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  • Hubble's new superpowers

    ESA
    Click for video: Atlantis grabs hold of the Hubble Space
    Telescope in this artwork illustrating the mission plan. Click on
    the image for more about Hubble and its new instruments.

    When astronauts from the shuttle Atlantis open up the Hubble Space Telescope for its final extreme makeover, much of the work will be aimed at fixing what's been ailing the world's premier orbiting observatory. It'll get fresh batteries and brand-new gyros, and if all goes well, Hubble's Advanced Camera for Surveys and the Space Telescope Imaging Spectrograph will be back in full working order for the first time in years.

    But this is not just a fix-up mission. Two new instruments are due to be swapped into the mix, and those enhancements should give Hubble superpowers it never had before: for example, three-in-one vision that spans the spectrum from ultraviolet to infrared, and the ability to make out the cosmic cobwebs that stretch out between galaxies.

    "We're all looking forward to seeing how well the new installations and the instrument repairs go," Ken Sembach, Hubble project scientist at the Baltimore-based Space Telescope Science Institute, told me this week. "We're looking forward to an improved Hubble."

    The new instruments, known as the Wide Field Camera 3 (WFC3, or "Wiff-see-three") and the Cosmic Origins Spectrograph (or COS), should open the way for new wonders and speed up the pace of discovery during Hubble's final five years. They're designed to complement the two instruments being repaired - or replace them in case they can't be fixed.

    Here's a quick guide to Hubble's future superpowers and how they'll mesh with the space telescope's pre-existing capabilities:

    NASA
    Computer-generated graphics show where the Wide Field Camera 3 will go.

    WFC3: Superman's three-in-one vision
    The $75 million Wide Field Camera 3's superpowers have their roots in its enhanced sensitivity in wavelengths ranging from the ultraviolet part of the electromagnetic spectrum, through visible wavelengths and into the infrared.

    "This camera basically is doing the work of two or even three cameras, if you think about the previous generations of instruments," Sembach said. He said its sensitivity to infrared light is 10 to 30 times that of Hubble's old workhorse for those wavelengths, the now-dormant Near Infrared Camera and Multi-Object Spectrometer, a.k.a. NICMOS.

    WFC3 takes full advantage of manufacturing standards that just weren't available for earlier instruments - such as the camera it's replacing, the Wide Field and Planetary Camera 2 (WFPC2, or "Wiff-pic-two"). During image processing, engineers usually have to work around the small blemishes caused by imperfections in the camera detectors, but with WFC3, "we can remove almost all of those to very high precision," Sembach said.

    Once the camera gets to work, you can expect bunches of eye-popping, color-enhanced images that combine ultraviolet, visible-light and infrared data. "One of the real drivers behind this camera, scientifically, was really wanting to understand what's going on in star-forming regions," Sembach explained.

    The infrared detectors can pick up the light that filters through warm clouds of interstellar dust, while the ultraviolet/visible light detectors can spot the hot blue stars that are just crackling into existence. "You can start to build up a more complete picture of how these stars are forming, and how they're interacting," Sembach said.

    To get an idea how observations from multiple wavelengths can be put together, check out the Hubble/Spitzer/GALEX image of the galaxy M81, and the Chandra/Hubble/Spitzer/GALEX view of the galaxy M51.

    WFC3 also is equipped with "grisms" - grating-equipped prisms that can analyze the spectral signature of light and determine how distant a celestial object is, based on its redshift.

    "One of the other things that WFC3 was really designed for is to look back at earlier times of the universe and pick out really red things, as a precursor to what we'll be doing with the James Webb Space Telescope in the 2013-2014 time frame," Sembach said. "It's going to be a very interesting time to look at, when galaxies are just first coming together."

    The new camera could help Hubble double or triple the rate of discovery for extremely distant supernovae. Those are just the kinds of observations that can help sort out the mysteries surrounding the accelerating expansion of the universe. For more about that and other WFC3 wonders, check out this NASA Web page.

    NASA
    An artist's rendition shows an astronaut installing the Cosmic Origins Spectrograph.

    COS: The Flash's speediness for spectroscopy
    We've already mentioned how WFC3 can analyze the characteristics of light from distant galaxies to figure out how far away they are. When it comes to ultraviolet wavelengths, the $70 million Cosmic Origins Spectrograph is built to conduct that kind of analysis with far greater sensitivity than WFC3 or the space telescope's other spectrograph could manage.

    The Space Telescope Imaging Spectrograph, or STIS, performed a similar duty before it broke down in 2004. But COS is built to handle light far more efficiently. "In STIS, there are many, many bounces before the light gets into the detector. In COS, there's only one bounce. ... You gain a lot just by not absorbing that light," Sembach said.

