>First, we don't know how to protect humans from Cosmic radiation on even a short voyage, let alone a super long 300 year voyage.

Actually we do. A few meters of water or other hydrogen-rich substance. Very low-tech, but heavy. But a generational spaceship would inevitably be heavy, and would need a very large reservoir of water anyway. The water would not have to be hauled up from Earth, there is plenty of it in the outer solar system, in icy moons. Possibly even in our own Moon. By the time building generational starships becomes feasible, accessing extraterrestrial water resources is probably routine.

Is there some fundamental reason why ion engines cannot have a higher thrust, assuming you have the energy available (like from a nuclear reactor)?

>The _only_ time an energy inefficient light source is wasting energy is when you are not heating the house. For most of the UK population, that's about 1/4 of the time.

But it is quite a bit more than that in countries south of UK! Especially if you have air conditioning, the traditional light bulbs put you in the absurd situation of using energy both to heat and cool the room at the same time... Another thing is that the light bulbs in typical lighting fixtures are inefficient as heaters. Most of the heat goes and stays near the ceiling, which is not where most people spend their time. Even ignoring that, direct electric heating is usually more expensive than other heat sources. (This of course depends on where you live).

By the way, I'm from Finland, so from my point of view the UK is one of those balmy southern European countries. And I have gradually replaced most of the bulbs in my house with compact fluorescents and LEDs. The latter have come down in price in recent years, and solve the worst annoyance of compact fluorescents: they turn instantly on with full power.

>Neither IE9 nor IE10 are available on XP.

The Google stuff works better on Firefox anyway. Or on Chrome.

>Too many companies have learned this lesson the hard way, launching invasive new services that have triggered class action lawsuits, Congressional inquiries, and media firestorms.

Shouldn't that read "Too few companies have learned ..."? Otherwise the problem would not exist.

Anyway, I think this can only be fixed by legislation. Companies have too much monetary incentive for privacy violation to do anything else than token improvements. "Industry self-regulation" is nothing but newspeak for "foxes guarding the henhouse".

> But what if we read their thoughts and Stalin really thought he was doing a good thing

No need for mind-reading here. Stalin no doubt thought he was doing a good thing: he was convinced he knew what was best for everybody, there just were all those dunces that disagreed and tried to sabotage his benevolent plans... The same is true of other classic dictators. They are all extreme cases of narcissist personality disorder, who unfortunately managed to gain great power.

Were I live (Italy) we switched to DGTV some time ago, and last time I checked, Teletext was working just fine

Same thing in Finland. It is actually still quite popular, many years after the digital switch-over. If you have your TV already on, it is the fastest way to peek at the latest headlines or weather report. Another popular application seems to be horse racing scores. Kiosks selling bets almost always have a TV constantly showing Teletext at the relevant page. Works without any net connection.

A nice result of the Teletext limitations is that the pages show just the data without fancy formatting, and whoever creates the content must make the best of the limited space, choosing words carefully. This means the system is really very efficient for the reader, you don't have to wade over fluff... (unfortunately because of the way the pages are rotated in the transmission, you may have to wait a bit until your page comes up, unless your receiver implements good caching. Old implementations did not, and that made reading slow.).

The you mention are plausible extrapolations from the state of technology in the 1990's, not "unobtainium", although we now know the time table was way too optimisitic, as usual. As noted by another poster, the thousands of small windmills were aknowledged to be a bad idea even within the books (their inventor Sax Russell attends a conference on terraforming, where one paper accounts for the warming effects of various methods, and dismisses the windmills). As for solar warming, remember the terraforming also tapped geothermic (areothermic?) energy (the "moholes"), and collected more solar energy than the surface area of Mars allows by the use of space mirrors (the "soletta" of the books).

The "Red Mars", "Green Mars", "Blue Mars" trilogy by Kim Stanley Robinson is a great future history that lays out a credible way the Mars colonisation could play out, including the inevitable revolt against the megacorporations. Enjoyed it last summer. The books were written in the early 1990's, evidenly with the best knowledge about Mars available then. At times it feels like the author had visited the place in person... There is no technobable, no miracle technology, this is hard sci-fi at its hardest. But much of the story is really about social effects, the tensions between early Mars settlers, newcomers, people who want to terraform Mars and those that desire to preserve it, and the corporations that just want to extract maximum profits from Mars. Earth future history is also explored with the unexpected discovery of a life-prolonging treatment (who gets it?), and an environmental crisis caused by volcanism in the Antarctic (a huge flood, but not fashionably by global warming).

And you get hit by a ton of patent lawsuits, if it looks like you will be succesful :-(

In Finland, every publisher is required by law to submit a copy of every printed work published in the country (not just books, but newspapers and magazines as well) to the National Library and a few other university libraries (so the system has redundancy). This has been going on since 1829. I suppose many other countries have similar laws.