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Enceladus Geysers Mask Saturn’s Day

by Paul Gilster | Mar 23, 2007 | Outer Solar System | 3 Comments

What is it about Enceladus? I doubt anyone would have thought the tiny moon would weigh so heavily in our thinking about Saturn before Cassini, but now comes the news that Enceladus is distorting the planet's magnetic field to the point that it becomes tricky to measure the length of the Saturnian day. Count the electrically charged particles originating in the moon's geysers as the culprit -- they're actually causing Saturn's magnetic field lines to slip relative to the planet's rotation. The process seems to work like this: Gas particles are ejected from the geysers on Enceladus and become electrically charged. Captured by Saturn's magnetic field, they form a disk of plasma that wraps around the planet's equator. The rotation of the plasma disk slows down enough due to interactions with the magnetic field that the rotation period Cassini has been measuring -- based on radio emissions -- is not actually the length of Saturn's day. Instead, it's the rate of rotation of the plasma...

Asteroid Deflection: The Nuclear Option

by Paul Gilster | Mar 22, 2007 | Asteroid and Comet Deflection | 19 Comments

NASA's March report to Congress on deflecting Near-Earth Objects offers some startling assessments. Specifically, the report says this: "Nuclear standoff explosions are assessed to be 10-100 times more effective than the non-nuclear alternatives analyzed in this study. Other techniques involving the surface or subsurface use of nuclear explosives may be more efficient, but they run an increased risk of fracturing the target NEO. They also carry higher development and operations risks." Fair enough re setting off a nuke on the surface of an asteroid. But aren't we jumping the gun on other nuclear options when alternatives seem available? That's certainly the view of Rusty Schweickart, founder of the B612 Foundation, which is all about spreading the word on the threat these objects may pose to Earth. Alan Boyle discussed these matters with Schweickart in a recent post, from which this on the non-nuclear option: Schweickart argues that the so-called "nuclear standoff" option should be...

New Optics Paint Orion’s ‘Bullets’

by Paul Gilster | Mar 22, 2007 | Deep Sky Astronomy & Telescopes | 3 Comments

When you can work with a deformable mirror that compensates for atmospheric distortions, wondrous things can emerge. The Gemini Observatory (Mauna Kea, HI) used such a system coupled with a laser guide star as reference to produce an image of fast-moving 'bullets' of gas and the wakes they leave as they move through molecular hydrogen in the Orion Nebula. Some 1500 light years away from Earth, this stellar nursery has much to teach us about the birthing of stars. What we're looking at appears to be the movement of clumps of gas that have been ejected from within the nebula by some kind of violent event. They're moving outward at about 400 kilometers per second, vast gaseous agglomerations roughly ten times the size of Pluto's orbit around the Sun. At the tip of each clump you can see the blue glow of iron atoms shock-heated by friction with the surrounding cloud. The long wakes of their motion appear as orange smudges in the image below. Image: This composite image at infrared...

Institute for Advanced Concepts Scrapped

by Paul Gilster | Mar 20, 2007 | Culture and Society | 28 Comments

I've been waiting for something official re the reported closing of NASA's Institute for Advanced Concepts, but now that New Scientist is confirming the story that Keith Cowing at NASAWatch broke earlier this morning, I think it's time to comment on this grim development. NASA will save $4 million in its annual budget by closing NIAC. That means closing a program that regularly sought ideas from people outside the agency, funded them in a first round to see if they held promise, and offered more substantial second round funding to advance the best of them still further. Institute director Robert Cassanova has championed innovative ideas in propulsion, robotics, spacesuit design and more. In fact, NIAC-funded studies are so rich that browsing through this material could give science fiction authors ideas for years. I'll add that Cassanova's enthusiasm for the work was communicable. He was a great help when I was gathering NIAC material for Centauri Dreams (the book), and although he...

Quantum Weirdness and Communications

by Paul Gilster | Mar 20, 2007 | Communications and Navigation | 25 Comments

'Spooky action at a distance' is still spooky no matter how you explain it. Einstein famously used the phrase to describe quantum entanglement, where two entangled particles appear to interact instantaneously even though separated in space. Now we're talking about using the effect for communications, following the news that European scientists have proven that entanglement persists over a distance of 144 kilometers. Fortunately for would be communicators, a pair of entangled photons can be created in a process called Spontaneous Parametric Down Conversion. Once entangled, the photons stay entangled until one of them interacts with a third particle. When that happens, the other photon changes its quantum state instantaneously. The beauty of entanglement for communications is that anyone trying to listen in on a message invariably disrupts the entangled system, a result that would be easily detectable. The security potential is obvious in a world where so much banking information takes...