    As a result, COS will be 10 to 30 times more sensitive than STIS was, depending on the brightness of the object you're observing. "If you want to take a spectrum of a star or a quasar or galaxy, what normally would have taken you 10 orbits will just take one orbit," Sembach said.

    And when it comes to dimmer objects, COS can do more in two weeks than STIS could do in a year. That opens up whole new vistas in astronomy. Job No. 1 is to chart the ethereal cosmic web that apparently provided the framework for galaxy clusters soon after the universe was born - hence the reference to "Cosmic Origins" in the contraption's name. Learning more about the cosmic web may also tell astronomers more about the mysterious unseen stuff known as dark matter.

    "That cosmic webbing can't currently be imaged with Hubble or any other observatory up there," Sembach said. "There's no way to study it other than to observe the light that's processed through it. You're looking for the 'fingerprint' of that stuff on the light, basically."

    Eventually, COS' scientists will use hundreds of fingerprint analyses, pointing in all directions into the sky, to build up what they call a "CAT scan of the universe."

    But wait ... there's more: COS should be able to track the flow stellar winds and even sample the starlight shining through the atmospheres of alien planets. "For example, you might be able to see whether a planet's atmosphere has hydrogen or carbon or oxygen in it," Sembach said.

    COS will be installed in a slot currently taken up by a corrective-optics package known as COSTAR. Spacewalkers installed COSTAR back in 1993 to compensate for Hubble's incorrectly shaped mirror. But now all of Hubble's instruments have their own built-in corrective optics, so COSTAR is no longer needed. It will be brought back down to Earth aboard Atlantis, along with WFPC2.

    What's ahead: The League of Extraordinary Instruments
    If everything goes right, Hubble will have two cameras, WFC3 (new) and ACS (repaired) ... and two spectrographs, COS (new) and STIS (repaired). Does it sound as if there's some NASA-style redundancy going on? Maybe a little bit. After all, it's by no means certain that ACS and STIS will be repaired.

    NASA
    A diagram shows the location of Hubble's instruments after servicing: Wide Field Camera 3 (WFC3), Near
    Infrared Camera and Multi-Object Spectrometer
    (NICMOS), Space Telescope Imaging Spectrograph
    (STIS), Cosmic Origins Spectrograph (COS);
    Advanced Camera for Surveys (ACS) and Fine
    Guidance Sensors (FGS) for pointing and astrometry.

    Hubble's handlers say the instruments will complement each other instead of duplicating each other. For example, ACS is particularly good at taking pictures in visible-light wavelengths, but not as good at either end of the spectrum. In contrast, WFC3 is optimized for the ultraviolet and the infrared wavelengths.

    When it comes to taking pictures of the dusty protoplanetary disks around stars, or even directly imaging planets around other stars, ACS will be the instrument of choice because it has a coronagraph that can block out a star's glare. WFC3, which was designed before ACS went on the fritz in 2007, doesn't have one.

    That doesn't mean WFC3 is totally incapable of seeing an extrasolar planet. "If conditions are right, it might be possible to get a direct image with some clever observing techniques," Sembach said. But the example does show that the old instruments can still do some things better than the new ones.

    It's the same with STIS: "It's capable of spectroscopy at optical wavelengths, which COS is not," Sembach said. If STIS is returned to working order, it will be the instrument of choice for analyzing alien atmospheres and watching black holes gobble up gas. Generally speaking, COS can gather light more efficiently, but STIS can study areas of the sky in higher resolution.

    Having instruments with overlapping capabilities is a good thing, Sembach said: "Being able to do something two different ways provides validation that what you're seeing is correct, or maybe confirmation that it isn't."

    Sembach and his colleagues on the Hubble team should find out how much capability they'll have soon after each of the Atlantis crew's five spacewalks. First there'll be an "aliveness test" to make sure all the circuitry is hooked up correctly. If the connections needs tweaking, the job might have to be handled during a later spacewalk. Later, Hubble's engineers will conduct functional tests and calibrate the instruments.

    "We'll start interleaving some science observations with the calibration observations sometime in July and August," Sembach said.

    Meanwhile, the Hubble team will try to bring NICMOS back online as well. "It relies upon a cooling system that has been off since September of last year, and we've been unable to restart it," Sembach said. "We will try again to restart it this summer."

    Look for the first fruits of Hubble's new (and restored) superpowers to be revealed shortly after Labor Day.

    More about Hubble and Atlantis' mission:

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  • Ethanol vs. electricity

    UC Merced
    Click for graphic: See
    how biomass is converted
    into ethanol or electricity.

