despite many claims, planet discoveries via astrometry have yet to be confirmed. The technique has had a checkered history. William Herschel studied the effects of what he believed to be an unseen companion on the star 70 Ophiuchi in the 18th Century, and numerous claims involving other nearby systems have been made over the years, most recently one involving a Jupiter-class object around the nearby red dwarf VB 10 and a 2010 study of HD 176051. But the changes in stellar position involved are so tiny that we need a new generation of instruments to really put the method to work.
The late, lamented Space Interferometry Mission would have been such an instrument, but of course it never flew. Now we have Gaia to look forward to, and as the mission progresses, we’ll follow its observations with interest. The sunshield has deployed and Gaia is moving toward L2, some 1.5 million kilometres beyond Earth as seen from the Sun. Gaia will measure stars with micro-arcsecond precision. Astrometry is most sensitive to planets with large orbits, which makes it a useful complement to radial velocity methods that are most sensitive to nearer objects.
For our purposes today, though, the Boffin team used the FORS2 instrument on ESO’s Very Large Telescope at Paranal to image Luhman 16AB in the spring and early summer of this year, looking for displacements of the two brown dwarfs in their orbit. Says Yuri Beletsky (Carnegie Institution for Science):
“The two brown dwarfs are separated by about three times the distance between the Earth and the Sun. Binary brown dwarf systems are gravitationally bound and orbit about each other. Because these two dwarfs have so little mass, they take about 20 years to complete one orbit.”
Measuring down to a precision of a few milli-arcseconds, the researchers found small deviations from the expected motion of the two brown dwarfs around each other. The preprint of the upcoming paper in Astronomy & Astrophysics has this to say:
The FORS2 data, once combined with the data of Luhman (2013) and Mamajek (2013), yield a significant improvement of the precision of the parallax derived by Luhman (2013). Yet, the FORS2 positions alone indicate that a two-body system is very unlikely whereas an additional companion would explain the observed wobbles. Such a companion must have a mass lower than the brown dwarfs in the system, because i) it would otherwise have been seen in direct imaging or spectroscopy, and ii) a system with two equal mass brown dwarfs would not be detected as there would be no motion of the photocentre.
We can say little about the putative companion, with Boffin’s team noting only that its likely mass is between a few and up to 30 Jupiter masses, but the paper points out that an object of the latter size should be detectable by adaptive optics given the size of the expected separation. As to the brown dwarfs themselves, their masses are predicted to be 0.04-0.05 solar masses for the primary and 0.03-0.05 for the secondary. The system seems to present itself to us nearly edge-on, making for the possibility of a radial velocity follow-up with a robust signal.
Assuming we really do have a planet here, it would be the second closest exoplanet to the Earth (assuming that Alpha Centauri Bb is eventually confirmed). Previous brown dwarf planets have been found by microlensing and direct imaging, with microlensing able to find relatively close planets and direct imaging helpful at planets with large separation from their host star. Luhman 16AB gives us a chance to study a planet at an intermediate distance as we try to learn more about brown dwarfs and the planet formation processes that may be at work around them.
The paper is Boffin et al., “Possible astrometric discovery of a substellar companion to the closest binary brown dwarf system WISE J104915.57-531906.1,” accepted at Astronomy & Astrophysics (preprint).
New Views of Titan’s Lake Country
Titan has about 9000 cubic kilometers of liquid hydrocarbon, some forty times more than in all the proven oil reservoirs on Earth. That’s just one of the findings of scientists working over the data from recent Cassini flybys of the Saturnian moon. Each flyby snares our attention because this is the only other place in the Solar System that has stable liquid on the surface, even if it’s not water. That’s part of Titan’s fascination, of course, because it’s similar to the Earth in terms of basic interactions between liquids, solids and gases but completely alien in terms of temperatures.
