Is there a 'goldilocks' class of meteorite, one in which we can say that conditions were just right for producing the stuff of life? That's one of the conclusions scientists at NASA's Goddard Space Flight Center are reaching by studying samples taken from twelve carbon-rich meteorites, nine of them recovered from Antarctica. Their evidence shows that some of the building blocks of DNA, which carries the genetic blueprint for life, were most likely created in space before falling to Earth through meteorite and comet impacts. Thus we move closer to answering a key question: "People have been discovering components of DNA in meteorites since the 1960's, but researchers were unsure whether they were really created in space or if instead they came from contamination by terrestrial life," said Dr. Michael Callahan of NASA's Goddard Space Flight Center, Greenbelt, Md. "For the first time, we have three lines of evidence that together give us confidence these DNA building blocks actually...

By Larry Klaes Tau Zero journalist Larry Klaes gives us a look at a NASA publication whose authors tackle the biggest questions imaginable for our culture. Usefully, this volume, whose authors include major names in fields ranging from astrophysics to cultural evolution, is available online at no charge. As Larry points out, it deserves wide readership, for the issues of our place in the universe and how we respond to potential extraterrestrial contact via SETI will guide our future, both on Earth and in space. It is often difficult to get a wider perspective on existence, especially when you and the rest of your species have been stuck in one place for all but the smallest and most recent of times. This has certainly been the case with the species known as humanity. While a few ancient philosophers guessed that we live on a world surrounded by an immense amount of stars and space, it has only been in the last few centuries that both the scientific and general communities came to...

Just how the Moon originally formed is under renewed scrutiny given the finding that it contains larger amounts of water than previously thought. We'll look at that issue in depth another time, because it's far from resolved. The generally accepted account of the Moon's formation involves a giant impact with a planetary embryo that has been called Theia. The name is a nod to the Greek story of the titan that gave birth to Selene, the Moon goddess. After its formation, the Moon would have been closer to a much more quickly rotating Earth, inducing huge tidal forces that may have had repercussions on the evolution of the earliest life on the planet. All of this has a further bearing on life's emergence because a large moon can affect the tilt of a planet's rotation relative to its orbit around the star. The term for this degree of tilt is 'obliquity,' and its effects on global climate can be profound. If there is little or no tilt, the poles become colder and heat flows in their...

The canonical notion of the 'water hole' is that the kind of life we are looking for in our SETI searches will only thrive where there is liquid water. A quiet stretch of the radio spectrum, the water hole has two natural boundaries: The 18 cm emissions from the hydroxyl ion (OH) and the 21 cm emissions from neutral hydrogen. But the choice of frequencies for SETI is obviously not based on mere symbolism. The water hole is a window in the radio spectrum where radio emissions are not significantly absorbed by interstellar dust and other matter between the stars. It's a natural place to look, and SETI@Home users worldwide have used Arecibo data from the waterhole to participate in the hunt, in what has turned out to be a massive distributed computing project. But the latest SETI project to hit the news following the hibernation of the Allen Telescope Array last month goes where Arecibo cannot. This is a new effort at a storied place, the Green Bank facility in West Virginia. This is...

Tau Zero journalist Larry Klaes has been fascinated by SETI -- and its offshoot METI (Messaging to Extraterrestrial Intelligence) -- for a long time now. Here he steps back to look at METI in context, offering up an examination of the advantages of sending signals to the stars and the offsetting risks. We've looked at many viewpoints on the subject in these pages since Centauri Dreams came online in 2004. But has Larry hit upon a key fact that may trump the arguments of both sides? Is there something about human nature that makes METI more or less inevitable? By Larry Klaes SETI, or the Search for Extraterrestrial Intelligence, has been conducted by a variety of professional and amateur scientists since 1960 (or 1924 if you want to count a campaign that year which listened for any radio messages from the presumed natives of Mars). SETI primarily involves the passive listening or looking for transmissions from alien civilizations. More recent SETI projects have also attempted to...

What is 'space situational awareness,' and what does it have to do with SETI? The answer begins with the collision of a Russian Cosmos 2251 satellite with one of the 66 communications satellites that comprise the Iridium satellite constellation, a worldwide voice and data system. The collision, which occurred on February 10, 2009 produced hundreds of pieces of debris. The Air Force Space Command needs ways of tracking such debris, which poses a threat in the increasingly crowded skies above our planet. Enter the Allen Telescope Array, known primarily as a state-of-the-art center for the SETI effort to identify other intelligent species in the galaxy. The ATA caught the Air Force's eye as a way of tracking and cataloging man-made objects in orbit. Located in a volcanic valley near the Lassen National Forest in California, the array has proven its worth at this task in early tests, a fact that could inspire a new funding source for the observatory. And as we learned to our dismay...