    Suppose you take an acre's worth of switchgrass and turn it into ethanol for your flex-fuel car, while your neighbors take their acre's worth and burn it in a power plant to generate electricity for their plug-in hybrid. Which car would go farther?

    If you guessed that your car would, you'd be way off. About 7,000 miles off, in fact.

    In a study published online today by the journal Science, researchers say using biomass to generate electricity is more efficient for transportation than making biofuels - and might actually do more to cut CO2 emissions as well.

    So does that mean bioelectricity is better than bioethanol? Wrong again.

    "Currently, at a commercial scale, we're only beginning to explore these two different scenarios," said lead study author Elliott Campbell, an engineering professor at the University of California at Merced. "In both cases, it really remains to be seen which technology pathway can develop quicker."

    Another co-author of the study, Stanford University's David Lobell, said the analysis was meant to spark a debate, not settle one.

    "What we are hoping is that this will open up a broader discussion on renewable energy for transportation, and not just renewable liquid fuels," Lobell told me. "It wouldn't surprise me if there are some strong reactions to this study, on both sides. Our hope is just to bring this general point to the forefront: Maybe we should be thinking about how efficiently we use our land, and not just about what's the best way to do ethanol."

    The enthusiasm over ethanol has cooled a bit over the past couple of years, due to concerns about food-vs.-fuel price competition and as well as the environmental and mechanical downsides of ethanol production. In addition, last year's plunge in gasoline prices made ethanol less economically attractive.

    Nevertheless, ethanol production has been growing, and that trend appears likely to continue as the technology advances. Just this week the White House highlighted the promise of cellulosic ethanol - which is a better option than the corn-based ethanol currently on the market. This type of ethanol could be produced from non-food cellulose, ranging from wood chips and yard waste to high-yield grasses such as miscanthus and switchgrass.

    The tricky part is that the cellulose can also be used to fire electric power plants, usually in co-production with coal. In the study published today, Campbell, Lobell and the Carnegie Institution's Christopher Field ran the numbers to see which energy pathway would provide more get-up-and-go for next-generation automobiles.

    They gathered up a wide range of existing statistics for energy costs and benefits - including the cost of raising the crops, the cost of making and disposing of the cars, the efficiency of ethanol-fueled vs. electric-powered cars and the value of at least some of the byproducts. Then they put all those factors together to come up with the "miles per acre" (or kilometers per hectare, if you swing that way) for the two different pathways.

    "The final metric that we showed is not the type of metric that you see in many previous bioenergy studies, so that's something new," Campbell said.

    The verdict? When it came to converting switchgrass, the average payoff was 81 percent higher for electric vehicles than for ethanol-fueled vehicles, primarily due to the higher efficiency of the all-electric drive. For a small SUV, that translates to 15,000 miles per acre for electric vs. 8,000 miles per acre for ethanol.

    The bioelectricity pathway also resulted in more than twice the benefit when it came to reducing greenhouse-gas emissions over the vehicle's life cycle.

    So why go to the effort of making ethanol at all? Even though their figures look better for bioelectricity, the researchers acknowledge that liquid biofuels will have to be part of the energy equation for a long time to come. For one thing, not all transportation vehicles can just be plugged into an outlet. "I don't think anybody is talking about electric planes anytime soon," Lobell said.

    And even when it comes to highway transportation, there are good reasons for preferring liquid fuel to electrical juice. "We don't use electric cars because, unless you're talking about specialized applications like forklifts or golf carts, they are not terribly efficient," said rocket scientist Robert Zubrin, who gives biofuels a strong boost in a book titled "Energy Victory."

    "All this stuff about the efficiency of ethanol compared to burning switchgrass for electricity misses the point," Zubrin told me. He said liquid-fueled vehicles beat out electric vehicles in the earliest days of the automobile and will continue to do so, primarily due to convenience and cost considerations.

    He pointed out that it takes just a couple of minutes to put enough ethanol blend in your gas tank to go more than 100 miles. "Imagine trying to put that much energy down a wire in a minute, or 10 minutes," Zubrin said.

    Plug-in hybrid electric vehicles rely on battery power as well as liquid fuel to extend their range - but the dual propulsion system makes such cars thousands of dollars more expensive as well as more complicated to produce, Zubrin said. President Obama's recent call to put a million plug-in cars on the road by 2015 may sound impressive, but it would hardly make a dent in the energy situation.

    "There are 200 million cars in the United States," Zubrin said. "That means that in 10 years he will have replaced one-half of 1 percent of the nation's cars."

    Mandating the production of more flex-fuel cars - which are capable of using alternative-fuel blends or straight gasoline - would produce a much quicker and larger payoff, according to Zubrin and other biofuel boosters. Such a mandate is contained in the Open Fuel Standards Act, currently under consideration in Congress.

