Starshades and Terrestrial Worlds

A starshade shaped like a daisy? Centauri Dreams remains entranced with the concept, known as New Worlds Imager and now getting renewed attention thanks to the efforts of astronomer Webster Cash (University of Colorado, Boulder). We've seen before that Cash is hoping to land a NASA Discovery-class mission for a starshade that would block the light of a nearby star to reveal the planets around it. The starshade would work in tandem with a telescope mounted on a separate spacecraft 15,000 miles away, with the shade being moved as needed to place it into the line of sight of stars of interest. The result: the ability to image planetary systems including terrestrial worlds, and even to analyze exoplanetary atmospheres. Cash's latest thoughts on the subject appear in the July 6 issue of Nature, where he describes a starshade some 50 yards in diameter and its associated space telescope. Both could be launched into an orbit roughly a million miles from Earth, where shade and telescope could...

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Marc Millis Interviewed on Cosmic Log

An interview with Marc Millis, founder of the Tau Zero Foundation, was posted yesterday on Alan Boyle's Cosmic Log on the MSNBC Web site. After discussing the so-called 'antigravity' phenomenon known as the Podkletnov effect, which has been called into serious question by recent studies that found no evidence for it, Millis went on to discuss other, more intriguing research. From the interview: Millis is more interested in research into the Woodward effect - "a transient inertia effect" that could eventually have implications for propulsion, if verified - as well as a more recent study of "a fairly large gravitomagnetic effect, too large to be explained with general relativity as we understand it so far." He cautioned that "we're not talking about an immediate propulsive effect, and it might be a measuring artifact." But at least the research illustrates that there are still mysteries out there that could someday turn those science-fiction dreams into practical starflight. Centauri...

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Proxima Centauri and Habitability

So much good material has run lately on planet-hunter Gregory Laughlin's systemic site that Centauri Dreams feels seriously remiss in returning to it so infrequently. So there is catching up to do, but we focus today on Laughlin's new work, with UCSC graduate student Jeremy Wertheimer, on an intriguing question about Proxima Centauri. Is the tiny star in fact gravitationally bound to Centauri A and B? Surprisingly, much recent work has suggested otherwise, including a 1993 paper by Robert Matthews and Gerard Gilmore that set the tone for Proxima research in that decade. But Laughlin notes that the European Space Agency's Hipparcos satellite has firmed up our knowledge of the position, distance and velocity of nearby stars, enough to demand a new look at this question. After all, Proxima is roughly 15,000 AU from the Centauri binaries, and shows only a small velocity relative to them. It would seem unlikely these stars would not be bound into a triple system, and Laughlin and...

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A Primordial Blob of Dark Matter?

When I was growing up, 'blob' was a word associated with a classic horror movie starring none other than Steve McQueen. Today, blobs are starting to show up in astronomical discussions. Exactly what they are is unknown, but they seem to be as large as galaxies and marked by low luminosity. The latest, an apparently energetic but not very bright object some 11.6 billion light years away, is fully twice the size of our Milky Way and emits the energy of some two billion suns. It is, nonetheless, invisible in images from telescopes looking all the way from the infrared to the x-ray wavebands. How do you find invisible blobs? Astronomers working with the European Southern Observatory's Very Large Telescope used a narrow-band filter with the FORS1 spectrograph that allowed them to observe emissions from hydrogen atoms. Applying energy to hydrogen atoms causes their electrons to make a quantum leap to a higher energy level. Upon return to their initial state, the electrons release excess...

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Closing in on Beta Pictoris

Back in 2003, while researching Centauri Dreams, I interviewed physicist Geoffrey Landis at Glenn Research Center in Cleveland. At that time, Landis' office was packed with Mars images, apropos for a man who had done so much work on rover technology. I asked him whether, after all this study, Mars had taken on the aspect of a real place to him, like Cleveland. Not surprisingly, he said that it had, and he credited 3-D images from Mars Pathfinder for that. Wearing glasses, Landis said, "It was as if you were standing on Mars. You could see ups and downs, ridges and valleys. That changed the view of Mars from another planet to a place you could go out and walk around." We're a long way from 3-D close-ups, but I suspect some astronomers are starting to feel that way about Beta Pictoris, a young star some 63 light years away in the southern constellation Pictor that first drew attention to itself because of excess infrared radiation. A warm circumstellar disk was surely the cause, and...

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Interstellar Migration and the Human Experience

Centauri Dreams returns to its normal schedule on Monday, following a week devoted to the emergence of the Tau Zero Foundation. Next week will be a busy one, with a new and significant study of Proxima Centauri, a more detailed than ever look at the complicated happenings around Beta Pictoris, and a paper presenting a fast, beamed propulsion mission to Alpha Centauri serving as the highlights. Thanks to all who wrote asking for further information about the Tau Zero Foundation and its plans to support research practitioners in work that may one day lead to interstellar flight. I'll continue to follow Foundation news here as the group works towards the launch of its own Web site. It's heartening to see the spirit of exploration embraced by readers and advocated on the Net, as noted, for example, in this post on Brian Wang's Advanced Nanotechnology site. A snippet: If we had the will we would mount a D-Day scale invasion of space. The current space effort, as noble as it has been, was...

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Charter

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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If you'd like to submit a comment for possible publication on Centauri Dreams, I will be glad to consider it. The primary criterion is that comments contribute meaningfully to the debate. Among other criteria for selection: Comments must be on topic, directly related to the post in question, must use appropriate language, and must not be abusive to others. Civility counts. In addition, a valid email address is required for a comment to be considered. Centauri Dreams is emphatically not a soapbox for political or religious views submitted by individuals or organizations. A long form of the policy can be viewed on the Administrative page. The short form is this: If your comment is not on topic and respectful to others, I'm probably not going to run it.

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