Tag Archives: bracewell probes

Centauri Dreams: To Build the Ultimate Telescope

Paul Gilster posts:

In interstellar terms, a ‘fast’ mission is one that is measured in decades rather than millennia. Say for the sake of argument that we achieve this capability some time within the next 200 years. Can you imagine where we’ll be in terms of telescope technology by that time? It’s an intriguing question, because telescopes capable of not just imaging exoplanets but seeing them in great detail would allow us to choose our destinations wisely even while giving us voluminous data on the myriad worlds we choose not to visit. Will they also reduce our urge to make the trip?

Former NASA administrator Dan Goldin described the effects of a telescope something like this back in 1999 at a meeting of the American Astronomical Society. Although he didn’t have a specific telescope technology in mind, he was sure that by the mid-point of the 21st Century, we would be seeing exoplanets up close, an educational opportunity unlike any ever offered. Goldin’s classroom of this future era is one I’d like to visit, if his description is anywhere near the truth:

“When you look on the walls, you see a dozen maps detailing the features of Earth-like planets orbiting neighboring stars. Schoolchildren can study the geography, oceans, and continents of other planets and imagine their exotic environments, just as we studied the Earth and wondered about exotic sounding places like Banghok and Istanbul … or, in my case growing up in the Bronx, exotic far-away places like Brooklyn.”

Webster Cash, an astronomer whose Aragoscope concept recently won a Phase I award from the NASA Innovative Advanced Concepts program (see ‘Aragoscope’ Offers High Resolution Optics in Space), has also been deeply involved in starshades, in which a large occulter works with a telescope-bearing spacecraft tens of thousands of kilometers away. With the occulter blocking light from the parent star, direct imaging of exoplanets down to Earth size and below becomes possible, allowing us to make spectroscopic analyses of their atmospheres. Pool data from fifty such systems using interferometry and spectacular close-up images may one day be possible.


Image: The basic occulter concept, with telescope trailing the occulter and using it to separate planet light from the light of the parent star. Credit: Webster Cash.

Have a look at Cash’s New Worlds pages at the University of Colorado for more. And imagine what we might do with the ability to look at an exoplanet through a view as close as a hundred kilometers, studying its oceans and continents, its weather systems, the patterns of its vegetation and, who knows, its city lights. Our one limitation would be the orbital inclination of the planet, which would prevent us from mapping every area on the surface, but given the benefits, this seems like a small issue. We would have achieved what Dan Goldin described.

Seth Shostak, whose ideas we looked at yesterday in the context of SETI and political will, has also recently written on what large — maybe I should say ‘extreme’ — telescopes can do for us. In Forget Space Travel: Build This Telescope, which ran in the Huffington Post, Shostak talks about a telescope that could map exoplanets with the same kind of detail you get with Google Earth. To study planets within 100 light years, the instrument would require capabilities that outstrip those of Cash’s cluster of interferometrically communicating space telescopes:

At 100 light-years, something the size of a Honda Accord — which I propose as a standard imaging test object — subtends an angle of a half-trillionth of a second of arc. In case that number doesn’t speak to you, it’s roughly the apparent size of a cell nucleus on Pluto, as viewed from Earth.

You will not be stunned to hear that resolving something that minuscule requires a telescope with a honking size. At ordinary optical wavelengths, “honking” works out to a mirror 100 million miles across. You could nicely fit a reflector that large between the orbits of Mercury and Mars. Big, yes, but it would permit you to examine exoplanets in incredible detail.

Or, of course, you can do what Shostak is really getting at, which is to use interferometry to pool data from thousands of small mirrors in space spread out over 100 million miles, an array of the sort we are already building for radio observations and learning how to improve for optical and infrared work on Earth. Shostak discusses a system like this, which again is conceivable within the time-frame we are talking about for developing an actual interstellar probe, as a way to vanquish what he calls ‘the tyranny of distance.’ And, he adds, ‘You can forget deep space probes.’