    "Flex-fuel adds only $100 to the cost of a new car," Zubrin said. "We'd have 30 million to 50 million of these things on the road in the next three to five years."

    Promoting alternative fuels could yield a geopolitical payoff as well.

    "By making flex-fuel the American standard to sell a car in the U.S.A., this would compel the foreign automakers to switch, too," Zubrin said. "That is how we destroy OPEC - because, you see, it's a question of creating opportunity for alternative-fuel makers to enter the market. ... Liquid fuels are what is needed to replace oil."

    Bioethanol vs. bioelectricity? Or both? Experts on all sides of the debate agree that both will be needed - it's just a question of where to put the policy emphasis.

    "The current situation is that there are lots of different things you can do with biomass and fossil fuels," the Carnegie Institution's Field told me. "As we build up the infrastructure for biomass one way or the other, it will tend to lock us into using that approach over the life of a factory, which could be 10, 20 or 30 years."

    So which blend of energy resources should we go with? Feel free to weigh in with your comments below.

    Update for 2:40 p.m. ET: Before you comment, here are three more considerations to throw into the mix:

    • The Science study considered a lot of factors, including the cost of transporting biomass to an electric plant or ethanol plant and delivering the resulting energy to vehicles. But it didn't consider other issues such as water consumption, air pollution or the cost of technological development and deployment.
    • The researchers acknowledge that there are plenty of other tradeoffs to consider. They noted that "the competitiveness of biomass ethanol depends on the cost of petroleum, whereas the competitiveness of biomass electricity depends on the cost of coal, wind, hydro, solar and nuclear." It may turn out that wind power makes more economic sense than biomass for electric generation, while biomass makes more sense than oil (on economic or national-security grounds) for liquid-fuel production.
    • Because biomass is usually co-fired with coal, there is a concern that boosting biomass could have the effect of promoting what is currently a cheap but dirty energy technology. "A lot of electricity today is mainly coal-based, so without the right policies in place you could envision that this would just transition things from ethanol to coal, and that wouldn't be the right policy for climate issues," Lobell said. On the other hand, if "clean-coal" technologies become reality, the pollution from biomass burning could be cleaned up along with the coal-burning pollution. That would add to biomass' appeal for locking up greenhouse-gas emissions.

    More about energy alternatives:

  • Is nature one mean mother?

    NASA
    A color-coded image from NASA's Aqua satellite
    shows levels of outgoing long-wave radiation
    during the deadly European heat wave of 2003.

    Swine flu? Global warming? Toxic oceans? Why does Mother Nature sometimes seem to be on the attack? According to the decades-old "Gaia hypothesis," it's because Earth is a self-regulating system that is responding to our own excesses. In a new book titled "The Vanishing Face of Gaia," British biologist James Lovelock says humanity is "Earth's infection."

    "Individuals occasionally suffer a disease called polycythaemia, an overpopulation of red blood cells. By analogy, Gaia's illness could be called polyanthroponemia, where humans overpopulate until they do more harm than good," Lovelock writes. He says the cure won't come until the human tribe is trimmed back from its current 6.8 billion to, say, 1 billion people.

    Now University of Washington paleontologist Peter Ward has proposed an alternate theory that suggests Earth is set up to kill off life when it spreads too widely. Humans wouldn't be the first victims of this periodic biocide. The dinosaurs may have been killed off by an asteroid, he says, but during the planet's other mass extinctions, millions of species were done in by good old Mom.

    "I hypothesize that life and its processes, together often referred to as 'Mother Nature,' was, is, and will be anything but a good mother to her many evolved and evolving species," Ward contends in his new book, "The Medea Hypothesis."

    Gaia vs. Medea ... that sounds like the start of a philosophical catfight.

    Ward, however, says he's not just trying to pick a fight with the 90-year-old Lovelock. "Most every scientist is trying to 'pick a fight' with another scientist," he told me today. "We try to do it in a collegial fashion. ... I'm trying to do science, but I'm also trying to point out that there has never been opposition in a formal sense - it's been Gaia, Gaia, nothing but Gaia."

    Actually, Ward agrees with Lovelock that the world is facing an increasingly imminent crisis over climate change. The sharp rise in global average temperatures seems certain to lead to an unstoppable rise in sea levels that will change our coastlines, cities and croplands, Ward said. (He'll address this subject in depth, so to speak, in his next book, "The Flooded Earth.")

    "The short term is a nasty, nasty situation," Ward said. "Where we differ is in his sense that if humans would somehow go away, there would be this natural, pristine world."

    The way Ward sees it, we're the solution, not the problem. "In the short term, we are responsible for 'Medean' effects, but it's going to be our long-term stewardship and engineering that makes things work," he said. "I view humans as the only Gaians on the planet. Everything else is Medean."