Just how extensive are those seas and lakes we’ve found in Titan’s northern hemisphere? Cassini’s radar instrument has given us our best views to date with the mosaic shown below, one that’s based on multiple images from flybys tracking areas at various angles. Kraken Mare, Titan’s largest sea, and Ligeia Mare, the second largest, appear along with nearby lakes. We learn not only that Kraken Mare is more extensive than first thought, but that almost all the lakes on Titan are in an area some 900 kilometers by 1800 kilometers. A mere three percent of the liquid on Titan is found outside this region. Cassini radar team member Randolph Kirk explains:
“Scientists have been wondering why Titan’s lakes are where they are. These images show us that the bedrock and geology must be creating a particularly inviting environment for lakes in this box. We think it may be something like the formation of the prehistoric lake called Lake Lahontan near Lake Tahoe in Nevada and California, where deformation of the crust created fissures that could be filled up with liquid.”
This JPL news release adds that processes like these on Earth lead to the formation of faults that create basins broken by mountain ranges. Much of present day Nevada was, some 13,000 years ago, flooded by Lake Lahontan in a configuration that resembles, on a smaller scale, Titan’s closely packed seas.
Image: This colorized mosaic from NASA’s Cassini mission shows the most complete view yet of Titan’s northern land of lakes and seas. In this projection, the north pole is at the center. The view extends down to 50 degrees north latitude. In this color scheme, liquids appear blue and black depending on the way the radar bounced off the surface. Land areas appear yellow to white. A haze was added to simulate the Titan atmosphere. Kraken Mare, Titan’s largest sea, is the body in black and blue that sprawls from just below and to the right of the north pole down to the bottom right. Ligeia Mare, Titan’s second largest sea, is a nearly heart-shaped body to the left and above the north pole. Punga Mare is just below the north pole. Credit: JPL.
Note the smaller lakes above and to the left of the north pole, which are about 50 kilometers across or less. Moreover, the new data are finally telling us how deep at least one of the seas is. Because the liquid methane of Ligeia Mare is very pure, Cassini’s radar signal passes through it easily and can detect a signal from the sea floor. The lake turns out to be about 170 meters deep, and in at least one place is deeper than the average depth of Lake Michigan. With northern summer approaching, Titan’s lake country should be entering an interesting meteorological phase for Cassini’s future studies as the atmosphere heats up.
Water Vapor Detected Above Europa
Last week’s look at Europa examined the possibility of primordial impacts there that might have brought organic materials to the moon, focusing especially on clay-like minerals that a JPL team found in data from the Galileo mission. I had barely finished that article before the news from Hubble arrived with observations of water vapor above the southern pole of Europa, a possible indication of water plumes erupting from the moon’s surface. That work ran in Science Express and was reported at the meeting of the American Geophysical Union in San Francisco. Lead author Lorenz Roth (Southwest Research Institute) described it this way:
“By far the simplest explanation for this water vapor is that it erupted from plumes on the surface of Europa. If those plumes are connected with the subsurface water ocean we are confident exists under Europa’s crust, then this means that future investigations can directly investigate the chemical makeup of Europa’s potentially habitable environment without drilling through layers of ice. And that is tremendously exciting.”
Exactly so, for now we can start thinking about doing something similar to what has been envisioned at Enceladus, flying a spacecraft through a plume to study what’s below the ice. As the comments on last Thursday’s post (Europa: Minerals from an Ancient Impact) have shown, the question of ice thickness on Europa is wide open, and scientists studying the matter are divided on it — once again I point you to Richard Greenberg’s Unmasking Europa (Copernicus, 2008) for a lively defense of thin ice.
Image: This graphic shows the location of water vapor detected over Europa’s south pole that provides the first strong evidence of water plumes erupting off Europa’s surface, in observations taken by NASA’s Hubble Space Telescope in December 2012. Hubble didn’t photograph plumes, but spectroscopically detected auroral emissions from oxygen and hydrogen. The aurora is powered by Jupiter’s magnetic field. This is only the second moon in the solar system found ejecting water vapor from the frigid surface. The image of Europa is derived from a global surface map generated from combined NASA Voyager and Galileo space probe observations. Credit: NASA, ESA, and L. Roth (Southwest Research Institute and University of Cologne, Germany).
