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Starshot and the Gravitational Lens

by Paul Gilster | Apr 25, 2016 | Missions | 54 Comments

Although the idea of a mission to the Sun's gravitational lens has been in Claudio Maccone's thinking for a long time, it has never been linked with the financial resources of a concept study like Breakthrough Starshot. The Italian physicist led a conference on mission concepts in the early 1990s and submitted a proposal for an ESA mission in 1993. What's striking to me is that throughout that time, Maccone has explored aspects of the mission he calls FOCAL that at one point seemed far too futuristic for our era. Could we, for example, do SETI with a FOCAL mission? Could we use it to enhance communications with an interstellar probe? The answer to both is yes, but the problem was pushing a spacecraft out to 550 AU in the first place, a challenge involving flight times of many decades. Then the Breakthrough Starshot initiative emerged and suddenly Maccone found himself in Palo Alto talking about a well-funded study, one that looked to FOCAL to support interstellar probes both in terms...

Starshot: Concept and Execution

by Paul Gilster | Apr 22, 2016 | Missions | 54 Comments

Because I get irritable when I don't get my walking in every day, I made sure when I arrived in Palo Alto to cram as much as I could into the day before Breakthrough Discuss began. That meant heading out from the hotel just after noon and putting in about five miles. Palo Alto is a very walkable place and I found myself ambling up and down shady streets past gardens bright with spring flowers. We had superb weather for the entire conference, but naturally when things got going, both days were crammed with talks and long walks were out of the question. But the day before, as I walked, I pondered the schedule of the conference, wondering how a mission to Alpha Centauri fit into the overall plan. In addition to the $100 million going toward Breakthrough Starshot, Breakthrough Initiatives has also put up $100 million for its SETI project, which has already begun operations at Green Bank (West Virginia) and is slated to operate at the Parkes dish in Australia as well, giving SETI the...

Breakthrough Discuss: SETI in the Optical

by Paul Gilster | Apr 21, 2016 | Astrobiology and SETI | 36 Comments

At the Yuri's Night party on Yuri Milner's Palo Alto estate, I found myself thinking about a novel, Allen Steele's Arkwright. Like Breakthrough Starshot, initial work on the starship in the book is funded by a wealthy man who wants to see a human future among the stars. The propulsion method is a beam-driven sail, though at that point the comparisons get strained, for Steele is assuming a much larger craft and a mission of colonization rather than a flyby. Even so, there was enough similarity to make a book I had been reading on the airplane seem prescient. The music on Yuri's Night was loud, the gathering crowd relaxed, and I had imagined it would be an entirely social event, but after a time we were called in to watch a short video about Starshot and then participated in a question-and-answer session with some of the project's principal players, including Milner himself. It was a good chance to hear some of the challenges the project faces examined, and tomorrow we'll look at many...

Alpha Centauri, SETI and Detectability

by Paul Gilster | Apr 20, 2016 | Astrobiology and SETI | 23 Comments

Heading for the hotel lobby the first night of the Breakthrough Discuss meeting, I thought about a major theme of the Breakthrough Starshot initiative: Making things smaller. Robert Forward wrote about sails hundreds of kilometers in diameter, and vast lenses deep in the Solar System to collimate a laser beam that would drive them. But Breakthrough Starshot is looking at a sail four meters across, carrying a payload more like a smartphone than a cargo ship. That big lens in the outer system? No longer needed if we can power up the sail close to home. How to Look at Alpha Centauri Digitization works wonders, and Moore’s Law takes us into ever smaller and more tightly packed realms on silicon chips. The trend affects every aspect of spaceflight and astronomy, as witness ACEsat, a small coronagraph mission with an explicit mission, the search for planets around Alpha Centauri A and B. Ruslan Belikov (NASA Ames), working with Northrop Grumman, led the team that conceived this mission,...

Focus on Alpha Centauri

by Paul Gilster | Apr 19, 2016 | Exoplanetary Science | 22 Comments

At Palo Alto's superb Amber India, I was thinking about Alpha Centauri. There are several Amber India locations in the Bay area, but the Palo Alto restaurant dishes up, among other delights, a spicy scallop appetizer that is searingly hot and brilliantly spiced. Greg and Jim Benford were at the table, Claudio Maccone and my son Miles. It was the night before Breakthrough Discuss convened. And while the topics roamed over many aspects of spaceflight, it was that star system right here in our solar neighborhood that preoccupied me. How lucky could we be to have not one but two stars this close and so similar to our own? Centauri A is a G-class star, Centauri B a K, and if we hit the jackpot, we could conceivably find planets orbiting both. Then there is Proxima Centauri, an M-dwarf that is the closest star of all to the Solar System. The presence of so many astronomers on the Breakthrough Discuss roster made it clear we'd get the latest on the hunt for planets here, a vital factor as...

