In a 1955 letter to the British rocket scientist Val Cleaver, Arthur Clarke wrote about his view from the island then called Ceylon: "Beautiful night last night. Southern Cross (a very feeble constellation) just above the front gate, with Alpha Centauri beside it. It always gives me an odd feeling to look at Alpha and to realize that's the next stop." The next stop indeed. Cleaver was a fellow member of the British Interplanetary Society who, like Clarke, was instrumental in energizing the society after World War II. Both men served the BIS as its chairman in those years, and after Cleaver's wartime work at De Havilland, he would go on to start a rocket division for the company and become chief engineer for the rocket division of Rolls-Royce. He is perhaps best known as the man behind the Blue Streak missile, but for those with a passion for the works of Arthur C. Clarke, he will always be remembered for his deep friendship with the man, and his energetic contribution to British...

Tau Zero's founding architect brings news of a recent European Union meeting that included starships and their implications on the agenda. Here's hoping that while he was there he also had the chance to sample some of those fabulous Belgian ales... by Marc Millis The European Union recently held a conference to collect information to plan for the coming decades of science and technology priorities. This included the theme of international collaboration and the implications for all humanity across the globe. As a part of this conference, the EU organizers invited Mae Jemison of the 100 Year Starship organization to chair a session about interstellar flight. Mae rounded up a suite of speakers including Buzz Aldrin (a genuine space celebrity), Jill Tarter (SETI), Lou Friedman (solar sail advocate and former Planetary Society director), Kathryn Denning (space anthropologist), Pam Contag (microbiologist), Marc Millis (propulsion physicist), and about half-dozen more. Image: Outside the...

Jules Verne once had the notion of a comet grazing the Earth and carrying off a number of astounded people, whose adventures comprise the plot of the 1877 novel Off on a Comet. It's a great yarn that was chosen by Hugo Gernsback to be reprinted as a serial in the first issues of his new magazine Amazing Stories back in 1926, but with a diameter of 2300 kilometers, Verne's comet was much larger than anything we've actually observed. Comets tend to be small but they make up for it in volume, with an estimated 100 billion to several trillion thought to exist in the Oort Cloud. All that adds up to a total mass of several times the Earth's. Of course, coming up with mass estimates is, as with so much else about the Oort Cloud, a tricky business. Paul R. Weissman noted a probable error of about one order of magnitude when he produced the above estimate in 1983. What we are safe in saying is something that has caught Freeman Dyson's attention: While most of the mass and volume in the galaxy...

by Kelvin F. Long The chief editor of the Journal of the British Interplanetary Society here offers part II of his article on the Society's history. If there is one BIS project that captures the imagination above all others, it's surely Project Daedalus, the ambitious attempt to design a spacecraft capable of reaching a nearby star within 50 years. But the motivations for Daedalus were wide-ranging and the conclusions of the study may surprise you. The success of the design effort showed us what was possible with the technology of its time, while subsequent studies like Project Icarus upgrade the vessel and take us that much closer to what may one day be a working craft. Les Shepherd took things to new heights with the publication of his seminal 1952 paper "Interstellar Flight". This was the first paper ever to properly address the physics and engineering issues associated with sending a probe to another star and it is what I regard as the beginning of interstellar studies as a...

by Kelvin F.Long Centauri Dreams readers will know Kelvin Long as the Chief Editor for the Journal of the British Interplanetary Society, but the résumé hardly stops there. He is also the Deputy Chair of the BIS Technical Committee and a member of the governing council. Long is the co-founder of Project Icarus, co-founder of the non-profit Icarus Interstellar (formerly serving as the Vice President European Operations) and is the co-founder of the pending Institute for Interstellar Studies. He is the managing Director of the aerospace company Stellar Engines Ltd. Here Kelvin begins a two-part article (to be completed on Monday) highlighting the British Interplanetary Society and its numerous contributions to spaceflight concepts both interplanetary and interstellar. Liverpool is a unique location in British history. Not just because of the Beatles or Olaf Stapledon, but because this is where the British Interplanetary Society (BIS) was founded in 1933 by a Cheshire-born...