Geysers on Europa could indeed be a signature of a thin ice crust, but as reader Andrew Tribick has noted here, they could also flag a lake enclosed within a thick crust. The key question, of course, is just where the water is coming from. “Do the vents extend down to a subsurface ocean or are the ejecta simply from warmed ice caused by friction stresses near the surface?” Roth asks. So far we don’t know. And as to the source of the faint emissions detected by Hubble, the long cracks on Europa’s surface known as lineae may well be the answer. That would correspond to the fissures that the Cassini spacecraft has seen near the south pole of Enceladus.
But whatever the thickness of Europa’s ice, flying through a plume rather than drilling would make our task immeasurably easier. We can also take up Freeman Dyson’s suggestion, noted in the comments by Larry Klaes, that space around Europa should be investigated for the possible remains of aquatic life forms that could have been blown out by impact events.
Another reminder of Enceladus is the fact that the intensity of the plumes detected on Europa varies with the moon’s orbital position. The jets are detected only when Europa is at the farthest point in its orbit from Jupiter, while signs of venting disappear when the moon is closer. Are we looking at tidal flexing caused by Jupiter’s gravitational pull? That’s what one would expect with a subsurface ocean placed in this environment. It’s interesting that Europa’s own gravity, twelve times that of Enceladus, would cause any water vapor to fall back to the surface, leaving surface features near the south pole that may be observable by future spacecraft.
The paper is Roth et al., “Transient Water Vapor at Europa’s South Pole,” published online in Science 12 December 2013 (abstract).
Vessel: A Science Fiction Prototype
Futurist and librarian Heath Rezabek returns with further thoughts on preserving mankind’s heritage through Vessels that would contain everything we are as a species. But in an unusual offering, he goes on to provide a fictional look at how such Vessels affect the future. Just how do we preserve and present Earth’s cultural and biological heritage against events we cannot predict? And if we succeed, what shape will our Vessels take, and who will find them? Join Heath as he ventures into ‘science fiction prototyping’ as a way of influencing outcomes.
by Heath Rezabek
I’ve described The Vessel Project in three prior posts:
August 29, 2013 – Deep Time: The Nature of Existential Risk
October 3, 2013 – Visualizing Vessel
November 7, 2013 – Towards a Vessel Pattern Language
Each month I’ll try to do a new A/B sorting survey on the topic of very long term preservation. Past Poll: “Which positioning / placement of a Vessel archive or haven would take priority?” is continually open for refining votes. (http://www.allourideas.org/vessel-positioning-2013)
Current top three: 1st “Tranquility Base (Moon)”, 2nd “Lunar South Pole”, 3rd “Co-located with the 10,000 year clock (Long Now Foundation)”
This month’s new A/B Sorting Survey is:
Which works depicting cultural, biological, or scientific archival / remembrance / recovery would you recognize as exemplars of their kind? (Books, movie, or any other medium. Please add more…)
(http://www.allourideas.org/precursor-works)
– – –
It is my hope that the ideas explored in this series and in my work will help to inspire others with greater means to make these approaches into realities, as it is truly impossible to undertake such large-scale projects alone. Very long term archival and knowledge preservation seems to me a key step on the path towards an eventual interstellar civilization, and the more we explore all aspects of this journey, the greater our chances of collectively making it.
What can’t be clearly imagined can hardly be achieved. When it comes to creating artifacts that might influence or inspire others, the direct route need not be the only one. Methods such as art and fiction, in particular, can be very powerful in the effort to blaze trails towards possible futures. In this regard, one recent development of great interest to me is that of Design Fiction (sometimes also called Science-Fiction Prototyping).