I doubt we would do that, however, because we can hope that among the many worlds such a space-based array would reveal to us would be some that fire our imaginations and demand much closer study. The impulse to send robotic if not human crews will doubtless be fired by many of the exotic scenes we will observe. I wouldn’t consider this mammoth space array our only way of interacting with the galaxy, then, but an indispensable adjunct to our expansion into it.

Of course Shostak takes the long, sensor derived view of exploring the Universe, his life’s work is radio telescopes.

Gilster is correct that interferometry will be an adjunct to sending robotic probes to distant interstellar worlds, you can’t make money by just gawking at places.

Or can you? 

Original post.

Robotic Interstellar Galactic Networks

Interstellar Galactic Federations and Empires not withstanding, Einstein’s Special Theory of Relativty still rules.

However, Paul Gilster posts on his blog Centauri Dreams that below light speed colonization of the galaxy can have a normal, more organic method of colonizing the galaxy by human, or alien intelligences:

Imagine a future in which we manage to reach average speeds in the area of one percent of the speed of light. That would make for a 437-year one-way trip to the Alpha Centauri system, too long for anything manned other than generation ships or missions with crews in some kind of suspended animation. Although 0.01c is well beyond our current capabilities, there is absolutely nothing in the laws of physics that would prevent our attaining such velocities, assuming we can find the energy source to drive the vehicle. And because it seems an achievable goal, it’s worth looking at what we might do with space probes and advanced robotics that can move at such velocities.

How, in other words, would a spacefaring culture use artificial intelligence and fast probes to move beyond its parent solar system? John Mathews ( Pennyslvania State) looks at the issue in a new paper, with a nod to the work of John von Neumann on self-reproducing automata and the subsequent thoughts of Ronald Bracewell and Frank Tipler on how, even at comparatively slow (in interstellar terms) speeds like 0.01c, such a culture could spread through the galaxy. There are implications for our own future here, but also for SETI, for Mathews uses the projected human future as a model for what any civilization might accomplish. Assume the same model of incremental expansion through robotics and you may uncover the right wavelengths to use in observing an extraterrestrial civilization, if indeed one exists.

Image: The spiral galaxy M101. If civilizations choose to build them, self-reproducing robotic probes could theoretically expand across the entire disk within a scant million years, at speeds well below the speed of light. Credit:  STScI.

But let’s leave SETI aside for a moment and ponder robotics and intelligent probes. Building on recent work by James and Gregory Benford on interstellar beacons, Mathews likewise wants to figure out the most efficient and cost-effective way of exploring nearby space, one that assumes exploration like this will proceed using only a small fraction of the Gross Planetary Product (GPP) and (much later) the Gross Solar System Product (GSSP). The solution, given constraints of speed and efficiency, is the autonomous, self-replicating robot, early versions of which we have already sent into the cosmos in the form of probes like our Pioneers and Voyagers.

The role of self-replicating probes — Mathews calls them Explorer roBots, or EBs — is to propagate throughout the Solar System and, eventually, the nearby galaxy, finding the resources needed to produce the next generation of automata and looking for life. Close to home, we can imagine such robotic probes moving at far less than 0.01c as they set out to do something targeted manned missions can’t accomplish, reaching and cataloging vast numbers of outer system objects. Consider that the main asteroid belt is currently known to house over 500,000 objects, while the Kuiper Belt is currently thought to have more than 70,000 100-kilometer and larger objects. Move into the Oort and we’re talking about billions of potential targets.

A wave of self-reproducing probes (with necessary constraints to avoid uninhibited growth) could range freely through these vast domains. Mathews projects forward not so many years to find that ongoing trends in computerization will allow for the gradual development of the self-sufficient robots we need, capable of using the resources they encounter on their journeys and communicating with a growing network in which observations are pooled. Thus the growth toward a truly interstellar capability is organic, moving inexorably outward through robotics of ever-increasing proficiency, a wave of exploration that does not need continual monitoring from humans who are, in any case, gradually going to be far enough away to make two-way communications less and less useful.

Paul calls robotic networks “organic” in the way they might grow, but there is a commenter on the post who disagrees with it and I might agree with that.

