The thread on SETI's Paradox and the Great Silence has continued with considerable gusto, enough so that we're pushing the database limits on comments there. So I'm starting an overflow topic for those who want to keep the debate going. Please post any further responses to the SETI thread here, where we'll have plenty of room.
It's been some time since Centauri Dreams looked at the work Gregory Benford (University of California at Irvine) and his brother James (Microwave Sciences) are doing with solar sail concepts. But I just noted, in paging through a back issue of the Journal of the British Interplanetary Society, that their proposal for a microwave-beamed sail was written up there, based on a talk at the 2005 IAA symposium in Aosta, Italy. And because I want to keep sail concepts visible in a time when funding constraints have all but driven them from the news, let's revisit that work. What got the Benfords headlines not so long ago was the speeds they were proposing. Five years or less to Pluto? That's almost a halving of New Horizons' travel time, and it makes for some intriguing conjecture indeed. The Benfords learned from earlier laboratory experiments that heating up ultralight carbon sail materials causes accelerations greater than would be expected from the pressure of photons alone. Apparently...
The news about possible surface water on today's Mars points out how far we are from characterizing life's possibilities even in our own Solar System, much less around other stars. It may take boots on the ground on Mars to solve the question once and for all, but life in underground aquifers certainly is a plausible proposition, and the sooner we have proof (and samples to study), the better for astrobiology in general. Meanwhile, we push on with the very early wave of exoplanet studies, remembering that it's just over a decade since 51 Peg gave us the first confirmed detection around a main sequence star. I can't imagine a more fruitful field for a young astronomer to head for, with so many possibilities for study that you begin to wonder whether we'll have the human resources to keep up with the vast data inflow that's coming. Some of the more intriguing recent work concerns binaries and the planets around them. If we're getting fairly sanguine about the possibility of planets...
A note from Ian Jordan (Space Telescope Science Institute) passes along the welcome news that presentations and webcasts from last week's Astrophysics Enabled by the Return to the Moon 2006 workshop at STScI have been posted online (available here). There's plenty to dig into here, but of specific note for exoplanet research are the presentations by Webster Cash, Maggie Turnbull, Sara Seager and Peter McCullough. Centauri Dreams readers have read about all four of these scientists in the past year or so. Maggie Turnbull (Carnegie Institution of Washington) specializes in identifying stars that may have terrestrial planets around them. In an earlier post, we looked at some of her picks. Sara Seager (also at Carnegie) is particularly known for her work on HD 209458B, a hot Jupiter that transits its star and thus offers up much useful data. And Peter McCullough (Space Telescope Science Institute) is getting remarkable results from the XO telescope in Hawaii, collaborating with amateur...
The COROT satellite, slated for transit studies of nearby stars in search of exoplanets, has completed fueling up operations. Launch is scheduled for December 21 at the Baikonur cosmodrome in Kazakhstan. Nine days were required to top the satellite's tanks even though it is only carrying 40 litres of hydrazine, due to the highly poisonous nature of the fuel. A French project with ESA participation, COROT will be the first space misson specifically dedicated to finding extrasolar planets, and it may give us our first detection of rocky worlds only a few times larger than Earth.
One reason our SETI searches may be turning up nothing is that everywhere in the cosmos, civilizations exist that are much like ours. They may be, in other words, what Alexander Zaitsev calls 'dismally monotonous,' capable of being no more than passive when it comes to other living worlds. They are listening rather than transmitting. And Zaitzev is at the forefront of the movement to change all that, at least where Earth is concerned. Zaitsev's new paper lays out the basics of METI -- 'Messaging to ETI' -- the idea being to transmit purposely to likely stellar systems. The Russian scientist is fascinated by the question of consciousness. How widespread is it, and is it not the aim of SETI to find out whether it is a universal phenomenon or a singular one, isolated on our own world? On this score, all kinds of speculation are possible, and I rather like this Arthur C. Clarke quote cited by Zaitsev as one of various hypotheses: "...it is almost evident that biological intelligence is a...
It's always good to see Green Bank in the news. The West Virginia facility was the site of Frank Drake's pioneering SETI attempt called Project Ozma back in 1960. Now Green Bank's newest dish has been used to discover the first negatively charged molecule in space, a useful building block in our understanding of how interstellar matter turns into planets that can eventually produce life. The molecule in question is called C6H-, described as a chain of six carbon atoms with one hydrogen atom at the end and an extra electron. That makes it a molecular 'anion' -- a molecule with a negative charge because of the extra electron -- and it's a bit of an anomaly. You would think that ultraviolet light would dislodge that spare electron, but this molecule survives. In fact, it's larger than most neutral and all positive molecules known in space. Image: The Green Bank Telescope at dusk. Courtesy of NRAO/AUI. Astronomer Michael McCarthy (Harvard-Smithsonian Center for Astrophysics) calls it 'a...
Because it's hard to argue with people once involved in Nobel Prize-winning work, I take Warren Nagourney (University of Washington) at his word. At one time Nagourney assisted Hans Dehmelt, the UW scientist who won the 1989 Nobel Prize in physics. Now he's working with John Cramer on a project so bizarre that, as this Seattle Post-Intelligencer story reports, he understands it only faintly. That makes Centauri Dreams' chances of understanding it all but infinitesimal. And because the work involves the paradoxical quantum behavior called 'entanglement' and implies communicating information backwards in time, it also conjures up memories of another man one hesitates to challenge. It was Einstein who called certain weird quantum behaviors 'spooky action at a distance' and cultivated a continuing distaste for the paradoxes of quantum mechanics. These are formidable scientists, but then so is Cramer, and in a way he seeks to confirm something Einstein said a long time ago. Einstein...
The evidence for dark matter keeps piling up, even if we still don't know what it is. Back in the 1930s, Fritz Zwicky noted that the galaxies he was observing weren't massive enough to account for the way they cohered into clusters. Vera Rubin later took the idea of missing mass further, seeing that stars in the outer parts of galaxies rotated too quickly for the presumed mass of the galaxy. So we've known for a long time that something mysterious is out there. Groups studying the phenomenon focus on odd, hypothetical particles called WIMPS -- Weakly Interacting Massive Particles. To make them fit a theoretical model of how dark matter works, scientists assume WIMPS are neutral in charge and about 100 times more massive than a proton. The problem is that they don't interact with most matter. If they're to be found, they'll have to be detected in a rare collision within extremely sensitive detectors. Image: The CDMS II detectors (hexagons) are stacked in an icebox with six insulating...