Breakthrough Discuss: Initial Thoughts

by Paul Gilster | Apr 18, 2016 | Culture and Society | 26 Comments

The Breakthrough Initiatives conference I've just returned from, called Breakthrough Discuss 2016, had been a bit of a puzzle going in. Still bleary after an early morning arrival in Palo Alto, I was looking forward to getting to the Stanford campus for the first sessions the next day. Breakfasting at a small cafe near the hotel, I mulled over the possibilities. The emphasis was on astronomy, given the list of attendees, which included top names in the exoplanet hunt, but of course Breakthrough Initiatives is also funding a major SETI effort, so that would be a theme. And then there was the looming presence of the just announced Breakthrough Starshot. Balancing all this out looked to be a challenge, but as it turned out, there was a strong cross-pollination among the various themes, with the Starshot -- an unmanned flyby of Alpha Centauri and an infrastructure to sustain a further interstellar effort -- woven into the proceedings. I knew I'd come back with material for a week's worth...

On Track for ‘Breakthrough Discuss’

by Paul Gilster | Apr 14, 2016 | Culture and Society | 18 Comments

Expect no new posts until Monday and a slowdown in comment moderation as I attend the Breakthrough Initiatives event in Palo Alto. As has been my practice at previous such events, I won't try to cover the talks and discussions live. While 'live blogging' has its place and seems to work for things like product introductions, I don't find it useful for scientific conferences, where I need to take lots of notes and think about the implications of what I've written. But I'll come back from Stanford with plenty of things to talk about, and we'll use all of next week sorting them out. Dinner tonight with Jim and Greg Benford, my son Miles, and my old friend Claudio Maccone, with whom I'll be talking SETI, the FOCAL mission (to the Sun's gravity lens), and the best methods of data retrieval for a mission like Breakthrough Starshot. Many more good discussions ahead. SETI is a big part of this conference, but Alpha Centauri looms large.

The Odds on Starshot

by Paul Gilster | Apr 13, 2016 | Missions | 112 Comments

Yesterday's announcement of Breakthrough Starshot brought an email from exoplanet hunter Greg Laughlin (UC-Santa Cruz), whose work has been an inspiration to me since the early days of Centauri Dreams. One of Greg's new projects, working with Anthony Aguirre (Foundational Questions Institute) and several other colleagues, is a website called Metaculus, which bills itself as "a community dedicated to generating accurate predictions about future real-world events by aggregating the collective wisdom, insight, and intelligence of its participants." In other words, this is a kind of prediction market space for science and tech issues. Breakthrough Starshot fits the bill here exactly, because Metaculus is all about the probability of future events, some of which can be predicted to a high degree, while others are purely a matter of calculated odds. The site is open to all and contains the basic information about its methods, and any logged in user can propose a question for consideration....

Breakthrough Starshot: Mission to Alpha Centauri

by Paul Gilster | Apr 12, 2016 | Missions | 133 Comments

Here on Centauri Dreams we often discuss interstellar flight in a long-term context. Will humans ever travel to another star? I've stated my view that if this happens, it will probably take several hundred years before we develop the necessary energy resources to make such a mission fit within the constraints of the world's economy. This, of course, assumes the necessary technological development along the way — not only in propulsion but in closed-loop life support — to make such a mission scientifically plausible. I get a lot of pushback on that because nobody wants to wait that long. But overall, I'm an optimist. I think it will happen. Let's attack the question from another direction, though, and leave human passengers for a later date, as Yuri Milner's Breakthrough Initiatives, aided by Stephen Hawking, is doing today in a New York news conference. What if we talk about unmanned missions? What if, in fact, the question is: How soon can we put a scientific payload...

The Snowbank Orbit, Redux

by Paul Gilster | Apr 8, 2016 | Missions | 48 Comments

We haven't yet found Planet Nine, but the evidence for its existence is solid enough that we can start thinking about its possibilities as a mission target. That work falls in this essay to Adam Crowl, a Centauri Dreams regular whose comments on articles here began not long after I started the site. An active member of the Project Icarus attempt to re-design the 1970s Project Daedalus starship, Adam is also the author of Crowlspace, where his insights are a frequently consulted resource. Today he harkens back to a 1960s science fiction story that has given him notions about a way not only to reach Planet Nine but to establish orbit around it. by Adam Crowl Fritz Leiber is better known for his fantasy and SF-fantasy, but he could write hard-SF too. A fine example is his 1962 story, "The Snowbank Orbit", the title of which alludes to World War II tales of pilots surviving bailouts without parachutes by plunging into snow-drifts. Five spacecraft, racing towards Uranus at 100 miles per...

