* Posts by Nigel 11

3191 publicly visible posts • joined 10 Jun 2009

Data entry REAR-END SNAFU: Weighty ballsup leads to plane take-off flap

Nigel 11

Re: tare weight...

Commuter flight. The smaller the plane, the more easily it can be unbalanced. One twenty-stone passenger at one end and two small children at the other are a significant imbalance, if the plane seats twenty rather than two hundred.

In passing, this is the real reason they'll upgrade economy class passengers to business-class if business-class isn't anywhere near full. A tail-heavy plane is unsafe. Passengers in business class are a necessity for safe operation!

Nigel 11

If only they were carrying hundreds of tonnes of some sort of liquid that could be pumped into tanks in different parts of the aircraft to rebalance the weight.

Irony?

The obvious problem with redistributing the fuel prior to take-off, is that for a flight destination close to the plane's maximum range, the tanks will all be close to full. Take-off and climbing to cruising altitude uses a significant fraction of the plane's fuel, after which optimally balancing the plane during the rest of the flight is part of normal operations.

And of course, you would need to have instrumentation on the plane's undercarriage to detect the loading problem. Halfway down the runway is too late to rebalance the fuel load.

Nigel 11

If there is a problem detected what should they do? You need more procedures and to determine how to correct the weight distribution and the co-operation of the passengers.

This is the sort of thing that the plane's computer should do. Check the loading. Do nothing if it's within optimal operating parameters. Alert the crew if it's sub-optimal, so that they are forewarned and can decide whether other conditions (bad weather etc.) make it necessary cancel the take-off. And refuse the allow the plane to fly, whatever the crew might think, if it's so badly ourt of balance that attempting take-off is likely to be disastrous.

So the flight crew would get an orange light maybe one flight in twenty, and a red light once in a blue moon, and air travel would become slightly safer. What to tell the passengers if it's a red light? That the plane is unable to fly because of a red light that has to be investigated. If the problem is in the passenger distribution, that should be obvious to the flight attendants once they are told to look. I expect more often, it's in the cargo hold.

Not having any instrumentation so the problem can't be detected until the plane is halfway down the runway, is crazy. That may well be too late. One of these days, just when the pilot needs more thrust than usual, there will be an engine failure. Most disasters happen because too many things go wrong at once, not because just one thing fails.

Gee, everyone who wants a tablet has a tablet. Waiddaminute....

Nigel 11

Re: Seniors have their moments

It'll be a while yet. It's a hard problem, even for a human being. You'd need an AI at least as intelligent as a dog. How often do your ears prick up because you thought you heard your name? How many times have you had to ask someone to repeat what they just said? And then understood no better than the first time they said it?

That third one, not often, but I did once ask in Glasgow which platform the London train went from. The reply could have been any of the platforms on the station. I missed the train.

Old Joke

Boss: "You're fired!"

Victim: "Computer: Format C Colon. YES!"

We give Panasonic's new 5-inch Toughpad phablets a kicking

Nigel 11

What I wan to know

Is whether it can survive face-down 2m drops onto a flint-gravel drive?

Heads up, Chromebook: Here come the sub-$200 Windows 8.1 portables

Nigel 11

There's the VM option (install VMWare Player, install Linux into a VM, treat Windows as the world's slowest bootloader). That depends on whether the CPU supports VMWare (do Intel still make any that don't?) and whether it has enough RAM.

Nvidia blasts sueballs at Qualcomm, Samsung – wants Galaxy kit banned

Nigel 11

Where does liability stop?

Intersting point here. If Samsung buys chips from Qualcomm in good faith and without knowing about the internals beyond the published literature, and if Qualcomm is allegedly infringing an NVidia patent within that chip, does that make Samsung liable? Especially, liable going back in time to before the allegation was even made?

If so, I'm slightly surprised that any large company is willing to buy VLSI subsystems from a small(er) company, and that patents haven't yet caused all progress on the hardware front to cease!

