May 2015

Transhumanism and Adaptive Radiation

May 29, 2015

Centauri Dreams regular Nick Nielsen here tackles transhumanism, probing its philosophical underpinnings and its practical consequences as civilization spreads outward from the Solar System. In a sense, transhumanism is what humans have always done, the act of transcendence through technology being a continuing theme of our existence. But accelerating technologies demand answers about human freedom […]

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Into Plutonian Depths

May 28, 2015

The image of Pluto on the right — an artist’s impression, to be sure (credit: NASA, ESA and G. Bacon, STScI) — suggests Ganymede to me more than Pluto, but we’ll have to wait and see what New Horizons turns up as it continues to close on its target. It’s worth thinking about how our […]

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LightSail Glitch: Hoping for a Reboot

May 27, 2015

The Planetary Society’s LightSail won’t stay in orbit long once its sail deploys, a victim of inexorable atmospheric drag. But we’re all lucky that in un-deployed form — as a CubeSat — LightSail can maintain its orbit for about six months. Some of that extended period may be necessary given the problem the spacecraft has […]

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Exoplanet Exploration Organization Proposed

May 26, 2015

We’ve recently looked at the role of small spacecraft, inspired in part by The Planetary Society’s LightSail, a CubeSat-based sail mission that launched last week. It’s interesting in that regard to consider small missions in the exoplanet realm. ExoplanetSat, for example, is a 3-unit CubeSat designed at MIT as a mission to discover Earth-sized exoplanets […]

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A Mass-Radius Relationship for ‘Sub-Neptunes’

May 22, 2015

The cascading numbers of exoplanet discoveries raise questions about how to interpret our data. In particular, what do we do about all those transit finds where we can work out a planet’s radius and need to determine its mass? Andrew LePage returns to Centauri Dreams with a look at a new attempt to derive the […]

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LightSail Aloft!

May 21, 2015

One of the joys of science fiction is the ability to enter into conjectured worlds at will, tweaking parameters here and there to see what happens. I remember talking a few years ago to Jay Lake, a fine writer especially of short stories who died far too young in 2014. Jay commented that while it […]

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Enter the ‘Warm Titan’

May 20, 2015

Our definition of the habitable zone is water-based, focusing on planetary surfaces warm enough that liquid water can exist there. New work by Steven Benner (Foundation for Applied Molecular Evolution) and colleagues considers other kinds of habitable zones, specifically those supporting hydrocarbons, which can be liquids, solids or gases depending on the ambient temperature and […]

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Exoplanets: The Hunt for Circular Orbits

May 19, 2015

If you’re looking for planets that may be habitable, eccentric orbits are a problem. Vary the orbit enough and the surface goes through extreme swings in temperature. In our own Solar System, planets tend to follow circular orbits. In fact, Mercury is the planet with the highest degree of eccentricity, while the other seven planets […]

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Spacecoach on the Stage

May 18, 2015

I’m glad to see that Brian McConnell will be speaking at the International Space Development Conference in Toronto this week. McConnell, you’ll recall, has been working with Centauri Dreams regular Alex Tolley on a model the duo call ‘Spacecoach.’ It’s a crewed spacecraft using solar electric propulsion, one built around the idea of water as […]

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Doppler Worlds and M-Dwarf Planets

May 15, 2015

Finding small and possibly habitable worlds around M-dwarfs has already proven controversial, as we’ve seen in recent work on Gliese 581. The existence of Gl 581d, for example, is contested in some circles, but as Guillem Anglada-Escudé argues below, sound methodology turns up a robust signal for the world. Read on to learn why as […]

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