    While Lovelock uses "Gaia" to refer to Earth's biosphere as a kindly mother goddess, Ward uses "Medea" as a reference to the mother in Greek myth who killed her own children. Ward says life, like Medea, eventually sows the seeds of its own near-destruction - over and over again. "Life boils up and bubbles up, and through its own waste products and activities makes the planet no longer inhabitable," he said.

    Medea's weapon of choice is the interaction between the atmosphere, oceans and land, Ward said. For years, he has contended that climate set off history's biggest-ever die-off, the Permian-Triassic extinction that occurred 250 million years ago.

    Ward's "rotten-eggstinction" scenario begins with a shift in climate that sparks blooms of sulfur-loving microbes in the world's oceans. Their belches of hydrogen sulfide - the gas commonly associated with rotten eggs - triggers a sequence of events that end with a global poisoning of marine and land species. (This scenario is detailed in Ward's previous book, "Under a Green Sky.")

    In "The Medea Hypothesis," Ward sketches out similar biocidal scenarios for other extinction events. He goes with the conventional wisdom that a huge asteroid touched off the Cretaceous-Tertiary extinction that killed off the dinosaurs, but says continent-spanning forest fires most likely sparked a global winter that finished the job. Thus, he writes, "it could be argued that the effects of life magnified the extent of the extinction."

    The current swine-flu outbreak may not come anywhere close to these past bio-crises, but it does demonstrate that Mother Nature can have some nasty surprises in store. "This is another case showing that evolution works really quickly on microbes," Ward said. "It also underscores the fact that microbes are our biggest enemy on Earth."

    Today, there are fresh signs of a rotten-egg uprising, such as a recent eruption of hydrogen sulfide off the coast of Namibia. And it's not just Namibia: Ward pointed to research conducted in the waters of Washington state's Commencement Bay, where high sulfide concentrations are hammering marine seagrass.

    "It may be we are just starting to see the first effects of this poisoning of seagrass," he said. And that's just the first link in the chain. "Seagrass is where the herring breed," Ward noted.

    So what is to be done? Ward says humans will have to engineer new ways to cope with a mad mother - for example, to counter rising carbon dioxide levels in the short run. By the way, Ward defines the "short run" as lasting more than 3,000 years. (What did you expect? He's a paleontologist, not a stockbroker.)

    In the long run, over the course of many, many thousands of years, "the engineering challenge will be getting carbon back into the atmosphere," Ward writes in his book's final chapter:

    "Even with an enlarging sun, the long-term drop in CO2 as it is put into storage within contenental rock poses the most significant threat to planetary biomass. No plants means no oxygen, so we will require ever present efforts to move carbon from limestones and other continental rocks back into the atmosphere. This is relatively simple, as we know now - burn hydrocarbons. But as these will ultimately be used up, some kind of heating of limestones on a massive scale will do the trick."

    By that time, won't we be moving on (and despoiling) a new home in outer space? "That may not be an option," Ward told me. In his view, the costs and distances involved in moving outward from the solar system - or even terraforming the moon or Mars - just don't seem worth the effort.

    On this point, Ward and Lovelock seem to agree: Whether she's good or bad, we're pretty much stuck with the mother we were born with.

    "The only 'out' is intelligence," Ward said. "Our intelligence is the only way that we can extend the longevity of the biosphere."

  • Hard-wired for a song

    McGovern Institute / MIT
    Click for audio: Zebra finches may be hard-wired to sing a particular
    kind of tune. Click on the image to hear CCNY researcher Olga Feher
    explain how the tune changed over the course of generations.

    A songbird's brain may be programmed to gravitate toward a particular kind of tune, even if it's been taught from infancy to sing to the beat of a different warbler, researchers say. They go on to suggest that a similar neural mechanism might be behind the way our brains handle language.

    "I think we humans, and songbirds, are probably born with some innate predisposition to communicate in a particular way," Olga Feher, a biologist at The City College of New York, told me this week.

    The findings from Feher and her colleagues appear in this week's issue of the journal Nature. The experiments suggest that phenomena rooted in a species' culture - for example, singing for birds, using language for people - may be rooted in a species' genome as well.

    "People have theorized long and hard about how the evolutionary process applies to culture," another co-author of the study, Partha Mitra of Cold Spring Harbor Laboratory, said in a news release. "This experiment takes culture and puts it into a laboratory setting. We've tested some questions, asked by others over many years, in a mathematically and experimentally crisp manner and come up with a concrete answer."