Another Small Step Toward Fusion?

by Paul Gilster | Mar 19, 2007 | Advanced Rocketry | 31 Comments

We're a long way from achieving practical fusion to supply our power needs, much less fusion rockets to the stars. Just how far can be gauged by a look at current research. The principle seems straightforward: Heat hot, ionized gas to the point of ignition and you can fuse hydrogen into helium. But can you contain the plasma while you're heating it? More to the point, can you get more power out of your device than you put in? Most of the effort these days is going into tokamak designs that use magnetic fields to contain the plasma. But tokamaks tap plasma currents to produce at least part of the needed field. And, says John Canik (University of Wisconsin), "The problem is you need very large plasma currents and it's not clear whether we'll be able to drive that large of a current in a reactor-sized machine, or control it. It may blow itself apart." Enter the stellarator, an alternative plasma confinement method that uses no plasma currents, but one that loses energy at a high rate...

A Practical Use for Antimatter

by Paul Gilster | Mar 17, 2007 | Antimatter | 6 Comments

If we need a huge particle accelerator to produce antimatter and use it only for exotic experiments, how are we ever going to ramp up production to the point where it becomes practical as a propulsion system? One answer may be that as we study the minute amounts of antimatter available for study today, we are learning how to use it in ways that are far more likely to catch the public eye, as in medicine. And treating cancer effectively -- ask any patient -- is anything but theoretical. At CERN (European Organization for Nuclear Research), the Antiproton Cell Experiment (ACE) has been running since 2003. It's an attempt to look at antimatter's effect on cancer cells, and its results are startling. Antiprotons, it turns out, are four times more effective than protons at destroying live cancer cells. Here's CERN's Michael Holzscheiter on the encouraging news: "To achieve the same level of damage to cells at the target area one needs four times fewer antiprotons than protons. This...

Mulling Robots and Their Names

by Paul Gilster | Mar 17, 2007 | Autonomy and Robotics | 14 Comments

Lee Gutkind takes a look at the Robotics Institute at Carnegie Mellon in Almost Human: Making Robots Think (W.W. Norton, 2007), a book entertainingly reviewed in this weekend's Los Angeles Times. Out of which this wonderful clip from reviewer M.G. Lord: I wish Gutkind had spent more time on an area that I find fascinating: the anthropomorphizing and gendering of robots, which science-fiction author Robert A. Heinlein famously explored in his novel The Moon Is a Harsh Mistress. What Heinlein created was a computer that, depending on circumstances, could switch between masculine and feminine identities. Robots are heaps of hardware, not biological entities, yet humans apparently feel more comfortable if they assign them a gender, regardless of the crudeness of the gender stereotype. The institute, for example, has robot receptionists with gendered personalities: Valerie, a "female" who complains about her dates with vacuum cleaners and cars, and Tank, a "male," who has blundered so...

Making the Case for Space

by Paul Gilster | Mar 16, 2007 | Culture and Society | 5 Comments

When you think about it, so much of science involves putting our instruments into the right place at the right time. The transit of Venus across the Sun in 1769 was an opportunity to use triangulation from opposite sides of the Earth to calculate the distance to the Sun more accurately. That effort took James Cook to Tahiti, and though the experiment failed, it remains an inspiring example of the human intellect trying to solve questions by exploration, determination and hard work. We saw yesterday that if we put instruments into much further places, we may be able to identify oceanic worlds and perhaps map their continents. Peter McCullough (Space Telescope Science Institute) wrote the most recent paper on this concept and presented it at a conference on missions that could be enabled by a return to the Moon. But the Moon itself may not be the best venue for the instruments in question, as McCullough noted in an e-mail after reading yesterday's entry: "I might comment (in...

Light Off an Alien Ocean

by Paul Gilster | Mar 15, 2007 | Exoplanetary Science | 5 Comments

If you want to put the hunt for planets around other stars in perspective, consider this. For almost all of our species' time on this planet, we have looked at the planets in our own Solar System as unresolved points of light that seemed to move upon a celestial sphere. The brief time that we have been able to see more is measured since the invention of the telescope, a tiny window compared to the millennia that went before. We are now working hard to see extrasolar planets as unresolved, moving points of light. In doing so, we're looking at ways to image these planets that would yield the greatest scientific return. Recall former NASA administrator Dan Goldin's wish to actually see the surfaces of distant exoplanets -- he talked to putting such images on the walls of our schools. One day, starshade technologies coupled with space-borne telescopes may make that possible. For now, though, there is the real potential of something closer: identifying exoplanets with oceans. The beauty...

