AMONGST THE THINGS that differentiate America from the rest of the world are the Constitution, the Bill of Rights, an almost fanatical devotion to the gun, and continued insistence on paying lipservice to the notion of personal freedoms while simultaneously supporting politicians who erode them.... oh sod it, I'll come in again!

So, first assume a perfectly spherical car...

....and she keeps denying you privileges?

I'm not even going to start making jokes about penetration testing...

Hey, 1914 called, they want their.... oh.

In the first dot-com boom, I worked on a large groups application, kind of like what Google Groups is now. We had ~3m users, uploading thousands of images per day. For the first 6 months or so, it was the developers who had to do the moderation. We saw a lot of stuff that we could (and, frankly, had to) laugh about - anatomically impressive feats of stretching, comically ludicrous insertions, etc - but then there was the other stuff, the ones that you just couldn't laugh off. Stuff being done to others who clearly weren't old enough to consent. Some of the things I saw cannot be unseen or forgotten, however much I've wanted to in the ten years or so since.

After a while it does get you down. The very ordinariness of the backdrops was what got to me. People's ironing boards in the background. Their work uniforms hanging on the back of the door. You realise that this kind of shit is not done by crazed inbreds in the mountains or by foaming-at-the-mouth psychos, but by everyday people like the ones you sit next to on the bus or who smile at you as you buy a coffee from them every day. And that really got to me. I started looking at people and society very differently, and feeling constantly angry or sad.

In the end we hired a team of dedicated moderators, who had an enforced 1-to-1 counselling session every week. We also started working with law enforcement and people in suits whose cards just listed their job as 'the home office', and every now and again we'd get an email from the higher-ups telling us that our evidence had been crucial in securing a conviction in some case that had been in the news recently. And that helped.

There are far worse things on the internet than Goatse or tub girl, and a depressingly large number of people who produce them, consume them, and share them with others. Anyone who does that job for a sustained period has not only my sympathies, but my thanks

I actually asked an OFSTED inspector why Comic Sans is always used in schools and nurseries - she said that it's one of the only commonly-available fonts that draws the lowercase letter "a" in the same way they teach children to draw it (no stalk on top)

Fair enough. You are of course, right - I just usually find it best to stick to one unfamiliar concept at a time. Saves my typing as much as anything else :)

Why does light bounce off objects like mirrors then?

Because of electromagnetic interactions with the atoms on the surface of the mirror

Why are they attracted at mass at all?

Because, as Einstein's famous General Theory of Relativity explained, gravity is not just a force between two masses like you were taught at school, it's actually a curvature of the geometry of space-time. The maths gets really complex really quickly, hence the web is full of analogies like the rubber-sheet model that can lead laymen to appealing but incorrect conclusions. But when you do do the maths, it works astonishingly well - and it's the simplest explanation we have that fits all the observed data.

If completely massless, wouldn't they be able to escape a black hole?

See the previous answer - no, they wouldn't, because it would need an infinite amount of energy to do so. When you do the math (one example chosen at random is here, there are many others) it turns out that the curvature of space-time becomes so strong near a black hole that inside the event horizon, space and time kind of switch roles - to move further away from the centre would mean moving backwards in time.

Sounds a bit kooky in words, true, but makes perfect sense in mathematical terms - and again, GR's predictions have been experimentally verified time and time again.

The famous example being that you are not allowed to accuse anyone of lying. The verbal tricks and convolutions that Commons veterans employ to get round this restriction are a connoisseur's spectator sport in their own right. For instance, Dennis Skinner :

Dennis Skinner: Mr Speaker, half the members opposite are liars!

Speaker: You will have to apologise, Mr Skinner.

Dennis Skinner: I apologise, Mr Speaker. Half the members opposite aren't liars!

The BBC micro was the 'standard' educational model, not least because of the BBC brand and the association with the Beeb's educational TV programs. The home market was dominated by Spectrums and C64s.

