Evi: desperately hoping you're in a life raft somewhere and will get to laugh your laugh at some of the kids posting here today. A great big IETF hug to you, wherever you are.

I'm in my mid 40s, already got kids, am reasonably fit, have a scientific background, and I've probably got the right sort of technical skills for such a trip. I'm half-way through a pretty successful academic career at this point in my life. In 15 years time (when such a trip might be feasible), I'll be 60. My kids will have left home, and I'll be looking forward to retirement.

Trouble is I'm not the sort of person to settle down and play golf. If, instead of retiring, I could do something really amazing with the last few years of my (productive) life, I'd jump at the opportunity. Assuming I'm still fit enough, I'd jump at the chance to go to Mars on a one-way trip. Likely it would shorten my life significantly. But I'll have already lived most of it anyway - what a way to go out!

The tough part wouldn't be missing Earth, or spending 6 months in a large can, but missing my family. Video conferencing isn't the same, especially with the time lag. But even so, I reckon I'd still go, if they gave their blessing. I think they'd probably understand, even if they weren't happy about it. Some things are just worth devoting the rest of your life to, even if it turns out to be short.

As a nerd, I like to be able to see how my watch works:

http://www.thewatchhut.co.uk/Rotary-Gents-Mechanical-Skeleton-Strap-Watch-GS02521+06.html

Or maybe it's an indication that 28 years of experience post-degree is more relevant than the degree itself.

The same may not be true if you've recently graduated.

I've always found that I can take notes, or understand, but I can't do both. Back when I was a student, i generally taken almost no notes - just perhaps half a page to a page in an hours lecture - just the key points and nothing else to act as reminders later. It always worked well for me - I seemed to be the only person who actually understood stuff.

Of course, revision for exams was interesting, but it really was revision, because I didn't have enough notes to attempt to learn anything during revision. Probably fits with the article - remembering during revision was hard, but once I had remembered, I really knew it well.

One of the most difficult parts of science is knowing what questions are worth answering. Coming up with a good question - one that is worth answering and can be answered - is often the hardest part of a PhD. Younger scientists generally have more difficulty with this than older scientists - it is something that you get better at with experience and with making a good network of people you interchange ideas with. But often younger scientists are (or rapidly become) better at the fine details when pointed in the right direction, but getting that direction in the first place is crucial. All this points to collaboration between people of different generations as being a very pretty effective way to have impact.

Interestingly, what Fukushima did show was that several pretty large explosions inside the reactor buildings didn't really cause damage to the reactor containment. So you're almost certainly right that a terrorist with a backpack bomb probably isn't actually going to cause a disaster.

Even so, I wouldn't be surprised if they shot protestors next time.

Sounds like the came very close to proving that no such hole existed - when you call ahead to tell the police not to shoot your guys, you're not proving much.

So now when the real terrorists break in, they just have to phone to warn the police that Greenpeace is breaking in?

By the time you're 20 you kinda get the plot, and it usually doesn't get any better after that.

I disagree strongly with that. I'm in my mid-40s, and so far I have to say that life has got better with each passing decade. Not necessily easier, mind you, but certainly better. My job has never been more interesting, and my kids are getting old enough to be not just fun but interesting to have deep discussions with. Perhaps most importantly, I know myself, my strengths and weaknesses better than I ever used to, I've got far more confidence than when I was younger, I'm happy with who I am, and I know how to apply myself and to work with the people around me to get stuff done.

Life is what you make of it. Whatever age you are.

The evidence from supernova 1987A seems to contradict this. Neutrinos from the supernova would have arrived years before the light if c were 0.03% faster than we measure on Earth. Instead they arrived a few hours earlier, which is to be expected, as light from the initial explosion took some time to emerge from the exploding star whereas the neutrinos did not.

A friend of mine who is a professor at a Romanian university mentioned to me that in Romania if you've a Computer Science degree and work as a programmer, you're exempt from paying income tax. No surprise that they've no shortage of smart CS graduates.

Oops, missed the transistor. That's Lilienfeld, a canadian. Shockley and the Bell labs team built some of their early transistors based on Lillienfeld's patent.

Well, the light bulb was Joseph Swan, an Englishman.

The telephone was invented by Antonio Meucci, an Italian. Alexander Graham Bell, himself, was Scottish, though he'd been in the US for four years when he did his telephony work.

Velcro is Swiss.

The nuclear bomb, I'll give you, though of the key people on the Manhattan project, Fermi and Segre were Italian, Teller, Wigner and Szilard were Hungarian, Bohr was Danish, Frisch was Austrian, Block as Swiss, Fuchs, Peierls and Franck were German. But at least Oppenheimer, Bohm and the finance was American.

Packet Switching was independently invented by more than one person, including Donald Davies at NPL in the UK.

Many of the principles later used in TCP/IP including the basic datagram concept came from Louis Pouzin and the French CYCLADES network.

Of the original three TCP/IP implementations, one was done at University College London.

(Most of Europe then wasted a decade on the dead-end that was OSI, but history is written by the victors)

GSM was European.

The Web was European.

Skype was European.

Linux was European.

ARM is European.

I agree the successful big portal sites tend to be American - maybe related to having a large market that all speaks (almost) one language. But I just want to point out that the US does not have a monopoly on innovation.

I can also do this, though I'm better outdoors than in. I can pretty much always get north to within 45 degrees. I can also pretty much look at a map once, memorize the key features, and then mentally navigate on that map, mentally keeping the map orientated to north even if I'm travelling in some other direction. Few people I've talked to seem to do this.

I'm not convinced any of this is magnetic though. I've travelled a fair bit, and I've noticed several failure modes in my navigation ability:

• In countries near the equator, I get north and south switched round fairly often.
• In the southern hemisphere, until I get used to it, I consistently swap north and south.
• In cities where the grid is at 45 degrees to north, I sometimes get north out by 90 degrees.
• I'm not as accurate at night and indoors, though I'm still pretty good.

Because my navigation is normally so good, when I do get it wrong, I really believe my error for quite a while, which is not so great.

The north/south swap in the southern hemisphere leads me to believe that the dominant factor is to do with the position of the sun in the sky. I don't do it consciously though, and I live in London, and it still works on frequent cloudy days, so however it works, it's subtle.

The 45 degree grid shift one is strange and very disconcerting. I think what happens is my accuracy is only to the nearest 45 degrees, and I mentally orientate the grid to north. The mismatch between mental model and reality combined with my limited accuracy can cause the whole mental model to jump 90 degrees. Too much thought - should just trust the instinct.

The fact that it all still works at night and indoors could just be that I'm pretty good at dead reckoning. But maybe there is a magnetic aspect - if so it's not the dominant factor.