July 2006

Finding Hidden Black Holes

July 31, 2006

The super-massive black holes thought to lurk in nearby galaxies present us with a problem. They should suck in surrounding gas and dust to produce x-rays, and it has been the assumption that black holes hidden by such materials, also known as ‘Compton-thick objects,’ are responsible for much of the overall x-ray background. Yet an […]

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Extraterrestrial Inflows and Ice Ages

July 29, 2006

40,000 tons of extraterrestrial matter are believed to hit the Earth every year. This from the current issue of Science, where researchers from New York (Columbia University) and Bremerhaven (Alfred-Wegener-Institut) present a study of helium isotopes found in Antarctic ice cores. Over the last 30,000 years, the scientists believe, the amount of 3He, a rare […]

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A Fine Drizzle on Titan

July 28, 2006

The current issue of Nature features a look at Huygens data with a big payoff: rain is falling on Titan, continues to fall as we speak, and will probably keep falling for a long time. Says Christopher McKay (NASA Ames), a co-author of the paper, “The rain on Titan is just a slight drizzle, but […]

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Zoom in on COSMOS

July 27, 2006

We are entering a great era when it comes to research tools for the study of deep space. But as new technologies create datasets we’re able to distribute globally, we need to consolidate our gains to make them available to broader audiences. That’s why the creation of a Web-based utility called COSMOS SkyWalker is such […]

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55 Cancri: Modeling a Terrestrial World

July 26, 2006

For Centauri Dreams, the most exciting part of the exoplanet hunt is the refinement of our models. We know, for example, of numerous planetary systems dominated by gas giants. Now we’re trying to figure out which of these may contain smaller, rocky worlds, and that means learning more about solar system dynamics. A step in […]

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Dust and Planet Formation in T Tauri Stars

July 25, 2006

One of the beauties of the Spitzer Space Telescope is that it can pinpoint the swirling dust disks around distant stars. Such dust, heated by the star, puts out an infrared signature that Spitzer can analyze to a degree hitherto unattainable. Now a team of astronomers has observed some 500 young T Tauri stars in […]

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Calculating the Distance to a Star

July 24, 2006

Centauri Dreams‘ fascination with the history of science occasionally yields to forgetfulness. Which is why this piece on German mathematician and astronomer Friedrich Wilhelm Bessel, runs two days after his birthday rather than on the occasion itself. Bessel (July 22, 1784 – March 17, 1846) would go on to perform remarkable work in the study […]

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Exploration as Necessity

July 22, 2006

“The urge to explore, the quest of the part for the whole, has been the primary force in evolution since the first water creatures began to reconnoiter the land. We humans see this impulse as the drive to self-transcendence, the unfolding of self-awareness. The need to see the larger reality — from the mountaintop, the […]

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A Dead Star Brightens

July 21, 2006

RS Ophiuchi, a binary system some 5000 light years from Earth, has given astronomers plenty to talk about since February, when it suddenly brightened. The phenomenon wasn’t unusual — RS Ophiuchi undergoes periodic outbursts — but this was the first since 1985, allowing powerful radio telescope arrays to study the results. By coordination between radio […]

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Radar Views of Xanadu

July 20, 2006

Xanadu, that bright continent-sized aberration on the surface of Titan, begins to look somewhat familiar in new radar images from the Cassini orbiter. It’s surrounded by darker terrain, cut by rivers and filled with hills and valleys. Cassini could identify a crater, probably created by asteroid impact, and flatter areas into which the rivers flow […]

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