After spending the summer playing with my friends' ZX81, I got a Spectrum for christmas at the age of 8, and every week I would pester my dad to buy me "Your Spectrum" and "Your Sinclair" magazines, with their pages upon pages of type-em-in program listings. I'd then piss off my sister by monopolising the TV for 3hrs while I typed in the latest greatest amazing game .... and spend 5 minutes playing the inevitable top-down scrolling dodge-em-up before thinking "surely I could do better than that!". So I set out to try.

30 years later, I'm making a good living as a senior programmer, and I put it all down to those early days of truly accessible computing. The Spectrum was the ideal balance between entertainment machine and experimentation platform, amazing a geeky 8yr old with its possibilities while its limitations positively encouraged anyone with the right mindset to try and work around them. Hacking infinite lives with PEEK and POKE... designing game graphics pixel by pixel and then converting them to integer data... figuring out how to give the illusion of full-colour graphics when you only had one foreground and one background colour per 8x8 character square... i learned so much about computing from those days. Thanks Sinclair, you were awesome.

Seconded. I spent about fifteen years gigging pretty constantly, on average maybe once a week over that whole time. I lost count of the number of times venues would charge us to play, and give us tickets to sell in order to make it back. They'd even take a cut of the ticket sale price. As long as there were more acts than venues, they could get away with it.

Make time to leave the house at least once every day. Seriously, enforce a lunch break, leave the house and TALK TO PEOPLE - go to the coffee shop, go get a newspaper, whatever, but you need genuine face-to-face human contact every day, otherwise you can go a bit.... weird.

I worked from home for 3 months before my current startup had an office, and my wife would ring me every day at about 2pm. The conversation would go something like this:

"Now, have you left the house yet today?"

"No, I just want to get this bit finished first..."

"Have you spoken to anyone yet today?"

"No, but I will once I..."

"LEAVE....THE....HOUSE.... OK?"

"...OK"

IIRC, that's pretty much exactly what they did with the financial sector throughout the last twenty years. Yeah, that worked out well....

I spent 3 weeks in the Himalayas last year, with a Power Monkey solar panel strapped to the back of my pack. I figured the odds of a decent charge were good - we were in direct sun for ~8hrs a day, and the UV at >5000m altitude is seriously intense.

In practise, I usually managed to get enough charge at the end of the day to power up my HTC Desire for about 20mins, with wi-fi turned off and making no calls - essentially using it as a notepad and sending the odd "we're OK!" text to my family. So, not a viable option for anything more than one emergency call, really.

BUT - having said that, up there, there really isn't any other option. Generators at lodges are becoming more common, but it'll cost you 250 rupees for half an hour charge (that's about 2GBP/3USD) in a country where over 30 per cent of Nepalese live below the poverty line of US$12 per person/per month.

When there's no electricity, no landlines, and no way between villages other than long, steep, gruelling high-altitude hikes, and the nearest medical assistance is often over a days hike away, that one emergency mobile phone call can become pretty damn important for the locals. So irrespective of whether it's a desirable lifestyle choice for the first world, THAT's why this research is worth pursuing.

I'm not a "real" physicist - but I did study this at undergrad level, so here goes:

Heisenberg's Uncertainty Principle ( http://en.wikipedia.org/wiki/Uncertainty_principle ) states that there must always be a minimum uncertainty in certain pairs of related variables - e.g. position and momentum, i.e. the more accurately you know the position of something, the less accurately you know how it's moving. Another related pair is energy and time - the more accurately you know the energy of something, the less accurately you know when the measurement was taken.

(disclaimer - this makes perfect sense when expressed mathematically, it onlysounds like handwavery when you translate it into English, as words are ambiguous and mean different things to different people)

Anyway, this uncertainty means that there is a small but non-zero probability of a higher-energy event occuring in the history of a lower-energy particle (often mis-stated as "particles can borrow energy for a short time, but check the wiki page for a more accurate statement). It sounds nuts, I know, but it has many real-world implications that have no explanation in non-quantum physics. Particles can "tunnel" through barriers that they shouldn't be able to cross, for instance - this is how semi-conductors work.

By implication, there is a small probability of the neutrino acting as if it had a higher energy, and *this* is how neutrino-flipping occurs without violating conservation of energy.