Design Fiction, briefly discussed in the October 3 entry, can be described as fiction whose primary goal is to paint a picture of the possible, without too much concern for filling in all the details beyond the elements being suggested or explored. Science fiction as a speed-sketch: The goal is to strike sparks, since even small sparks can light the wayfinding torches of others — can inspire and motivate through suspension of disbelief. A recent essay on Design Fiction is useful reading. Bruce Sterling’s “Patently untrue: fleshy defibrillators and synchronised baseball are changing the future” in Wired UK is useful reading in coming to terms with this technique of idea exploration.
My Centauri Dreams contribution this month, then, is a brief detour through the realms of the possible, in an original short piece of design fiction.
– – –
Woven Light (I)
Image: Woven Light (Detail) by Heath Rezabek.
Dust, undisturbed for centuries, billowed as it was brushed aside by alloy digits. In darkness this deep, unaided eyes were blind. Yet the sensors attached to these arms soaked up the bare wisps of light and sound in this place, resolving those streams into a coherent model of surrounding space and time.
Deep set into a dais rested a prism, a cubic matrix tilted and sunken halfway into its setting. Recognizing its target, focal beams pierced the vault and the prismatic cube, splitting and refracting as they traced the edges of frozen memory to recover the data there dreaming. For this slow and steady work, long ago Tracer Aakanthia [9T33] had been conceived.
This particular prism was not the only one, but it was part of a set sharing some unique properties. Among them, the fact that light sent through its channels this way would coalesce into myriad forms above and around it, hanging dimensional in space and rotating in time, glowing softly, changing subtly, as the artifacts encoded here resolved and restored their ancient forms.
In the inky black hung an index, a tapestry of woven light, intricate patterns tracing and retracing, spinning outwards and upwards to mark the collections they mapped. Aakanthia scanned back and forth, both reading and rendering as a holographic memory of New York City (circa 2023) replayed. Compression had eroded some of its infinite edges, but fractal resuggestion was a venerable technique for good reason.
There, suspended like smoke in a sunbeam, unfurled countless moments and relations, each endlessly combining and rejoining. The tracer watched and waited, seeking at the speed of split light for the moment it had triangulated as embedded here. And finding it, slowed time to pause and hover amidst the assembly there gathered at a research lab, long since gone, which had released in prior days the fleets of tiny surveyors that had gathered the data mapped here.
Now, records had suggested, they were poised to release a second fleet, this one bound to double the resolution encoded up to then. Yet there would be a problem, and the second array would not finish its task before other needs intervened. Here, shivering and frozen forms waited for the story to retell itself once more.
The light blinked, and darkness collapsed around Tracer Aakanthia [9T33], its momentary mission complete. Gently lifting the cubic shard, it hovered and drifted back towards an array of its own, a cellular framework of woven carbon splines leading it fore towards the sail sections, slipstreaming starward…
Image: NYC (Fractal Resuggestion) by Heath Rezabek.
– – –
The first Vessel Haven installation ever founded had not been fancy, or even enduring; but at least it had been built. After spending years as a virtual shadow-box of sprawling possibilities suspended in naught but 3D space, seen by few and appreciated by fewer, it had finally been realized, a sort of an imaginary Epcot Center, as (of all things) a theme camp at the Burning Man festival that year.
From without, its most striking feature had also been among its most mundane — simple structural realities had collided with the Vessel habitat’s mission to determine that its outer form was that of a good ol’ geodesic dome. Though once these had been notorious for leakages, advances had changed that; and in any case, the desert was a fairly rain-free place for a mock-up. Advances in the autonomy and resourcefulness of the Replicator Bot had meant that the caliber of trusswork needed to seal and harden the thing at 500 feet in diameter could be achieved: silicate-sourced and fabbed on site.
Its distant bulk and form had seemed a sort of postcard from 1969, oddly comforting and quaint; yet when the notoriously brutal sandstorm of that year finally came, no small number of adventurers ended up finding shelter within its sturdy scope. Thus at last the basic function and mission of a Vessel archive could be transmitted in part and whole to a critical mass of curious minds.