But that doesn’t discount a more “cybernetic” approach in which the combination of machine with organic technology is the more “natural” extension or evolution of intelligent lifeforms.

I would look for rigidly constructed organic molecular structures in the interstellar medium as materials for Bracewell Probes.

Robotic Networks Among the Stars

“…wash, rinse, repeat…”

Reporting from Edwards Air Force Base — NASA rolled out its next-generation space capsule here Wednesday, revealing a bulbous module that is scheduled to carry humans back to the moon in 2020 and eventually onward to Mars.
Unlike the space-plane shape of the shuttles, the new Orion Crew Exploration Vehicle looks strikingly similar to the old Apollo space capsule that carried Neil Armstrong, Buzz Aldrin and Michael Collins to the moon and back in 1969, with Armstrong and Aldrin becoming the first humans to walk on the lunar surface.
There is one key difference, however. The test module, unveiled at NASA’s Dryden Flight Research Center, is substantially bigger — 16.5 feet in diameter compared with Apollo 11’s 12.8 feet.
Still, cramming six astronauts inside will make it “pretty cozy,” he said.

The craft’s extra girth will allow it to carry six astronauts instead of Apollo’s three.

“This is the same shape as Apollo,” said Gary Martin, the project manager for the test program at Dryden. “But the extra space translates into twice as much volume as Apollo.”

Oooh, I’m impressed! /not!

How many times can the wheel be reinvented?

Quite a few apparently.

New NASA capsule Orion resembles Apollo


Finding ancient meteorites on the moon would be exciting enough, but what they may contain really interests Houtkooper.

Consider simple bacterial life on the early Earth, existing inside a rock which is then blasted off the surface of the planet by a large impact. In theory, some of these samples could have landed in lunar craters like Shackleton. Once there, they would be perfectly preserved in a deep freeze for billions of years. Life carried to the moon in this way would almost certainly be dead, although it is possible that some hardy creatures could survive the journey in a dormant state. As Houtkooper succinctly states, “there could be signs of life from early Earth on the moon.”

Things get particularly interesting when a large impact on the moon by an object around 10 km in diameter is considered. If that were to occur, enough material would be thrown up to create a very thin lunar atmosphere. This tenuous atmosphere could last a few hundred years, just enough time to spark into action any dormant life that had been carried to the moon from other worlds.

So it is possible that, dotted throughout the moon’s colorful history, it may have hosted simple but live alien organisms.

Panspermia has made a comeback in recent months, both as a means of transferring life throughout the Cosmos naturally and artificially.

Viability of the organisms being transported about is the issue.

How can living things withstand the rigors of freezing cold, solar and cosmic radiation?

Here are some articles that might answer some of these questions:

Eight-Legged Space Survivor Gives ‘Panspermia’ New Life

Cold Storage: Moon Might Preserve Alien Life


Here’s something from Crowlspace that should’ve been in my recent SETI post:

A ~ 10-metre object on a heliocentric orbit, now catalogued as 1991 VG, made a close approach to the Earth in 1991 December, and was discovered a month before perigee with the Spacewatch telescope at Kitt Peak. Its very Earth-like orbit and observations of rapid brightness fluctuations argue for it being an artificial body rather than an asteroid. None of the handful of man-made rocket bodies left in heliocentric orbits during the space age have purely gravitational orbits returning to the Earth at that time, and in an3′ case the a priori probability of discovery for 1991 VG was very small, of order one in 100,000 per anmun. In addition, the small perigee distance observed might be interpreted as an indicator of a controlled rather than a random encounter with the Earth, and thus it might be argued that 1991 VG is a candidate as an alien probe observed in the vicinity of our planet.

I think mainstream SETI is afraid of finding Bracewell Probes, because it shakes them from the comfortable notion that material interstellar travel is impossible and any civilization is a safe thousands of light-years away, accessible only by micro and radio waves.

Adam Crowl does ask an interesting question, “…if it is a probe, then why is it suddenly becoming visible? Based on our primitive attempts at invisibility cloaks using meta-materials I suspect any advanced technological species will be able to remain unseen by primitive eyes… yet here we have a probe making itself blatant. Hmmm…”

Hmmm indeed Adam.

