33 posts • joined 30 Jan 2012

### Four hydrogen + eight caesium clocks = one almost-proven Einstein theory

#### Re: Equivalence orinciple (was @ Adalat)

Sorry tfb, I give up. I think we are arguing at cross purposes. It isn’t my job to reconstruct my experiment to fit the theory, by tilting or pivoting the track.

My example is a straight horizontal track. My point is that pushing the rail car by locomotive or by gravity are not equivalent or indistinguishable, if I were inside the car. Einstein’s “thought experiment” might be true in a vertical sense, but I can’t see that it applies in a horizontal dimension.

#### Re: Equivalence orinciple (was @ Adalat)

“…you know that it is not being accelerated by, say, a locomotive, however;”

But that is exactly my point. Without looking outside of the car, just by seeing the ball move, you can tell that the car is being accelerated, and that it is by a locomotive, not by gravity.

So the forces of locomotive and gravity are not universally equivalent.

Ok, so notwithstanding the statement "...the occupant of a windowless lift ... is unable to tell the difference between gravitational pull and acceleration" that principle somehow doesn't apply to my rail car?

Suggestion to editors: is it time to delete posts that are (way) off topic?

I have a problem with the equivalence of inertial and gravitational mass. My thought experiment:

I set up a straight level railway line. On the line is a single freight car, which has a plain smooth flat deck. On the deck is a steel ball bearing.

Now at the end of the line, I put a massive object (a mountain or an asteroid). The freight car, and its load, feel the attraction of gravity and moves (on its frictionless wheels) towards the massive object.

Now start over, but this time I couple an engine to the freight car and tug on it. In my mind’s eye I can see the freight car accelerating, but the steel ball rolls back towards the far end and falls off. Has the steel ball detected the difference between the pull of gravity and the pull of an engine?

I think this illustrates a hidden assumption, that everything in the frame-of-reference elevator is physically attached to it.

Am I missing something?

### Uber's disturbing fatal self-driving car crash, a new common sense challenge for AI, and Facebook's evil algorithms

#### Re: Cameras != Eye Balls - particularly in low/no light

"The camera picks up the pedestrian and her bike at the last minute..." I would hope that autonomous driving software uses something better than a dashcam for its vision of the road ahead. If it can't see better than human eyes then it shouldn't be on the road.

And do they not use radar as well? I thought somebody would have learned that lesson when the Tesla plowed into the side of a truck, and the excuse was that LIDAR couldn't discriminate between the white-painted truck and the white cloudy sky behind it. That example was white-on-white and this event appears to be black-on-black, but its the same issue.

I also read that police investigators found the car was logged as doing 38mph in a 35mph zone. That is already a chargeable offence in my jurisdiction. My own car's cruise control works better than that! WTF was this software doing? Checking its e-mails?

#### Re: You've missed the scariest parts

"Please cite where the information is that the car was speeding..."

see for example

http://fortune.com/2018/03/19/uber-self-driving-car-crash/

#### Re: Uber Lidar

That had me wondering as well. A point I haven't seen anywhere is whether the car was petrol engine or electric (and therefore making little noise)? Why did the pedestrian not detect the car is as much a question as why did the car not detect the pedestrian. Don't these self-driving cars carry normal headlights?

### NASA budget shock: Climate studies? GTFO. We're making the Moon great again, says Trump

So if a Chinese company made an offer for the US share of ISS ...?

### Going to Mars may give you cancer, warns doc

#### Its a different world

Let's keep this in perspective. The first people living on Mars are not candidates for a quiet retirement. They will face a number of risks, including (but not limited to) their rocket blowing up, their rocket crashing on arrival, decompression by a punctured space suit, decompression of their accommodation module, running out of oxygen or water or food, a war on Earth interrupting their supply ships, and so on and so on. If they live long enough to die of cancer they will be lucky.

### Britain's on the brink of a small-scale nuclear reactor revolution

#### Re: Placed underground you say ?

The essential problem is cooling. Coal fired power plant chimneys obviously blow out a lot of CO2 smoke, but what is less obvious about a coal-fired plant is that the chimney takes away a massive amount of waste heat. Nuclear power plants typically have huge cooling towers precisely because they have no chimney. Putting them underground would create impossible cooling problems.

Submarine reactors are generally much smaller in output than you would need to power a town. They are built with special constraints that make them uneconomic for commercial use (which is incidentally why commercial ships don't use nuclear power). That is ok for the navy because they have a defence budget to pay for them. And as to cooling, submarines have an ample supply of seawater.