Space writer Keith Cooper, the editor of the UK's Astronomy Now, is currently attending the Royal Astronomical Society's meeting in Llandudno, Wales -- in fact, the photo of him just below was taken the other day in Llandudno. But the frantic round of presentations hasn't slowed Keith down. When last spotted in these pages, he was engaged in a dialogue with me about SETI issues. That exchange got me thinking about having Keith talk to Michael Michaud, considering their common interests and realizing that they had already met at last year's Royal Society meeting where so many of these issues were discussed. Michael was kind enough to agree, and what follows is an exchange of views that enriches the SETI debate. Centauri Dreams readers know Michael Michaud to be the author of the essential Contact with Alien Civilizations: Our Hopes and Fears about Encountering Extraterrestrials (Springer, 2006), but he's also the author of over one hundred published works, many of them on space...

Having just finished Iain Banks' The Player of Games, I'm thinking about the 'orbitals' he describes in his series of novels about the Culture, a vast, star-crossing civilization that can build space habitats in the form of massive rings. Orbitals are smaller than the kind of 'ringworld' Larry Niven envisioned, but huge nonetheless, bracelets of super-strong materials housing billions who live on their inner surfaces as they orbit a parent star. The visual effects Banks pulls off in describing these habitats are spectacular. And now a new paper by Duncan Forgan (University of Edinburgh) and Martin Elvis (Harvard Smithsonian Center for Astrophysics) has me wondering about the kind of mining activities it would take to produce the raw materials for such constructs. Forgan and Elvis are interested in what they describe as a multi-wavelength, multi-signal approach to SETI. We're used to the idea of huge radio dishes listening for extraterrestrial signals, but SETI is evolving through the...

An article in Time Magazine's latest issue caught my eye as I thumbed through it while waiting in line at the grocery store. The magazine is running a feature called '10 Ideas That Will Change the World,' and they tend toward being optimistic takes on huge problems. Thus the deficit gets an essay about how we're going to fix it, while Afghanistan gets a thumbs-up for progress in the right direction. The article finds gold in everything from direct mailings (OK because they help charities raise money) to modern airports, which are creating a new kind of community. And in the midst of this is a puzzling piece by Jeffrey Kluger called 'Relax: You Don't Need to Worry About Meeting E.T.', where the upshot is: 'Don't worry about contact with extraterrestrial civilizations. It will never happen.' Here's a quote: Humans and aliens haven't connected yet, but with 1022 stars out there (that's 1 with 22 zeros), it's just a matter of time — right? Wrong. If exobiologists have learned...

Two kinds of astrobiology stories are in the wind this morning. One of them has to do with the weekend eruption of stories concerning evidence of fossilized life inside a meteorite. The other deals with scientific investigation off-planet, and although sparsely covered, it's the one with the greater significance for finding life elsewhere. But first, let's get Richard Hoover's paper about meteorite life out of the way, for the growing consensus this morning is that there are serious problems with his analysis, especially as regards contamination of the sample here on Earth. I have no problems with the panspermia idea -- the notion that life just may be ubiquitous, and that planetary systems may be seeded with life not just from other planets within the system but from other stellar systems entirely. It's an appealing and elegant concept, but thus far we have no proof, and despite what Dr. Hoover is seeing in samples from three meteorites, we still can't definitively say that we've...

Last October, a conference at the Royal Society looked into "the detection of life, the communication with potential extra-terrestrial civilizations, the implications for the future of humanity, and the political processes that are required." It was a fascinating gathering, one whose results I've been able to study ever since thanks to Keith Cooper, who forwarded videos of a debate there on interstellar messaging (METI) and passed along transcripts of the various panels. Keith is editor of the superb Astronomy Now and is an accomplished writer on space exploration and astronomy, with over 100 articles published. I especially want to mention SETI: Cosmic Call and SETI: Terminating the Transmission in relation to what follows below. For as Keith and I discussed these issues, it occurred to me that our correspondence in the form of a dialogue was a natural for Centauri Dreams. So here's a slightly edited version of some recent thoughts of ours on SETI, the strength of extraterrestrial...

A planet that wanders through the night far from any star is a fascinating notion, one that resonates on some primal level with me because of my childhood viewing of the 1951 film The Man from Planet X. In the movie, a scientist on a remote Scottish moor observes a rogue planet as it approaches the Earth, and deals with a visitor from that world whose apparent good intentions are brought to ruin by a self-serving character intent on exploiting the situation. I doubt similar viewing of this old classic motivated many of my readers, but evidently the idea of a rogue planet does inspire thought, given how many people wrote me about new work on the idea of wandering planets. The paper is by Dorian Schuyler Abbot and Eric Switzer (University of Chicago) and follows up studies of similar ‘dark’ planets by John Debes (Carnegie Institution) and Steinn Sigurðsson (Penn State) -- more about the latter duo in a moment. For now, focus on the process. We know that planets can be thrown out of...

As a fan of I Love Lucy since childhood, I've always been pleased that this show -- and not, say, Milton Berle or Sid Caesar -- is the one always referred to when talking about Earth being detected by other civilizations. And when I first thought about it, the idea that there was a detectable bubble of TV transmission forging out into the galaxy since Lucy's first show in 1951 seemed completely wondrous. I Love Lucy is 60 light years from us now, or will be with this October's anniversary of that first show. I've always wondered what extraterrestrials would make of Fred Mertz. The film Contact mines the theme of stray transmissions from Earth, although in the case of Sagan's story, it's the transmissions from the 1936 Olympics in Berlin that trigger the detection and subsequent transmissions to Earth. A writer and music critic who I've known over the years once asked me about the expanding wavefront of Earthly transmissions, pondering how marvelous it would be to somehow get out in...