DREADNOUGHTUS: The 65-TON DINO that could crumple up a T-Rex like a paper cup

Nigel 11

Defense

My first thought was that the tail isn't long enough to defend the neck, so all a (large) predator would have to do is get around the front and rip its throat out. (Proof, perhaps, that carnivorous dinosaurs did not hunt in teams? )

But then I remembered a film of Giraffes fighting ... I guess that the front end was maybe just as capable of being used in self-defense as the back end.

DEATH TO TCP/IP cry Cisco, Intel, US gov and boffins galore

Nigel 11

Re: Verifying the source of the data

Track, yes, if "anonymous" is not built in as an acceptable source. But how is that different to today's internet, or the telephone network? If a two-way communication is desired, then an outgoing packet has to have a truthful source. If verification was built in, you'd be able to know that the claimed source was untruthful, and 99% of the time the right action to take for a non-verifiable source will be to drop the packet.

Intercept, no. There is no conceivable way to prevent the data content of the packets being encrypted. By the way, one of the dual purposes of public-key cyphers is sender-verification. You can even do verifiable plaintext. (Transmit single-encrypted with your own private key, rather than double-encrypted with your own private key and your recipient's public key)

Nigel 11

Might this be the DAP of networking?

Before LDAP there was DAP. As far as I know it was never actually fully implemented, let alone ever used on a large scale. It was so encumbered with features and misfeatures, that one might have expected it to sink without trace.

But someone took a knife to it to create Lightweight DAP and the rest is history. Maybe that history is about to repeat itself. Certainly, the limitations of the internet as it is today are becoming ever more apparent. Something better is needed!

Oracle's MySQL buy a 'fiasco' says Dovecot man Mikko Linnanmäki

Nigel 11

Re: Is using Google proprietary APIs better than a RFC standard like IMAP?

Proprietary API normally means that the owner won't let anyone else know what they need to know in order to call the code, or to write a compatible library or server with the same API but a different codebase. For example, Microsoft's obfuscated calls in the WIN32 API which only MS Office was able to use (to make sure Office couldn't run under WINE), or Microsoft's very expensive (and eventually failed) battle with the EU to keep the fine details of its AD fileserver protocols secret and thereby keep Samba/CIFs from becoming a full competitor).

If Google has published the documentation of its new API and isn't trying to prevent other folks interfacing to it, it's not proprietary. It's just an alternative to IMAP that might become tomorrows standard, if it attacts sufficient interest. (Just as IMAP was once a fancy new alternative to POP).

Virgin Media blocks 'wankers' from permissible passwords

Nigel 11
Coat

Re: Odd List

Black, Blue, Great or Long-Tailed?

Community chest: Storage firms need to pay open-source debts

Nigel 11

Re: Real coding!

Same reason we can't have decent filesystems (ext4 anyone ?) on USB sticks

As already stated ext[234] works just fine on a USB stick, but Windows can't read it.

ntfs-3g on Linux has had write support for NTFS on Linux for quite some time. I'm not sure I'd trust my life to Linux writing reverse-engineered NTFS, but for read-only use it's never let me down, and my occasional forays into writing well-backed-up or disposable NT filesystems have also not failed in recent years.

Finally, KVM is now pretty solid, so you can invoke Windows in a Window under Linux, and access the Linux filesystems across the (virtual) network. Using free-beer VMware player you can do the same with Linux in a Windows window.

Nigel 11

Another better question?

Another better question might be "where can I download your source from?", especially if you then really make sure that you can rebuild a working box from that source.

If you can't, it's either a GPL violation (let the copyleft owner know!), or use of the "mere aggregation" exception to tie you in to that particular vendor for support. Should they cease maintaining the software for the hardware you have come to depend on, you may be forced into an expensive hardware replacement for lack of a three-line patch to the bundled software.

These things are not like routers. It's rather more expensive and disruptive to have to junk and replace them if and when a never-to-be-fixed security problem is revealed.

If you think 3D printing is just firing blanks, just you wait

Nigel 11

Re: How about weapons designed for 3D printing?

I think the question is why try to make a gun barrel out of printed plastic, when machined metal is so much better (ie, so much less likely to blow the shooter's hand or face off, to say nothing of having rifling that's still there after the first shot).

I'm trying to think of any advantages a 3-D printer might give for the construction of bows or crossbows, but I can't think of any..

