September 2008

500,000 Near Earth Objects?

September 30, 2008

Are we going to detect 500,000 near-Earth objects in the next fifteen years as technologies improve? The Association of Space Explorers thinks so, and lays out its view of the danger we face from asteroids and other near-Earth objects in a new report. I’m looking through an executive summary of Asteroid Threats: A Call for […]

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Musings on the Ages of Man

September 29, 2008

Centauri Dreams takes an optimistic view of the human future, one in which interstellar flight becomes a reality at some point in this millennium. My impression is that we’d all better be optimists. Think about the Drake Equation. Perhaps its most significant variable is the lifetime of a technological civilization, a figure that has implications […]

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Latest Carnival: Electric Sails and More

September 27, 2008

The latest Carnival of Space is stuffed with good things, among them Dave Mosher’s manipulations of an asteroid impact calculator run by Cardiff University’s Ed Gomez. Dave works through a worst-case scenario — a 1300-foot wide asteroid striking the East River, turning most of New York City into a crater. Fascinatingly, the impact calculator lets […]

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Rough Sailing on the Solar Wind

September 26, 2008

All of nature is a kind of laboratory, which is why good propulsion ideas can flow from astronomical observations that show us how things work. Recent news about the solar wind is a case in point. An analysis of data from the Ulysses spacecraft shows that the solar wind is now lower than at any […]

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Colliding Worlds: The Ultimate Extinction Event

September 25, 2008

When Worlds Collide, the 1932 novel of planetary catastrophe, presented the most extreme extinction event imaginable. A pair of wandering planets enters the Solar System, one on collision course with the Earth, the other destined to be captured into orbit around the Sun. The doughty crew of an escaping rocket, on their way to a […]

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A Dark Flow in the Cosmos

September 24, 2008

Seeing things that are otherwise invisible means looking for their effect on the things we can see. Examples abound: The presence of dark matter was originally inferred from the shape of galaxies, and the fact that the mass of what we could see couldn’t explain how these cities of stars held together. Dark energy turned […]

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Interstellar Flight in Context: A Bet Already Won?

September 23, 2008

The staggering difficulty posed by interstellar flight pushes us to imagine alternatives to today’s technologies. Using conventional rocketry we’re forced to amass so much propellant that the craft we want to send seem impossible to build, even if we could afford the vast fuel bill. A jacked up rocket engine is, of course, nothing but […]

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Notes & Queries 22 September 2008

September 22, 2008

Hugh Everett’s ‘many worlds’ interpretation of quantum mechanics spawned not just the idea of a multiverse, but apparently quite a few interpretations on what a multiverse implies. If you’re intrigued by the notion that our cosmos is one of what may be an infinite number of universes, you’ll want to read Dan Falk’s report in […]

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Exoplanets on the Fringe

September 20, 2008

Most Centauri Dreams readers will be familiar with the concept of interferometry by now. The idea is to combine light from multiple telescopes, allowing the combined array to act like a single telescope with a diameter equivalent to the distance between the telescopes. Thus we have the European Southern Observatory’s VLTI (Very Large Telescope Interferometer), […]

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Dark Matter’s Galactic Implications

September 19, 2008

Segue 1 is one of the tiny satellite galaxies orbiting the Milky Way whose dark matter component has caused great astronomical interest. As we saw in this post a couple of weeks ago, these ultra-faint objects have been turning up in Sloan Digital Sky Survey data, surprising astronomers by their mass, which indicates they’re dominated […]

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