Deep Space Challenge: Shrinking the Tools

by | Nov 10, 2006 | | 8 Comments

Shrinking our instrumentation is one of the great hopes for extending spacecraft missions into the Kuiper Belt and beyond. No matter what kind of propulsion system we're talking about, lower payload weight gets us more bang for the buck. That's why a new imaging system out of Rochester Institute of Technology catches my eye this morning. It will capture images better than anything we can fly today, working at wavelengths from ultraviolet to mid-infrared. It also uses a good deal less power, but here's the real kicker: The new system shrinks the required hardware on a planetary mission from the size of a crate down to a chip no bigger than your thumb. The creation of Zeljko Ignjatovic and team (University of Rochester), the detector uses an analog-to-digital converter at each pixel. "Previous attempts to do this on-pixel conversion have required far too many transistors, leaving too little area to collect light," said Ignjatovic. "First tests on the chip show that it uses 50 times...

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Probing Distant Atmospheres for Life

by | Nov 9, 2006 | | 2 Comments

Hunting for terrestrial planets is not going to be easy, and even when we start getting images of such worlds, there will be plenty of questions to answer. How to detect life on a terrestrial planet was one of the subjects that came up in September at the Pale Blue Dot workshop at Adler Planetarium in Chicago. Cassini's recent picture of Earth from Saturn space, much like Voyager's 'pale blue dot' image of 1990, reminded everyone at the conference of our fragile place in the cosmos. It also forced the question of how we might find other such worlds. And finding a blue planet in a star's habitable zone isn't enough. As laid out in this JPL backgrounder, the key will be to gather enough spectral data to make a judgment call that could change how we view our place in the universe. Breaking down the light from a distant planet should tell us much about its chemical composition. Carbon dioxide and water vapor, for example, are both clues to life, their dual presence suggesting both an...

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A Spectacular View of Orion

by | Nov 8, 2006 | | 1 Comment

Though I hadn't planned another entry for today, this is just too beautiful to pass up. We're looking at the Orion nebula (be sure to click the image to enlarge) in infrared, ultraviolet and visible light, a composite using both Hubble and Spitzer data that brings out unheard of detail -- the green swirls are from Hubble's ultraviolet and visible light detectors; the red and orange are Spitzer working in the infrared. This massive star formation region located in the sword of Orion is home to about 1000 young stars. Note the set of stars called the Trapezium, identifiable as a bright area near the center of the image. Each of these massive stars pours out ultraviolet that heats hydrogen and sulphur in the nebula. The stellar wind from clusters of stars embedded in the dust and gas helped to create the distinctive shapes and swirls of this celestial artwork.

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Titan’s Haze May Mimic Early Earth’s

by | Nov 8, 2006 | , | 1 Comment

Titan's atmosphere may be telling us something about conditions on the early Earth. It's thick and filled with interesting things like organic aerosol particles that form through the reaction of sunlight with methane gas. Translate that into terrestrial terms and you get a similarly hazy early Earth whose surface receives more than 100 million tons of organic materials every year. "As these particles settled out of the skies, they would have provided a global source of food for living organisms," said Melissa Trainer (University of Colorado - Boulder). Trainer is principal author of a new paper that examines the chemical qualities of these aerosol particles in the laboratory, studying their chemical composition, size and shape. The method: expose a mixture of methane and nitrogen to ultraviolet light, then add carbon dioxide to see if organic haze forms. And indeed, the haze forms readily in a wide range of methane and carbon dioxide concentrations. That smoggy sky over Titan may be...

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Flares, Asteroids and Extinctions

by | Nov 7, 2006 | | 5 Comments

Imagine our Sun spewing out a flare 100 million times stronger than usual, releasing the energy of 50 million trillion atomic bombs. The effect on our planet would be catastrophic. Fortunately, what the Swift satellite has spotted occurred a bit further away in a binary system called II Pegasi, some 135 light years from Earth. Swift is designed to detect gamma-ray bursts -- the most powerful of all explosions -- and this flare was energetic enough to produce a false alarm for such a burst. NOTE: The original entry here referenced the power of 'fifty trillion' atomic bombs; the actual figure used by NASA was corrected, as above, to 'fifty million trillion.' Thanks to Robin Goodfellow for catching the typo. II Pegasi is an interesting system. The flare star is 0.8 times the mass of the Sun; its companion is 0.4 solar masses, and the stars are separated by only a few stellar radii. That produces fast rotation on both stars, and while II Pegasi may be a billion years older than the Sun,...

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Followup on the Red Dwarf Planet Hunt

by | Nov 7, 2006 | | 0 Comments

Jacob Bean, lead author of the paper on red dwarfs discussed here yesterday, weighs in with additional useful information about the study. "The planet-metallicity connection has been firmly established for high-mass (Jupiter and super Jupiter) planets," wrote Bean. "I believe there is not supposed to be a low-mass, including terrestrial, planet formation dependence on disk metallicity (except in the very extreme case of zero metal disks)." The upshot: pre-selecting M dwarfs for possible terrestrial planets still isn't possible based on metallicity, though it may be predictive of gas giant worlds. The expanding dataset on M dwarf metallicity should eventually tell us more.

