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....

The ‘slow boat’ to Centauri concept we’ve discussed before in these pages envisions generation ships, vessels that take thousands of years to cross to their destination. And based on current thinking, that’s about the best we could manage with the propulsion systems currently in our inventory. Specifically, a solar sail making a close solar pass (a ‘sundiver’ maneuver) could get us up to 500 or 600 kilometers per second (0.002c), making a 2000-year journey to the nearest star possible. It’s hard to imagine under what circumstances such a mission might be launched. But let’s think long-term, as Greg Matloff (New York City College of Technology) did in a session that just concluded at the International Astronautical Congress in Prague. Matloff, a solar sail expert and well known figure in the interstellar community, notes that when the Sun leaves the main sequence and becomes a red giant, its luminosity may have increased by a factor of a thousand. Imagine using that kind of star as...

The European Planetary Science Congress ends today in Rome even as scientists and engineers on the astronautical side of things head for Prague, where the International Astronautical Congress convenes on Monday. I'll be keeping an eye on events in Prague and wishing I could join the gathering of Tau Zero practitioners that will be taking place there -- Marc Millis will be presenting four papers, and many of the Project Icarus team members are also making the journey, so we should be getting regular updates on matters interstellar. Nor do I want to neglect the Royal Society meeting on extraterrestrial life, coming up early in October in Buckinghamshire in the UK. Emails from James Benford (Microwave Sciences) and Richard Carrigan (Fermilab) tell me both will be speaking at the session, which reminds me that it was way back in April that I promised more on Carrigan's notions of interstellar 'archaeology,' a form of SETI that makes no assumptions about the originating civilization. It's...

Is anyone out there in the galaxy aware of our presence? If so, it's most likely through detection of our planetary radars, like those at Arecibo and Evpatoria that are used to detect and study nearby objects like asteroids, and provide a valuable part of our planetary defense. Sure, we've been pumping television and radio signals into the deep for a long time now, but Arecibo is the most powerful radar in the world, its 430 MHz transmitter offering a maximum total peak pulse output power of 2.5 MW. The planetary radars at Arecibo, Goldstone and Evpatoria are sending far more powerful signals than the faint traces of our early TV broadcasts. It's one of the hopes of SETI that we might detect a similar transmission from another civilization, but in saying that we run into all kinds of assumptions. How long a time-frame does a civilization have before it develops technologies far superior to planetary radars for studying nearby objects? For that matter, how long would any sort of...

A symposium celebrating the first fifty years of NASA' exobiology program takes place on October 14 in Arlington, Virginia. 'Seeking Signs of Life' looks all the way back to 1959, when NASA funded its first exobiology investigation, an experiment for a future spacecraft to detect life on Mars. The actual exobiology program was established in 1960, and led to the three Viking experiments that eventually flew. Exobiology has these days morphed into 'astrobiology,' as we look at topics as diverse as chemical evolution in interstellar space and planetary formation. For those in range of Arlington, more information is available here. Be aware as well of a workshop on SETI that is now taking place at the National Radio Astronomy Observatory in Green Bank, WV, marking the 50th anniversary of Frank Drake's first search for extraterrestrial signals. Webcasts begin at 0830 EDT (1230 UTC), and will include Drake's views on 'SETI in 2061 and Beyond' at that time on September 15. Further...

Enrico Fermi's paradox has occupied us more than occasionally in these pages, and for good reason. 'Where are they,' asked Fermi, acknowledging an obvious fact: Even if it takes one or two million years for a civilization to develop and use interstellar travel, that is but a blip in terms of the 13.7 billion year age of the universe. Von Neumann probes designed to study other stellar systems and reproduce, moving outward in an ever expanding wave of exploration, could easily have spread across the galaxy long before our ancestors thought of building the pyramids. Where are they indeed. Kelvin Long, one of Project Icarus' most energetic proponents, recently sent me Poul Anderson's thoughts on the subject. I probably don't need to tell this audience that Anderson was a science fiction author extraordinaire. His books and short stories occupied vast stretches of my youth, and I still maintain that if you want to get not so much the tech and science but the sheer wonder of the...

It's been a week with an exoplanet focus, what with the interesting Kepler results yesterday and the five, or perhaps seven, planets found around the same star by the HARPS instrument. But I can't close the week without recourse to Seth Shostak's recent comments on biological versus machine intelligence. Paul Davies took much the same tack in his recent book The Eerie Silence (Houghton Mifflin Harcourt, 2010), arguing that any civilization we encounter will likely be composed of intelligent machines. Shostak thinks SETI should take that seriously. Searching for Doppelgängers Right now we're searching for what Shostak calls 'doppelgängers of humans' -- i.e., SETI has focused on places that could support life forms that do more or less what we do, which includes not only using radio to communicate, but much broader traits like living for finite lifetimes, following basic biochemical dictates and being subject to evolution. That biases the search toward places that could sustain life as...

Although he doesn't post nearly as often as some of us would like, Caleb Scharf's Life, Unbounded site is always worth reading. Scharf, author of the textbook Extrasolar Planets and Astrobiology (University Science Books, 2008) is the director of the Columbia University Astrobiology Center. As such, he's positioned to offer valuable insights into our investigations of the forms life might take on other worlds. Not long ago he wrote a fascinating post for Scientific American on a statistical approach to astrobiology, a timely idea as we discuss ongoing missions like Kepler and proposed space telescopes like WFIRST. Natural Selection on a Galactic Scale Scharf's latest is a quick take on panspermia, the idea that viable organisms may be exchanged between planets as various early impacts spread debris through a planetary system. We know that surface material moves continually between the rocky moons and planets of our own system, and we've also come to understand that microbial...