Centauri Dreams is happy to welcome Dr. Cameron M. Smith, a prehistorian at Portland State University's Department of Anthropology in Portland, OR, with an essay that is the capstone of this week's worldship theme. Dr. Smith began his career excavating million-year-old stone tools in Africa and today combines his archaeological interests with a consideration of human evolution and space colonization. He is applying this interest in his collaboration with the scientists at Icarus Interstellar's Project Hyperion, a reference study for an interstellar craft capable of voyaging to a distant star. Recently Dr. Smith presented a paper at the NASA/DARPA '100 Year Starship Study' conference in Houston, Texas. His recent popular science publications in this field include "Starship Humanity" (Scientific American 2013) and the book Emigrating Beyond Earth: Human Adaptation and Space Colonization (Springer-Praxis, 2013). We can look forward to a follow-up article to this one in coming weeks. by...

The assumptions we bring to interstellar flight shape the futures we can imagine. It's useful, then, to question those assumptions at every turn, particularly the one that says the reason we will go to the stars is to find other planets like the Earth. The thought is natural enough, and it's built into the exoplanet enterprise, for the one thing we get excited about more than any other is the prospect of finding small, rocky worlds at about Earth's distance from a Sun-like star. This is what Kepler is all about. From an astrobiological perspective, this focus makes sense, as we want to know whether there is other life -- particularly intelligent life -- in the universe. But interstellar expansion may not involve terrestrial-class worlds at all, though they would still remain the subject of intense study. Let's assume for a moment that a future human civilization expands to the stars in worldships that take hundreds or even thousands of years to reach their destination. The occupants...

Those of us who are fascinated with interstellar travel would love to see a probe to another star launched within our lifetime. But maybe we're in the position of would be flyers in the 17th Century. They could see birds wheeling above them and speculate on how humans might create artificial wings, but powered flight was still centuries ahead. Let's hope that's not the case with interstellar flight, but in the absence of any way of knowing, let's continue to attack the foundational problems one by one in hopes of building up the needed technologies. Marc Millis, who ran NASA's Breakthrough Propulsion Physics project at the end of the 20th Century, always points out in his talks that picking this or that propulsion technology as the 'only' way to get to the stars is grossly premature. In a recent interview with the Australian Broadcasting Corporation's Antony Funnell, Millis joined physicist and science fiction writer Gregory Benford, Icarus Interstellar president Richard Obousy and...

One of the pleasures of conferences like the recent Huntsville gathering is the chance to meet up with old friends. Richard Obousy and I had been talking about his offering a review of Icarus Interstellar's recent work for some time, and Huntsville gave us the chance to firm up the idea. The article below is the result, an examination of the Icarus team's current structure and planning as they continue with the Project Icarus starship design and look toward other interstellar possibilities. The president and senior scientist for Icarus, Richard is a familiar face on Centauri Dreams. He did his doctoral work at Baylor University, studying the possibility that dark energy could be an artifact of Casimir energy in extra dimensions. He's now engaged in planning the Icarus conference this summer, about which more shortly. By Richard Obousy Having served as President of Icarus Interstellar for 18 months now, I've been privileged to be knee deep in the evolving face of this exciting...

If the title of this piece conjures up exotic images, that's all to the good. In fact, I'm surprised that "Alpha Centauri Sunrise" hasn't been the title of a science fiction story somewhere along the line, but a quick check shows no such reference. Thus when Robert Kennedy (The Ultimax Group) created a drink called the Alpha Centauri Sunrise at our recent conclave in Huntsville, he was breaking new ground. And maybe images of a double sunrise also came to mind, the view from an as yet undiscovered world where Centauri A is a bright flare in the morning sky while a still closer Centauri B begins to nudge up over the hills, flooding the scene with orange light. And what happened to Proxima Centauri? It would not be a factor in a scene like that, its light so dim that it would not stand out from other stars in a completely dark sky. Only its proper motion would alert local astronomers to how close it was (roughly 15000 AU). But let's drink to Proxima anyway. I promised the recipe for...