A Young, Free-Floating Jupiter Analog in TW Hydrae

by Paul Gilster | Apr 7, 2016 | Exoplanetary Science | 7 Comments

A stellar association is a loose grouping of stars of similar spectral type and age that share a common motion. About 90 percent of all stars are thought to originate as members of associations. The TW Hydrae association (TWA) is a case in point: The group is made up of about thirty young stars, each thought to be roughly ten million years old. This is the youngest grouping of stars in the neighborhood of the Sun. You may recall 2M1207, which has turned up in these pages before, a brown dwarf member of the TWA that has a companion of planetary mass. Now we learn of another exotic find, a young, bright free-floating planet-like object. Jonathan Gagné (Carnegie Institution for Science) used the FIRE spectrograph on Carnegie's Baade 6.5-m telescope in Chile to measure the line-of-sight velocity of the object, known as 2MASS J1119-1137. This along with the sky motion of the object allowed researchers to make the definitive call that 2MASS J1119-1137 is indeed a member of the TW...

Supernova at Twilight

by Paul Gilster | Apr 6, 2016 | Deep Sky Astronomy & Telescopes | 8 Comments

In his novel The Twilight of Briareus (John Day, 1974), Richard Cowper, who in reality was John Middleton Murry, Jr., wrote about a fictitious star called Delta Briareus that goes supernova (true, there is no constellation called Briareus, but bear with me). Because it is only 130 light years out, the supernova showers the Earth with radiation, with consequences that are in some cases obvious, in others imaginative in the extreme. It's a good read, one that at least one critic, Brian Stableford, has compared to J. G. Ballard's early disaster novels. The novel contrasts an earthy domesticity with the celestial display that soon shatters it. It's worth quoting a patch of the book: It so happened that I, in common, no doubt, with several million others -- was among the first in England to observe that 'majestic effulgence' within seconds of its arrival. At about twenty past nine on the Tuesday evening I switched off the telly and suggested to Laura that we could do worse than saunter...

SETI: A New Kind of ‘Water Hole’

by Paul Gilster | Apr 5, 2016 | Uncategorized | 28 Comments

Some of you may recall an episode of Star Trek: The Next Generation in which the inhabitants of a planet called Aldea use a planetary defense system that includes a cloaking device. The episode, “When the Bough Breaks,” at one point shows the view from the Enterprise’s screens as the entire planet swims into view. My vague recollection of that show was triggered by the paper we looked at yesterday, in which David Kipping and Alex Teachey discuss transit light curves and the ability of a civilization to alter them. After all, if an extraterrestrial culture would prefer not to be seen, a natural thought would be to conceal its transits from worlds that should be able to detect them along the plane of the ecliptic. Light curves could be manipulated by lasers, and as we saw yesterday, the method could serve either to enhance a transit, thus creating a form of METI signaling, or to conceal one. In the latter case, the civilization would want to create a change in brightness that would...

A Transit Signature for SETI?

by Paul Gilster | Apr 4, 2016 | Astrobiology and SETI | 16 Comments

David Kipping and Alex Teachey have a new paper out on the possibility of ‘cloaking’ a planetary signature. The researchers, both at Columbia University, make the case that any civilization anxious to conceal its existence -- for whatever reason -- would surely become aware that all stars lying along its ecliptic plane would see transits of the home world, just as its own scientists pursued transit studies of planets around other stars. And it turns out there are ways to make sure this signal is masked by adjusting the shape of the planet’s transit light curves. Now this is a fascinating scenario as presented by the head of the Hunt for Exomoons with Kepler, whose business it is to know about the slightest of variations in light curves because they may contain information about exomoons or rings. Thus Kipping is a natural to look into the artificial manipulation of light curves, a study with definite SETI implications. Because methods like these work in two directions -- a...

John Ford Fishback and the Leonora Christine

by Paul Gilster | Apr 1, 2016 | Missions | 41 Comments

Like the Marie Celeste, the Leonora Christine is a storied vessel, at least among science fiction readers. In his 1967 story "To Outlive Eternity," expanded into the novel Tau Zero in 1970, Poul Anderson described the starship Leonora Christine's stunning journey as, unable to shut down its runaway engines, it moved ever closer to the speed of light. Just how a real Leonora Christine might cope with the stresses of a ramjet's flight into the interstellar deep is the subject of Al Jackson's latest, which draws on memories not only of Robert Bussard, who invented the interstellar ramscoop concept, but a young scientist named John Ford Fishback. by A. A. Jackson Project Pluto - a program to develop nuclear-powered ramjet engines - must have been on Robert Bussard's mind one morning at breakfast at Los Alamos. Bussard was a project scientist-engineer on the nuclear thermal rocket program Rover -- Bussard and his coauthor DeLauer have the two definitive monographs on nuclear propulsion...