### Schrödinger's cat explained with neutrinos

#### Re: But

If the cat knew what else was in Schrodinger's box, yes I am sure it would be unhappy.

#### Re: Observation of neutrinos

If you open the box a week later, it will be obvious that the cat didn't go dead just at the moment you opened the box. (Note: this is best left as a thought experiment.)

#### Don't confuse the cat with the uncertainty

Sub-atomic particles may be subject to quantum effects like superposed states, but the consequences do not inherit that uncertainty. Stuff happens, without anybody observing it. My uncertainty is my problem, not the cat's. The cat may be unhappy at being locked in this stupid box, or it may be dead, but it is not uncertain.

### Australian Information Industries Association*: you're not the future of democracy, so please shut up

Once you have successfully passed the identification checks to vote in this electronic system, how then do you vote anonymously? Or will voting be "transparent", ie not anonymous, like our census this year?

### This is how the EU's supreme court is stripping EU citizens of copyright protections

No, the point is that a library catalogue enables access to the content. As does a hyperlink. To replicate the situation physically, let's do a thought experiment: it would be possible these days to build a library with a robot to fetch a book off its shelf and put it on a desk for you to read (there are modern warehouses that fetch stock and load trucks this way). Would that breach copyright?

Libraries do have exemptions, but only for educational or non-commercial use. You breach copyright when you photocopy the book to avoid buying it.

What is new about the internet is the ephemeral nature of the content, and the ease and speed with which it can be copied. Copyright law generally has not caught up with these factors, so to that extent the CJEU does have scope to be creative (as do other jurisdictions). The disruption can be seen (for example) in Wikipedia's article on Copyright, in particular the second paragraph explaining the weight given in existing law to copyrightable content being in some fixed physical form, and inconsistencies between jurisdictions on that point. Put it another way, you can copyright a book, but can you copyright a story? That seems to be a moot point. It also observes that copyright in many places is a civil matter anyway, protection by legislation is by no means universal. If a "book" or "movie" is originally created in digital form, and never put to paper or celluloid, there are already jurisdictions where copyright law is a hollow threat.

We also need to be careful of the distinction between copyright and right to privacy, which is a separate issue.

I think there are valid physical analogies because although the internet is new, the human behaviour is at least as old as writing. If a hyperlink is (or is deemed to facilitate) a breach of copyright, where does that leave a public library catalogue?

### 'Panama papers' came from email server hack at Mossack Fonseca

#### Pointless closing the stable door now

2.6TB? I'm sure such a leak won't happen again... there wouldn't be that much left!

### How the FBI will lose its iPhone fight, thanks to 'West Coast Law'

#### Re: I think there is an answer

Charles 9 If you don’t see a need for law enforcement then consider this scenario: a terrorist group has ordered one of its sleeper operatives to plant a bomb in your city. A SWAT team caught up with him but he was killed in the fire fight. All they have to work on is his iPhone, which contains his orders of where and when the bomb is set to go off. There are many variants of the scenario but they all reach the same ethical / legal issue. What rights should law enforcement have to hack this phone?

#### Re: I think there is an answer

Oengus Secret keys are released from the government-run registry subject to court order (as I said).

If you don't trust anybody, why would you trust Apple Corporation not to build in their own undisclosed back door, or any of their software engineers to privately create one? What brand of phone do you recommend then?

#### I think there is an answer

"I wish I could give the good guys the access they want without also giving the bad guys access, but I can't..."

Actually you can. We need to stop thinking about a single master key that unlocks every phone. Instead, give every smartphone a unique serial number (that is visible), and an associated secret key (invisible), hard coded by the manufacturer into its chipset, that can override its other security features. The disclosure or compromise of any one secret key would be no detriment to any other phone in the world because each key is different, and only works on the serial numbered phone it was made for. Make it as secure as you want, eg ten failed tries and it locks out. Once these numbers are set, the phone manufacturer does not keep a copy of the secret key, nor a process to recover it. The manufacturer gives the serial number / secret key pair for every phone to a central register which keeps them in escrow on a server that is offline (not hackable) and secure like a bank vault. The central registry makes the secret key for any individual phone available to law enforcement or national security only with a court order, following laws that define how serious a case needs to be (eg public safety would qualify, tax evasion might not). Each country that manufactures smartphones could maintain its own national key registry, and law enforcement agencies can exchange information under international agreements against terrorism, as they do now.

### DARPA's made a SELF-STEERING 50-cal bullet – with video proof

#### Re: "imagine what a trained Scout Sniper can do"

Not that a smooth bore is required, but rather that a rifled bore is unnecessary. Smooth bore as a general rule delivers higher muzzle velocity. But falls short in range because the drag of a tumbling bullet defeats the benefit. A rifled bore imparts spin which mitigates the problem of tumbling. But if the bullet can somehow maintain its orientation by other means than spin, then its back to smooth bore. Which incidentally simplifies manufacture and reduces wear.