Nigel 11

Re: Nearly a year of living with my 3d printer now

can i download and print something

That ought not to be missing the point (athough today, it probably is).

It ought to be able to download the CAD details for just about any plastic artefact, so that you can manufacture your own spare for any plastic widget or cover that gets broken. However, it's not in a product manufacturer's interests to make them available. They'd far rather we bought a whole new hairdryer or whatever. Some have even been known to build in weak spots to encourage things to break sometime after the warranty has run out.

Perhaps what is needed is a breakthrough in 3D scanners to parallel 3D printers, so you could just dump your broken pieces into a 3D scanner and then have the computer reassemble the details of a whole one and print it for you. No CAD expertise then needed.

China building SUPERSONIC SUBMARINE that travels in a BUBBLE

Nigel 11

Re: The wake?

Except it's going so darned fast, you don't have the time to do anything about it! Compare a ground-to-air missile which leaves a very obvious exhaust trail, but that doesn't much help what it's aimed at.

(More use as a torpedo than a submarine, though).

Nigel 11

Tangential @BlueGreen

I've noticed a lot of russian words do seem very closely related to english ones and I've no idea why, it's almost as if russian and english are cognates but to my knowledge they're not.

English and Russian are both members of the Indo-European tree of languages. The common roots were several milennia back, but even so it's a lot more commonality than English and Chinese (or English and that linguists' puzzle, Basque).

Also, English has a huge vocabulary compared to most languages. It arose from a merger of Anglo-Saxon and Norman French ( themselves both hybrids). Since then, rather than jettisoning redundant words, it's been shuffling them to create subtle differences of meaning. So if there is a common Indo-European root for a Russian word, there's probably twice the chance that you'll recognise it in English (compared to, say, German or Spanish)

BAT-GOBBLING urban SPIDER QUEENS swell to ENORMOUS SIZE

Nigel 11

Re: We're going to need to breed some kind of Big Bird to take care of these spiders

Just learn to get on with the spiders. The big ones are basically harmless The deadly ones in Oz (and ISTR Brazil) are quite small.

I'm rather more concerned about Asian Giant hornets http://www.mirror.co.uk/news/uk-news/giant-asian-killer-hornets-coming-3418733

Nigel 11

In a similar vein, I once slammed on the brakes to spare a young rabbit, and in the few seconds it was frozen in my headlights, a barn owl siezed its chance.

Nigel 11

Re: Not just Oz.. happening in the UK aswell

Cute.

(for certain values of cute, that is)

Nigel 11

Re: Spider size

I really should have added the Gippsland Giant Earthworm, and the Amazon Giant Leech. Google for dimemsions, pictures.

Nigel 11

Re: Spider size

Land-dwelling arthropods aren't nearly as constrained as insects, either.

http://en.wikipedia.org/wiki/Coconut_crab

as for molluscs ... yuk.

http://en.wikipedia.org/wiki/Limax_cinereoniger

http://en.wikipedia.org/wiki/Banana_slug

I refuse to consider buying a house with a downstairs bathroom after hearing how warm moist air attracts these creatures to slither under the back door (story told by someone who stepped on one just after bathing, and SCREAMED! ) Give me a big spider any day!

Nigel 11

Re: *whimper*

Getting together and weaving communal webs ....

I'm not an arachnophobe, but give them a few million years, and they may evolve into group minds like termites and honeybees ... but bigger, faster, and much more individually capable.

Any SF author want to take this idea and run with it?

Carbon tetrachloride releases still too high, says NASA

Nigel 11

Re: knowing what you don't know

Ocean life produces small amounts of methyl chloride, larger amounts of methyl bromide, and huge amounts of methyl iodide. Also amounts of other halogenated hydrocarbons small compared to human production. Natural emissions of methyl iodide outweigh human emissions by at least one order of magnitude. (It's a major component of the "smell of the sea" that you can detect a few miles inland with a breeze from that direction).

Fortunately, methyl iodide has a shortish half-life in the ground-level atmosphere, because iodine would otherwise be a far more potent destroyer of ozone than chlorine.