The camp was run in such a way that the business of a Vessel Haven was acted out in small scenes by a vast cast and crew, interspersed with the sheltering crowd. Here you’d look and see what seemed for all the world like a clear cryogenic chamber filled with Indo-Burmese rainforest biomass, in transit to a holding tank; there you’d spy an engineer, smartly sporting a color-coded labcoat, trekking a blinking cube of clearstone circuitry from one node of the Vessel Lattice to another.
At regular intervals, hexagonal worktables hosted scale models and reconstructions of all sorts of things — from a nanoscaled reconstruction of the circular ruins of ancient Rujm el Hiri, to the proverbial kitchen sink (impossibly recovered from Frank Lloyd Wright’s Imperial Hotel) — yet there was nary a taxonomist in sight.
On the outer edges, aproned Learning Lab educators walked the curious through the finer points of a vast mural depicting the Long Now Time Diagram, augmented and expanded and overlaid with projected animations of culture’s machinations bootstrapped through time.
All came to a point here, embodied in one stunning and forward-facing lightsail, its Benford-inspired beamed design hauling a streamlined Voronoi spaceframe, zooming out and back in time to reveal the long meander of the technologies and biophilic designs which had suggested it, planted firmly on a foundation of architectural advances and accidents, interwoven with wood and stone and precious flowing water to reveal the vast work of nature and biology supporting it, and out still further, silt sliding, plates upheaving, until geology blurred with planetary formation and the furnaces of infinity ignited in reverse like campfires in the night. Of course, these were exhibits that would normally be shown to the young, but here the young at heart were well practiced at standing in.
Among those present at the Long Now holomural when the presenter had moved aside to make way for the transport of an autopallette of interlocking twisty-puzzle prisms was 17 year old Aben Ramer. First generation HexaYurt builder and second generation Jungian Surrealist, Aben had come for the Hex Space, hearing that one of the largest complexes of interlaced HexaYurt structures ever conceived had been trussed together here-in.
Image: Hex Space Blueprint by Heath Rezabek.
And this much was true. The basic module, just over 13 feet across but infinitely variable through subdivision of standard 4×8 panels, had finally been iterated into multistory structures some while back; but Aben had never seen anything like the interlocking Çatalhöyük of honeycombed spaces layered here. Circumambular disorientation fades fast for the hex-saavy, but still he was impressed by the care clearly woven into a pattern language that had clarified living centers, promenades, and sheltering spaces for all sizes and sorts of activity as one slowly spiralled inwards towards the staff-only areas.
It was then that one of the crystaloid twisty puzzles fell from the autopallette as it passed him by, landing at Aben’s feet so obviously that he suspected synchronistic dramaturgy. Picking it up, he shook his head at this six-edged mirage, thinking he’d got too much hex on the mind. But then a cube resolved as he turned it, and visually slipped again into what seemed like the form of a flattened hexagonal piezoelectric shard.
“What the hell.” But then, before he could move to execute even a single twist of the subshards around which the puzzle had been designed, he thought of his mother.
His mother, he remembered, was at a workshop in New York City. Aben knew well enough — as well as his mother could tell him — that she was at work on a very long term data storage project. (He wondered then whether that connection, too, had brought him to this Vessel in the storm, though he’d swear he hadn’t been conscious of that overlapping theme before he’d arrived.) She couldn’t say as much about the project’s scope or sponsors as she could about some of its requirements.
The team was struggling with the capacities needed for immersive motion holography. She wanted, she’d said, to preserve not just datapoints but dataflows through time. And she wanted to build a seamless bridge that any sentient being could cross, moving (however long it took) from a simple visual understanding that an artifact embodied signal, to the building of the means to decode that signal, and the finding in that signal of ever deeper construction sets leading all the way down to the digital DNA storage technologies that their holography solution had to hug.
Last month they had released a pod of mappers in Central Park, and he knew this week they were there to analyse the results. But the means to store this signal as portably and fluidly as they’d needed had so far eluded them.
