Michael Anissimov looks out at a universe devoid of intelligence other than our own. Here's a clip, referring to Frank Tipler's 1980 paper "Extraterrestrial intelligent beings do not exist": It was quite a few years ago when I looked up to the stars, with Dr. Tipler's book in my hand, that I realized he was right - the stars are empty, ready to be harvested and spun into pure energy with the help of gravitational singularity goodness. No aliens, green bug-eyed ones or otherwise, are waiting there to be inconvenienced. And this: Luckily, hypertelescopes may finally put the nail in the coffin of SETI - perhaps 100 years from now. We will be able to see even the simplest of flora, if they exist in large numbers on exoplanets. (Though what we should really be looking for are Dyson spheres or disappearing stars, and as far as we can tell, there are absolutely none.) After we look at a good thousand earth-sized objects and see nothing there but vast, dead wastes, we'll start getting used...

Some day alien civilizations may pick up television or radio signals from Earth. But does this mean they're likely to visit us? Danish researcher Rasmus Bjørk (Niels Bohr Institute, Copenhagen) doubts it. "Even then, unless they can develop an exotic form of transport that gets them across the galaxy in two weeks it's still going to take millions of years to find us," says Bjørk in an article in The Guardian. "There are so many stars in the galaxy that probably life could exist elsewhere, but will we ever get in contact with them? Not in our lifetime." Bjørk is in the news because he set up a computer simulation to investigate how long it would take to explore the galaxy. Suppose we build eight probes which, along the way, send out eight more mini-probes, all headed for different stars that are likely to have life. Bjørk's plan is to search only within the galactic habitable zone, to use flyby probes only, and to fan out the spacecraft at one tenth the speed of light. The aim is to...

It's a pleasure to see that Cosmic Search is now accessible on the Internet. Appearing first in 1979, this magazine devoted solely to SETI was well ahead of its time, trying to generate interest in a popular audience that had not yet become familiar with the concepts driving the search for life in the universe. In those days long before SETI@Home, I learned about Cosmic Search through the Society of Amateur Radio Astronomers, a group I had joined in the mistaken belief that I had could create my own receiving station and do interesting science. That hope was never realized, a victim of my clumsiness with hardware, and I contented myself with reading and learning. Cosmic Search was a true gift, covering the range of SETI investigations and stuffed with reading from the likes of Philip Morrison, Frank Drake, Ronald Bracewell and many other familiar names. Go to the site, where you can scroll through the listings and see for yourself how SETI looked 25 years ago. Cosmic Search will...

The buzz about the Viking landers continues. Yesterday at the American Astronomical Society's meeting in Seattle, two scientists argued that we can reinterpret the data from the Vikings' 30-year old mission in the light of recent findings regarding life in extreme conditions on Earth. Doing so leads to an intriguing possibility: Viking may have found microbes that use water and hydrogen peroxide to survive in the cold, dry Martian climate. The researchers are Dirk Schulze-Makuch (Washington State) and Joop Houtkooper (Justus-Liebig-University, Germany). Here's a link to an early article on this work that explains the beauties of hydrogen peroxide in this scenario. For one thing, its freezing point is low, but even better is the fact that when its temperature drops, it doesn't form the kind of crystals that can destroy cell structures, as water by itself would. But how do you protect a cell from the corrosive effects of hydrogen peroxide? From the article: Schulze-Makuch said that...

We've had some lively discussions about SETI in the past year and 2007 should be equally provocative, especially as we keep tackling topics like the Fermi question and METI, the attempt to signal extraterrestrial civilizations from Earth. Most people don't realize that messages other than the famous 1974 signal from Arecibo have already been sent. But to cite just one example, the so-called ‘Cosmic Call 1? message targeting four Sun-like stars was transmitted from the Evpatoria Planetary Radar site in the Crimea in 1999, as discussed earlier in these pages. There have been others. Trying to place passive SETI listening activities and their 'active' METI component into perspective demands we be aware of the issues and able to place them into a civilization-wide context. On that score, I'll be interested to see Michael Michaud's book Contact with Alien Civilizations: Our Hopes and Fears about Encountering Extraterrestrials (Springer, 2006). The book, says David Brin in an Amazon...

Is there a galactic habitable zone, a region within the Milky Way where conditions for life are optimum? If so, we want to know its parameters, as they would help us define the search area for living worlds. The concept has kicked around for a while, and now surfaces again in an interesting paper by Nikos Prantzos (Institut d'Astrophysique de Paris). Prantzos ponders the main variables and, while concluding that the galactic habitable zone is far from well understood, believes it conceivable that the entire galactic disk may, at this stage of its evolution, be suitable for life. That conclusion goes further than Charles Lineweaver and team's work in 2004, the latter having found that the zone for complex life exists in a ring a few kiloparsecs wide surrounding the galactic center and gradually spreading outward as the Galaxy evolves (our earlier story on that work and habitable zones in general is here). Like Lineweaver, Prantzos looks at planet formation in terms of stellar...