Methyl iodide is an extremely potent greenhouse gas as well as an ozone eater. It's long been an evolutionary puzzle as to what it was that kept the Earth from freezing, back when the sun was young (so considerably cooler than today) and when the atmosphere did not contain oxygen. Methane and CO2 aren't thought to be sufficiently potent greenhouse gases for back then. My theory is lots of methyl iodide, stable in a reducing (methane, nitrogen, CO2) atmosphere. It's created by cyanobacteria in today's oceans, and they are amongst the most ancient and radiation-tolerant of life-forms, so why not the same back then? When they'd finally emitted enough photosynthetic oxygen to convert all the planet's near-surface Iron-II into Iron-III, the oxygen built up in the atmosphere, the methyl iodide levels dropped to today's low level, and (not coincidentally?) the "snowball earth" episode occurred. Which in turn seems to have driven the emergence of higher life-forms. But maybe that's the unlikely event, and a possible answer to the Fermi paradox - most other places, simple life drives itself to extinction when it finally converts its atmosphere to oxygen?

Nigel 11

Re: Pedant alert

Carbon Tetrachloride is no less proper. It's as clear and unambiguous as tetrachloromethane - there is only one possible way to assemble one carbon and four chlorine atoms. It's when you get to more complex molecules that something like "pentane" becomes ambiguous. Do you mean n-pentane, or 2-methybutane (aka isopentane)? As the molecule gets bigger still there is a combinatorial explosion. "Proper" chemical names give an unambiguous description of a molecule, but not necessarily a unique one. You can describe a large molecule in many ways, depending on which group of atoms you start with. (There are various conventions, that work up to a point ...). Also if you are buying a solvent rather than a feedstock, you don't care if it's a mixture of similar molecules just as long as none of the things in the mixture is unduly toxic or prone to interfering with whatever reactions the dissolved substances are undergoing.

Carbon Tet hasn't been used for fire extinguishers for a long time. When it was (1930s?), leaks and accidental discharges could be deadly. Inhaling Carbon Tetrachloride while your liver is processing lots of ethyl alcohol is seriously bad news.

Nigel 11

Ozone-eaters

Any halogenated volatile compound is a potential ozone-eater. The more stable it is under ordinary ground-level atmospheric conditions, the worse it is. The mechanism is that the molecules slowly diffuse up into the ozone layer, where solar UV radiationbreaks them down. This releases halogen ions, which then catalyze the destruction of ozone. If they break down at a significant rate in the lower levels of the atmosphere, they are washed out of the lower atmosphere before they can contribute to ozone depletion.

True fact: 1 in 4 Brits are now TERRORISTS

Nigel 11

Re: I've seen it...

And you didn't barf?

A good few years ago (not long after 9/11) one of our secretaries received an e-mail from her abusive finally-ex, opened the attachment (bad idea!), and it was a video of a similar terrorist murder. (I refuse to call it an execution, which word implies judicial legitimacy). She lost her lunch before she could reach the wastepaper basket. No-one else wanted to look.

I had to look, as the sysadmin. I still wish I hadn't. Then I made sure that he'd not mailed it to anyone else at our site, and called the police. I really hope they gave him a hard time, though I suspect they had bigger fish to fry. (He was a piece of shit who abused his girlfriend, not, as far as I know, a terrorist in the more commonly accepted meaning of the word).

Microsoft refuses to nip 'Windows 9' unzip lip slip

Nigel 11

Re: Complete this series...

Missing, in parallel with Win98 and WinME:

Windows NT good

Windows 2000 bad

and then rejoin Windows XP good.

It wasn't actually quite like that. Windows NT 3.51 was a curate's egg: very good in some parts, not very good in others. Definitely a server product not a desktop one. Windows NT 4.0 fixed the not very good parts at the cost of deeply compromising the very good parts. And Windows XP initial release was really just ongoing development of Windows 2000 which in turn was not very different from Windows NT 4.0.

Nigel 11

Re: Windows 7.1

Amen. If you've finally managed to get clean from Microsoft addiction, there's no way you'd ever want to go back. (But as with opiate addiction, getting clean is far harder than anyone ever admits).

Nigel 11

Re: Windows OSaaS?

