December 2008

A New Angle on Dark Energy

December 18, 2008

The best news about recent dark energy findings is that they offer new ways to study the phenomenon. It’s only been ten years since dark energy — thought to be the origin of the universe’s accelerating expansion — emerged from the study of supernovae. Simply put, these exploding stars weren’t slowing as they moved away [...]

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Life Beyond the Snow Line

December 17, 2008

The nice thing about our conventional idea of a habitable zone is that liquid water can exist on the surface. The less helpful part of that definition is that water is more readily available much further out in a planetary system, where it usually shows up as ice. Think in terms of the ‘ice line,’ [...]

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Giuseppe Cocconi, SETI Pioneer

December 16, 2008

By Larry Klaes Tau Zero journalist Larry Klaes gives us a look at the immense contribution of physicist Giuseppe Cocconi to SETI. It’s sobering to realize how new a study SETI really is. Frank Drake’s Project Ozma began less than fifty years ago, while estimates of the number of extraterrestrial civilizations are just now scaling [...]

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Habitability Around Red Giants

December 15, 2008

The prospect of habitable planets around red giant stars fires the imagination, enough so that quite a few readers forwarded me the link to a recent paper looking at this question. I’m reluctant to speak for others, but I suppose a major reason we’re so interested (and I, too, had flagged the paper as soon [...]

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Europa: Tides of Life?

December 13, 2008

Europa is interesting enough without throwing in a new theory about energy sources. But Robert Tyler (University of Washington) has been studying the possibilities in Europan tides, using computer simulations that offer a different way of getting energy out of this icy world. We’ve speculated that Europa experiences enough tidal flex from Jupiter to create [...]

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Brown Dwarf Observations and Speculations

December 12, 2008

It’s tantalizing to speculate that there might be a brown dwarf system nearer to us than the Alpha Centauri stars. The odds seem long, but the discovery of a pair of brown dwarfs that are each no more than a millionth as bright as the Sun makes for exciting reading. The objects were originally cataloged [...]

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Carbon Dioxide Found on Distant World

December 11, 2008

Among the many things that boggle my mind is the fact that we can learn things about the atmosphere of planets that we can’t even see. Take well-studied HD 189733b, a gas giant in close orbit around a K2-class star some 63 light years from us. No one has ever laid eyes on this beast, [...]

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Alpha Centauri Back in the News

December 10, 2008

Here I was all set to write about the discovery of carbon dioxide on HD 189733b when Alpha Centauri made its way back into the news. Twentieth Century Fox will be transmitting the re-make of the science fiction classic The Day The Earth Stood Still to Alpha Centauri on Friday the 12th, timing the event [...]

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A Micro-Fusion Descendant of Daedalus

December 9, 2008

Back in 1966, the Jet Propulsion Laboratory’s Dwain Spencer laid out the principles of a fusion engine that burned deuterium and helium-3 (an isotope of helium with a nucleus of two protons and one neutron). Deuterium and helium-3 make a good combination for rocket propulsion because a fusion-based drive based on them releases one-hundredth the [...]

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Two Important New Texts

December 8, 2008

Caleb Scharf is director of the Columbia Astrobiology Center and author of a new book I intended to mention in Saturday’s Notes & Queries section before running out of time. I want to be sure to insert it now, because if you’re getting serious about the study of astrobiology, you’ll want to know about this [...]

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