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Into the Wormhole

by Paul Gilster | Feb 3, 2007 | Exotic Physics | 42 Comments

Can we find and actually traverse a wormhole? Crowlspace looks at the possibilities and links to a paper by Nikolai Kardashev that we'll be examining here in the next week or so. A snippet: Relativity gives no clear indication of where wormholes end. They might link to other places (and times) in our Universe or in other Universes. When the worm-ways of the Universe are finally explored there will be a whole new breed of adventurers required to travel to their far-ends, risking being lost in a wholly other Universe and time. After hardy explorers have mapped the wormhole network of the Universe what will happen then? A provocative scenario indeed! Read the whole thing here.

The Approach of Gliese 710

by Paul Gilster | Feb 3, 2007 | Culture and Society | 17 Comments

The Astroprof's Page takes a look at the interesting star Gliese 710, a K7 dwarf with a particular claim to distinction: it's headed in the direction of our Sun at about 24 kilometers per second. Give it 1.4 million years and the star will have closed to within a light year of Sol, shining at a magnitude of 1.2 and disturbing the icy debris out in the Oort Cloud. A rain of comets moving into the inner system is the probable result. Barnard's Star is moving towards us too, closing to within four light years around 10000 AD, but we needn't wait for a close stellar pass to start worrying about catastrophic collisions. As the battered surface of the Moon suggests, the Solar System can be a hostile place, making a space-based infrastructure to prevent future disaster an imperative.

Davies and the ‘Goldilocks Enigma’

by Paul Gilster | Feb 3, 2007 | Exotic Physics | 2 Comments

A recent mention of Paul Davies reminds me (belatedly, to be sure) to point you to "We Were Meant to Be Here," an interview Phillip Adams conducted with the physicist on ABC Radio National. The occasion was Davies 60th birthday last June, the conversation's title reflective of the usual Davies range across the deepest issues of life in the cosmos. Davies, formerly at Macquarie University, has left Australia and is now active at Arizona State, where he is establishing the Institute for Fundamental Concepts in Science. Other good audio is available at Davies' site. Also, a review of his The Goldilocks Enigma: Why is the Universe Just Right for Life? (Allen Lane, 2006) is available here.

Darwin and Luna

by Paul Gilster | Feb 2, 2007 | Culture and Society | 6 Comments

Some years back, the fine space writer William E. Burrows helped to establish ARC, the Alliance to Rescue Civilization. ARC's purpose was to create an imperishable archive that would contain a record of our civilization in the event of catastrophe. Now a part of the Lifeboat Foundation, ARC envisioned making a 'backup' of the human experience, with the Moon as just one venue. In today's Wall Street Journal, Burrows looks at the dangers of returning to the Moon vs. staying home: It is therefore reasonable to ask whether such an incredibly expensive and dangerous undertaking is worth it. The answer is an unequivocal yes. But the truly compelling reason to build a lunar base is not for adventure, though there will be plenty of that. Nor is it to mine resources to gain riches, though that will eventually happen. The overriding reason to establish a colony on the moon is humanity's survival: Darwin achieves liftoff. Do we really need the current space station? Burrows says no -- we...

An Oscillating Universe After All?

by Paul Gilster | Feb 2, 2007 | Exotic Physics | 12 Comments

Expansion, turnaround, contraction and bounce. Those are the four components of a new model of the universe created by researchers at the University of North Carolina at Chapel Hill. Their work offers an alternative to the Big Bang theories in the marketplace and sets up a cyclical progression in which an infinite number of independent universes emerge from what's left of matter just before the end of time. Tough going, this. But think of the universe's vast expansion pushing everything progressively further out until all matter disintegrates. This is the turnaround point, and it is here that each fragmented 'patch' of what had been matter collapses and contracts. "We discuss contraction which occurs with a very much smaller universe than in expansion," write the researchers, "and with almost vanishing entropy because it is assumed empty of dust, matter and black holes." The key is that this collapse occurs individually, so that rather than causing the Big Bang to run in reverse,...

