by Paul Gilster | May 29, 2006 | Research Tools
Centauri Dreams continues to champion innovative tools that get scientific findings out to a broader audience. On that score, be aware of QCShow, a freely downloadable player that synchronizes PowerPoint and PDF presentation materials with audio. We’ve discussed this software before, when QCShow’s parent company, New Mexico-based AICS Research, made sessions from NASA’s Institute for Advanced Concepts meeting in 2005 available. Now a weekly series of recorded lectures on astrobiology has launched in this format.
Short of attending a conference on astrobiology yourself, it would be hard to top the list of participants here. Planet hunter extraordinaire Geoff Marcy (University of California, Berkeley) leads off with a 52 minute talk entitled “Exoplanets, Yellowstone & the Prospects for Alien Life.” As the discoverer of roughly 70 of the first 100 exoplanets to be found, Marcy’s thoughts on planetary diversity and its implications for life are well worth hearing, but he’s followed up in coming weeks by, among others, names like Greg Laughlin (UC-Santa Cruz), Webster Cash (University of Colorado), David Grinspoon (Southwest Research Institute) and Matt Golombek (Jet Propulsion Laboratory).
The Astrobiology lecture series can be found here, with archives available. QCShow is a fine tool for distributing this kind of presentation — it is a low-bandwidth solution that focuses on what really counts, the slide show delivered by the presenter coordinated with audio of his or her discussion of the material. My own view is that lectures and conference sessions will one day be routinely distributed through downloadable video files (the burgeoning of digital storage makes it all but inevitable, and preferable to bandwidth-hogging streaming techniques), but as we create that infrastructure, QCShow gets the job done now, and is building expertise for the future dissemination of scientific materials.
by Paul Gilster | May 16, 2006 | Exoplanetary Science, Research Tools |
‘Umbras’ is Latin for ‘shadows,’ and it becomes a fitting acronym for projects to block the light of stars so that astronomers can see the planets around them. The unwound acronym is Umbral Missions Blocking Radiating Astronomical Sources, which refers to both an imaging technique and a class of space missions. The basic idea is this: deploy a space telescope flying in formation with a second, distant companion spacecraft that carries an occulting screen. We’re looking for direct pictures of planets by reducing a star’s glare, and there are a number of projects aimed at making them, including one we’ve discussed here many times, the New Worlds Imager mission championed by Webster Cash.
I pulled both images in this post from the UMBRAS Web site, where these ideas are explored as a way of pooling talent in the disparate occulter community. Remember, almost everything we know about exoplanets has come from radial velocity studies, microlensing and planetary transits. At best, we are studying variations in starlight that provide solid evidence, but do not yield images or spectroscopy. The next big step in exoplanet observation will surely be direct imaging, even as we continue to make new discoveries with our time-tested methods.
The images are telling. The first (above) shows a bright star whose light obscures the field of view. Any planets around such a star would be drowned in the starshine. The image at left shows the light reduced orders of magnitude by an occulter. Now we can see the light of a possible planet around this star, and if this were an actual photograph, we would be able to measure the planet’s motion and, possibly, take stellar spectra. Clearly, this kind of view takes us into a new realm of exoplanet discovery, and the effort going into finding the best technologies to make this happen should pay off in superior results.
A coronagraph is another way to reduce starshine, but an occulter is not built into the telescope and is thus able to reduce scattered light due to the various optical surfaces and apertures involved. The potential for a clean image is dramatically enhanced. A key problem is to reduce diffraction, which is what happens when light bends around the edges of an object to converge on the opposite side. From the UMBRAS site:
If we consider a square occulter 45 m on a side at a distance of 16,000 km from the telescope, it has a width of 0.58 arcsec. A pattern of light from a blocked star will be visible within the shadow of the occulter. The diffraction pattern within the shadow area will be surrounded by a series of bright and dark (null) fringes with bright diffraction spikes due to straight edges of the occulter.
The goal, then, is to suppress not just the central light from the star being studied, but also to suppress or alter the shape of the diffraction pattern so that planets near the star can be studied. All of this is here conceptualized within the framework of an UMBRAS mission, based on a xenon-based ion thruster propulsion system that would station both telescope and occulter in an orbit around one of the Lagrangian points. This is far enough from the Earth to allow the spacecraft to maintain its alignment without disruptive effects caused by Earth’s gravitational pull. Some design concepts can be found here.