Planets, Comets & Footballs

by Paul Gilster | Mar 14, 2007 | Outer Solar System | 13 Comments

I remember talking to the exuberant astrophysics professor Sheridan Simon about a football-shaped planet he had created one Super Bowl eve. This was at a science fiction convention and it must have been fifteen years ago. Simon frequented such venues because he had built a cottage industry around creating planets for various science fictional settings. As a lark, he had run the numbers on what would happen to the atmosphere of a world shaped like a pigskin and wound up announcing the result: "It's plaid! That's what you would see. A plaid football!" I think he was pulling my leg, and that wouldn't have been out of character either for this generous, gregarious man who died all too young. But Mike Brown's new paper in Nature brought back memories of that conversation with Sheridan Simon in spades. Brown (California Institute of Technology), who specializes in the exotica at the fringes of our Solar System, has been examining an object his team originally found. 2003 EL61 is also...

The Seas of Titan

by Paul Gilster | Mar 13, 2007 | Outer Solar System | 15 Comments

If the dark features Cassini has found near Titan's north pole really are filled with liquid, they're seas more than lakes, one of them larger than any of the Great Lakes in North America. The image below says it all, comparing the largest of these features with Lake Superior. This work is being done through radar imaging, detecting dark radar surfaces that imply smoothness. Cassini's visual and infrared mapping spectrometer is also at work as the liquid hypothesis at Titan's surface is explored. Image: This feature on Titan is at least 100,000 square kilometers (39,000 square miles), which is greater in extent than Lake Superior (82,000 square kilometers or 32,000 square miles), which is one of Earth's largest lakes. The feature covers a greater fraction of Titan than the largest terrestrial inland sea, the Black Sea. The Black Sea covers 0.085 percent of the surface of the Earth; this newly observed body on Titan covers at least 0.12 percent of the surface of Titan. Because of its...

Enceladus: Hot at the Core?

by Paul Gilster | Mar 13, 2007 | Outer Solar System | 6 Comments

Every time we get new information about Enceladus, I keep thinking about how the original Orion team would have felt if they really had made the trip to Saturn they once discussed for their fabled atomic rocket. Enceladus, thought Freeman Dyson, looked to be a logical place to refuel because it was believed to be rich in ice and hydrocarbons. But no one in those pre-Cassini days could have imagined what Dennis Matson (Jet Propulsion Laboratory) is now talking about: "Deep inside Enceladus, our model indicates we've got an organic brew, a heat source and liquid water, all key ingredients for life. And while no one is claiming that we have found life by any means, we probably have evidence for a place that might be hospitable to life." All of which falls into the 'never in my wildest dreams' category, for Enceladus has hardly led the list when one discusses life's possible venues in the Solar System. But Cassini found geysers ejecting water vapor and ice from the moon's south polar...

Exobiology and the Press

by Paul Gilster | Mar 12, 2007 | Culture and Society | 16 Comments

When and if we discover extraterrestrial life, the handling of the news will be interesting. Recall the tumultuous media circus following the announcement in the movie Contact. Carl Sagan knew a little about dealing with the press, and the film version gets across what might happen when you start broadcasting public fear and fascination through a cable TV and Net-connected world. Or think of the recent rumblings when the SETI Institute said it was about to make a 'major announcement,' which turned out to be business related and not extraterrestrial at all. And in point of fact, we do have one actual experience of trying to announce extraterrestrial life. That was in 1996, when a team of researchers had submitted a paper, subsequently accepted, to Science. The contents were dynamite, for the authors proposed that the Antarctic meteorite ALH84001 might be evidence of life on Mars. The team had studied four potential biomarkers within the meteorite, which had earlier been determined to...

Whither the Science Fiction Magazines?

by Paul Gilster | Mar 10, 2007 | Culture and Society | 14 Comments

Back in the 1950's, science fiction magazines were all over the newsstands. That's significant for Centauri Dreams' purposes because these titles spurred many a career in science and a fascination with astronomy, astrophysics and engineering. Many is the scientist I've talked to who fondly reminisces about stories that proved inspirational, and in today's math-challenged world, getting students to start thinking about pursuing work in physics or other sciences is a serious concern. Which is one reason Paul Raven's recent essay on the declining fortunes of the science fiction magazines caught my eye. Paul writes Velcro City Tourist Board, the site I turn to when I want to know what's worth reading on the modern SF scene. He's well plugged in -- Paul writes reviews for Interzone, the fine British magazine, among other things -- and for those of us whose SF tastes run to older material, he provides a wonderful way of keeping up with new trends and making sense out of where the field is...