Philosophia Naturalis #6 Now Online

by Paul Gilster | Feb 2, 2007 | Culture and Society | 0 Comments

The sixth edition of Philosophia Naturalis is out, published by Charles Daney on his Science and Reason blog. It's a 'carnival' of interesting writing in the weblog format, pointing to writing by diverse and sundry authors on the physical sciences and technology. Carnivals like this one seem to be gaining popularity, a welcome thing because they offer pointers to sites I hadn't known about, and the topics are always interesting. Good coverage of the American Astronomical Society meeting shows up here, along with work on dark matter, the Antikythera Mechanism, and a wonderful explanation of light cones and Einsteinian relativity. I'm pleased that Philosophia Naturalis includes two recent posts on the James Webb Space Telescope from these pages.

The End of Super-Civilizations

by Paul Gilster | Feb 1, 2007 | Astrobiology and SETI, Exotic Physics | 13 Comments

Is energy consumption a good way to measure a civilization? The Soviet astronomer Nikolai Kardashev thought so, using it as the basis for his famous classification scheme. A Type I civilization could harness the energy resources of its home world, while a Type II could use its own star's entire energy output. A Type III, the most exotic of all, could tap the energy of an entire galaxy, making it a plausible SETI target if we assume we can identify its exotic activities for what they were. But some are questioning whether energy consumption is the best marker for looking at possible extraterrestrial cultures. Zoltan Galantai (Technical University of Budapest) notes that expecting vast energy use may simply be the marker of an adolescent technology, one that assumes all possible futures will look something like our own present extrapolated forward. He points out as well that there is no fast correlation between energy consumption and the spatial growth of a civilization. If that one...

Hubble’s Woes, JWST’s Promise

by Paul Gilster | Jan 31, 2007 | Deep Sky Astronomy & Telescopes | 8 Comments

With its Wide Field Planetary Camera 2, Near Infrared Camera Multi-Object Spectrograph (NICMOS), and Fine Guidance Sensors still operational, the Hubble Space Telescope isn't exactly blind. But the loss of the Advanced Camera for Surveys would be a serious one, and the bad news is that the next servicing mission, scheduled for mid-2008, probably won't be able to fix the problem. ACS lived out its five year operational life but dazzling vistas like the Ultra Deep Field make us yearn for more. Hubble's other instruments are still doing good science. Recall that the UDF itself is actually made up of images from the ACS and NICMOS, leading Centauri Dreams to believe that many observational programs will go forward after adjusting to the change in instrumentation. As always, we make a virtue of necessity, a phrase first recorded by Chaucer that resonates even now in the realm of deep space exploration. Meanwhile, we receive more positive news from the testing of the James Webb Space...

A Close Eye on Fomalhaut

by Paul Gilster | Jan 30, 2007 | Deep Sky Astronomy & Telescopes | 6 Comments

It took six years to develop the design for the 'microshutters' that will fly aboard the James Webb Space Telescope. They will work with its near infrared spectrograph to screen out light from foreground objects. The advantages are enormous: The Webb telescope will be able to adjust its light mask with exquisite precision, something that previous technologies could not achieve to anywhere near this level of performance. We're talking thousands of tiny shutters -- 62,000 to be exact -- each measuring 100 by 200 microns, arranged in four identical grids. They'll function in front of an eight million-pixel detector, allowing only the light from the specific areas under observation to reach the instrument. Moreover, the new technology greatly widens the efficiency of the instrument in terms of observational time. Says Harvey Moseley (principal investigator for the microshutter at GSFC): "The microshutters provide a conduit for faint light to reach the telescope detectors with very little...

Hot Jupiters: The Metallicity Question

by Paul Gilster | Jan 29, 2007 | Exoplanetary Science | 8 Comments

A globular cluster is a glorious thing. Consider Omega Centauri, a vast city of stars about 15,000 light years from Earth. Clusters like this one are composed of millions of Population II stars, meaning they're among the oldest observed stars and may date back as far as twelve billion years. A result of their early formation is that they remain deficient in metals (in astronomical terms, the elements above hydrogen and helium), making them ideal laboratories for a particular branch of exoplanet studies. Image: This image of Omega Centauri, the brightest and largest globular cluster in the sky, was obtained with the Danish 1.5 m telescope at the ESO La Silla observatory. It shows the central part only; the cluster is actually much larger than the field reproduced here. Credit: European Southern Observatory. A growing assumption about the massive 'hot Jupiters' we've found in our early planet hunting is that their existence depends upon a relatively high metallicity in their host star....