He blinked at the apparition, the amusement, in his hands. Tilting it upwards, he beamed a slim vector of light at the puzzle. As he’d expected, he watched it splay through the prism into myriad forms suspended and projected all about. “It’s full of…”
He twisted a shard and beamed it again. Though the patterns had shifted, their subject was clear. Orion’s belt swung gently before his gaze, and then spun. And spinning, dissolved as something else entirely resolved itself anew. He had never seen a white dwarf this closely before; and indeed it was impossible. Yet here it floated, and here he gazed at this impossible diamond adrift in a dome of sky.
He was pretty sure he had found something, at this temporary “here” in the middle of nowhere; a skeleton key for the work his mother was doing.
It would be generations before the Tracer Guild could confirm that Aben’s hunch had been an astronomical understatement.
Image: Beta Vessel by Joshua Davis.
Europa: Minerals from an Ancient Impact?
Europa continues to fascinate those hopeful of finding life elsewhere in our Solar System, and it’s easy to see why. Consider everything the Jovian moon has going for it. Although it’s a long way from the Sun (Jupiter is 5 AU out), Europa gets internal heat from its interactions with the gravitational well around Jupiter, which causes the moon to be stretched and squeezed. We have an ocean whose occasional eruptions into the ice above allow mixing with surface materials and, as this JPL news release points out, salts on the surface that create an energy gradient. These factors have been in place on Europa since the moon first formed.
Now an analysis of data from the Galileo mission has turned up something else needed for life: The likelihood of organic materials. The assumption has been that comet or asteroid impacts could provide these, and the data that Jim Shirley (JPL) will discuss tomorrow at the American Geophysical Union meeting in San Francisco show the presence of clay-type minerals on the moon, assumed to have been delivered by just such a collision. Says Shirley:
“Organic materials, which are important building blocks for life, are often found in comets and primitive asteroids. Finding the rocky residues of this comet crash on Europa’s surface may open up a new chapter in the story of the search for life on Europa.”
Image: This image, using data from NASA’s Galileo mission, shows the first detection of clay-like minerals on the surface of Jupiter’s moon Europa. The clay-like minerals appear in blue in the false-color patch of data from Galileo’s Near-Infrared Mapping Spectrometer. Surfaces richer in water ice appear in red. The background image is a mosaic of images from Galileo’s Solid State Imaging system in the colors that human eyes would see. A version of the image without the infrared area is on the right. Credit: NASA/JPL.
The pattern of the detected minerals gives us some idea about the impactor that brought them. Shirley’s work suggests an asteroid about 1100 meters across or a comet about 1700 meters in size, either of these striking at a shallow angle. The minerals, called phyllosilicates, showed up in near-infrared images from Galileo, appearing as a broken ring about 40 kilometers wide that is 120 kilometers from the center of a central crater site. We’re probably looking at the backsplash of ejected materials from a strike at an angle of about 45 degrees or more off the vertical — a head-on collision would have vaporized the impactor or driven its materials below the surface.
All this assumes, however, that the organic materials did not come from Europa’s interior in the first place. The JPL news release notes that this is unlikely because of the thickness of the icy crust over Europa’s ocean, assumed to be as much as 100 kilometers thick. But the thickness of that crust is still the cause of some controversy, and for that I turn you to Unmasking Europa: Of Ice and Controversy, which looks at Richard Greenberg’s book on the moon and discusses surface features that may indicate a much thinner crust. What we obviously need to make this call is more information, and that may translate into a Europa mission with lander capabilities.
Encounter with a Blue/Green Planet
When I first read about Project Daedalus all those many years ago, I remember the image of a probe passing through a planetary system, in this case the one assumed to be around Barnard’s Star, at high velocity, taking measurements all the way through its brief encounter. And wouldn’t it be a fabulous outcome if something rare happened, like the reception of some kind of radio activity or some other sign of intelligent life on one of the planets there? That thought stayed with me when, much later, I read Greg Matloff and Eugene Mallove’s The Starflight Handbook and began thinking seriously about interstellar flight.