Before the recent American Astronomical Society meeting in Seattle gets too far behind us, I want to be sure to include an interesting story on red dwarfs in the coverage here. The story involves an extrasolar planet survey called SWEEPS -- Sagittarius Window Eclipsing Extrasolar Planet Search, which used the Hubble Space Telescope to monitor 215,000 stars in the so-called Sagittarius Window (also called Baade's Window, after Walter Baade, who discovered it with the 18" Schmidt camera on Mt. Palomar). The 'window' offers a view of the Milky Way's central bulge stars, which are otherwise blocked by dark clouds of galactic dust. M-dwarfs are by far the most common type of star in the Milky Way, and therefore have major implications for the search for extraterrestrial life. We now know from SWEEPS data that these small stars are given to stellar flares that can have major effects on a planetary atmosphere. Flares have often been mentioned as a serious problem for the development of life...

As if it were news, one thing the great flap over astrobiology and yesterday afternoon's NASA news conference tells us is that anything smacking of extraterrestrial life brings over the top commentary long before the findings are officially discussed, as should be clear from some of the Internet blogging about the GFAJ-1 bacterium found in Mono Lake. And what a shame. Despite the astrobiology teaser, GFAJ-1 does not in itself tell us anything about alien life and does not necessarily represent a 'shadow biosphere,' a second startup of life on Earth that indicates life launches in any available niche. But the find is remarkable in its own right. Let's leave the astrobiology aside for the moment and simply focus on the fact that life is fantastically adaptable in terms of biochemistry, and can pull off surprises at every turn. That's always a result worth trumpeting, even if it leaves the wilder press speculations in the dust. After all, it's long been assumed that the six elements...

I never have trouble finding topics to discuss on Centauri Dreams, but this morning's take was unusually bountiful. For the past several days I've had two embargoed stories to choose from, both going public this PM. Do I write about tripling the number of stars in the universe, or do I choose the first analysis of a 'super-Earth' atmosphere? It's a tough choice, but I'm going with the stars, given that the story relates to what I consider the most fascinating venue for astrobiology, planets around red dwarfs. We'll do the super-Earth atmosphere -- fascinating in its own right -- tomorrow. The story comes out of Yale University, whose Pieter van Dokkum led the research using telescopes at the Keck Observatory in Hawaii. We've long known that because of their faintness and small size, getting a handle on the red dwarf population was problematic. Usually, I've seen a figure around 75 percent cited for the Milky Way, meaning most stars in our galaxy are red dwarfs (the Sun, a G-class...

Keeping space missions separate can be a difficult challenge when so many satellites are launched on a single rocket. Take O/OREOS (Organism/Organic Exposure to Orbital Stresses). The small satellite rode into space on an Air Force Minotaur IV rocket on the 19th, a launch we noted here in connection with the NanoSail-D solar sail demonstrator. For NanoSail-D was itself carried into space as part of the FASTSAT payload bus (Fast, Affordable Science and Technology Satellite), and FASTSAT and O/OREOS were subsumed under a mission called Space Test Program S26. Not to mention a number of other satellites from universities and industry that hitched a ride on the same booster. All of this produces not just confusion but acronym fatigue. Nonetheless, interesting science is in the works. O/OREOS is all about conducting astrobiology science experiments on the cheap using nanosatellites (CubeSats), helping scientists plan future experiments on how organic molecules are changed by exposure to...

Stephen Baxter's "Turing's Apples," which originally ran in a collection called Eclipse Two (2008), is an intriguing take on SETI and the problem of extracting meaningful information from a signal. It's a bit reminiscent of Fred Hoyle's A for Andromeda (1962) in that the SETI signal received on Earth contains instructions for building something that may or may not pose a threat to our species. Sorting out the issue involves discussion of information theory and Shannon entropy analysis. Say again? Best to handle this by quoting from the story. In this scene, the protagonist's brother, who is obsessed with the signal his team has received from the direction of the Eagle Nebula and, ultimately, the galactic center, is explaining how information is being extracted from it. Shannon entropy analysis looks for relationships between signal elements. The brother goes on: "You work out conditional probabilities: Given pairs of elements, how likely is it that you'll see U following Q? Then you...

What happens in the atmosphere of a tidally locked world in the habitable zone of a red dwarf? We have solid work suggesting through simulations that habitable conditions could exist there, but it's also true that we're in the early stages of these investigations and we have no actual examples to work with. Drawing hasty conclusions is always dangerous, particularly when we're talking about the details of atmospheric circulation on a planet no one has ever seen. Take Gliese 581g. Assuming it exists -- and there is still a bit of doubt about this, although the consensus seems to be that it's really there -- we can place it in a temperature zone that would allow life. We don't know for a fact, though, that it isn't a water world, covered entirely with deep ocean, a planet that migrated from beyond the snowline into its present position. And even if it is a rocky planet with a substantial atmosphere, our simulations of atmospheric circulation only represent the best that is known today....