First Views of 21-Lutetia

by Paul Gilster | Jan 27, 2007 | Outer Solar System | 4 Comments

Centauri Dreams' view is that the more we can learn about asteroids, the better. And the interest isn't purely scientific. One day we may have to set about nudging an approaching asteroid so as to prevent a collision with Earth, and if that day comes, we'll need to have a plan in place that depends upon a thorough understanding of these objects and their composition. In the long run, asteroid studies are anything but optional. The European Space Agency's Rosetta mission is filling in some of the gaps enroute to comet 67P Churyumov-Gerasimenko. In its sights are two asteroids -- 2867-Steins and 21-Lutetia -- orbiting between Mars and Jupiter. We'll learn a lot more about both between now and July of 2010, by which time Rosetta will have viewed each at close range. Meanwhile, the spacecraft has taken a first look at 21-Lutetia using the onboard OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) instruments. At the time of its observations, the vehicle was roughly 245...

The Big Questions Explored

by Paul Gilster | Jan 26, 2007 | Culture and Society, Exotic Physics | 1 Comment

Sometimes what we don't know is more interesting than what we do. I'm always confounded when I hear people lay out confident scenarios for the human future, each different from the next, when we're still at a stage where we don't even know what the universe is made of. While we're figuring out dark matter and (even worse) dark energy, we can answer some of the other big questions looked at in this article in Wired. What happens to information in a black hole? What causes gravity? How do entangled particles communicate? Some significant names tackle these questions -- not all cosmological by any means -- in entertaining form.

Toward a Soft Machine

by Paul Gilster | Jan 26, 2007 | Autonomy and Robotics | 3 Comments

When Project Daedalus was being designed back in the 1970s, the members of the British Interplanetary Society who were working on the starship envisioned it being maintained by 'wardens,' robots that would keep crucial systems functional over the 50-year mission to Barnard's Star. Invariably, that calls up images of metallic machines, stiff in construction and marked by a certain ponderous clumsiness. True or false, it's a view of robotics that has persisted until relatively recently. But if you're going to do long-term maintenance on a starship, you'd better be more flexible. And that makes a Tufts initiative interesting not just from a space perspective but for applications in medicine, electronics, manufacturing and more. The Biomimetic Technologies for Soft-bodied Robots project aims to produce machines that draw on the model of living cells and tissues. Five Tufts departments will work with a $730,000 grant from the W.M. Keck Foundation to get the job started. Check out what's...

A Cometary Transformation

by Paul Gilster | Jan 25, 2007 | Outer Solar System | 10 Comments

Somehow I missed Mike Brown's recent thoughts on 2003 EL61, the oddly elongated Kuiper Belt object that's as big as Pluto along its longest dimension. Fortunately, the BBC recently covered the story. At the American Astronomical Society meeting in Seattle, Brown (Caltech) had discussed the instability of the object's orbit, pointing out that it is headed for an eventual encounter with Neptune. A possible outcome: Two million years from now, 2003 EL61 may be a comet. "When it becomes a comet," says Brown, "It will be the brightest we will ever see."

First Light for COROT

by Paul Gilster | Jan 25, 2007 | Exoplanetary Science | 3 Comments

The COROT space telescope doesn't start scientific observations until February, but the protective cover of the 30 centimeter instrument has now been opened. So far so good. A preliminary calibration exercise -- using the constellation of the Unicorn near Orion -- delivers data of excellent quality. This news from the European Space Agency should keep exoplanet hunters primed as the search for transiting worlds takes to space. A diagram of COROT's interesting orbit can be found here.