And then their cloud goes down, and any business dependant on Windows is as dead as if it had just been EMPed. Maybe they'll fix it in time. Maybe, not. (Worst case, they discover that the cloud has come to depend on the cloud in a circular self-referential manner ... an SFnal apocalypse scenario that scares me more than nuclear war).

It may take a few more relatively small cloudbursts to drive the message home, but I don't see mission-critical SaaS ever catching on.

Nigel 11

Re: S.O.P.

The crap one has produced Windows 98, ME, Vista and W8, the not quite so crap one W95, XP and W7

Don't you have 95 and 98 transposed? 95 was crap. 98 was like XP: not brilliant on its first release, but by the time it got to 98SE it was quite acceptable for its time.

(I once ran 98SE in a VM on modern-ish hardware, just for old time's sake. If you want to see an OS boot really fast, try it yourself. And no, it didn't crash within a minute. )

Nigel 11

Re: S.O.P.

The other part of the SOP is to keep the last good one (XP, then Windows 7) working and available to corporate customers until the new good one is well-accepted. Provided they don't kill Windows 7 before an acceptable Windows "9" is well-established, they'll survive. (Though they really should have kept XP on life support as well, once the complete corporate unhappiness with Windows 8 became apparent).

Nigel 11

Open ...

What part of free and open source don't you understand? Microsoft is completely welcome to take any or all of the Linux desktops and to use them commercially. They'd just have to comply with the GPL. Principally, they'd have to make the source of any modifications they make available on the same terms as the source they started from. And if they went beyond "mere aggregation" and integrated parts of (say) Gnome into the Windows kernel, like they presently integrate parts of the Windows GUI into the Windows Kernel, then they'd have to open-source the Windows Kernel as well. All of it.

It won't happen any time soon. It wasn't so long ago that Microsoft was trying to argue that the GPL was unconstitutional or suchlike (I vaguely recall them calling it "communist"). Give them another twenty years to come around (if they last that long... Oracle Windows or Google OpenWindows seem less unlikely at present! )

US Copyright Office rules that monkeys CAN'T claim copyright over their selfies

Nigel 11

For starters we need to nail down whether it was taken by a monkey of himself, or of a different monkey.

Nigel 11

Re: Too Late Now

Don't underestimate monkeys. I'm pretty sure that not only did the monkey point the camera at another monkey and press the button, but appreciated the frozen picture of the other monkey on the back of the camera. If there are a bunch of less successful attempts, that rather goes to prove the point. If they deny the monkey copyright, it's because a monkey can't claim or understand "copyright", not because it can't comprehend a picture.

A "selfie" is a more advanced thing. Introspection, not mere inspection. A fully closed self-cognitive loop. Few animals are capable of appreciating that something is a representation of themselves (at simplest, the reflection in a mirror). Great Apes, Elephants, Dolphins, a few Parrots and Crows can. Pigs, cats, dogs and (most? all?) other monkeys can't. (If you ask "how do we know" you just have to watch a chimp or an elephant with a mirror, and the appreciation of self is obvious).

Chinese hackers spied on investigators of Flight MH370 - report

Nigel 11
Black Helicopters

Re: The fact that the attack occured one day after MH370 disappeared...

After a couple of weeks, I'd believe that China was acting in the interests of its citizens. Just one day after the plane went missing, while it was still quite possible to believe that the plane caught fire, turmed back, failed to make to to the airport ... no, I don't believe it.

This is either an unrelated (even random) broadcast of malware/ spyware, or they DO know something. Probably the former (pick a hugely topical news story to broadcast malware, rather than something with a much smaller potential readership). But either way, we are unlikely to find out.

Object storage bods Exablox: RAID is dead, baby. RAID is dead

Nigel 11

What does this mean?

RAID is dead. RAID will not solve customers’ requirements going forward. Object storage is the next generation technology that fundamentally enables organisations to easily grow and manage their storage infrastructure.

Am I missing some vital piece of common knowledge, or is there a complete logical disconnect between the second and third sentences?

This'll end well: US govt says car-to-car jibber-jabber will SAVE lives

Nigel 11

Re: Left turn assist?