AEGIS: A Deep View of Galactic History

by Paul Gilster | Mar 9, 2007 | Deep Sky Astronomy & Telescopes | 0 Comments

Out near the end of the Big Dipper's handle is a strip of sky the width of two full moons that looks all but empty to the naked eye. But take a closer look, as the ongoing AEGIS survey is doing across the electromagnetic spectrum -- from radio and infrared through visible light up to the x-ray regions -- and you'll find more than 150,000 galaxies. AEGIS is examining galaxies up to 9 billion years back in time. The name stands for the All-wavelength Extended Groth Strip International Survey, and when I first wrote about it, I didn't have this link to the nineteen papers about the survey that will appear in the Astrophysical Journal Letters in the spring. What's exciting about the survey is its sheer breadth -- no other region of the sky this large has been examined quite so intensively. Cosmologist Jeffrey Newman (Lawrence Berkeley National Laboratory) puts it this way: "We have looked at this patch of sky with every possible telescope, at wavelengths covering nine orders of magnitude...

Sun Boosts Asteroid’s Spin

by Paul Gilster | Mar 8, 2007 | Asteroid and Comet Deflection | 8 Comments

OK, we sometimes encounter scientific terms with large numbers of syllables, but how about this one, perhaps the prize winner: the Yarkovsky-O'Keefe-Radzievskii-Paddack Effect. This multicultural monicker -- drawn on the names of a Russian engineer, an American scientist, a Russian astronomer and a NASA aerospace engineer -- has something interesting to say about sunlight. As solar radiation heats and cools an asteroid, released energy can change its rotation. In the case of the asteroid 2000 PH5, the effect increases the spin rate to the point where the asteroid may eventually come to spin faster than any asteroid known. This complicated study used a variety of telescopes to make the case that the asteroid's rotation period decreases by 1 millisecond every year. That's a long and slow effect, but the results build over time, and they're more readily observable because 2000 PH5 approaches Earth every year. The cause is the heating of the asteroid's surface by the Sun. Stephen Lowry...

Learning How Galaxies Form

by Paul Gilster | Mar 7, 2007 | Deep Sky Astronomy & Telescopes | 1 Comment

By analyzing a carefully selected set of 544 distant galaxies, researchers are beginning to learn how galaxies take their mature forms, becoming the glorious objects we see today. Sandra Faber (University of California at Santa Cruz), puts it this way: "We are now well on our way to seeing how galaxies evolved over the last half of the age of the universe. This work is not over, but the outlines of a theory are emerging." The galaxies in question weigh in with redshifts in the range of 0.1 to 1.2, which translates to 'look-back' times of between 2 and almost eight billion years. These adolescent galaxies are far more disordered than nearby ones, but it turns out that the relationship between a galaxy's mass and the orbital speed of its stars and gas is consistent over different types of galaxy and over billions of years of galactic evolution. In other words, the more massive a galaxy is, the faster the stars and gas inside it move. That analysis includes a 'dispersion component' that...

Asteroids: The Threat and the Budget

by Paul Gilster | Mar 6, 2007 | Asteroid and Comet Deflection | 5 Comments

NASA is putting the number of potentially hazardous asteroids and comets at 20,000 in a report that will be released later this week, according to an AP story now circulating. And the report, reviewed at a Planetary Defense Conference in Washington yesterday, pegs the cost of finding 90 percent of these objects at $1 billion. That's bad news for those worried about Earth-crossers. For AP quotes NASA Ames director Simon Worden: "We know what to do; we just don't have the money." And as Larry Klaes wrote me this morning, "But just imagine the bill after a big space rock hits Earth." NASA is already tracking some 769 objects in a search now described as behind schedule. From the story: One solution would be to build a new ground telescope solely for the asteroid hunt, and piggyback that use with other agencies' telescopes for a total of $800 million. Another would be to launch a space infrared telescope that could do the job faster for $1.1 billion. But NASA program scientist Lindley...

Philosophia Naturalis #7 Now Available

by Paul Gilster | Mar 6, 2007 | Culture and Society | 0 Comments

The seventh iteration of Philosophia Naturalis is now online at geek counterpoint. These 'blog carnivals' are increasingly helpful because they cluster articles of interest, and I always wind up learning about new things to read. This carnival's find is Rob Knop (Vanderbilt), whose Galactic Interactions blog offers an intriguing entry on what he calls 'The Greatest Mystery in All of Physics," which turns out to be the link between gravitational and inertial mass. Another find: Cosmic Variance's take on relativity and why E=mc2. Which gets us into a thought experiment: Think of a physicist, standing at one side of a large box, which itself is sitting on a perfectly frictionless surface (think of ice if you like). The physicist possesses a large cannon, which she is using to hurl heavy cannonballs across the box. What happens to the whole system? The answer is informative and entertaining, particularly when you replace the cannon with a powerful laser. Read the rest at the site, and...

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In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For many years this site coordinated its efforts with the Tau Zero Foundation. It now serves as an independent forum for deep space news and ideas. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image courtesy of Marco Lorenzi).

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