‘Light Science’ Finds Titan Jet Stream

by Paul Gilster | Jan 25, 2007 | Outer Solar System | 2 Comments

When I interviewed the Jet Propulsion Laboratory's James Lesh several years ago, he explained how space scientists could use radio signals to do science. It's the ultimate technique for taking advantage of what's at hand. If your spacecraft is moving behind a planet it's investigating as seen from Earth, the changes to its signal as it disappears behind the disk tell you much about the composition of the planetary atmosphere. "One person's noise," said Lesh, "is another person's signal." Of course, that kind of work isn't limited to radio. Twice on November 14, 2003 Titan passed in front of a star, the events separated by just seven and a half hours. As you would expect, the occultation tracks were different, one visible from the Indian Ocean and southern Africa, the other from the Americas and western Europe. The effects of Titan's atmosphere on the starlight have, in each case, supplied information about the movement of gases around the frigid world. This work required observations...

Tweaking the Past

by Paul Gilster | Jan 24, 2007 | Exotic Physics | 1 Comment

It was Richard Feynman who proposed that particles like positrons -- the antimatter equivalent of the electron -- were actually normal particles traveling backward in time. Feynman would develop the idea with John Wheeler, and it continues to resonate with John Cramer (University of Washington), whose 'transactional' interpretation of quantum mechanics works with particle interactions that depend upon movement forward and backward in time. In December we looked at an experiment Cramer is developing to study this effect, which is best known as retrocausality. So it's nice to see that Patrick Barry's fine article on Cramer's work, and retrocausality in general, is available online from the San Francisco Chronicle. Originally written for New Scientist, the article is thus freed from that magazine's firewall and available for general access. A snippet: While Cramer last week prepared to start a series of experiments leading up to the big test of retrocausality, some researchers expect...

SETI and Its Critics

by Paul Gilster | Jan 24, 2007 | Astrobiology and SETI, Culture and Society | 8 Comments

From the Paramus Post, a story by Bruce Lieberman looks at contrasting views of SETI: On both sides of the SETI debate, scientists acknowledge that what's certain is the limit of what they know. "I personally think that because the origin of life is an extremely difficult process ... even simple life is very rare in the galaxy," Zuckerman said. "But I have no particular claims other than my gut feeling." Shostak has publicly debated Zuckerman on the issue, and he remains confident that future searches will make contact. "I doubt that I would conclude that nobody's out there," he said. "To me that seems like a last-resort option. But that's simply my feeling on the matter. And my feeling on the matter ... actually means nothing because what counts is what you can find. "That's the difference between science and belief." A quick overview of the topic, available here.

A World Lit by Three Suns

by Paul Gilster | Jan 23, 2007 | Exoplanetary Science | 12 Comments

Habitable planets in multiple star systems are one of science fiction's great tropes. Find a second star somewhere in the daylight sky and you know you're not in Kansas anymore. It makes slow going today, but as a kid I was struck with William F. Temple's The Three Suns of Amara (1962), a story whose questionable science and creaky plot was somewhat mitigated by its striking imagery. For Amara managed to weave its orbit through a triple star system in which each star was a different color. Talk about great visual effects! Image: My battered copy of Temple's The Three Suns of Amara, rescued from a closet. Not the best novel I've ever read, but it did instill a lifelong fascination with habitable planets in multiple star systems. Yesterday we looked at Elisa Quintana's work on habitable planets in binary systems, and while reviewing for that story, I found Temple's Amara again coming to mind. For it turns out we do have five confirmed exoplanets known to orbit one member of a triple...

Binary Stars and Terrestrial Worlds

by Paul Gilster | Jan 22, 2007 | Exoplanetary Science | 12 Comments

The findings about possible terrestrial worlds around the Alpha Centauri stars have become more encouraging than ever. Key work in this regard has been performed by Elisa Quintana and collaborators, who have shown in their simulations that, depending on initial disk inclinations, 3-5 such planets might form around Centauri A and 2-5 around Centauri B. We've already discussed that research and I don't want to linger on Quintana's 2002 paper (reference below) other than to note one interesting comparison. When the same initial disk parameters are placed around a single star like the Sun, the accretion of the planetary disk occurs over a much larger expanse of time. Evidently a stellar companion hastens the process of planetary formation, one billion years in the case of the Sun vs. perhaps 200 million years in the Centauri scenario. Quintana, Jack Lissauer (both at NASA Ames) and team went on from that study to look at planet formation around close binaries. And they've now turned to...

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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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