SNAP: Probing Dark Energy

by | Sep 10, 2007 | | 3 Comments

Saul Perlmutter, Brian Schmidt and their respective teams received the Gruber Cosmology Prize last Friday at the University of Cambridge. Doubtless the awards will keep coming, for these are the researchers who discovered, more or less simultaneously, that the expansion of the universe was accelerating. That, in turn, gives us a look at the far future, suggesting that the universe will expand faster and faster forever. It hasn't even been a decade since the discovery was announced, but now we routinely discuss a dark energy force that seems to account for three-quarters of the density of our universe, a dazzling notion that recapitulates Einstein's cosmological constant and humbles us with the thought that, between dark energy and dark matter, we see only four percent of what is actually out there. Needless to say, interstellar theorists note with interest the idea of an effect that seems to oppose gravity itself. If such things exist, will we one day make enough sense of them to...

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Notes & Queries 9/8/07

by | Sep 8, 2007 | | 7 Comments

What would be the best design for a submarine that could explore the deep and possibly life-bearing ocean beneath Europa's ice? Carl Ross (University of Portsmouth, UK) has been pondering the matter, proposing a 3-meter long cylindrical vehicle made perhaps of a ceramic composite to offer the best combination of strength and buoyancy. And for getting through the ice itself? "It may be that we will require a nuclear pressurized water reactor on board the robot submarine to give us the necessary power and energy to achieve this." Details to be found in A Submarine for Europa, recently published on Universe Today. ------- If your sense of wonder could use the occasional jolt (and this can happen to us all), do check out the work of another Ross, Aaron by name. The film student has put together a terrific short (first noted here on The Discovery Enterprise) based on Arthur C. Clarke's Rendezvous with Rama. Ross manages to capture in just a few minutes the mystery and majesty surrounding...

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A Planet-wide Telescope Array

by | Sep 7, 2007 | | 8 Comments

Following up on yesterday's news about spectrometer advances at the Automated Planet Finder installation at Lick Observatory comes news of a different kind of telescope breakthrough. A radio telescope in Shanghai was linked via computer network to a five telescopes in Europe and another in Australia to study the active galaxy 3C273. A galaxy with a major black hole at its core is obviously interesting, but what stands out in the recent experiment is the working procedure. Never has very long baseline interferometry been pushed to such extremes. Image: Widely spaced telescopes combine their data to boost resolution, creating a kind of 'world telescope.' Credit: Paul Boven/JIVE. Satellite image: Blue Marble Next Generation, courtesy of NASA Visible Earth (visibleearth.nasa.gov). The idea of interferometry is straightforward: Combine signals from multiple telescopes to produce higher resolution data than could be obtained by any of the telescopes individually. Spread your telescopes out...

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APF: Boosting the Terrestrial Planet Hunt

by | Sep 6, 2007 | | 4 Comments

It's long been my belief that getting more private money into space research is essential, given the uncertainties of government funding and the need to inject outside ideas and enthusiasm into the game. We're already seeing what will, I think, become explosive growth in commercial rocket ventures aimed at finding cheaper and better ways to reach low-Earth orbit. On the interstellar front, the Tau Zero Foundation is being built to parlay philanthropic donations into a solid base for funding cutting edge research into advanced propulsion technologies. The hunt for exoplanets also partakes of this largesse, as witness a $600,000 gift from the Gloria and Kenneth Levy Foundation that will fund a new spectrometer designed for the Automated Planet Finder being built at Lick Observatory. The instrument will check twenty-five stars every night, studying 2000 stars within 50 light years over the next decade. Doppler shifts in the wavelengths of starlight provide the telltale signs of an...

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Asteroid Breakup May Have Doomed Dinosaurs

by | Sep 5, 2007 | | 1 Comment

It's a disaster scenario that Hollywood has picked up on (think Deep Impact). An incoming object menaces the Earth. Scientists try to destroy it with nuclear weapons, but the horrified populace soon discovers that the blast has simply broken the object into pieces, each with the potential to wreak havoc planet-wide. Now we learn that an impact between two asteroids causing a similar crack-up may have resulted in the cataclysmic event some 65 million years ago that destroyed the dinosaurs. Researchers from Southwest Research Institute and Charles University (Prague) have been studying the asteroid (298) Baptistina, combining their observations with numerical simulations to model the impact event. As the theory goes, Baptistina's parent body, some 170 kilometers in diameter, was hit by another asteroid approximately 60 kilometers wide. The result: The Baptistina asteroid family, a cluster of fragments in similar orbits that once included 300 bodies larger than 10 kilometers and 140,000...

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Recent Progress on Solar Sails

by | Sep 4, 2007 | | 12 Comments

'Leave the propellant at home' is a key maxim of deep space exploration. If we can find ways to substantially reduce or even eliminate the need for on-board fuel tanks, we maximize the payload and enable missions that would otherwise be impossible. In the near term, solar sails are the ideal way to realize this goal. Driven by the momentum transfer of solar photons, sails can achieve high speeds and, by tacking methods that are in ways analogous to conventional ocean sailing, can move to and fro in the Solar System on their free photon ride. Laser and microwave beaming to sails is another thing entirely. We'll one day use those technologies for extended missions into the Kuiper Belt and the Oort Cloud and, if the dreams of some theorists come true, perhaps for interstellar missions at ten percent of light speed. But all that depends upon learning how sails work, and on that score, it's useful to know of the continuing NASA work on sail technologies. A recent paper by Les Johnson, Roy...

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Life from Interstellar Dust?

by | Sep 3, 2007 | | 7 Comments

Does adenine, a key organic molecule, occur in interstellar dust clouds? If so, those clouds could have delivered the molecule to Earth billions of years ago, a possibility interesting not only in terms of life's formation on this planet but, of course, on other worlds as well. And as University of Missouri chemist Rainer Glaser notes, the idea of space-borne adenine is not implausible, for adenine is known to occur in meteorites and was identified in 1986 in the organic mantle surrounding comet Halley's core. Could adenine have been synthesized on the early Earth? Perhaps, but there are reasons for finding an outside delivery mechanism provocative. Note this from the paper on this work, which appeared in the journal Astrobiology (internal references omitted for brevity). HCN refers to hydrogen cyanide, which can flag the presence of adenine: The idea of prebiotic adenine synthesis on Earth remains controversial. The HCN-based syntheses rely on the presence of a reducing atmosphere,...

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Notes & Queries 9/1/07

by | Sep 1, 2007 | | 1 Comment

The Sun's evolution from protostar to stability on the main sequence, then red giant and, finally, white dwarf plays out over a bit more than twelve billion years, according to figures provided by Adam Crowl. Earth, of course, dies long before the white dwarf stage; in fact, life a mere billion years from now will be getting seriously problematic on Terra. Could future civilizations engineer a longer lifetime by controlling the Sun's energy? This ingenious post on Crowlspace runs through the options, from inducing convection via magnetic manipulation to controlling gravitational collapse. 20 trillion years of energy hang in the balance. ------- "The arts and sciences are connected," sys Ray Bradbury. "Scientists have to have a metaphor. All scientists start with imagination." True enough, and those mind-bending tales of Martian cities and a thousand other fantastic notions never relied heavily on scientific accuracy. But they challenged us all to dream big dreams, as Bradbury has...

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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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