Hmm, it seems that /.ers don't have children (even the ones who can remember back to the '80s). In the school where my kids go, a local robotics nerd is teaching programming to grades 3 and onwards using Scratch and they're loving it. Yes, Scratch has a colourful GUI for junior programmers and doesn't let you edit your code in vi, but it has loops, objects, methods, variables, and most of the constructs that older programmers use.

Now if I could only get my 6th grader to stop fixing bugs in his maze and start watching his TV like he's supposed to ....

I'm not from Europe, I'm from the country that invented rugby :-) and I played it as a kid.

First, in rugby you're not allowed to run into any player who isn't carrying the ball, which cut down the number of impacts relative to American football.

Secondly, we were trained to take down an opposing player with our shoulders and arms (sweep his knees out form under him) in the run-and-strike part of the game. Hitting with your head, or hitting his head, was so obviously a bad idea that I don't think it was even mentioned.

Third, the wrestling part of the game (the "scrum") begins with players already in contact, so there's no impact -- and the contact is shoulder-to-shoulder. This contrasts vividly with the American face-off where players seem to start about a yard apart, so the first thing they do is crash into each other.

Fourth, as my mother used to say, "[soccer] is a gentle game for rough people, rugby is a rough game for gentle people."

How about we get kids who want to be able to write a piece of English that explains something, and let them review each others' work while the algorithm helps them with punctuation and spelling. The teacher can review a semi-finished product from each group of, say, four kids.

How do we motivate the little monsters? Once kids have been shown a piece of bad writing and asked to make sense of it, then a day or two later been shown a piece of good writing, they'll be merciless critics, and other kids may listen better to their peers than to a teacher who doesn't really have time to talk to them anyway. We might even let them take the work home and show it to their parents, who could provide feedback. Bottom line: school is a place to learn how to do things well, not a place to be told how badly you do them.

To prevent the obvious abuses, and to make some room to assess individual contributions, rotate the kinds through different combinations of groups. Other refinements are left as an exercise to the reader.

They're not way stations; they're destinations, at least for a few decades. If there are 100,000 of them per star, then they're distributed maybe a tenth of a light year apart, so that primitive sub-relativistic vehicles (only a hundred times as fast as what we now have) can get to them within a human lifetime. The first visitor will be an automated probe, which will assay a planetoid for useful supplies and leave a beacon to guide future ships in. Later, a bigger robot homes on the beacon, mines the supplies, and does two things:

1. sets up a fusion reactor and starts growing spinach
2. fuels up a handful of automated probes and launches them towards the next few planetoids

A century or so later, humans who are tired of the Eight Worlds will simply move to a handy planetoid. With almost any non-magical technology, travelling a tenth of a LY is cheaper than travelling to another star with a livable planet. The near-certainty of not meeting intelligent aliens will be, to some of them, an added plus. But maybe they'll get a surprise :-)

The last page of http://en.wikipedia.org/wiki/Player_Piano

Or maybe the last couplet of http://www.purelyrics.com/index.php?lyrics=lgatwosh

The real problem is that the payload would reach 8km/s speed before leaving the atmosphere. Think frictional heating. Think sonic boom. Think shock waves hammering the rail or the structure that supports it. Sure you can embed the whole thing in the ground, then it'll be strong enough, but your payload will come out doing 8km/s horizontally, not very useful.

Also think that turning a railgun that can do 2km/s into one that can do 8km/s may not be any easier than taking my car and turning it into one that can go four times as fast.

For an alternative, look up "laser launch" on a good search engine. It's still rocket propulsion, but with potential for significantly better specific impulse.

Darn it, I cheerfully would have paid per playback out of my own money, and still might do so, at certain price points. If I can listen to the 30sec sample for free, then it might make sense to listen to the entire song for oh, a dime, and then either decide to buy a copy, or to bookmark it and see if I still remember it a week later. No doubt there's a reason why no-one is doing this, but it escapes me.

Sails have to be rigid? Have you looked at a sailing boat lately?

Reflectivity would double the thrust over simply absorbing the photons, but any metal coating except maybe lithium or beryllium would more than double the mass, right? So I'll take naked graphene, with some kind of rip-stop reinforcement of course.

The Darth Vader coins.

Yes ... but it took millions of years for something as massive as the sun to condense. These craft will have be lighter and have somewhat less gravity than the cloud of gas that gave birth to the Sun. By the time they form a compact ball, it's even possible that the US debt limit will have been raised.

SpaceX, for one, has several contracted launches (announced on their web site) that aren't from NASA. The PR verbiage suggests that they won some of these on price. They'll charge NASA more than an ordinary customer, of course.

The big difference is that, under cost-plus, the contractor gets more profit by the simple and undemanding expedient of making the vehicle more expensive than it needs to be. That's how we got to this place where only megamillionaires can afford a ride to orbit. With fixed bids, the contractors get more profit by making the vehicles as cheap as they can be, consistent with safety and reliability (and no, I don't think any of those CEOs want their names to be coupled in the history books with dead astronauts). That has the potential to lead to a place where I could afford to take the trip. Not probable, but better than no hope at all.

Oh yes, and with four or five suspects, real competition is more likely to emerge than from a cosy duopoly.

This update points out that dark forces within NASA are urging the return of cost-plus contracting for crew transport (scroll down to "Commercial Crew" section therein). This will get us straight back into the traditional world of missed schedules and massive overruns, if it's allowed to happen. USAan readers please hold yourselves in readiness to contact your elected lords and, um, representatives.

Good point indeed. Bear in mind that satellites in orbits very close to each other would be unstable: the orbits would change in a time much shorter than it would take life to evolve. IIRC the closest pair of Galilean satellites are in a 3:2 resonance ... lemme see ... actually 2:1 by http://en.wikipedia.org/wiki/Galilean_moons and their closest approach is 250,000 km, which makes for tides about four times as strong as on Earth (tidal force is inversely proportional to the cube of distance). With bigger satellites the tides would be stronger in proportion to their masses. OK, so a system with two Earth-sized satellites might have very big tides.

1. The moon would be tidelocked, if it were close enough to have such huge tides, no question.

2. Depends on the orbital period; three of Jupiter's Galilean satellites have periods of a week or less, and a quick calculation based on the diameter of Jupiter versus the diameters of their orbits suggests that none of them is in total eclipse for more than a few hours ... better numbers here. Since I routinely survive a twelve-hour night with no ill effects, the eclipse seems to be a minor problem. A tidelocked planet would have a day equal to its month, though, which might be a problem if the month were more than two or three days, but a lot would depend on the presence of oceans, which are huge reservoirs of heat, and on wind patterns.

"Those who refuse to do arithmetic are doomed to talk bollocks."

And what does the gov't produce that a teenager would want to listen to?