And how would such a mission take shape, once past initial testing? Larger missions might involve the James Webb Space Telescope, as we saw earlier in a study of Webster Cash’s ideas, or (depending on budgetary constraints) smaller space telescopes could be dedicated to the project. With a scalable architecture, an UMBRAS mission might involve relatively small occulters, too, with a screen as minimal as 5-8 meters across, although such a mission would be more technology demonstrator than full-scale mission. Even so, it should be able to observe at least some of the easier targets.
This post is intended to call your attention to the fact that occulter technologies are being approached from a number of different angles. The UMBRAS site offers numerous background papers that should be of use. The key question before us is whether or not an occulter design will be chosen for a planet-finding mission in the relatively near future. From my own reading of Cash’s work and the UMBRAS papers, it seems likely that occulters, especially if capable of working with JWST and therefore not needing a separate telescope, will offer a way to image exoplanets that is much less expensive than older Terrestrial Planet Finder designs.
But more on this tomorrow. As Ian Jordan (Space Telescope Science Institute) has reminded me, the history of occulters is a long and interesting one. I want to probe a little deeper into this subject, and we should look at some of the other ideas posted on the UMBRAS site.
by Paul Gilster | May 1, 2006 | Research Tools |
It’s fascinating to watch as new publishing models unfold using digital tools. Coverage is uneven at present, but the day will come when the average conference makes its proceedings available in audio and video format on the Web, with the once essential printed volume now playing a supporting but still vital role in libraries and on the shelves of researchers. On the journalism side, the growth of weblogs and self-publishing tools makes possible the coverage of stories from a wider variety of perspectives than ever before.
We’re a long way from the demise of printed books, but electronic publishing is beginning to offer new options for authors as well. One harbinger is the arrival of an new e-book called Kosmos: You Are Here, billed as “a look at science, life, evolution, cosmology and other fundamental concepts,” and written by a community of online volunteers with proceeds going to support the YearlyKos political conference this June. Cosmology, geology, evolution and climate science are among the topics discussed, with comments from online posts supplementing the science essays and numerous illustrations.
So can ‘virtual communities’ pull together the artistic and literary talents of their members to challenge what used to happen in large publishing houses? It’s early in that game, but the upcoming release of new electronic book readers from Sony and iRex, both equipped with e-ink technology, is also noteworthy. A segment of the publishing world is looking for ways to extend print into truly readable, powerful small devices, a trend that could help those of us who take Web materials with us as we travel, and should continue to blur the lines between online and off. What’s needed most: a realistic solution to digital rights management problems that have made many purchased e-books useless to their owners when they upgrade devices.
by Paul Gilster | Mar 6, 2006 | Research Tools
It’s a pleasure to report that the proceedings volume for last June’s New Trends in Astrodynamics conference in Princeton has been published. You can find the contents here. Three papers tackled issues with interstellar implications:
Gregory L. Matloff, Travis Taylor, Conley Powell, and Tryshanda Moton, “Phobos/Deimos Sample Return via Solar Sail” Ann NY Acad Sci 2005 1065: 429-440. An examination of sail technologies for a practical mission within the Solar System.
Marc G. Millis, “Assessing Potential Propulsion Breakthroughs,” Ann NY Acad Sci 2005 1065: 441-461. A summary of the methods, findings, and benefit predictions of breakthrough propulsion physics.
Paul A. Gilster, “The Interstellar Conundrum: A Survey of Concepts and Proposed Solutions,” Ann NY Acad Sci 2005 1065: 462-470. A look at the ingenious ways theorists have envisioned taking us to the stars with near-term technologies.
The Princeton event was a marvelous experience (my recollections are online), not just in the chance to talk to Ed Belbruno, whose work I have long admired, but also to have dinner with interstellar theorist Gregory Matloff and his wife, the artist C Bangs, as well as a long and enjoyable breakfast with the Matloffs and Claudio Maccone in Princeton’s Nassau Inn. Next August’s conference should feature a greatly expanded interstellar session, and I’ll have more details on participants as they become available.
by Paul Gilster | Feb 18, 2006 | Research Tools |
Ernst Rutherford once said that a good scientist should be able to explain his work to a barmaid. Rutherford’s point was well-taken. He did not mean to say that every layman could or should be brought to understand the details of every scientist’s experiments. But he did believe that scientists have an obligation to communicate their findings and to keep in touch with the community around them.
