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Comment Re:I could be missing something (Score 1) 96

"As seen from the moon, the Earth is only about two degrees across"


At the time of the late heavy bombardment, the moon was a _lot_ closer than it is now. Close enough that the earth was a fairly effective shield.

It also means that tidal forces and heating effects would have been a lot stronger too.

Comment Re:Yeah, and? (Score 1) 56

"Gold, platinum, iridium, rhodium, osmium, indium and palladium hover in the rough ballpark of $10000-60000 USD per kilogram; gem-quality peridot about the same"

You face a double-barrelled problem.

1: Space is currently expensive enough that recovering any of these materials is uneconomic even if there were ingots stacked on an asteroid (or the moon) awaiting collection.

2: Supply and demand. As soon as you start landing significant quantities of these materials the price will tumble.

The logical target market for space mining is space manufacturing and consumption. It's obscenely expensive to haul stuff out of a gravity well using chemical rockets. Space elevators are some time off (if ever), ditto Lofstrom loops or similar technology and Orion-class launchers contravene nuclear limitation treaties.

The two single largest resources available are iron/water and they're not something that's exactly in short supply on earth. Concentrations of other minerals may be a lot higher than on earth but the problems of zero-g extraction and smelting are hundreds of times more complicated in the short term. Even if you can match ground-based production costs, the moment you bring large quantities of supply online is the moment those precious metals/minerals are no longer precious ones unless cartel tactics are used (Like de Beers have used for over a century to hold gem diamond prices at least 10 times above what they should be)

Comment Re:Smart man (Score 1) 378

One of the most efficient propulsion systems in space is a nuclear bomb. If you want to run that far you wouldn't use chemical or ion reactions, they're far too inefficient.

With regard to shielding (which is the big bugbear people keep ignoring) - water is one of the best shielding materials that exists and there's a lot of it on Ceres. Once in the right shape it can be left to freeze. Water is at _least_ as important as mining metals for this reason.

Comment Re:Heinlein quote. (Score 1) 378

"Then there is the reality that the Earth is going to be literally cooked by the Sun eventually"

Eventually being about 500 million years, not the oft-quoted 4 billion.

The sun is gradually increasing in output (it's significantly brighter than when life first crawled out of the oceans). Long before it goes red giant, surface temperatures will be too high for liquid water to exist and once that happens Venus isn't far off.

Comment Re: Religion (Score 1) 519

"This is hardly a Muslim-only problem, in fact this is an argument I hear all the time from Christians, but its the first time I've heard it acknowledged by a Muslim."

Pretty much all religious people will say the same thing (including jews), EXCEPT the hardline fundamentalists or whatever faith it happens to be.

The core message of almost every major religion has been "Be nice, don't be an asshole"
This has been twisted around at some point by someone to be "Kill anyone who isn't like 'us'"

Politicians have always been around and a lot of them dress up as religious leaders because that way their motives don't get questioned.

Comment Re:Holy Flamebait headline Batman! (Score 1) 366

"Two different people made two different errors while calculating the weight using two different methods"

That's highly unlikely and probably an ass-covering excuse.

The more likely scenario is that one crewmember made an incorrect calculation and the other said "looks about right". Humans are humans, etc.

What I can guarantee is that both pilots will always crosscheck in future, no matter who they fly with. That degree of error would make the feel on takeoff "wrong" enough to be a brown-trouser moment.

Comment Re:Data data everywhere and not a drop to think (Score 1) 366

"Is there any reason you don't just slam the throttles open on a modern jetliner until you are off the ground?"

Firstly: In most parts of the world: Noise laws

Secondly: Going to 120% power dramatically shortens engine life so you only do it in an emergency (yes, you turn it up to 11, but there are tradeoffs). Engine overhauls are extremely expensive. Management frown on pilots who cost the company too much.

This was an aircraft that was 10 tons heavier than calculated - on a 737 that's easily a 15-20% variation on nominal MTOW. That makes a large difference to the rotate and liftoff velocities. These are precalculated based on the aircraft's assumed weight to give optimum climbout rate.

If you rotate early or overrotate, the aircraft takes longer to get to liftoff velocity. If you rotate late the ride is bumpy and that is bad for both the nerves of the passengers and the fatigue life of the airframe (late rotation is used in hot'n'high conditions or where you need to "spring" off the runway, but generally strongly discouraged). Taking longer to get to liftoff velocity may mean running out of runway.

The surprise is that they only kissed the tarmac. It must have been a long runway with an easy climbout. If they'd done that at Queenstown (where 737s have to fly out with the front 4 rows empty in order to be able to climb over terrain) this would have resulted in a messy smear mark over a nearby mountainside.

Comment Re:It's even worse than that now. (Score 1) 366

Ok, so a big-ass weighstation platform. Let's ignore the logistics of something that size that for a moment

Weighing accurately from under 1 ton to over 700?

Compensating for rain? Compensating for wind? (This will make apparent weight change. A parked 747 in even a mild breeze moved and heaves like a beast wanting to leap into the air)

Calculating the centre of mass too? (This is at least as important as overall TOW)

Comment Re: 20 cores DOES matter (Score 1) 167

"Memory bandwidth can become an issue"

Bandwidth is almost never an issue. _Latency_ is another matter.

There are a lot of tricks and bits to optimise things regarding locality (mainly around row based and lookahead accessing. CPUs aren't the only devices trying to predict what will be read next) and controller optimisation, but the underlaying dynamic ram itself hasn't actually improved much over the last 20 years in terms of time between addressing a random cell and getting an answer back from it. The big improvements have been around the number of requests you can make while waiting for that answer instead of being in request-answer lockstep and there is only so far that can be taken.

_true_ 1GHz ram would have 1ns latency, not 12-30ns - and the reason that L1/L2/L3 is so important is because of that poor response time.

Comment Speed fallacies. (Score 1) 167

"it could potentially trail behind the Core i7-6700K, a quad-core Skylake processor clocked at 3.4GHz (base) to 4GHz (Turbo)."

Not by much.

If you want to see the true speed of any CPU, look at the memory speed. Internal multipliers make some steps run faster but the overall effect isn't high enough to justify the cost deltas on the higher-clockrate CPUs. In general the sweetspot is 2-4 steps below the top step.

If you have a proper multitasking operating system it will take as much advantage of extra processors even if individual programs don't. For that reason I always bias toward more CPUs than higher clockrate when specifying servers for the datacentre, whilst aiming for maximum possible memory speed (That used to mean trying to keep to one bank on DDR3, but it's a bit easier with LRDIMMS and DDR4)

We don't run much virtualisation, as the kind of loads being run invariably max out the raw systems so there's no point, however in a virtualised environment "More CPUs" always beats "faster ones" as long as hyperthreading is disabled (if a virtualised box gets assigned a HT "CPU" then it will crawl).

Higher CPU clocking is mainly good for willy-waving, other than in quite specific tasks where you can keep everything important in L1/L2.