    The experimenters started out by raising zebra finches in isolation, in soundproof boxes. For decades, scientists have known that an isolated songbird's innate song is different from the song that is "learned" from its feathered tutors as it grows up. In fact, different genes come into play as a songbird's song matures. So does the classic zebra finch song emerge merely as a cultural norm among the songbird set, or is there some sort of hard-wired inevitability about the tune?

    Chalk one up for hard-wired inevitability: It's true that an untutored male bird can come up with a song that sounds raspy, screechy, off-rhythm or overlong. But when it's time for that odd bird to tutor the next generation, his students start introducing variations that bring the song closer to the "cultured" norm. After just four generations, the isolated zebra finches are singing the species' standard song.

    "There's no good reason for them to do that," Feher, who worked on the study for her doctoral thesis, told me. "We think it's most likely that they have genetically encoded some sort of biases that enable them to judge a song and make it more 'wildlike.'"

    Ofer Tchernichovski, a CCNY biology professor and Feher's thesis adviser, said the same pattern emerged whether the isolated male birds were raised among their tutors one-on-one, or raised in a colony, or raised among female zebra finches, which do not sing.

    "This is the first time that cumulative culture has been demonstrated in the lab," he told me. "Culture emerges from scratch under very controlled conditions."

    The fact that the cultured song emerged so quickly meant that natural selection didn't play a role in fine-tuning the song. But the neural mechanism behind the fine tuning most likely is a product of evolution. "That would be really interesting to know - the functional part of this whole phenomenon," Feher said.

    Perhaps the females are programmed to respond to a particular kind of song as a signal of reproductive fitness, and thus the males who possess the fine-tuning mechanism have a better chance of survival. "We just don't know," Feher said.

    But there is some evidence that the human brain works the same way: The researchers noted that a similar phenomenon of language convergence has been observed among deaf children in Nicaragua. The individual children developed a rudimentary sign language in their homes, but that language quickly evolved into a sophisticated system when the children were put together in a school for the deaf.

    "That's pretty much the only documented case of real, dramatic language convergence in humans," Feher said. Subsequent research, involving deaf Bedouins in Israel, have provided further insights into the processes that may (or sometimes may not) lead to language convergence.

    Some may argue that language changes too rapidly to be influenced by our genes, but even those researchers acknowledge that genetics laid the groundwork for language to emerge in the first place.

    The latest study suggests that our brains and birdbrains may not be as different as they seem. We all come up with some crazy, oddball ideas when we're left alone. The key step is to figure out how birds (and humans) decide which of those ideas should be preserved, and which should be thrown out.

    "When the bird is deciding what it comes up with [in the song it learns], what are the parameters that the bird is deciding to attend to?" Tchernichovski said. "The bird does not seem to have any bias against imitating the wrong song. He just imitates and 'improves' it. ... Maybe the bird doesn't listen to himself like he listens to others."

    In addition to Feher, Tchernichovski and Mitra, the team behind the Nature study includes Haibin Wang of Cold Spring Harbor Laboratory and Sigal Saar of The City College of New York. Click here to listen to an MP3 audio clip of multigenerational zebra-finch songs. 

  • 50 years of seeking E.T.

    Imaginova
    Click for video: The Drake Equation estimates the likelihood
    of alien intelligence, based on assumptions about life in the
    universe. Click on the image to watch a Space.com video
    featuring the SETI Institute's Seth Shostak and Frank Drake.

    It's been almost 50 years since scientists first came up with the idea of looking for radio signals from extraterrestrial civilizations - and although there have been a couple of curious blips, we haven't yet definitively heard E.T.'s cosmic call. Now the experts in the search for extraterrestrial intelligence, or SETI, are wondering whether we've been looking in the wrong places for the wrong kinds of signals.

    Or maybe we just haven't been looking long enough.

    All of those possibilities are considered in "Confessions of an Alien Hunter," a new book from Seth Shostak, the SETI Institute's senior astronomer.

    Shostak's "confessions" are actually Shostak's arguments for why the SETI search makes sense - leavened with dramatic accounts of the effort's best-known false alarms (including an episode that Shostak wrote up for msnbc.com a decade ago) and folksy metaphors that would put Dan Rather to shame (including this one: "Life is as durable as Christmas fruitcake").

    The California institute where Shostak works is the primary standard-bearer in the search for alien signals. That search dates back to 1960, when astronomer Frank Drake (now the SETI Institute's president) aimed an 85-foot radio telescope in West Virginia skyward in hopes of tuning in the extraterrestrials.

    After his initial foray, Drake and his fellow seekers moved on to bigger and better telescopes, including the old 140-foot Green Bank Telescope and the 1,000-foot Arecibo Observatory. But the strategy was pretty much the same: Check one star for an unnaturally steady radio signal, then move on to the next star.

