The thrust to weight ratio of the rocket motor only really matters near the end of a burn when the motor weight becomes a significant part of the total vehicle mass at that time after hundreds of tonnes of fuel and propellant have been expended. It's a good thing to have a lightweight motor but shaving a hundred kilos off the motor mass isn't as important as boosting the Isp by, say, ten seconds as that boost improves the performance all the way through the burn and has a much bigger impact on payload to orbit with given hardware. SpaceX have been working hard to improve Isp, of course -- the Merlin first-stage 1D motors are a lot better than the original flight motors they started their operations with and they now have optimised upper-stage versions of the 1D for vacuum with improved Isp figures.

I know other manufacturers have looked at methane-oxygen engines in the past but not progressed with them. Why they didn't I'm not sure. LOX/RP-1 has a good track record and decades of actual operation to work with (which SpaceX took advantage of), LOX/CH4 is more of a leap in the dark. Building a big LOX/CH4 motor as the first flight item is another big step and obviates the cheap multi-motor Falcon vehicle platform SpaceX have been developing over the past few years.

Most new airline designs are slower than 1970s models (and that's not including Concorde and the Tu-144 either), for fuel efficiency reasons. They're much more reliable and safer, can carry more passengers and freight further per tonne of fuel, cheaper to operate and cycle gate-to-gate, cleaner, quieter etc. but not faster.

There are no miracles in rocket engine design. The RD-180 has pretty much the best performance to be wrung out of a sea-level-to-altitude LOX/RP-1 motor in terms of efficiency. SpaceX is still playing catchup in that area, trading off the lower cost per Merlin motor for a lower Isp from a simpler design.

As for the Raptor the "new" liquid-methane/oxygen fuel mix it will burn has the potential to produce a higher Isp than the current mainstream LOX/RP-1 mix used in motors like the Merlin, the RD-180 etc. but it comes with downsides -- it means a redesign of the rocket structure to support fully cryogenic tankerage (although not requiring the sorts of extreme temps or processing LH needs), launchpad facilities for fuelling and defuelling rockets will need to be revamped, liquid methane is half the density of RP-1 so the tanks and the rocket structure need to be larger and heavier to contain equivalent amounts of fuel and so on.

The final stage that was meant to put the two satellites into their proper orbit was a Fregat-MT upper stage built by the Russians and supplied as part of the complete Soyuz stack.

The satellites have their own motors used for station-keeping, trimming orbit etc. but I doubt they have enough fuel to move themselves to the planned orbit. Even in the wrong orbit the satellites will still work and provide position data to GPS receivers but they will not provide the sort of whole-sky coverage originally planned. They are high enough that they're not likely to deorbit within the next few years at least.

The complete Galileo constellation is intended to consist of twenty-four working satellites and six spares so ESA and the Galileo consortium have some leeway. They might revamp the deployment schedule to use fewer Soyuz launches and more Ariane V launches for the rest of the constellation though unless the Russians can explain what went wrong with the Fregat-TM and guarantee it won't happen again.

Ten trillion nuclear disintegrations of potassium-40 occur in a cubic kilometre of seawater every second. A single nuclear disintegration per second is a becquerel (Bq). Usually Bq are qualified by being associated with a mass or volume, Bq/litre or Bq/kg. Radioactivity in seawater is usually measured in terms of litres but if you make the sample size big enough (cubic kilometres) the numbers can look really scary.

A cubic kilometre of seawater contains about 10 trillion becquerels of the naturally-occurring potassium K-40 isotope. That's ten fucking disasters per cubic kilometre using your scale and there's a lot of seawater on this planet (1.3 billion cubic kilometres according to most sources).

Modern nuclear reactors can load-follow quite well, swinging output by 30% in fifteen minutes thanks to newer control tech and a lot of operational experience over the past 50 years. Load-following can even be done somewhat with older second-generation LWR plants. It's not actually done much since baseload nuclear power is very cheap in terms of fuel consumption and refuelling tends to be done at fixed intervals anyway. Other thermal generators like gas where the fuel is a major part of the cost of operations are normally used to top-up baseload stations -- in the UK the nuclear generators run full-out as much as possible with gas filling in much of the rest and coal as a cheap backstop, limited by pollution and carbon controls.

Most renewable generators get a guaranteed minimum payment for electricity they feed into the grid (in the UK where I live windfarm operators get about £145 per MWh) so the "excess" production is not free, it is paid for by the grid operators and ultimately the consumers even if it is not needed sometimes. If the renewable generators stored their excess production and dispatched it into the grid at times of low output that would be a different story, but that would cost them money so they don't do that. The round-trip efficiency losses are even more reason for them not to build storage into their operations.

Storage costs money. Lots of storage costs lots of money. Storage wastes energy too -- pumped hydro, the cheapest form of bulk energy storage has an input-to-output efficiency of about 65 percent. Baseload coal, gas and nuclear generation doesn't need storage to be useful and meet demand 24/7/365 unlike intermittent renewable generating capacity, but no-one ever adds the cost of storage to the cost of renewables when comparing prices.

You mean like the major Japanese Army command centre in Hiroshima? Or the extensive Naval dockyards and repair facilities in Nagasaki, close to where the Allied invasion was going to hit the beaches in Kyushu? Nagasaki was actually a secondary target due to bad weather over the primary target, a place called Kokura Arsenal which might give you an idea why it was on the target list.

In reality the atomic bombs were used because they were ready to be used, just one more wonder weapon in a war filled with wonder weapons. They contributed to the decision by the Japanese War Party, the military/political group in power at the time, to surrender but it was mostly down to the Russians declaring war on Japan on the 9th of August 1945 and promptly destroying the last major Japanese army outside Japan itself, the million plus Manchurian occupation force with embarrassing ease.

Diesel engines typically run at twice the compression ratio of a gasoline/petrol engine. They also last a lot longer than petrol engines in my experience. This may be because they are designed to deal with the higher compression and greater loads on crankshaft bearings etc. from day one. They do tend to be heavier than gasoline engines of the same power and torque though.

ITER is not run by Americans so it is, de facto, poorly managed.

A Korean comics artist name of Anyan does a web manga with anthropomorphic representations of military aircraft as high school girls. Tu-95 is very inquisitive, always sticking her nose in other people's business and always surprised that folks notice her doing it because of the racket she makes.

http://www.batoto.net/read/_/1...

A couple of Tu-95 Bears flew down towards the north of Scotland a few weeks back, the RAF went up to welcome them outside the national limit and got some nice pictures. I grabbed them off the MoD website and bundled them up since most of my friends are Apple fans and don't do Flash.

https://www.mediafire.com/?fs5...

Runs to about 12MB or so as a zip download.