SETA and VG 1991


Monument Beacons of SETI

Centauri Dreams:

The Benfords — Jim at Microwave Sciences, Gregory at the University of California’s Irvine campus, and Dominic (Jim’s son) at NASA GSFC — believe that advanced societies, if they are to be found, ought most likely to exist toward the galactic center, and probably at distances of over a thousand light years. We’re thus talking, in all likelihood, about interstellar beacons rather than targeted transmissions when it comes to SETI. And if beacons are indeed at play, what can we say about their costs, and do our own standards of terrestrial cost have any application in an ETI context?

The message here is that any SETI search has to make assumptions about the beacon builders, and if we can determine something about the economics of the situation, we may learn how to target our searches more effectively. Here’s the essence of the argument about ETI:

We assume that if they are social beings interested in a SETI conversation or passing on their heritage, they will know about tradeoffs between social goods, and thus, in whatever guise it takes, cost. But what if we suppose, for example, that aliens have very low cost labor, i. e., slaves? With a finite number of slaves, you can use them to do a finite number of tasks. And so you pick and choose by assigning value to the tasks, balancing the equivalent value of the labor used to prosecute those tasks. So choices are still made on the basis of available labor. The only case where labor has no value is where labor has no limit. That might be if aliens may live forever or have limitless armies of self-replicating automata, but such labor costs something, because resources, materials and energy, are not free.

Our point is that all SETI search strategies must assume something about the beacon builder, and that cost may drive some alien attempts at interstellar communication.

SETI always seems to come with a built-in willingness to think the best of extraterrestrial cultures. If an alien civilization is sending out a message, it must be doing so out of altruism. The Benfords, though, are interested in exploring motivations from a different angle. They’d like to relate them to the only case of a technological civilization we know of, ourselves, and speculate based on human history. From that perspective, there are two reasons for sending out messages across vast time scales.

Think about what people do. You can go to the Tower of London and explore the chambers where famous prisoners like Thomas More were kept. Invariably, on the walls, you’ll find graffiti, names written into the stone. People have an apparently robust need to engage in one-way communication, putting a note in a bottle and throwing it. Indeed, the Pioneer and Voyager spacecraft are examples of the impulse. Is it likely that any of these tiny vessels will ever be intercepted? Yet putting our names, our stories, our music and our pictures on board outgoing vehicles is a method that resonates. We have a need to encapsulate who we are.

A second reason is the drive to communicate the optimum things about our culture, what Matthew Arnold called “…the best that has been thought and said in the world.” Here the Benfords cite time capsules and monuments as examples of our need to propagate our culture. The contemplation of a legacy is involved here, especially in a scenario where human lifetimes are rising. Here again the communication can be one-way. The statue of King Alfred my wife and I admired in Winchester some years back was not built to impress people within a tight time frame, but to stand as a monument that would reach future generations.

So imagine scenarios like this: A civilization with an ability to plan over millennial time scales foresees problems that are beyond its capabilities. A SETI beacon might encapsulate a call for information and help — send us everything you have on stellar warming…

Here’s another: A civilization in its death throes decides to send out an announcement of its existence. We were here and are no longer, but as long as this message endures, so in a sense do we. And let’s not discount sheer pride of the sort that could keep a beacon in operation long after the beings that built it were gone. Robotically maintained, it might boast of achievements set against the backdrop of the ruin that may eventually attend all technological cultures. Or perhaps we’ll run into interstellar proselytes, out to convert the galaxy to a particular set of beliefs by placing their highest values into their outgoing signal.


I’m glad that finally somebody in mainstream SETI studies have proposed something different to think about when it comes to listening to, or broadcasting signals.

While I feel SETI should do more than just do the radio thing and look for possible Bracewell Probe signals, the Benford Clan at least looked outside the box.


The Monument Beacon theory sounds good, but something else should be added onto that.

If a suspected source is found, perhaps we should train all of our available listening, optical, and any other measuring devices we can muster to locate a Transcension Fossil in its general direction.