    Now that's changing. The Allen Telescope Array, a joint venture involving the SETI Institute and the University of California at Berkeley, will allow bunches of stars to be studied at once. Like microchips, the efficiency of SETI has been improving at a geometric pace in agreement with Moore's Law. If that pace continues for the next two dozen years, more than a million stars will be checked for signs of on-air life, Shostak notes.

    Shostak and Drake say that sampling should be big enough to result in contact - assuming first that the aliens exist, and then that they think like we do. The first assumption is big, but the second one is even bigger. If the search for signs of microbial life on Mars and more distant worlds requires a correct understanding of astrobiology, the search for intelligence beyond our own solar system requires something more: astropsychology, perhaps?

    Over the decades, the strategy for SETI has by necessity been dictated by a cosmic Golden Rule: We look for communication in the channels that we use to communicate. A generation ago, that might have been the analog television signals that carried "I Love Lucy" out to the cosmos. Today, Drake speculates that the aliens might be transmitting digitally, with lasers instead of monster radio antennas.

    During a weekend talk in Seattle, Drake pointed out that the just-completed National Ignition Facility can focus the light of 192 lasers to create a pulse that lasts just a few nanoseconds but far outshines the sun. "Those lasers can make pulses of light which are visible to very small telescopes all across the galaxy," he noted.

    Shostak theorizes that E.T. might have two types of transmitters going: one that flashes such pulses of light toward a long list of target planets that might be habitable - including us - and another "low-power, omnidirectional broadcast that tells you how to join their book club, or whatever." For that reason, SETI searchers have started conducting surveys for those tiny flashes of light as well as for sustained radio traffic.

    So where should we look? Historically, the SETI Institute's target list has favored Earthlike planets where life as we know it might have taken root. But in "Confessions of an Alien Hunter," Shostak suggests that on the basis of what we're learning about artificial intelligence, the most likely aliens to send signals would actually be artificially intelligent machines.

    If E.T. is a big shiny robot, the strategy of targeting Earthlike worlds orbiting sunlike stars may turn out to be "a very antiquated idea," Shostak acknowledged during a weekend interview. "A world on which the whole thing can rust might not be the best place for it," he said. A better place, from the machine's point of view, would be in orbit around a star hot enough to provide the prodigious power required for the big broadcast.

    But Drake said the other end of the stellar scale shouldn't be overlooked, either. It turns out that about three-quarters of the stars in our galaxy are red dwarfs, which are dimmer than the sun but still could provide a home for E.T. Those stars have been overlooked in past SETI searches.

    The bottom line, Drake said, is that "our simple picture was really way too simple" when it came to visualizing the kinds of places in the universe where life might lurk.

    That's one of the reasons why Drake isn't discouraged that the SETI quest has come up empty, even after 50 years. He pointed out that only a thousand stars or so have been studied, over bandwidth that accounts for just a few percentage points of the potential spectrum. "We've looked at something like 10-5 of the possible combinations," he said.

    Shostak said he felt confident that solid evidence of life beyond Earth will be found within two dozen years - either by continuing with SETI, or by analyzing exoplanet atmospheres, or by digging into the dirt on Mars or the ice on Europa or Enceladus. Drake, meanwhile, had a longer timetable in mind. "I don't think 2025 is going to happen unless we're very lucky," he told me. "Maybe it'll take twice as long - maybe 2050."

    Other experts have suggested time frames of 100 to 200 years.

    Of course, such timetables assume that SETI efforts around the world will continue to attract followers and funding. SETI efforts in the United States are funded privately rather than publicly, and Drake said it's getting tougher to raise money. "As long as the recession keeps going on, we have to move that [timetable] back," he said.

    Could there ever come a point when the experts decide there's no E.T. out there to phone home? What would Shostak do if he hasn't heard from the aliens after a century of searching (other than celebrating the fact that he's still alive in the year 2060, that is)?

    "I don't think I would be ready to say that they're just not there," he said, "but I might be inclined to say that we're barking up the wrong arboreal fixture ... that there's something fundamentally wrong with what we're doing."

    How common do you think extraterrestrial intelligence could be? Plug some figures into the Drake Equation and come up with your own estimate. Search for extraterrestrial intelligence on msnbc.com. Then weigh in with your comments below.

  • Enjoy the outer-space circus

    NASA / JPL-Caltech
    Rivers of stars create a smooth swirl in this infrared view of the galaxy NGC 2841,
    captured by NASA's Spitzer Space Telescope. Click on the image for a larger view.

    The month of May is bringing in so many outer-space wonders, it's as if a three-ring circus were rolling into town with four or five rings. Today is Space Day, which morphs into Astronomy Day and the Astronaut Hall of Fame on Saturday, followed by the peak of the Eta Aquarid meteor shower next week ... all leading up to one of the greatest shows off Earth, the final upgrade to the Hubble Space Telescope.

