That chart is too coarse-grained, in the time dimension to show the recent very sharp peak. The CH4 peaks (including the "present" one) on that chart
are at about 0.7 ppm and the current level is about 1.7. Similarly, the CO2 peaks are at about 280 ppm and the current level is around 385.

This is one of the hypotheses explored in the study. They find no support for it.

Several scientists have described schemes for manned insterstellar missions. They do use huge amounts of power, and are not likely to be practical for a century or two, but the sun produces a LOT of power which could be harvested.

However, what is really surprising if technological life is at all common in the galaxy is that no one has felt inclined to send out self-replicating robot probes or "spam" the galaxy with radio or laser messages. Robot probes travelling at even 0.1% of light speed would span the galaxy in a couple of hundred million year, a tiny fraction of its age, while laser or radio messages would take less than a million years.

Depleted uranium is barely radiioactive -- the half-life of U238 is billions of years. The problem is that it is a chemical poison.

We decided we couldn't outsource staff email to google or anyone like that, but student email was fine. We do now outsource staff email, but it's on dedicated servers (which I think we legally own).

That's your opinion, which you are rather close to trying to impose on others.

Other people take the view that it is ethical to encourage, or even compel others
to avoid some unethical behaviours, so they try to do that.

The X-rays will certainly heat the sample very rapidly indeed, and thereby probably increase the pressure in the cell, at least briefly, so I don't think the article is all wrong. Probably better to think of the diamond anvil cell as a pre-pressurizing step.

Large bright stars don't last nearly as long as smaller dimmer ones like the Sun, and it's the big ones that actually explode at the end of their lives and spray heavy elements into the interstellar medium, so, especially in the early life of a galaxy, gas may get processed through many generations of big stars.

That's actually impossible. The meter (or possibly the second) is defined by fixing the value of c.

Just did a bit of checking. For £249 including VAT you can get a mini-tower, dual core midrange CPU and 2GB RAM. A dozen or so of these and a switch looks very appealing if there is space. 300W PSU, so cluster should be under 5kW.

If your friend doesn't want to do a lot of engineering work, then for this price I would just buy 10 or so PCs (depending on memory/CPU tradefoffs) from wherever has a special offer, plus a gigabit switch and put them on shelves. If you need a lot of memory, or can usefully share memory then that would be a bit different, but you can buy a usable headless PC for £300-£400. This will also not be terribly power efficient, nor will components like motherboards be of the highest quality, but you get more bang for the buck that way than almost anything else except second-hand. At the other extreme, you could probably buy a single 24-core AMD box for the money with quite a lot of RAM and just run a lot of processes on it.

Talking of second-hand, the other thing to do is to see if anyone has a cluster they can't feed (ie power) any more. Our aplied maths dept is about to shut down a 3 year old 1000-core cluster because they can't afford the power to run it and their newer 2000 core cluster. A slice of that would be great and someone locally might be able to help you in a similar way.

In fact you correct the error by observing it.

Can I ask the same question for particle physics -- specifically non-abelian gauge theories. I'd like to be able to under stand the Higgs mechanism and supersymmetry properly and how the particles emerge from the symmetries of the fields.

My pure maths background is quite strong, but I stopped doing applied somewhere in my second undergraduate year and have forgotten most of the more advanced bits of it. So I have a hazy memory of curvilinear coordinates, and an even hazier one of Hamiltonians and Lagrangians. I can still more or less remember my SR course. On the positive side, I understand Lie groups and Lie algebras and their representation theory pretty well.

There are magnetohydrodynamic approaches. You make a lot of hot plasma, cool it by allowing to expand in one direction and then use a big magnet to separate the positive ions and negative electons, which impact different electrodes. I don't think it's terribly efficient (to put it mildly) and the wear on the electrodes is something chronic, but if you want a LOT of power (GW) for short periods (seconds to minutes) for some reason it might be usable. I think Jerry Pournells has a laser launcher powered that way, using rocket engines as the plasma source.

The idea, I think is that these servers are your cloud infrastructure, rather than being used for any local purpose.
Imagine a future where computer technology is a bit more stable than it is now, so a server has a 10 year or so useful life before becoming obsolete. Also you have fibre to every apartment building or office block.

Now, you want to convert some electricity into heat for whatever reason. So you buy/rent a "brick" of servers of suitable size, probably an all-solid state affair with no moving parts at all, plug it into the power and the internet and arrange to move heat out of it for whatever purpose you have. As far as you're concerned that's it, and this is cheaper for you than just buying or renting a conventional electric heating element (ie you get paid, or subsidised power for doing it).

As far as the user of the computation is concerned, they buy computation and related services from Amazon or someone, just as they do now.

The middle-man is running a complex management layer that migrates VM instances and data around the millions of "bricks" that they manage, and allocates each as much work to do as the demand for its heat output requires. Balancing the compute demand against the heat demand requires partly scale, partly non-urgent background jobs, partly blanacing load between time zones and hemispheres and partly a few conventional data centres that can fill in any gap.