One of the things I love about writing Centauri Dreams is that I learn something new every day. Often this comes from the research needed for individual stories, but just as often it comes from readers suggesting new directions or seeing nuances in an earlier story that I had missed. Yesterday's post on long-term thinking led to an exchange with Centauri Dreams regular NS, who questioned my ideas on longevity in the Middle Ages, and before long we were both digging up data to try to discover what the numbers really are. It's an ongoing process, and if you're interested in such arcana, you can follow it in yesterday's comments thread. If you're just joining us and wondering why we're discussing medieval longevity, it ties into what I was saying about long-haul construction projects like cathedrals, and the question of what a worker on one of these projects might have thought of his chances of seeing its completion. You can also chalk it up to a fascination with the Middle Ages that...

I conceived an early love for Tennyson, but it wasn't until a bit later in life that I ran into his "Locksley Hall," which contains lines many science fiction fans are familiar with: Many a night I saw the Pleiads, rising thro' the mellow shade, Glitter like a swarm of fire-flies tangled in a silver braid. Here about the beach I wander'd, nourishing a youth sublime With the fairy tales of science, and the long result of Time; When the centuries behind me like a fruitful land reposed; When I clung to all the present for the promise that it closed: When I dipt into the future far as human eye could see; Saw the Vision of the world and all the wonder that would be.— and so on. The poem is the lament of a soldier returning to the places of his boyhood and eventually turning his thoughts, and his resolve, on the future. When I read the line 'the long result of time,' I realized that it was here that I found resonance with the poet. The idea of a remote futurity and the need to build...

It's surprising but gratifying that we can now talk about the 'interstellar community.' Just a few years back, there were many scientists and engineers studying the problems of starflight in their spare time, but when they met, it was at conferences dedicated to other subjects. The fact that the momentum has begun to grow is made clear by the explicitly interstellar conferences of recent memory, from the two 100 Year Starship symposia to the second Tennessee Valley Interstellar Workshop. Icarus Interstellar is mounting a conference this August in Dallas, and the Institute for Interstellar Studies plans its own gathering this fall in London. Of course the Internet is a big part of the picture -- Bob Forward and his colleagues could use the telephone and the postal service to keep in touch, but the energizing power of instant document exchange and online discussion was in the future. All this was apparent in Huntsville for the Tennessee Valley event, from which I have just returned....

Air travel presents us with challenges we seldom anticipate. Flying into Charlotte on Sunday I had developed a ferocious headache. I was headed to the Tennessee Valley Interstellar Workshop in Huntsville and had a long enough layover in Charlotte to seek out a pain reliever with decongestant properties. The ridiculous thing was that I couldn't get the plastic mini-pack open. The little symbol showed me tearing off the corner of the packet, but it wouldn't tear for me, and it wouldn't tear for the guy who happened to be sitting next to me at the USAir gate. It became clear that I needed something sharp to get into this packet, but it was also clear that I was in an airport, the very definition of which these days is to prevent passengers from having anything sharp. I finally took the packet back to the kiosk I bought it from and demanded redress. The lady looked askance at me, looked at the packet, and opened it effortlessly. Further comment seems superfluous. By the time I got off...

These days we know that perhaps a million objects the size of the Tunguska impactor or larger are moving through nearby space, and talk of how to deflect asteroids has become routine. Given our increasing awareness of near-Earth objects, it wouldn't be a surprise to hear of a new Hollywood treatment involving an Earth-threatening asteroid. But I wouldn't have expected a science fiction series that ran from 1959 to 1960 would have depicted an asteroid mission and the dangers such objects represent. Nonetheless, I give you "Asteroid," from the show Men Into Space, with script by Ted Sherdeman. Viewers on November 25, 1959 saw the show's protagonist Col. Edward McCauley (William Lundigan) take a crew to 'Skyra,' a 3.5-kilometer long rock that scientists believed might hit the Earth. The crew assesses whether the asteroid is salvageable for use as a space station and decides there is no other choice but to destroy Skyra, which they do at the cost of considerable suspense as McCauley...

