The great Ukrainian mathematician Israil Moiseyevich Gelfand was famous for his weekly seminars in Moscow, where sudden switches in topics and impromptu presentations were the norm. Although his listeners had heard it many times, Gelfand liked to tell this story: In the early 20th Century, a man approaches a physicist at a party and says he can't understand how the new wireless telegraphy works. How is it possible to send a signal without using wires? The physicist tells him it is simple. "To understand wireless telegraphy, you must first understand how the wired telegraph system works. Imagine a dog with its head in London and its tail in Paris. You yank the tail in Paris and the head in London barks. That is wired telegraphy. Wireless telegraphy is the same thing except without the dog." It always got Gelfand a laugh, but he liked to use the story for a deeper purpose. According to Edward Frenkel, who in his youth attended and presented at some of Gelfand's seminars, Gelfand would...

Because his new novel Shipstar had just reached the top of my reading stack, and because I had been writing about Shkadov Thrusters last week, I asked Gregory Benford if he could provide a deeper explanation of how these enormous structures might work. Greg had already noted in an email to me that a Shkadov Thruster is inherently unstable, and earlier discussions of the idea on Centauri Dreams had raised doubts about the acceleration possible from such a device. However, I’ve referred to what Benford and Larry Niven have created as a ‘modified’ Shkadov Thruster, and I was anxious to hear their thinking on what might be possible. Greg, an award-winning science fiction author and physicist, here offers his insights into -- and reservations about -- a propulsion scheme capable of moving stars. by Gregory Benford Physicist Leonid Shkadov first described in 1987 a stellar propulsion system made by putting an enormous mirror in a static, fixed position near a star. To stay there it had to...

I've always loved the idea of an O'Neill space habitat because of the possibility of engineering a huge environment to specification. That notion translates well to worldship ideas -- a multi-generational journey would certainly be easier to take in an environment that mimicked, say, a Polynesian island, than aboard something more akin to a giant metal barracks. But best of all is to take your environment with you, which is why the thought of moving entire stars and planets to another location has such appeal when we're talking on an intergalactic scale. Adam Crowl reminded us of the possibilities on Monday: In theory a tight white-dwarf/planet pair can be flung out of the Galactic Core at ~0.05c, which would mean a 2 billion year journey across every 100 million light-years. A white-dwarf habitable zone is good for 8 billion years or so, enough to cross ~400 million light-years. It'd be a 'starship' in truth on the Grandest Scale. Back in November of 1973, Stanley...

Andreas Hein, who has appeared in these pages before on the subject of worldships, here speculates about a much different kind of traveling: The uploading of consciousness. Andreas is Deputy Director of the Initiative for Interstellar Studies (I4IS), as well as Director of its Technical Research Committee. He founded and leads Icarus Interstellar's Project Hyperion: A design study on manned interstellar flight. Andreas received his master's degree in aerospace engineering from the Technical University of Munich and is now working on a PhD there in the area of space systems engineering, having conducted part of his research at MIT. He spent a semester abroad at the Institut Superieur de l'Aeronautique et de l'Espace in Toulouse, working on the numerical simulation of the hypervelocity impact of space dust on spacecraft antennas, and also worked at the European Space Agency Strategy and Architecture Office on stakeholder analysis for future manned space exploration. Today's essay is...

Les Shepherd's 1952 paper "Interstellar Flight" appears in the Journal of the British Interplanetary Society," a fitting place given Shepherd's active involvement in the organization. He would, in fact, serve the BIS as its chairman, first succeeding Arthur C. Clarke in that role in 1954, and returning in 1957 and again in 1965 for later terms of office. "Interstellar Flight" is one of those papers that turns people in new directions after they have read it, and we can see the gradual acceptance of travel between the stars as a possibility that does not violate the laws of physics beginning in its pages. Much less heralded but more widely seen was an adapted version of "Interstellar Flight" that appeared in Science Fiction Plus in April of 1953. The magazine was a revival of Hugo Gernsback's career as a science fiction publisher that ran for seven issues before its demise in December of the same year. Gernsback's name was revered in science fiction circles as the founder of Amazing...

I didn't have the chance to meet Mark Lupisella at the first 100 Year Starship symposium in Orlando, but the publication of Cosmos & Culture: Cultural Evolution in a Cosmic Context in 2013 made me wish I had sought him out. Co-edited with Steven J. Dick (about whom there are so many interesting things to say that I'll have to carry over into a future post with them), Cosmos & Culture offers essays from scientists, historians and anthropologists about the evolution of culture both on Earth and, most likely, beyond it. These are, of course, issues we've been considering recently in the work of Cameron Smith and Kathleen Toerpe, and in a broader sense they inform many of the SETI and astrobiology discussions we have here. Then Clément Vidal, who is an author and a post-doctoral researcher at the Free University of Brussels, passed along the paper I missed in Orlando, Lupisella's "Cosmocultural Evolution: Cosmic Motivations for Interstellar Travel." To be fair to myself, we all...

Can we overcome our preconceptions about extraterrestrial life? Kathleen Toerpe thinks the answer is yes, for we're moving from the era of ill-informed jokes about 'little green men' to a widening appreciation of our place in the cosmos. Dr. Toerpe is the Deputy CEO for Programs and Special Projects at the Astrosociology Research Institute and editor of The Journal of Astrosociology. She also serves as a NASA/JPL Solar System Ambassador, one whose educational efforts on behalf of space exploration have revealed that the younger generation is familiar with and inspired by the subject, a fact that gives this essay its welcome patina of optimism. The recent hearings on SETI in the U.S. House of Representatives show that, for some at least, old attitudes die hard, but ongoing research into astrobiology and SETI is likely to make the 'giggle factor' seem positively prehistoric within our lifetimes. by Kathleen D. Toerpe, PhD Flip through any newsfeed these days, and it seems that humanity...