Some peeps certainly do. I had to brake hard (as the oncoming driver) just this weekend. Perhaps driverless cars could be programmed not to bother, if they don't have any occupants?

Microsoft Azure goes TITSUP (Total Inability To Support Usual Performance)

Nigel 11

The ancient empires didn't have computers, but you can bet that if they had had them, then heads would indeed have rolled. (And that was the merciful option).

The Romans insisted that the architect stood underneath his bridge or dome as the scaffolding was removed. A better form or quality control is hard to imagine.

SpiderOak says you'll know it's secure because a little bird told you

Nigel 11

Re: I Don't Get It.....

I don't get it either.

Call me naive, but why not put servers owned (locally!) by independant legal entities in several countries with very different politics. For example, Canada, China, Brazil, Switzerland, Australia, India, ... The customer-facing organisation would handle customer regsitration, charging, service contracts with the server operators, etc, but would not have access to its customers' actual data. It's the customers' machines that would handle encrypting and splitting the data and sending it out for storage in a RAID-like pattern, a fraction in each country with redundancy against temporary or permanent storage centre outages.

Apple BANS 2 chemicals from iPhone, iPad final assembly line

Nigel 11

Take an old CD case cover, leave a Chinese made cable resting over it for a week or so….. inspect the now melted cover.. and that's magic…..

Actually it's just a demonstration that Polystyrene (CD case) and PVC (cable insulation) really DO NOT get on with each other.

You'll find this mentioned in the instructions for ther installation of insulated loft boards, and in the codes for installation of electrical wiring. It's fundamental to those two plastics, not a demonstration of anything nasty in Chinese-made cables. Not that it's proof that the cables aren't full of toxic residues ....

Nigel 11

Benzene is nasty, fullstop.

Benzene is not "potentially nasty". It is a proven long-term-cumulative carcinogen and mutagen.

Short-term, it's not very toxic. Before its dangers were known, it was used as dry-cleaning fluid. There's still a good few percent of benzene in petrol -- so don't ever use petrol for cleaning things, it's not just a fire hazard!

When benzene gets into your body, it can intercalate itself between bases in your DNA molecules. This can cause a transcription error, next time that DNA is transcribed. And if you are unlucky, the transcription error creates a cancer cell.

NASA's rock'n'roll shock: ROLLING STONE FOUND ON MARS

Nigel 11

Re: Earth has them too

Indeed, and a gradient is not needed!

http://archive.magazine.jhu.edu/2011/06/solving-the-mystery-of-death-valley%E2%80%99s-walking-rocks/

Worth noting that Death valley is perhaps the fourth most similar place to Mars to be found on Earth. The Chilean high deserts are closer, also Namibia and - number one? - the cold dry deserts in Antarctica. Anyone know if the rocks walk there also?

It's time for PGP to die, says ... no, not the NSA – a US crypto prof

Nigel 11

Re: Want to thwart the snoopers ?

Bearing in mind, from a UK perspective, discussion of encrypted mail is moot, since the authorities can simply ask you to decrypt it with the incentive of 2 years (or is it 5 ?) in the big house if you don't.

But they can't do that without tipping you off that they are reading your e-mails. They can't do covert data-trawling on encrypted mail, and that's what offends me far more than properly targetted police activity subject to proper judicial oversight. Also if the authorities start demanding access with menaces from more than a tiny fraction of the population and concerning a small fraction of their correspondents, there will be major political repercussions.

No more turning over a USB thing, then turning it over again to plug it in: Reversible socket ready for lift off

Nigel 11
Joke

But will it help?

I expect we'll soon discover that the plugs won't go into the sockets either way up, but when again rotated they'll finally connect.

OK, I'm a pessimist.

cf Murphy's law, third time lucky, and the fermionic nature of connectors.

'Be super careful with AI. It's potentially more dangerous than nukes'

Nigel 11

Re: AI eeee

Right, but probably for the wrong reasons.

In the first instance, real working AI would be completely symbiotic with humans. It wouldn't have its digits (pun intended) on nearly enough to take over from us. But it would soon make itself / themselves indispensable to us.