Which inspires a reminiscence on the same subject. Back in 1972, I was a graduate student taking a course in Indo-European linguistics, feeling overwhelmed with the details of sound changes as they moved through evolving languages and fascinated with their derivations in the modern world. One day in our campus cafe, I overheard two fellow students from the class discussing their work. Christmas break approached, and one of them observed, “My parents will want to know what I’m studying. How can I possibly explain Indo-European to them?”
And my thought was, if you can’t explain what you’re doing at this stage of your career, why on Earth do you think you can teach this subject later on? Let me add Erwin Schrödinger’s thought on the same subject to Rutherford’s: “If, in the end, you cannot explain your doings to the average person, your doing has been for naught.”
Of course, researchers aren’t necessarily teachers — at least, not happily so — and not everyone finds the time to bring complicated findings into the public arena, leaving that job to public relations departments and science writers. But physicists and astronomers who would like to tune up their communications skills have a wonderful tool at hand. The complete proceedings from the 2005 conference called “Communicating Astronomy with the Public” is available for free download online. Or if the size of this daunting PDF file puts you off, individual papers can be downloaded at this Web repository.
The conference, held at the European Southern Observatory’s headquarters, was a four-day affair attended by over one hundred astronomers, public information officers, science writers and other professionals with a stake in getting science across to the public. Topics ranged from broad issues like “Closing the Culture Gap between Scientists and Science Communicators” to highly specific case studies, such as “Communicating Chandra’s X-ray Astronomy to the Press and Public.” Tucked within these presentations are good ideas for any scientists hoping to explain someone else’s work or refine the public face of their own.
Centauri Dreams‘ note: Conference organizers should note how readily this ESO/ESA/IAU conference has been made available over the Internet. We need to consider how more scientific conferences can open up access in a similar way, not only through Web repositories of the relevant papers, but podcasts of their presentation. The tools for doing these things are becoming trivially simple to use.
by Paul Gilster | Dec 20, 2005 | Research Tools
Springer’s series on astronautical engineering produces expensive books, as the 1999 publication of Colin McInnes’ Solar Sailing: Technology, Dynamics and Mission Applications made clear. There is no more thorough analysis of solar sailing in print, but the title was designed for professionals and printed in small quantity, with a corresponding pricetag. I was able to snag a used copy for about $100, though Amazon now has a few for $70 or so. High quality, high expense information continues to flow, raising the question of how we can open up its pages to a wider audience.
Now Stephen Kemble’s Interplanetary Mission Analysis and Design is out from Springer at $179. Like the McInnes title, it’s a solid, detailed work. Of particular interest is a thorough discussion of gravity assist and transfer techniques, along with sections on deep space communications and navigation that update earlier references. Mission designs from nuclear to ion propulsion are presented along with specific deep space scenarios. Coupled with the second edition of Gregory Matloff’s Deep Space Probes: To the Outer Solar System and Beyond (Springer, 2005), the duo offer a comprehensive if expensive background on today’s state of the art. Any sound engineering library should have these and the McInnes volume on its shelves.
But surely the term ‘on its shelves’ points to the problem. We are not doing a sufficient job at exploiting digital text to broaden the reach of our information. The independent researcher is always bedeviled by this issue. Centauri Dreams is fortunate to have three outstanding universities within easy driving distance; library access to even the most obscure journals isn’t a problem, though finding the time for the needed library trip sometimes is. Online, some key journals can be found in full-text format, others by abstract only, and this is with full access to proprietary databases, which those without academic connections are unlikely to have. As for books, I can get to the Springer titles listed above (and usually cough up the money to keep such titles on my shelves anyway), but note how restricted the availability of such volumes is for those out of university range.
I’m now studying the excellent OpenReader concept that is producing XML standards for electronic texts. The ThoutReader software produced by OSoft is a superb platform for onscreen reading and research; OSoft also intends to produce a free e-text reader in early 2006, one that embraces the OpenReader standards. Because of their implications for cost-effective publishing and broadened information access, I will be keeping a close eye on these projects here on Centauri Dreams. We are a long way from having a true digital library, but projects like these show that good people are working on breakthroughs. You should also be aware of David Rothman’s excellent Teleread weblog; Rothman is a key player in OpenReader and a tireless advocate for a national digital library system.