SETI Looks at Red Dwarfs

by Paul Gilster | Mar 31, 2016 | Astrobiology and SETI | 15 Comments

When it comes to astrobiology, what we don't know dwarfs what we do. After all, despite all conjecture, we have yet to find proof that life exists anywhere else in the universe. SETI offers its own imponderables, adding on to the question of life's emergence. How often does intelligence arise, and if it does, how often does it produce civilizations capable of using technology? Even more to the point, how long do such civilizations last if they do appear? We keep asking the questions out of the conviction that one day we'll start retrieving data, perhaps in the form of a signal from another star. It's because of the lifetime-of-a-civilization question that I'm interested in a SETI search focused on red dwarf stars. True, M-dwarfs have a lot going against them, as Centauri Dreams readers know. A habitable planet around an M-dwarf may be tidally locked, which could be a showstopper except that some scientists believe global weather patterns may make at least part of such planets...

TVIW 2016: Worldship Track

by Paul Gilster | Mar 30, 2016 | Missions | 45 Comments

Our second report from the recent Tennessee Valley Interstellar Workshop is the work of Cassidy Cobbs and Michel Lamontagne, with an emphasis on the worldship track. Cassidy has an MS from Vanderbilt, where she studied ecology and evolution. She currently works at Memorial Sloan Kettering Cancer Center, doing traditional and next-generation gene and genome sequencing. Her interest in space travel/engineering was enhanced by attending Advanced Space Academy in Huntsville at age 14. Michel Lamontagne is a French-Canadian mechanical engineer, practicing in the fields of heat transfer and ventilation, with a passion for space. An active member of Icarus Interstellar, he tells me he has "been designing spaceships since he was 12 years old, and waiting for reality to catch up!" Photos throughout are from New York photojournalist Joey O'Loughlin, and are used with permission. By Cassidy Cobbs and Michel Lamontagne This year's Tennessee Valley Interstellar Workshop (TVIW-2016) was held in...

Of a Mountain on Titan

by Paul Gilster | Mar 29, 2016 | Outer Solar System | 6 Comments

If Saturn’s inner moons are, as we discussed yesterday, as ‘young’ as the Cretaceous, then we have much to think about in terms of possible astrobiology there. But Titan is unaffected by the model put forward by Drs. ?uk, Dones and Nesvorný, being beyond the range of these complex interactions. Huge, possessed of fascinating weather patterns within a dense atmosphere, Titan probably dates back to Saturn’s earliest days, in some ways a frigid ‘early Earth’ analog. When my son Miles was a boy, we drove through the Appalachians on a journey that eventually took us into Canada. Somewhere in the Shenandoah Valley he commented on how insignificant the mountains seemed compared to what he was used to out west, where the Rockies dominate the sky. True enough, but of course the Smokies and the Cumberlands have their own tale to tell. Once monumental, they’ve fallen prey to wind and rain, ancient relics of once grander peaks. The latest work on Titan from Cassini data now reveals something...

Saturn’s Moons: A Question of Age

by Paul Gilster | Mar 28, 2016 | Outer Solar System | 6 Comments

Some years back at a Princeton conference I had the pleasure of hearing Richard Gott discussing the age of Saturn’s rings. Gott is the author of, in addition to much else, Time Travel in Einstein's Universe (Houghton Mifflin, 2001). I admit the question of Saturn's rings had never occurred to me, my assumption being that the rings formed not long after the formation of the planet. But of course there is no reason why this should be, and a number of reasons why it should not. How long, for instance, does it take moons to collide with each other, contributing debris to a growing ring system? And are such collisions the only way a ring system can form? With all this in mind, I was interested in a new paper that a number of readers referenced in emails. Lead author Matija ?uk (SETI Institute), working with Luke Dones and David Nesvorný (both at SwRI), offers up the possibility that the inner moons of Saturn and possibly the rings were actually formed much later than we would expect. In...

Thirteen to Centaurus

by Paul Gilster | Mar 25, 2016 | Uncategorized | 115 Comments

J. G. Ballard (1930-2009) emerged as one of the leading figures in 20th Century science fiction. His fascination with inner as opposed to 'outer' space infused his characters and landscapes with a touch of the surreal, taking the fiction of the space age into deeply psychological realms. Christopher Phoenix here looks at the question of centuries-long journeys to the stars, with reference to a Ballard story in which a crew copes with isolation on what appears to be an interstellar mission. What we learn about ship and crew informs the broader discussion: If it takes more than a single generation to make an interstellar crossing, what can we do to keep our crew functional? And is there such a thing as happiness under these constraints? By Christopher Phoenix A few months back, Centauri Dreams ran Gregory Benford's review of Kim Stanley Robinson's novel Aurora. After reading that review and the discussion that followed, I began thinking about fiction that explores how starflight might...

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In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For many years this site coordinated its efforts with the Tau Zero Foundation. It now serves as an independent forum for deep space news and ideas. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image courtesy of Marco Lorenzi).

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