The chance of making such a detection would be all but non-existent if we just chose a destination at random, but by the time we get to actual interstellar spacecraft, we’ll also have an excellent idea — through space- and Earth-based instruments — about what we might find there. These days that ETI detection, while always interesting, isn’t at the top of my list of probabilities, but getting a close-up view of a world with an apparent living environment at whatever stage of evolution would be a stunning outcome. Let’s hope our descendants see such a thing.
Nearby Celestial Encounters
Triggering these musings was a space event much closer to home, the recent passage of the Juno spacecraft, which moved within 560 kilometers of the Earth’s surface on October 9 in a gravity assist maneuver designed to hasten its way to a 2016 encounter with Jupiter. Juno will orbit the giant planet 33 times, studying its northern and southern lights and passing through the vast electrical fields that generate them. I was fascinated to see that the recent close pass marked a milestone of sorts, for the spacecraft detected a shortwave message sent by amateur radio operators on Earth.
Image: Tony Rogers, the president of the University of Iowa ham radio club, mans the equipment used to send a message to the Juno spacecraft in October. The simple message “Hi” was sent repeatedly by ham radio operators around the world. Photos by Tim Schoon.
It’s not a starship picking up an alien civilization’s signals, but Juno did something that previous missions like Galileo and Cassini were unable to do. The latter were able to detect shortwave radio transmissions during their own Earth encounters, but it was not possible to decode intelligent information from the data they acquired. The Waves instrument on Juno, built at the University of Iowa, collected enough data that a simple Morse code message from amateur radio operators could be decoded, leading Bill Kurth, lead investigator for the Waves instrument, to say “We believe this was the first intelligent information to be transmitted to a passing interplanetary space instrument, as simple as the message may seem.”
The Juno team evaluated the Waves instrument data after the October 9 flyby and noted that the message appeared in the data when the spacecraft was still over 37,000 kilometers from Earth. The University of Iowa Amateur Radio Club contacted hundreds of ham stations in 40 states and 17 countries as part of the effort, which was managed through a website and a temporary station set up at the university. Operators from every continent coordinated transmissions carrying the same coded message, with results that can be heard in this video. As public outreach for an ongoing mission, this is prime stuff. Kurth continues:
“This was a way to involve a large number of people—those not usually associated with Juno—in a small portion of the mission. This raises awareness, and we’ve already heard from some that they’ll be motivated to follow the Juno mission through its science phase at Jupiter.”
Also qualifying as excellent public relations is the image below, which came as one of Juno’s sensors offered a low-resolution look at what a fast passage by our planet would be like.
Image: This cosmic pirouette of Earth and our moon was captured by the Juno spacecraft as it flew by Earth on Oct. 9, 2013. Image Credit: NASA/JPL-Caltech.
Scott Bolton, Juno principal investigator, likens the view to a rather famous TV show:
“If Captain Kirk of the USS Enterprise said, ‘Take us home, Scotty,’ this is what the crew would see. In the movie, you ride aboard Juno as it approaches Earth and then soars off into the blackness of space. No previous view of our world has ever captured the heavenly waltz of Earth and moon.”
Getting these images wasn’t easy. The sensors involved, cameras designed to track faint stars, are part of Juno’s Magnetic Field Investigation (MAG) and are normally used to adjust the orientation of the spacecraft’s magnetic sensors. The spacecraft was spinning at 2 rpm during the encounter, so a frame was captured each time the cameras were facing the Earth, with the results processed into video format. Juno now moves on to a Jupiter arrival on July 4 of 2016. If you want to see the Earth flyby with musical accompaniment, see this video and ponder what John Jørgensen (Danish Technical University), who designed the star tracker, says about the event: “Everything we humans are and everything we do is represented in that view.”
Rings a bell, doesn’t it? And why not. This is indeed another of those ‘pale blue dot’ moments.
Follow with RSS or E-Mail
