The waves actually change the refractive index of the vacuum between the mirrors - the mirrors themselves aren't moving. It's a subtle difference but it means there is no cancellation you speak of.

Oops, I didn't notice that!

Here we go: https://www.indiegogo.com/proj...

BBC.com is part of BBC World, which is not funded by British taxpayers. As such, it is necessary to advertise on the BBC.com pages, and I guess this makes the BBC execs think this would conflict with the 'we don't endorse any particular companies through advertising' stance that the rest of the (British taxpayer funded) BBC has, at least for UK viewers.

This seems kind of stupid. Since BBC World is (mostly, I think) owned by the BBC, they could surely take the advertising revenue hit and let UK viewers access the pages ad-free. A lot of the content on BBC World appears to come from the main BBC anyway - for instance, this bamboo news I heard last week in the 'In Our Time' show on BBC Radio 4 (taxpayer-funded).

Saying that, there is, of course, a version of the magazine available in PDF format. The subscription price is actually reduced by a fair amount to compensate for the lack of dead trees too (take note, Amazon).

A direct detection of a gravitational wave moving the mirrors of a large scale interferometer is up next. In the next few years, Advanced LIGO (US), Advanced Virgo (Italy) and KAGRA (Japan) will come online with the hope of directly detecting gravitational waves from sources such as supernovae and coalescing binary star systems. With this kind of network, it will then be possible to coordinate both electromagnetic and gravitational searches of our sky. This is useful for many reasons, one of which is that it lets us listen to the sound of black holes colliding where no light escapes.

Exciting times!

*Internationalisation

Gravitational waves are emitted at a wide spectrum of frequencies by different astronomical bodies. LIGO's frequency range is limited mostly by seismic activity at the low end and radiation pressure noise (essentially the momentum imparted by photons hitting mirrors) at the high end. It's about as well as we can do on Earth, currently. Indirect detections via astronomical techniques can avoid the issue of seismic activity disrupting measurements, and so it is possible to look at much lower frequencies. These frequencies, however, correspond to different sources to the ones LIGO can potentially see, so we can learn new information about different parts of our universe from both detection techniques.

The Guardian article refers to a detector which might have made an indirect detection of gravitational waves.

If two massive bodies such as neutron stars or black holes collide, the energy they lose in the form of gravitational energy is propagated away in waves. These waves are ripples in spacetime, and they are quadropolar in nature. This means that they stretch spacetime in one direction while squeezing it in the other.

Gravitational waves form part of the predictions of Einstein's Theory of General Relativity. They are the last piece of the theory yet to receive a direct detection. A notable indirect detection of gravitational waves is the measurements of the orbital decay of the PSR B1913+16 binary pulsar, for which Hulse and Taylor received the Nobel Prize in 1993.

For the purposes of direct detection of these waves, on Earth we've set up a network of laser interferometers (the major players are Advanced LIGO, Advanced Virgo, GEO-HF and KAGRA, though all but GEO are currently in the process of being commissioned). If we arrange our detectors on Earth at right angles, we become optimally sensitive to the majority of gravitational wave sources. If the masses of the bodies involved in the collision are big enough, the ripples in spacetime will be strong enough to change the time in which it takes light to travel along each arm of the interferometer - in one arm the light will take longer time to travel, and in the other it will take shorter time. If we recombine the light in each arm, we can sense via the interference pattern of the light whether a gravitational wave has passed through the detector. In practice there are loads of other signal sources present in the interferometer, and quantifying and eliminating these sources of noise are the major tasks facing these detectors. With these noise sources accounted for, the first direct detection of gravitational waves might be made in the next few years.

The LISA project referred to in the main article is dead since NASA pulled out funding. The project lives on in the form of the ELISA project, funded by European organisations. This has tentative approval for launch in the next 20 years. This mission is not intended to directly detect the 'first' gravitational wave, but rather to detect them in abundence. Indeed, the problem with this type of detector is dealing with the huge number of potential detections. ELISA is also designed to detect waves in a completely different spectrum from the ground detectors, and from different astronomical sources. By the time ELISA launches it is likely that the network of detectors as part of the LIGO Scientific Community will have made the first detection, here on Earth.

GEMA and their clients benefit from the use of their music on videos on YouTube. While it's not right that Google can strong-arm everyone into accepting too low a price for the licencing (which I guess is why so many videos are blocked in Germany), presumably Google has offered a similar deal to GEMA as it has done to the US, UK and other countries' music bodies, and this has in turn set the baseline. If GEMA are being greedy and asking for more, then they deserve to be made to look bad by YouTube's message.

It's already a stupid idea to make YouTube negotiate royalties with every national body whether an artist is based there or not. Videos are being blocked from US and UK artists in Germany because the German record industry can't negotiate terms. That's silly.

I know I'm making a lot of suppositions here, but I really have very little sympathy for most record companies and their collective bodies.

YouTube are right to pass the buck to GEMA. I've been living in Germany for 6 months after having lived in the UK all my life, and only having very rarely seen videos blocked by the UK music industry, almost all of the videos I try to watch on Facebook or similar (usually viral videos) are blocked. GEMA need to get with the times and realise they can't staunchly deny the internet the right to use its clients' music.

I've played Transport Tycoon Deluxe since I was 12 and I've played OpenTTD since it came out. I'll probably play OpenTTD for years more. As the original game said in its tagline: "This game will bring out the megalomaniac in everyone".

Where other games are pretty and complex, OpenTTD is just about micromanaging a massive transport network. It's really consuming. I've lost evenings to the game for years. Sometimes I don't play it for up to a year, then go back to it and lose a month.

This issue is fixed by making higher education free to everyone, which is what happens in Scotland. No fees to collect from fleeing emigrants. This works a treat because universities in Scotland are public institutions with the tuition fees they charge set/capped by the government (the rates they can charge the government, essentially). The country benefits from an educated workforce, especially because there are many high-tech businesses in the country that can employ them (letting the government recoup their investment in the form of income tax).

Loans for living expenses are also provided on a means-tested basis, and these are paid back by graduates only once they start to earn enough money. If they never earn enough money, they never have to pay their loan back. Also, if they haven't paid their loan back in full by the age of 50 (or something like that) then it is written off. These loans are provided by a semi-governmental organisation which has the power to collect the fees like any bank, so fleeing abroad will work only as well as it would for any kind of loan.

This probably sounds crazy to most Americans, but it works, and it receives overwhelming public support. It seems the only people complaining regularly are the universities who say they make a loss providing the education, but this argument is usually muted when you consider the huge amount of money the government spends on research in these universities (and lecturers are usually also researchers, so you can't really separate the two).

Although I don't so much mind this new addition if it brings in revenue to Mozilla, who are a nice company seemingly with the good of the web at heart, they have been playing one underhanded tactic recently with Firefox Mobile. On the mobile version, there is no way to remove the search providers pre-installed in the software (Bing, Amazon, Google, etc.). There used to be a way, but this feature was silently removed. I know I can just avoid using the search features (and untick the setting to automatically suggest search terms based on my input), but I should be able to uninstall search providers rather than give them free advertisement space on my browser.

Adi Shamir of RSA fame.