Although it seems a long way from interstellar space, the early Earth is a fascinating laboratory for life's development that should yield clues about how life takes hold elsewhere. Thus new work on the movements of the early continents catches the eye. In this case, the Gondwana supercontinent is found to have undergone a 60-degree rotation across Earth's surface during a highly interesting period, the Early Cambrian. This is the fecund era when the major groups of complex animals appeared in relatively rapid succession. Gondwana is what we can call the southern precursor supercontinent, a vast region that would eventually separate from Laurasia roughly 200 million years ago when the Pangaea supercontinent broke into two large areas. This Wikipedia article gives you the basics on Gondwana, noting that it included most of the landmass in today's southern hemisphere, including Antarctica, South America, Africa, Madagascar, Australia, New Guinea and New Zealand, along with the Indian...

It's heartening to see James and Gregory Benford's work on extraterrestrial beacons receiving broader coverage. We've looked at the relevant papers in these pages [run a search on 'Benford' in our database and you'll pull up articles by and about them], but news features like this one in TIME Magazine are pushing the Benford brothers' work out to a much larger audience. That's an important step, because right now the view of SETI most likely held by the average person relates to movies like Contact, in which huge dishes pointed at particular stars seem to be the way to proceed. The Benfords want to re-write that scenario in a big way. We'll have to leave as debatable the question about how far away our own television transmissions can be received. James Benford commented here not long ago that a civilization of approximately our technological level would not be able to receive broadcast signals as weak as those we've sent out carrying the likes of Milton Berle and I Love Lucy....

How big can an insect get? One night a few years back, I opened the door onto our patio to let the dogs out and an enormous flying, buzzing thing came through the door. When I say 'enormous,' I simply mean it was big enough to startle both dogs enough that they ran upstairs, causing me to grab for a flyswatter as it flitted and hummed around the room. I lost sight of it and suddenly all was silent. Our cat had sprung, and the bug was quickly dispatched. We dubbed it 'Mothra' and added it to our dog lore. After all, where were our Border Collie and Sheltie when we needed them? Peering down at us from the upstairs landing, while the cat did the dirty work. 'Mothra' was probably no more than an inch long -- he was noisier than he was big. But there was a time when 'enormous' really meant something. Meganeura is a genus of insects dating to the Carboniferous period when creatures related to our own familiar dragonfly boasted wingspans of two feet or more. Meganeura monyi is considered...

by James Benford We recently looked at a paper by Duncan Forgan and Robert Nichol on the question of detecting extraneous emissions from an extraterrestrial civilization using technology like the Square Kilometer Array. James Benford (Microwave Sciences) has some thoughts on the issue growing out of his own work with brother Gregory on interstellar beacons and SETI reception in general. No one has put the question of interstellar beacons to tighter scrutiny than the Benfords, with particular regard to bringing the SETI discussion, as Jim puts it, "onto a quantitative basis, as opposed to rampant speculation, as is typical of the playing-tennis-without-a-net approach taken previously." The Benfords' work on interstellar beacons appears this month in Astrobiology. I give full citations at the end of this post. The Forgan & Nichol paper on detection of leakage radiation does neglect our continuing use of microwave beams not only for radar, but also for likely future beaming of power for...

Take a look at the frequency range of our SETI searches and you'll see that we are probing into new territory. Project Phoenix, which ran from 1995 to 2004, used radio telescopes at Arecibo, Parkes (NSW, Australia) and Green Bank (WV, USA), working in a frequency range of 1.2 to 3 GHz. The BETA project used a 26-meter radio telescope to examine the so-called 'waterhole' frequencies between 1400 and 1720 MHz, which seemed a likely place to look for an extraterrestrial beacon because this range covers an unusually quiet band of the electromagnetic spectrum between the hydrogen spectral line and the strongest hydroxyl line. With the Allen Telescope Array coming online, we can look forward to a search of 250,000 stars in the 'waterhole' region, but new facilities like LOFAR (Low-Frequency Array) are pushing into the megahertz area in pursuit not only of SETI but also astrophysical studies of the early universe. LOFAR makes me think back to my shortwave radio days, tuning around these...

We often speak in these pages about extinction events, and cite such examples as the Cretaceous-Tertiary event some 65.5 million years ago, when the mass extinction of dinosaurs and numerous animal and plant species occurred. Whether caused by an incoming asteroid or comet or through a series of catastrophes including volcanic eruptions (the Deccan traps), the K-T event is the classic reminder of the perils that confront life. But perhaps the largest extinction event of all was the so-called 'oxygen catastrophe,' an environmental change that caused oxygen to become widely available in the atmosphere and shallow ocean water. The oxygen catastrophe occurred around 2.4 billion years ago and doomed the bulk of Earth's anaerobic inhabitants. Astrobiologists are fascinated with how life adapts to changing environments, so we'd like to learn much more about how these events proceeded. Now comes news of fossils in black shale formations in Africa that are apparently 200 million years older...

Are planets common around brown dwarfs? We aren't yet in a position to say, but the question is intriguing because some models suggest that the number of brown dwarfs is comparable to the number of low-mass main sequence stars. That would mean the objects -- 'failed' stars whose masses are below the limit needed to sustain stable hydrogen fusion -- could be as plentiful as the M-dwarfs that far outnumber any other type of star in the galaxy. If planets form around brown dwarfs, then we have to add them to our list of possible abodes for life. Evidence for Brown Dwarf Planet Formation But first, to the planet question. We can find suggestive analogs to planet formation around brown dwarfs in nearby space. The star Gl 876, some fifteen light years away, is not a brown dwarf, but this M-dwarf is only 1.24 percent as luminous as the Sun, with most of its energy being released at infrared wavelengths. We now know that at least three planets, two of them gas giants similar to Jupiter,...