This Lee Billings guest post at BoingBoing sums up the possibilities – given our current understanding of the laws of physics – of travelling to other star systems. Probably won’t be news to many readers here, but even unmanned missions beyond the heliopause will be technologically challenging, hideously expensive and incredibly slow to deliver results. None of which are reasons to write the idea off, though, at least not in my book.
I just wanted to pull out this paragraph, though:
… space is vast, and even the distance to the nearest star is mind-boggling. Let’s say the Sun is the size of a large orange, 10 centimeters in diameter. Place the orange on the ground, walk a bit more than 10 meters away, and you’re in Earth’s orbit. Finding our planet might prove challenging—it would be the size of a millimeter grain of sand. The walk out to Pluto, a speck of dust ten times smaller than our sand-grain Earth, would be nearly a half-kilometer, and along the way you’d be lucky to encounter any of the planets: Even the largest, Jupiter, would be no bigger than a small marble.
That pretty much sums up the sensawunda kick for me. So much space out there… and we’re still arguing over patches of ground and bits of coloured cloth down here at the bottom of the gravity well.
Another gorgeously science-fictional concept: that of the constantly 
You might think that a dwarf planet is, oh, a planet, and that would settle it. But the International Astronomical Union just decided that the new classification for Pluto-like objects such as Eris, Ceres — and, presumably, Sedna, Orcus, Varuna, and Quaoar — is 