Yeah I know, semi-religious technorapture crap and such an object would be hard to find, even if the broadcast signal was strong enough.

But if we were lucky enough to intercept a Beacon in the first place, why not trace it back to the source to see if such things as Technological Singularities take place?

It could explain the Fermi Paradox.

And give us a clue to our ultimate fate possibly.

SETI: Figuring Out The Beacon Builders


Transhumanism, Utility Fog and Rules of Uplift

Mac Tonnies sez;

I have a confession to make: I am a “transhuman ufologist.”

So far as I know, this is the first time the term has appeared on the Web, so I’ve yet to see if it has any staying power. But the idea, at least, is simple enough: I see absolutely no contradiction between the “hard” technological realities of the Kurzweilian Singularitarian crowd and the speculation of informed UFO researchers.

We transhuman ufologists are a witheringly small bunch; although I’ve come across provocative discussions about nanotechnology and machine intelligence within the more intelligent corridors of ufology, committed transhumanists approach the subject of UFOs and the “paranormal” with pronounced disdain. The very definition of “skeptic,” for instance, is summarily forgotten; among the more strident and vocal proponents of transhumanism, the very prospect of extraterrestrial visitation via UFO is considered naïve fantasy good for little more than placating true believers with elusive promises of galactic altruism. Certainly, they argue, we’re better off parroting the so-called Fermi Paradox. (link)

I have at one time or another speculated an advanced civilization that has gone through its own ‘Singularity’ event would use utility fog nanotech to present itself to primitive beings at various stages of its development by utilizing current cultural beliefs and mores.

This is a variation of Arthur C. Clarke’s Sentinal/Black Monolith/Bracewell probe method of contact via direct intervention and uplift. In 2001: A Space Odyssey, the apes at the beginning of the movie were ‘tweaked’ by the Monolith to be more aggressive and imaginative so they could survive the harsh environment of Africa. After that it left until humans dug up another Monolith on the Moon millions of years later, triggering it to send a message to another in orbit around Jupiter (Saturn in the novel). The idea here being that Mankind was ready for another ‘tweaking’ (Bowman into the Starchild).

In the ‘utility fog’ scenario, the probes didn’t leave, they stuck around to influence humanity during different stages of our development, possibly being the sources of demons, angels, gods, elves, dwarfs, fairies, sprites, other ‘magical’ creatures and of course aliens and UFOs. The idea here being the intelligence as represented by the nanoprobes is prepping the human race for eventual ‘contact’ with it.

I don’t know. My beef with this idea isn’t with Mac, but with the ‘utility fog’ itself if this is the case.  It hasn’t been very good or wise at preparing us. It’s like locking a two year old child in a room with a one-way observation window, giving him/her a book about life in the Universe, providing meals on occasion, expounding ‘proclaimations’ via loudspeaker and releasing the person when grown expecting them to behave intelligently. Oh yeah, the person has ‘free will’ to either obey ‘God’ and society, or be punished if they break the rules. And most people still aren’t able to tell the difference between aliens or demons, even if one came up and bit them in the arse! (Or stuck a probe up there anyways!) Some mentors! They put people in jail for that now-a-days!

Of course being alien nano-probes, they could be hardly sympathetic and altruistic to creatures they would consider lab animals. I would counter by saying that if such vast artificial intelligence(s) take it upon themselves to ‘uplift’ pre-sentient creatures, there must be rules and/or code of ethics to follow concerning such projects, as proscribed in David Brin’s Uplift novels. If the rule/laws are broken, the offending race/intelligence is punished. The most severe punishments go to beings who start uplift projects and then abandon them.

There’s no proof of course nanoprobe ‘utility fog’ intelligences are responsible for the UFO or related phenomena, or that we’ve been uplifted. Then again, Mac gives a very compelling thesis why UFO/alien sightings are perceived differently by the diverse peoples/cultures of Earth in prehistory and historically.

But if there’s such a thing as a Galactic Child Protective Services agency, our utility fog teachers should be thrown into the Milky Way crow-bar hotel for gross negligence!