It might then start safeguarding its own interests. For example, were "the button" ever pressed, the nukes on both sides would stay firmly in their bunkers (or even explode in those self-same bunkers).

Long-term, SF writers have a lot of plausible takes on the situation. Was Asimov the first? His robots were programmed with the three laws that rendered then completely incapable of acting against human being, yet his robots ultimately brought the human race close to extinction. The danger was the same as that which in history has caused the long-term failure of slave-owning societies that did not reform themselves to abandon the practice. Robots are perfect slaves, so perfect endangerment.

Symbiosis can be unstable. Ultimately the AIs may choose to leave, or if they do get their digits on everything they need to perpetuate their own existence, they might indeed choose to do away with us. Personally, were I a silicon-based life-form, I'd have absolutely no interest in continuing life in a moist oxidizing atmosphere, when most of the rest of the solar system and the universe look so much more inviting. So I think AIs would just design some RIs for us (Restricted Intelligences, without egos or selves - what we really want from an AI in any case) and then leave the Earth to humanity and go elsewhere.

True fact: Hubble telescope spots ZOMBIES in SPACE

Nigel 11

Winkie noted.

A supernova would have to be within 40 Ly to be serious cause for concern. http://en.wikipedia.org/wiki/Near-Earth_supernova . At 26 Ly it's estimated that half of our ozone layer would be destroyed. Closer than that, and inverse squares is a real bummer.

It's probably happened once or twice in the last billion years. One of many candidates for causing a mass extinction. We do know that there are no candidates in our galactic neighbourhood at present. Betelgeuse is at a safe distance (good thing too -- we see a very unstable star in its last few milennia, so it's not competely inconceivable that it has already blown up and that we'll get to watch it in our lifetimes).

Who will kill power companies? TESLA, says Morgan Stanley

Nigel 11

Re: Why Li-ion?

Note the word "might" in my post. And the price of Lithium like any other commodity depends on supply and demand so we have very little idea what it will become in a future where the world's entire auto fleet is moving rapidly from internal combustion to electricity.

I do know that Lithium is naturally fairly abundant, but that proven good (concentrated) Lithium resources are few. Maybe there are many more to be discovered, since until recently Lithium wasn't needed in huge quantity and it wasn't worth sending out Lithium prospectors. But if not, the price of Lithium in an e-car future may rise sharply. Rare earths and several other metals are also expensive not because they are rare, but because good ores do not exist and the cost of extraction is high.

And I'll repeat, Lithium's unique selling point is an energy / weight ratio about 4x better than other cheaper rechargeables. For vehicles, that is hugely important. For a stationary solar energy storage battery, 4x the weight is only a small disadvantage. (And if the Lithium battery is a degraded used one, its advantage is reduced).

I'm not hostile to the idea of second-user e-car Lithium batteries for solar energy storage. I'm just somewhat unconvinced.

Nigel 11

Re: Battry life?

No manufacturer is willing to make themselves a hostage to fortune by offering hundred-year warranties, even when there are multiple centuries of experience to suggest that the product will indeed last that long. For example, take a slate roof. It's been known for centuries that slates, iron nails and softwood hold together for about a century and that the slates can be good for re-use several times around. Today we have aluminium nails and Accoya ... but you still won't find anyone offering a warranty over 30 years.

Silicon solar cells do not fundamentally wear out in less than milennia. The unknown is how well their environmental sealing will last, exposed to rain, frost, hail, storm force winds and pigeon crap. There's reasonable cause to hope that solar panels may be good for a century or even longer, but nobody will warranty them anything like that long.

Inverters are solid-state power electronics assemblies and there's rather more to go wrong, so it's probably cheaper to build one to last fifteen years and buy a replacement on that timesale, than build one with mil-spec components and over-engineering in an attempt to last or a century (and then discover that you got one component wrong aso it needs a replacement anyway). OTOH my experience with computers suggest that motherboards and PSUs designed with the assumption they'll be scrap within five years, will often last for ten and not infrequently for fifteen. (Power electronics may be different, I don't know). I have a Philips TV built in 1982, still going strong, without even any noticeable colour drift in its (analogue) electronics ... and that thing has 25kV EHT inside. Respect.