    And if that still isn't enough rings for you, there's a sparkling new image of a ring galaxy from Hubble's younger sibling, the Spitzer Space Telescope.

    Rivers of stars
    The fresh infrared view of the spiral galaxy NGC 2841, which is 46 million light-years away in the constellation Ursa Major, figures in recently published research that looks at why stars become so smoothly distributed in such galaxies. After all, stars are created in bursts of clusters, and thus start out their lives in lumps.

    "Our analysis now answers the great puzzle," David Block, an astronomer at the University of the Witwatersrand in South Africa, said in a news release issued Thursday by Spitzer's science team. "By finding a myriad of streams of young stars all over the disks of galaxies we studied, we see that the mechanism for pulling the clusters of young stars apart is shearing motions of the parent galaxy. These streams are the 'missing link' we needed to understand how the disks of galaxies evolve to look the way they do."

    Spitzer's infrared camera peered through the galaxy's dust to spot the young stars hidden within. The image data was then manipulated to highlight the subtle structures associated with star formation. "The structures cannot be seen on the original Spitzer image with the human eye," said Ivanio Puerari of the Institut Nacional de Astrofisica, Optica y Electronica in Puebla, Mexico.

    The analysis highlighted the galaxy's hidden streams of stars - a feat of image processing that would have been impossible without Spitzer's infrared vision and the astronomers' computational firepower. The results were published in the March 20 issue of the Astrophysical Journal.

    Days of glory
    That's just one example showing how the space frontier brings a scientific as well as an aesthetic payoff here on Earth. Three events this weekend throw a spotlight on that same blend of exploration, education and entertainment from outer space.

    Today marks the 13th annual celebration of Space Day, an international educational initiative backed by a coalition involving government agencies, museums, educational institutions and aerospace companies. Almost 200 events have been planned under the Space Day aegis, stretching well into the summer. The main event actually takes place on Saturday at the Smithsonian's National Air and Space Museum in Washington.

    In addition to the events, teachers can work Space Day lesson plans into their curricula, students can have their signatures sent into space, and anyone with an Internet connection can play out-of-this-world online games.

    More opportunities for playtime are available courtesy of Astronomy Day, which is timed for Saturday to coincide with May's first-quarter moon. That lunar phase is preferred because it gives skywatchers a chance to see the moon in profile while leaving time for wide-open observing after the moon has set.

    Astronomy clubs generally schedule scads of events at this time of year: To find out what's going on in your area, check the listings offered by the Astronomical League, Astronomy magazine and Sky and Telescope. If you don't see your locality listed, click through this worldwide list of astronomy clubs and find out what's coming up.

    Saturday is a big day at Kennedy Space Center's visitor complex in Florida: Three space shuttle veterans - George "Pinky" Nelson, Bill Shepherd and Jim Wetherbee - are due to be inducted into the U.S. Astronaut Hall of Fame. If you happen to be in the Cape Canaveral area and get into rubbing elbows with astronauts, this is the place to be.

    More coming attractions
    There's more to come next week, when the annual Eta Aquarid meteor shower reaches its peak. This sky show flares up annually when Earth passes through the stream of cosmic grit left behind by Halley's Comet. (Actually, Earth sweeps through that particular comet's trail twice a year. The other meteors associated with Halley's Comet are the Orionids of October.)

    Roen Kelly / Astronomy
    The Eta Aquarid meteor shower peaks before
    dawn May 6. Click on the image for more
    information from Astronomy magazine.

    The peak night for observing is Tuesday night - or maybe you should make that very early Wednesday morning, as in 3 or 4 a.m. Meteor activity traditionally picks up after midnight, when the nighttime side of the planet is plowing right into the oncoming stream. Also, the moon is due to set around 4 a.m., eliminating an extra source of glare. To optimize your viewing conditions, find an open patch of ground with clear skies, far away from city lights.

    The Aquarids seem to emanate from the constellation Aquarius, but they can appear anywhere in the night sky. For more viewing tips, check out this guide from Astronomy magazine. Our "Meteor Show" interactive explains the science behind the shooting stars.

    While you're out, you can catch glimpses of several planets as well, especially if you follow the pointers in Sky and Telescope's weekly observing guide. The international space station may also be visible: NASA lays out a schedule for sighting opportunities that is customized for your viewing location.

    NASA will be gearing up for its final Hubble servicing mission, scheduled for launch on May 11. Follow the countdown via msnbc.com's Space section, and try your hand at the Hubble-mania edition of our Sci-Q test.

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