November 2011

Can Project Orion Be Re-Born?

November 15, 2011

Project Orion keeps surfacing in propulsion literature and making the occasional appearance on the broader Internet. A case in point is a vigorous defense of Orion-style engineering by Gary Michael Church on the Lifeboat Foundation blog. Church is rightly taken with the idea of propelling payloads massing thousands of tons around the Solar System, but [...]

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An Asteroid Born Near the Earth

November 14, 2011

This morning we stick with the planetary migration theme begun on Friday, when the subject was a possible ice giant that was expelled from the Solar System some 600 million years after formation. We have a lot to learn about the mechanisms that could force such ejections, but it’s becoming clear that objects up to [...]

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A Gas Giant Ejected from our System?

November 11, 2011

Free-floating planets — planets moving through interstellar space without stars — may not be unusual. If solar systems in their epoch of formation go through chaotic periods when the orbits of their giant planets are affected by dynamical instability, then ejecting a gas giant from the system entirely is a plausible outcome. David Nesvorny (SwRI) [...]

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A Look at Methane-Based Life

November 10, 2011

Could life exist on a world with a methane rather than a water cycle? The nitrogen-rich atmosphere of Titan, laden with hydrocarbon smog, is a constant reminder of the question. Cassini has shown us the results of ultraviolet radiation from the Sun interacting with atmospheric methane, and we’ve had radar glimpses of lakes as well [...]

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Pluto/Charon: A Dangerous Arrival?

November 9, 2011

We’ve often considered the effect of interstellar dust on a spacecraft moving at a substantial percentage of the speed of light. The matter becomes even more acute when we consider an interstellar probe arriving at the destination solar system. A flyby mission moving at ten percent of the speed of light is going to encounter [...]

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2005 YU55 Closest Approach Today

November 8, 2011

2005 YU55, an asteroid roughly the size of a city block, makes its closest pass today, approaching within 325,000 kilometers, closer than the distance between the Earth and the Moon. It will be another seventeen years before we get an asteroid as substantial as this in such proximity. That one is 2001 WN5, which will [...]

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The Light of Alien Cities

November 7, 2011

If you’re looking for a new tactic for SETI, the search for extraterrestrial intelligence, Avi Loeb (Harvard-Smithsonian Center for Astrophysics) and Princeton’s Edwin Turner may be able to supply it. The duo are studying how we might find other civilizations by spotting the lights of their cities. It’s an exotic concept and Loeb understates when [...]

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Millis: Of Time and the Starship

November 4, 2011

What next for the 100 Year Starship Study? NASA and the Defense Advanced Research Projects Agency will make the call, as Tau Zero founder Marc Millis told Alan Boyle in his recent interview. To talk to Boyle, Millis donned virtual garb and appeared in Second Life in robotic form, but the interview is now available [...]

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Dying Stars and their Planets

November 3, 2011

Although I can’t make the journey just then, I wish I could attend an upcoming conference at Arecibo (Puerto Rico) called Planets around Stellar Remnants. The meeting takes place twenty years after the discovery of the first exoplanets, the worlds orbiting the millisecond pulsar PSR B1257+12. I’ve been interested in the fate of planets around [...]

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Notes & Queries 11/2/11

November 2, 2011

Tau Zero in Second Life I have almost no experience with online virtual worlds like Second Life, but I do want to mention that Marc Millis will appear later today (Nov. 2) on the ‘Virtually Speaking’ talk show program, which can be accessed here as well as in Second Life. The focus of the interview [...]

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