How fast we go affects how we perceive time. That lesson was implicit in the mathematics of Special Relativity, but at the speed most of us live our lives, easily describable in Newtonian terms, we could hardly recognize it. Get going at a substantial percentage of the speed of light, though, and everything changes. The occupants of a starship moving at close to 90 percent of the speed of light age at half the rate of their counterparts back on Earth. Push them up to 99.999 percent of c and 223 years go by on Earth for every year they experience. Thus the 'twin paradox,' where the starfaring member of the family returns considerably younger than the sibling left behind. Carl Sagan played around with the numbers in the 1960s to show that a spacecraft moving at an acceleration of one g would be able to reach the center of the galaxy in 21 years (ship-time), while tens of thousands of years passed on Earth. Indeed, keep the acceleration constant and our crew can reach the Andromeda...

Sending messages into the galaxy normally goes under the rubric of METI - Messaging to Extraterrestrial Intelligence. In its electromagnetic form, the sending of directed signals to nearby star systems, it has proven more than a little controversial, as the work of Alexander Zaitsev at Evpatoria attests. But sending a message into space in the form of an artifact like the 'Golden Record' on the Voyager probes is also a form of METI, and one that excites as much introspection as passion. Larry Klaes has been looking at Trevor Paglen's Pictures from Earth project, which sends images of our world not to the stars but into a stable orbit near our planet. Who will eventually find these images and what will they make of them? What should we be thinking about when we represent ourselves to the universe? By Larry Klaes In the history of humanity, there have been a select number of key events which define the moments when our species became truly intelligent in terms of a self-aware...

How are you affected by the cave paintings at Lascaux? The paleolithic art in this region of southwestern France dates back perhaps 18,000 years, depicting large animal figures, human forms and abstract symbols. Some believe the paintings even contain astronomical pointers -- star charts -- but theories on how to interpret them abound, and whatever spin we put on them, we're confronted by the mystery of evocative imagery reaching out over centuries. Lascaux and other such sites take us beyond civilization and into the realm of deep time, a place where our parochial concerns are dwarfed by this reminder of humanity's aggregated experience. Early cave art reaches almost twice as far back as the 10,000 year clock proposed by Danny Hillis and the Long Now Foundation hopes to take us forward. Yet the experience of the two is in some ways similar. Building a clock designed to tell time by the year and century places our short lives in perspective and demands we take a view that encompasses...

Patrick Moore, the legendary figure of British astronomy who died recently at his home in West Sussex, was deeply familiar with Ptolemy. The latter, a 2nd Century AD mathematician and astronomer, was the author of the Almagest, an astronomical treatise that presented the universe as a set of nested spheres and assumed a geocentric cosmos. Moore's comprehensive knowledge of astronomy's history would naturally have included the Almagest and probably Ptolemy's astrological musings as well, but a different Ptolemy was a figure even more important to him, a cat of that name who was with him when he died. The author of 2012's Miaow!: Cats Really are Nicer Than People! never hid his love for his feline friends. I admire a man who, when faced with the reality that further treatments are unproductive, simply announces that he wants to go home. And go home he did, to the town of Selsey and the house called Farthings, where he died among family and friends. Moore was a man of fierce views and...

If Kansas may not be the first place that comes to mind when you think about interstellar matters, be aware that its state motto is 'Ad Astra Per Aspera' -- to the stars through difficulties. That's a familiar phrase for anyone who has pondered the human future in space, appearing in countless science fiction stories and often invoked by those with a poetical streak. It turns out that the Kansas motto was not, however, the work of some percipient 19th Century Robert Forward figure, but of one John Ingalls, a lawyer, scholar and statesman who introduced the motto as far back as 1861. And while its roots were in the coming Civil War, the story of Ingalls' motto is so entertaining that it merits inclusion here, as reported by biographer G. H. Meixell: "I was secretary of the Kansas state senate at its first session after our admission in 1861. A joint committee was appointed to present a design for the great seal of the state and I suggested a sketch embracing a single star rising from...