### ZOMBIE Google Glass 2 FEEDS ON Italian BRAINS, says specs supremo

If the Mini Augmented Vision project is any indication of the future then "unobtrusive" may not be a design parameter. Any bets on "Google Goggles" ?

### Tesla, Nissan, BMW mull all-for-plug, plug-for-all electrocar charger plan

#### Re: Electric car batteries don't "swap"

Ok, I'm wrong. And this is how it works:

http://www.forbes.com/sites/pikeresearch/2013/06/27/tesla-tries-out-battery-swapping/

"...Ideally, the [Tesla] Model S owner will return to the station and retrieve the original battery pack when finished with the replacement pack, once again paying the service fee [currently about \$60 to \$80]. The owner may choose not to go to the station and have the older pack delivered to them for a fee, or choose to simply keep the replacement pack and Tesla will submit a bill for the value difference of the battery pack based on its age."

And you do this every week, right? And you live handy to a Tesla Station? Or Tesla and BMW and Nissan will have interchangeable batteries?

But hey, why don't you keep a spare battery pack at home and swap it whenever it suits you (but did they mention that it weighs 544kg? see http://www.roperld.com/science/TeslaModelS.htm )

#### Electric car batteries don't "swap"

Why are we talking about battery swapping? Quoting Wikipedia on the Nissan Leaf for example "…the battery and control module together weigh 300 kilograms…" Batteries are built in to a car body (not the boot) with particular attention to weight distribution. They can't be "swapped" even with a forklift.

Notwithstanding all that, I do see a market for a portable and interchangeable small battery pack of maybe 15kg for emergency use to get you home, or to the nearest charging station. A stuck driver might call an RAC van to deliver a loan or leased battery (or two). To make such a service work needs a connector in the car boot, with standardised plug and voltage settings. Would be handy if more than one could be run in parallel, if only to keep the individual package weight manageable, so each battery pack would need an input and an output connection to make a daisy-chain. Car makers should seriously consider keeping that option open.

### Techies with Asperger's? Yes, we are a little different...

#### No need to see it as a problem.

Stuart, may I suggest that you don't have to "medicalise" your condition, unless you choose to. I am retired now but I recognize in myself and my early career that I was a classic example of Aspergers Syndrome long before the term was invented. My employers observed that I was better suited to some tasks than others, and I could see that was a fair assessment. I got on with my job and the boss was happy to keep me there. Diagnosing problems and thinking up treatments that might fix them is only a modern habit, decades ago we just worked around individual characteristics and they weren't regarded as problems, just "different strokes for different blokes".

### Under cap-and-trade, flying is greener than taking the bus

This is a highly academic re-statement of the bleeding obvious. Individually reducing emissions under a "cap and trade" system might save you money but does nothing to reduce total emissions if someone else fills in the space you create. And Australia's carbon tax is just as leaky. We tax the electricity that trains and trams use, but exempt the petroleum fuels that cars use... tell me again, why are we doing this?

"...For a typical cross-country flight in a commercial airplane, you are likely to receive 2 to 5 millirem (mrem) of radiation, less than half the radiation dose you receive from a chest x-ray. People in the United States receive an average of 360 mrem of radiation per year from natural and man-made radiation sources, which includes cosmic radiation exposure during commercial flights. "

I wonder how this compares with the x-ray scanners?

### Europe's prang-phone-in-every-car to cost €5m per life saved

My main concern is the emergency services and call centre time wasted on false positives. Bearing in mind that all the call centre knows is "something happened", and then have to figure out what, where, whether anyone was injured, match this call with bystander calls that might or might not be about the same accident, and whether to divert an ambulance that happens to be a block away on another job. Cost to install the hardware is only the start. By the way will tow truck drivers be notified?

### US Senator: 'Retest airport scanner safety'

"...For a typical cross-country flight in a commercial airplane, you are likely to receive 2 to 5 millirem (mrem) of radiation, less than half the radiation dose you receive from a chest x-ray. People in the United States receive an average of 360 mrem of radiation per year from natural and man-made radiation sources, which includes cosmic radiation exposure during commercial flights. "

I wonder how this compares with the x-ray scanners?

### SpaceShipOne man, Nobel boffins: Don't panic on global warming

It is not science to quote sixteen opinions, however well qualified (or not). What research have these people done that supports their argument, and where is it published?