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Red Dwarfs and Their Planets: A New Puzzle

by | Nov 6, 2006 | | 8 Comments

What kind of stars are most likely to have planets? Narrowing the search is crucial if the goal is to build a target list for space-based missions, especially when we're looking for terrestrial worlds. So learning that planet-bearing stars have higher metal contents -- the elements above hydrogen and helium, presumably as a relic of their protoplanetary disks -- would winnow the target list nicely, at least among Sun-type stars. And most of the extrasolar planets found thus far have been in orbit around stars of the spectral types F, G and K (our Sun is a G-class star). For various reasons, these are the usual targets for radial-velocity surveys, and they're also stars that can be readily analyzed for metallicity. But M dwarfs are the most common stellar type. We need to go to work on their parameters too, especially in the case of dwarfs that have known planetary companions. A stride in that direction is taken by Jacob Bean (University of Texas), Fritz Benedict and Michael Endl...

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Remembering Camille Flammarion

by | Nov 4, 2006 | | 5 Comments

Science writer Larry Klaes passed along a quote from French astronomer and writer Camille Flammarion that he posted in the SETI League's BioAstro list. It speaks nicely to the power of telescopes over the human imagination, even if it reminds us that the pleasures these instruments give often get lost in the distractions of everyday life. Here's the quote: "What intelligent being, what being capable of responding emotionally to a beautiful sight, can look at the jagged, silvery lunar crescent trembling in the azure sky, even through the weakest of telescopes, and not be struck by it in an intensely pleasurable way, not feel cut off from everyday life here on Earth and transported toward that first stop on celestial journeys? "What thoughtful soul could look at brilliant Jupiter with its four attendant satellites, or splendid Saturn encircled by its mysterious ring, or a double star glowing scarlet and sapphire in the infinity of night, and not be filled with a sense of wonder? Yes,...

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The New Worlds Starshade

by | Nov 3, 2006 | , | 8 Comments

Finding planets around other stars is tricky enough, but actually getting images of them is all but impossible. That's why Centauri Dreams has been so fascinated with the starshade concept, and with one particular design for it, called (depending on the mission) New Worlds Discoverer, New Worlds Observer or New Worlds Imager. We saw recently that Webster Cash (University of Colorado at Boulder) had been pitching NASA to do a concept study on New Worlds for a Discovery-class mission, but the proposal didn't make the cut, in this round at least. That's disappointing, but as Cash told me in an interview earlier this year, "If we don't win this one, we'll win the next one." There is reason for such optimism because the New Worlds mission designs offer many of the benefits of the Terrestrial Planet Finder mission once slated for this kind of work at a fraction of the cost, and as I mentioned earlier this week, New Worlds has the potential of working with the James Webb Space Telescope to...

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Unshrouding the Large Magellanic Cloud

by | Nov 2, 2006 | | 5 Comments

Learning how interstellar dust turns into stars is a major challenge. But the AKARI satellite, an infrared observatory created by the Japan Aerospace Exploration Agency, could become a breakthrough tool in these studies. Launched in February of this year, AKARI is engaged in an infrared All Sky Survey, with spectacular early results from the Large Magellanic Cloud. The far-infrared image shown below shows that clouds of dust are found throughout this satellite galaxy of the Milky Way. Image: This false-colour view of the Large Magellanic Cloud is a composite of images taken by AKARI at far-infrared wavelengths (60, 90 and 140 microns). The Large Magellanic Cloud is a neighbour galaxy to the Milky Way. Interstellar clouds in which new stars are forming are distributed over the entire galaxy. The bright region in the bottom-left is known as the 'Tarantula Nebula' and is a productive factory of stars. Credit: JAXA. Infrared is ideal for these studies because stars tend to form within...

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Globular Clusters: Seeding the Universe?

by | Nov 1, 2006 | , | 18 Comments

The view from inside a globular cluster has been the subject of recent speculation here, and I figure the man to imagine it is the gifted space artist Jon Lomberg. My new goal is to convince Jon to paint such a scene. They're surrounded by beauty, as Jon's painting would surely show, but would planets in these ancient clusters be inhabitable? Perhaps, but the stars in a cluster like M15 should also be ancient and metal-poor, meaning that planets around them may well be barren of life. In astronomical terms, anything heavier than hydrogen and helium is a metal, and it's long been thought that supernovae explosions are what spewed abundant metals out into the universe, resulting in more robust stars and solar systems like our own, where interesting chemical bonds begin to form. Hence the famous Saganism: 'We are star-stuff.' But new work at the University of Minnesota now points to an even richer conclusion. Using the Spitzer Space Telescope, a team led by Charles Woodward and Martha...

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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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