"Simple and cheap, like onion dip." That's how Seth Shostak (SETI Institute) refers to our early optical search systems, which have involved limited equipment in the hunt for extraterrestrial intelligence, at least when compared to the much more demanding resources deployed by the radio search. Cheap is good, but not when you can only check one part of the sky at a time. All this gets Shostak pondering in a recent article about the parameters of a laser signal from an extraterrestrial civilization. For if we might miss a faint signal, what about a really big one? Suppose an intelligent species somewhere out there is deliberately trying to contact our planet. Wouldn't it make sense, Shostak muses, to create a huge optical impression, a signal that would catch our attention so obviously that we could then focus in to detect whatever message might be streaming from that same location? Bright objects in the sky do appear and are usually recorded, as witness historical records of...

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.

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...

New work out of the Danish National Space Center (DNSC) suggests a startling connection between star-making in the Milky Way and the evolution of life on Earth. During a period of intense star-creation that began some 2.4 billion years ago, ocean-borne bacteria went through cycles of growth and decline of an intensity never since equalled. The Danish study links this variability with incoming cosmic rays that reach Earth from exploded stars. The star-making period in question was a time of numerous supernova explosions. To reach these conclusions, the Space Center's Henrik Svensmark studied the record of heavy carbon in sedimentary rocks. Growing bacteria and algae in ocean waters absorb carbon-12, leaving carbon-13 to enrich the sea; the latter begins to appear in the carbonate shells of sea creatures. By studying variations in carbon-13, Dr. Svensmark can see how much photosynthesis was going on when the shell-making species were alive. And it turns out that the biggest...

Astrobiology, the study of life as a planetary phenomenon, aims to understand the fundamental nature of life on Earth and the possibility of life elsewhere. To achieve this goal, astrobiologists have initiated unprecedented communication among the disciplines of astronomy, biology, chemistry, and geology. Astrobiologists also use insights from information and systems theory to evaluate how those disciplines function and interact. The fundamental questions of what "life" means and how it arose have brought in broad philosophical concerns, while the practical limits of space exploration have meant that engineering plays an important role as well. So goes the introduction to the Astrobiology Primer now available as a reference tool for those trying to acquire the fundamentals of this multidisciplinary subject. Ninety researchers contributed insights and information to the collaborative effort. The work ranges through stellar formation and evolution, planet detection and characterization...

Where did our planet get the stuff from which life is made? The sources seem surprisingly diverse, and we're learning more about how organic materials may have complemented each other in forming life four billion years ago. Extraterrestrial compounds -- biomolecules formed in deep space and falling to Earth -- probably contributed. And so did lightning and ultraviolet radiation, along with vulcanism and deep water chemical reactions that could enhance molecular synthesis. Now getting new emphasis is the role of mineral surfaces in helping to activate molecules essential to life, like amino acids (from which proteins are made) and nucleic acids (think DNA). In a recent study, Robert Hazen (Carnegie Institution Geophysical Laboratory) described where we stand at identifying the pairing of molecule and mineral. When molecules like amino acids adhere to mineral surfaces, a variety of organic reactions can occur that affect what life can emerge. "Some 20 different amino acids form...

An interesting story on Seth Shostak's recent appearances in Athens, OH ran today in The Athens News. In a pair of talks Shostak, senior astronomer for the SETI Institute (Mountain View, CA), explained to a general audience why he thinks extraterrestrial life is out there. He even gave a timeline for its discovery: within the next two dozen years (he went on to bet each member of the audience a cup of Starbuck's coffee on the proposition). Each SETI experiment, Shostak added, gathers more data than all the previous ones combined. Deep in the article are two Shostak suggestions for extending the SETI search. First, focus on the same area of sky for longer periods of time, instead of today's common practice of looking at a star for a few minutes and then moving on. Keep a longer gaze and look for signals of short duration that may repeat every few hours or days. The second tactic: work harder on binary systems. These may contain technological civilizations that have explored both sides...

Since we've kicked around the idea of searching for SETI signals in the television bands (as noted in a previous story on Abraham Loeb and the Mileura Wide-Field Array), it's interesting to note Seth Shostak's thoughts on the subject. Because although planet Earth has been broadcasting TV signals for some time now, our transmissions are unlikely to be received at any great distance. And that makes a search for accidental TV-like emissions even from relatively nearby stars problematic. Shostak imagines a civilization 55 light years away hoping to pick up I Love Lucy from Earth. He notes that the non-directional TV signal, assuming a million watts of transmitter power, will reach this distant world "...with a power density of about 0.3 million million million million millionths of a watt per square meter..." And because only a third of the transmission power is in the carrier signal -- the most readily detected part of the transmission -- even that number is too high. It's possible to...

Hunting for terrestrial planets is not going to be easy, and even when we start getting images of such worlds, there will be plenty of questions to answer. How to detect life on a terrestrial planet was one of the subjects that came up in September at the Pale Blue Dot workshop at Adler Planetarium in Chicago. Cassini's recent picture of Earth from Saturn space, much like Voyager's 'pale blue dot' image of 1990, reminded everyone at the conference of our fragile place in the cosmos. It also forced the question of how we might find other such worlds. And finding a blue planet in a star's habitable zone isn't enough. As laid out in this JPL backgrounder, the key will be to gather enough spectral data to make a judgment call that could change how we view our place in the universe. Breaking down the light from a distant planet should tell us much about its chemical composition. Carbon dioxide and water vapor, for example, are both clues to life, their dual presence suggesting both an...